Hello, everyone. My name is Alex. I'm a software engineer. I work at Redhead and I work on a project called OpenShift. This talk is going to be about a part of OpenShift called MachineAPI. You'll hear what MachineAPI is, the motivation of having it and what component it includes. And because this is a deep dive, I will assume that you know what OpenShift is, what Kubernetes is, and you are familiar with concepts like custom resources and controllers and the relation between them. But generally speaking, custom resource is like a model in your database and controller is just the piece of code that acts on changes of this model. Okay, let's start. So when you hear MachineAPI, this picture might appear in your head, but in fact we are doing something else. Well, maybe in some way we are trying to control the machines. And as you might know, OpenShift can run on different clouds, both public and private. There are just some examples on that slide, like Azure, Google Cloud, AWS, vSphere. It's not all the list, just a couple of examples. And in the end it's just some piece of hardware. So MachineAPI tries to solve the problem of managing cloud infrastructure. MachineAPI is located in the center of everything and it's crucial for running OpenShift. It talks with cloud APIs and provides communication layer between OpenShift users and cloud providers. So, shortly speaking, that is a part of OpenShift, an extension to its API that is responsible for creating and deleting hosts for nodes and it tries to make this process as easy as possible for users. So, it operates on top of public or private cloud infrastructure, that means it talks to cloud APIs, and part of our logic is also responsible for horizontal cluster scaling. But before we go on, it's very important to understand the difference between two concepts in OpenShift, the machine and the node. The node is just a representation of a virtual machine that runs on cloud provider and node is Cubelet plus the object in OpenShift's API. And Cubelet is a thing that makes the MNode and it's responsible for registering node object in API. Our first and main building block of MachineAPI is the MachineObject. MachineObject is an object that describes the host. The user creates or deletes the machines and our controller interacts with cloud APIs based on this action. It either creates or deletes machine from cloud. You can see that the machine is just a normal resource in Kubernetes. It has namespace, name, spec and status. And the important part here is provider spec because provider spec is a template for describing these machines. The definition for provider spec is a bit different for each cloud provider because it's based on cloud provider specifics. And that means that each cloud provider has its own provider spec. And provider spec is a place where you can specify options like instance size. However, this resource needs a controller to manage its lifecycle. And for this, we have a controller. So it's just a piece of code that holds all logic for a MachineObject. And it's basically just an endless loop that tracks resource state and performs certain actions based on it. But the process of synchronizing desired state and the actual state of the object is called reconciliation. It runs periodically in case of great update or deleting or it can be called manually from the code. And for managing machines, we introduce phases. These phases are reflected in machine status and they represent where a machine is located in its lifecycle path. There are five phases in total. I will describe what we mean in next couple of slides. And these phases are provisioning, provisioned, running, deleting and failed. So let's start from machine creation. There is a very long diagram, but I will try to make it simpler for you. One of the first things that our controller does is checking if MachineObject has a deletion timestamp. In Kubernetes, deletion timestamp means that someone is trying to delete a resource, but right now we're talking about the case where timestamp is not present. So next thing that we do is look if machine is in a failed state or not. Failed state is set when machine has invalid provider spec or created instance disappeared from the cloud for some reason. If the machine is in failed state, then the controller does nothing. So our first step. We are checking if cloud instance exists. In our case it doesn't. So what does that mean? That means that the instance was either not created or someone removed it. We know this by looking at the machine status. So we'll get back to detailed machine status in a moment. But if cloud instance can't be found and machine status is not populated with IP addresses or provider ID, that means that the instance was not created and we should start creating it. So our controller sets face to provisioning and then creates instance in the cloud using cloud provider API. In case when provider ID is missing we set face to failed because, sorry, in case when provider ID or IP addresses are present we set face to failed and do nothing, we just assume that something is broken. So provisioning phase means that cloud instance creation was started. Now let's get back to the first step of this diagram. Well, what happens if cloud instance exists? When then controller calls update for this provider and the update just synchronizes some data from cloud providers or performs some additional configuration that needs to be done after machine creation. Next it looks if node for this machine was created and I will explain how node-machine relationships work a bit later. If node exists when the phase is set to running, if node doesn't exist then the phase is set to provisioned. So running means that machine has a node associated with it and it has a cloud instance. Provision means that VM was created but node is still missing. Last part of machine lifecycle is deletion. The controller says the phase to deleting indicating that deletion process was started. Then it performs node draining and node draining is a process that blocks a node from scheduling new pods and terminating all running pods and if node draining is combinated with pod disruption budget which is an API for controlling graceful shutdown of your workloads then the impact should be minimal. Next thing that controller does after draining node it deletes the instance from the cloud and the last thing it does it deletes the node object from API. Okay, well that was all about machine objects. Now let's talk about our next resource in machine API that's called machine set and machine set is just a group of machines and you can think about machine sets as like replica sets and pods. That means that machines are not meant to be managed on their own like pods and there are resources that manage them. So in our case machine set manages machines. If you delete a machine that is managed by a machine set then machine set controller will recreate your machines like the same way you can see the pods are working. Like replica sets machine sets need to have a replica count set and provider spec should be present too. Next thing I want to talk about before moving to health checks and auto scaling I'd like to explain how machine and node relationships work. Well we created a controller for establishing this relationship and called it node link controller. After kiblet runs on created instance and node object is created the node link controller looks at provider ID and IP addresses of this machine and tries to connect nodes and machines using this information. Provider ID is the identification of node and it's also present on the machines and because the logic for creating this provider ID is similar then they should match. So after finding matching machine for node we set node reference in machine status. So after node reference is set machine gets to running stage. Our next resource is machine health checks. So how do machine health checks work and what are they? Well that's a resource that provides automatic remediation of unhealthy machines in a group of machine sets. The logic here is quite simple the controller finds unhealthy machines then if user defines a value for max unhealthy field in machine health checks spec then when remediation is not performed if the number of unhealthy machines exceeds the max unhealthy limit. This is a short circuit mechanism and it's useful when a large amount of nodes are down for example because of a networking issue. The last step is deleting unhealthy machines and because machines are managed by machine sets new ones are created to replace unhealthy ones. So you might have question how do we understand that machines are not healthy? Well we do this by looking at nodes associated with them and usually if node is unhealthy it's reflected in node status. So as all machines and machine sets machine health checks are another Kubernetes resource and in its spec you should specify a selector for selecting machine sets node startup timeout and max unhealthy for allowed unhealthy machines. Now let's move on to autoscaling. There are two resources for configuring the scaling of a cluster. The first one is called cluster autoscaling and it's a cluster-wide syncleton resource that defines a set of rules for scaling the cluster. It defines number of cores, nodes allowed, memory, GPUs and so on. And it's required to have a cluster autoscaler to make autoscaling work. It's a resource that turns autoscaling on because you cannot scale your cluster if there are no rules for scaling it. The second resource here is machine autoscaler. It sets the amount of minimal and maximal replicas count for a specific machine set and scales machine number by setting replicas count at the machine set. So it just controls the number of replica counts on the machine set and tries to follow the rules set by cluster autoscaler. Here you can see the comparison between these resources and the cluster autoscaler includes resource limits such as amount of nodes. Also it includes the scale down policy where you define rules for scaling down the cluster and machine autoscaler only contains minimal, maximal amount of replicas and also reference to target machine set. Okay, so thank you all for listening. Today we talked about motivation of having machine API, about machines, machine sets, machine health checks, cluster autoscaler and there are some useful links. I'll try to attach the presentation somewhere in case you want to take a closer look and let's see if we have any questions. Thank you very much, Alex. It has been great. We do have some questions for you. So let's get started. Let's just start with Christian Pasarelli. He's asking regarding machine dilation. Is the virtual machine directly dilated after the node train or it is first gracefully shut down? First we drain the node and then we delete the machine. So basically when you do keep CTL, delete machine, then we have a mechanism that just blocks this node from scheduling new pods. We try to evict all the pods from a node and then we delete the machine from the cloud. Shutting down the virtual machine and removing it is the last phase of machine lifecycle. Perfect. Let's go to the next question. Is there a way to adopt existing nodes as machines? I guess he means that converting a node to a machine set. Yeah, I think it is. You can try to. I'm not sure how this exactly works but I suppose it should be doable but I personally didn't try to do that. Next question. Is machine API doing requests to cluster machine approver? Or how does it validate that the CSR endpoint is actually approved or not? Good question. We have a controller called cluster machine approver and it is responsible for approving certificate signing requests. And no machine API doesn't send request to CSR directly. Sorry, to machine approver directly. It's done by the cubelet from the node, I guess. And there is some smart logic to approve a CSR on cluster machine approver. We check that... I might be wrong but I believe we check that the name of machine matches the name of node and there are some other security things we do before approving the CSR but machine API directly doesn't do any request as far as I know. It's only done from node side.


like you were struggling a little bit to find a rhythm out there at times. Yeah I think first three innings I was scattered.  I think I was working a little slow to start the game. Fourth and fifth inning were a lot better. When you say you were scattered what does that mean to you and why were things just a tick off. I just think I wasn't ahead of the count very often I think you know I was either even or a little behind at times. They also put those things on me you know got a couple ways to right field and obviously with the Braille Homer. Were you trying to go with that pitch to a brain. It was I think it was executed. I think it was a little in off where I was trying to go. You know having thrown two fast losses for that him falling that off I think it just sped up his bat and he was able to get to it. Mr. What's Clay Holmes meant to this team. He's been incredible. I still don't know how how we got him honestly. You know he's he's been an important piece since last year and I think he's just going to keep on building off what he's doing. And then being said he is the best sinker in the world right now. How would you describe that pitch and what you've seen from him throwing that pitch this year. Yeah I was watching him that last inning and that that fast by doing a Robert to strike him out was incredible. I mean 98 bottom of the zone moving so many horizontally big and it's it's incredible. It's pretty special.  I think I think early on the slider wasn't there. You know I was basically attacking with fastball cutters and at times I felt like my heater and cutter were up in the zone. I couldn't find that line that top of that top of the zone where where I can establish that pitch and and make them make them make them defensive there. You just talk about the feeling around the team you're winning every type of game these days. Yeah I mean we can beat you a lot of different ways.  So and our pitching has been great. Yeah I'm not I'm not too sure what happens you know with the talks out there obviously with Donaldson and Anderson out there. We're not there but you know what we're backing up JD out you know all the time you know as teammates I think that's what we should do and and honestly I mean I can't tell you what's going on because I'm not there during the conversation.


Shalom and welcome everyone to class. Thank you Rai Lama and Jefina for the class. John Paul, thank you for joining class. We'll begin our study of Romans Chapter 15. We already studied verses 1 and 2 on Friday. We'll continue studying the rest of this chapter today. I'll ask one of you to lead us in prayer please. Anyone can lead us in prayer? Father we thank you for this day you have given us as we come before you. We pray God that you would speak to each one of us, help us to know your word. We bless this time of learning. We ask for your grace to surround us. Give us a Salina, just an understanding to share your word and help all of us to listen. In Jesus name we pray. Amen. Thank you John Paul. So we began our study of Romans Chapter 15. We studied verses 1 and 2. Basically in Romans Chapter 15 Paul is continuing on what he had written in Chapter 14 and how we have to bear with those who are weak. Basically when we are using the word weak is those who are new in the faith or those who are already in the faith and they are growing. That's the first half of Romans Chapter 15. In the second part of this chapter he shares his ministry plans and begins to wrap up his letter that he is writing to the church at Rome. So in verses 1 and 2 we saw how he says we need to bear with the weak and not to please ourselves and he says that each pleases neighbor for his good leading to edification. We'll begin with the verse 3. So can one of you please read verse 3 please. For even Christ did not please himself but as it is written the reproaches of those who reproached you fell on me. Amen. So here the point he's basically making is, you know, he's telling the believers, the mature believers that, you know, those who are strong in their faith, basically he's saying how they need to bear with those who are weak, you know, and he says that they need to be of one mind relate to one another in unity and oneness. And even as they relate with these kind of people are new in their faith or growing in their faith, they need to be gentle and loving and show them from the word of God what they need to do, how they need to live, how they need to conduct their lives and how God wants us to live. Okay. And, you know, he says that you need to love your neighbor. Okay. Verse 2 says, you know, everyone has to please his neighbor. Why should we please our neighbor? What does he say? In verse 2, why should we please our neighbor? Yes, for their edification. Yes. And for their good. Okay. So that they can be edified and they can be good. Now, can we always, you know, love our neighbors and can we always be good to them? Can we always do things that can edify them? Is it humanly possible? It's challenging. It's difficult, you know. But then he's telling the, you know, the believers that those are strong in their faith. He's saying, you know, he points out to them an example. In the example, who is the example he points out to? Jesus Christ. Yes. He says, this is how Jesus Christ lived, verse 3. He says, the very people he came to die were the very people who, you know, belittled him, belittled him, sorry, belittled him.  But what did Jesus do? He just quietly took everything. Okay. Why did Jesus just quietly take on everything?  But in a very gentle, compassionate, sometimes it was a little hard and firm with them as well. But speaking the truth in love, of course, you know. But why do you think that, you know, Jesus did not retaliate? You know, why didn't he get back, you know, eye for eye, tooth for tooth? You know, why didn't he fight against them? Or, you know, why didn't he not get back? Why, what do you think? Because like Paul says, you know, he's telling his people, these are all minor things, you know. Don't major on these minor things. You know, what kind of food to eat. What, you know, what is more special than the other and all of those things. And even if Jesus went through all these things, he knew that it did not matter to him because it's going to be very temporary, right? He's not going to be here for everlasting amen. You know, he's going to go back to his father, but he's here for a specific reason, a specific purpose that is to do the will of God. And he knew that along with fulfilling God's plan and purpose for why he came under this earth, this was part of that. And that is what Jesus says, you know, if you're, you know, part of the kingdom of God, there will be persecution. He did not, there will be difficulties, there will be challenges.  Of course, that is what he has, you know, purchased for us. That is our spiritual inheritance, but we need to work that out in the natural. We need to speak to our giants, to our mountains, to our enemies. We need to, you know, be militant like in our spirit at times to take hold of the things that God has given to us. So we have to be aggressive and militant like in our spirit to fight against the enemy. And it is a fight that we fight, the good fight of faith, okay, as the word of God says.   And, you know, he's having that greater vision, the greater plan and the purpose for which he has come and says, for even Christ did not please himself. Okay, so Jesus is the ultimate example of one who did not please himself but put others first. And, you know, a classic development of this idea, which Paul is mentioning here, is what he has written all in Philippians chapter 2 verses 5 to 11. And it's a very important scripture, something that we read most often during the Christmas season, Philippians chapter 2 verses 5 to 11. Can one of you read that please? This might be in you, which was also in Christ Jesus, who being in the form of God did not consider the drop rate to be equal with God, but made himself of no reputation, taking the form of a born servant and coming in the likeness of men. And being found in appearance as a man, he humbled himself and became obedient to the point of death, even the death of the cross. Therefore, God has also has highly exalted him and given him the name which is above every name. At the name of Jesus, every knee should bow of those in heaven, of those on earth and of those under the earth. And that every tongue should confess that Jesus Christ is Lord to the glory of God the Father. Amen. Thank you, John Paul. So I think it's the NIV, it says, in your relationship with Paul begins like this in verse 5. In your relationship with one another, have the same mindset as Christ Jesus, who being in the very nature of God did not consider it equality with God. So we see that, you know, Paul is here giving us an example of Jesus who did not come to please himself and set us an example of how we need to relate with one another, having the same mindset that is in Christ Jesus, who being God did not consider it equality with God and made himself as nothing. And he took on the nature of a servant, came in human likeness. He humbled himself, even being obedient to the death on the cross. And that is how we need to be. That is the example that we need to follow. And he says it here in verse 3, but as it is written, okay. So as Jesus took abuse and suffered wrong for God's glory, he was basically fulfilling what was written in God's word, what was prophesied, what was spoken before about him. So Jesus showed us by his own life example that, you know, for most part, we are entirely, you know, very quick to vindicate ourselves most often, instead of letting God vindicate us. And, you know, Jesus showed us how the Father is able, well able, actually well able to vindicate us. There are times when we need to take those steps, you know, but also most often we need to just, you know, let God vindicate us just like Jesus did and follow his example. And he says, the reproaches of those who reproached you fell on me, okay. This commandment, Jesus fulfilled, which was written in Psalms, chapter 69 verse 7. Now, you know, how does it apply to us in our present day context? You know, it says in this verse that it was written, you know, which means it's written for our learning that we might have hope, knowing that, you know, even when we do all things that are right, when it is difficult, when it's challenging, you know, we have the hope. So everything that is written in Scripture, you know, all of these life examples of Old Testament characters, all of these are not just there in the Bible because, you know, it had to be there. But all of this is actually speaking to us, ministering to us, teaching us and helping us learn how we need to live our lives that we might have hope and also for us to know that when we do what is righteous in God's eyes, even when it's difficult, there is hope. God vindicates us and God will see us through, okay. We'll move on to verse 4. Can one of you please read verse 4 please? Anyone can read verse 4? For whatever things were written before, were written for our learning that we through the patience and comfort of Scriptures might have hope. Amen. So it says whatever things were written in the past in the Old Testament, you know, were written for our learning. In this context, it's the Old Testament because the New Testament was not yet in print like we have the Old and New, but for us it's both the Old and New, okay. So whatever things were written in the past in the Old Testament were written for our learning. So Paul is telling the church is written for our learning so that we can learn from Scripture. And he's going to point out to us, you know, what are those few Scriptures he's going to point out those verses to us. And he says even as we look at these Scriptures, you know, that is written for us, you know, we receive comfort and patience through these Scriptures. So for us, when you look at both Old and New Testament, we learn from various characters in the Bible from various, all of the writings of Paul, all of the experiences what Jesus thought and everything, you know, we receive comfort and patience through Scripture, okay. And there is an ability, you know, to have endurance, patience and comfort, strength, consolation and encouragement that can be brought into our lives even as we read Scripture, even as we meditate and dwell on Scripture. And even as we look at various people who have journeyed through life as it is written for us about their life journey in Scripture, okay. So when we look at Old Testament characters and how they journey with God, you know, through their lives, we receive or we learn, you know, perseverance, ability to endure, we receive comfort, strength, encouragement, consolation, and we have this hope or the ability to look forward with expectation, with hope, that, you know, what we are going through now, you know, is just momentary that there is hope in the future that God will see us through. God will bring about deliverance. God will make things beautiful. He will redeem things in our life.  So that is what is verse four. So some of us, you know, believe only in the New Testament, you know, being part of the church today, most of them just read the New Testament. They think the Old Testament is not needed, but, you know, we need to see Scripture as an entire whole, old and new. And both old and new, you know, teach us because what is written in the new is a fulfillment of what is written in the old. So we need to have the forward and backward look, even when we are studying Scripture just enhances our whole, enhances the truth and brings alive the truth and helps us to interpret the truth in context, even as we look at the truth in one verse, we need to look at it the entirety of Scripture, what Scripture is talking about, the whole truth about this verse in the entire sense of this. We can come to a place where we are misinterpreting Scripture and it can lead to false doctrines and misunderstanding of God's words. So we need the entire Scripture, old and new Testament, okay. We'll move on to verses five to verse seven. Before that anyone has any questions, anything that you'd like to say about verses one to four. Okay. If there's no queries, no comments, we'll move on. Can somebody please read verses five to verse seven please. Verse five. Now may the God of patience and comfort grant you to be like-minded toward one another according to Christ Jesus that you may with one mind and one mouth glorify the God and Father of our Lord Jesus Christ. Therefore receive one another just as Christ also received us to the glory of God. Thank you Rosalind. So he begins verse five says, sorry, yeah, verse five says now may the God of patience and comfort now may the God. So he says the fact that Paul puts these words into the form of a prayer demonstrates that he's actually recognizing that it is the work of the Holy Spirit that must be done inside us. Okay. So for us to not retaliate and to be like Jesus for us to, you know, be patient with others for us to please our neighbors and not to please ourselves.  This is the God of patience. Our God is a God who is patient with us. It's a God of patience.  Often, you know, we, we think the purposes of God or we assume or we seem to think that the purposes of God are delayed. You know, but even if God takes his own time to do things beautifully in his own time, you know, he always fulfills what he has planned and his purpose for us. And the promises that he has spoken over our lives. So we know that God's delays where we see it as delays is not delay on God's part, but we see it as delay or we see God as being slow. It's not actually his denials. He has a purpose for each one of us. His purpose is loving his loving purposes for each one of us. And he's never delayed in doing what he does. He always does it on time. But if there is a delay, there is nothing wrong on God's part. The problem is always with us, right? So the delay is from our part when we have not done what God wants us or we are not positioned ourselves in the right place, the right time doing the right thing that God wants us to be doing. We often love God's patience because he's very patient with us when we pray or when we look at our own lives and say, God, thank you for being so patient with us. He's so patient with his people and we need him to be patient with us. Sometimes we can also say, God, can you please be patient with me? I'm struggling in this area. God, please be patient.  We need God to be patient with us. But often we are not patient when God does not respond to us with his plan, with his purposes, answers to our prayer. We are not patient about why he's not fulfilling certain things in our life and we think that God should hurry up. He's being so delayed on what he's doing in this area of my life, we think like that. But whatever our circumstances, wherever we find ourselves, God is patient both with his people and with his plan and fulfilling his plan and purpose for our lives. So he says here that in verse 5, sorry, verse 6, that you may with one mind and one mouth glorify the God and Father of our Lord Jesus Christ. He says that you may. So the goal here is basically to glorify God, the Father and our Lord Jesus Christ. And how do we accomplish that goal? He says we accomplish this goal by having one mind and one mouth. Which means one mind and one mouth means being united in the way we think and we speak. In our thinking, not judging others, condemning others in our speech, not condemning and putting down others, judging about others, telling them what they should be doing, what they shouldn't be doing. But being one in mind and mouth, that is one in our thinking and speech. He says when we are one in these areas, we glorify God, the Father of our Lord Jesus Christ. So verse 6, basically what if we do what Paul has been instructing us in Romans chapter 14 and in Romans chapter 15 verses 1 and 2. He says we can be of one mind and one mouth glorifying the Lord together. So he says whatever you, if you follow my instructions that I've given in Romans, what I've written previously in my letter, the previous paragraphs for us, it's in chapter 14. And the beginning of chapter 15, 1 and 2, he says when you follow those instructions, you can be of one mind and one mouth. When you do that, you will be glorifying, or we will be glorifying the Lord together as a church. So in verses 5, 6 and 7, the apostle Paul, he basically wants the believers to be like-minded of one mouth, means one voice. And this is so important because as believers, we try our best to be like-minded and having one voice, we can glorify God again. And is this possible and easy in today's world on the church today being of one mind and one voice? Is it difficult? It is difficult. Yes, it is difficult for God's people to be like this, but it is something that we need to all pursue to do, to maintain the unity of the Spirit. Like Paul has already mentioned in chapter 14 where he says, don't let the non-essential things divide us. Don't judge another brother regarding the food he eats, the observance of certain days, but be patient, build each other up. So when we are working towards being like-minded, being one mind, one voice that we can glorify God together, sadly, these non-essential things become so big in our lives, in the church, among believers that people are arguing, fighting and they even get divided. So instead of fighting and arguing and getting divided on these things, let us please and edify one another so that we can be of one mind and one voice and glorify God again. Verse 7 he says, receive one another, just as Christ also has received us. So it says when we meet believers who are different from us, instead of allowing those differences to divide us, Paul is basically saying, receive them as believers as brothers, sisters in the faith. Be welcoming, be kind, just receiving and embracing them just like Christ has received us and welcomed us and embraced us and loved us again. So I think we can begin to do this and we can try to do this with other believers who may not believe everything we do will come from different denominations, different doctrines, different styles of worship, different ways of worship, different patterns, thought processes. Even though they come from different denominations, let's come to a place where we can actually love them, believe, just receive them, welcome them because even though they are from different denominations, we should come together. Is it possible for us to come together in unity even if they are from different denominations? What do you all think? Yes? No? Is it possible for us to come together even if we are from different denominations? Can we have some answers in the chat? You can just write yes, no? Yes? Okay, thank you, Zalutoli. Jevinah says yes. Thank you, John Paul. Why do you think we can come together even though our doctrines, styles of worship are different, liturgies are different? You know, what can bring us together? Okay, Jevinah says the love of Christ, yes? Very good. But I still have a doubt like some people they don't, like in some denominations even they don't consider Christ like when we go to this Roman Catholics. So I think it might be hard for us to be together in there but because their doctrine is totally wrong in some ways, I think that may cause so much damage in the unity. Yes, so when we talk about coming together as believers, we're talking in the context of believers in terms of, you know, those who are believing the Father, Son and the Holy Spirit only. Yeah, so Rosalind says yes, we can come together because of our faith in Jesus as the Son of God. So we're coming together, not on the grounds of doctrine but we're coming together on the basis of our faith. That is our foundation. Okay, so what is the basis of our faith? We believe in one God, Father, Son and Holy Spirit. What else is the basis of our faith? We believe in the, very good, the cross of Christ, the death, the resurrection, ascension, the seated of Christ, the right hand of God, the Father, yes? We are all cleansed by one blood, the blood of Jesus Christ. We all have, there's only one Holy Spirit that we believe in. There's one scripture, the Word of God, the Bible that we have. So these are all common basis, foundation for our faith. And on this foundation, you know, people have built up their own doctrine. So we can, yes, come together on the basis of our faith. And all of these are the foundations, are the important foundations of our faith. And that we are one body in Christ and even though we are different parts, and who is the head? Christ. Christ is the head. We have one head and we all belong to the same kingdom. We are all sons and daughters of the same of one Father and we belong to the kingdom of God. Okay. So these are some of the things that is the foundations of our faith. And so we all, we all agree on this. So we can all come together, you know, and join hands, partner, and together in unity and in oneness so that we can bring about city transformation. And together as a city white church, as a body of Christ, all the local churches coming together, we can transform our city. It's just some of the things that we studied, if you remember, in Kingdom Builders, the book Kingdom Builders. Okay. So, you know, what seven says we need to, hence we need to receive and accommodate one another. Okay. What seven therefore receive one another, just as Christ also received us the glory of God, therefore receive one and other. Okay. And he says above all of these things, you know, you know, we need to receive and accommodate one another. But when we receive and accommodate one another, does it mean that we do not correct each other or we overlook sin or we don't address sin? We do, right? Yes, we address sin. We do correct thing, but we do it lovingly. Because Paul has already written to us that the goodness of God leads to repentance, that God himself, you know, four news who are vessels of wrath and vessels for glory, you know, and those are vessels of judgment. And he says he's going to bring the wrath upon them, but he is long suffering. He's patient with them, not wanting anyone to perish. Okay. So yes, the same way we need to be patient, long suffering, you know, let the goodness of God through our lives lead them to repentance. But we do correct people. We do lovingly call out sin as sin. And we do all this in a way that honors God and his word. Okay. So any questions on verses five to seven? If not, we'll move on to verses eight to 13. Can somebody read verses eight to 13, please? Romans chapter 15 verses eight to 13. Now I say that Jesus Christ has become a servant to the circumcision for the truth of God to confirm the promises made to the fathers, and that the Gentiles might glorify God for his mercy. As it is written, for this reason, I will confess to you among the Gentiles and sing to your name. And again, he says, the joys of Gentiles with his people, and again, praise the Lord, all you Gentiles, love him, all your people. And again, Isaiah says, there shall be a root of Jesse and he who shall rise to reign over the Gentiles in him the Gentiles shall hope. Now, may the God of hope fill you with all joy and peace in believing that you may abound in hope by the power of the Holy Spirit. Amen. Thank you, Jeffina. In verses eight to 13, Paul points, you know, to Old Testament scriptures quoting a lot of Old Testament scripture here. He says, even though God was, and through these Old Testament scriptures, he's saying that even though God was working through the Jewish people, through them, you know, through the Jews, there was so much that was spoken of that the Gentiles would be blessed. So even though God was working his plans and purposes were for the Jews, but even through those Jewish people, you know, so much was spoken for the Gentiles, that the Gentiles would also be blessed. In verse nine, Paul is quoting from Psalm 18, verse 49, where he says, for this reason I will confess to you among the Gentiles and sing to your name. In verse 10, he's quoting from Deuteronomy chapter 32, verse 43, the joys of Gentiles with his people. In verse 11, he's quoting from Psalm 117, verse 1, praise the Lord, all you Gentiles, Lord him, all you peoples. And verse 12, he's quoting from Isaiah chapter 11, verses 1 and verse 10. So basically all these scriptures are saying that the Gentiles will praise God and they will give glory to God. So even there or even in these scripture passages, you know, we learned that while God was working with the Jews, he was giving them the promises. It was all being done so that the Gentiles would also glorify God. So this is what God has been working towards, not just for the Jews, but also that the Gentiles will glorify God. So Paul is reminding us here once again that he's a God of both the Jews and the Gentiles. And his promises that were spoken towards the Jews was ultimately also to bless the Gentiles. So verse 13 is almost like a benediction. And you know, verse five, he says, may the God of patience and comfort and here he says, the God of hope, you know. He says, the God of patience fill us with endurance. Here he says, God of comfort fill us with, you know, he says, may the God of, sorry, one minute. Verse 13. Can somebody read verse 13 please for us? We didn't read that. What did we read that? Okay. It says, may the God of hope fill you with all joint peace and believing that you may abound in hope by the power of the Holy Spirit. Okay. So there in verse five, he says, God of patience fill us with endurance. You know, here he says in verse 13, may the God of hope fill you with all joy and peace.  And he says, now may the God of hope fill us with all joy and peace in believing that, you know, we may abound in hope by the power of the Holy Spirit. Okay. So when we, you know, believe in hope, you know, with all joy and peace, you know, we can abound in hope. And, you know, the power of the Holy Spirit will be manifested in our lives. Okay. So in these verses, you know, till verse 13, Paul has basically been talking about the believers. He's been instructing the believers and how they should, you know, live towards others, how they should relate with others. Now in verses 14 onwards, he speaks about his plans, his travel plans. So we'll read about that in verses 14 to verse 21. Any questions so far? Till verse 13, anyone has any questions? Okay. If there are no questions, can somebody please read verses 14 to 21, please.  Nevertheless, brethren, I have written more boldly to you on some points, as reminding you because of the grace given to me by God, that I might be a minister of Jesus Christ to the Gentiles, ministering the gospel of God, that the offering of the Gentiles might be acceptable, sanctified by the Holy Spirit. Therefore, I have reason to glory in Christ Jesus in the things which pertain to God. But I will not dare to speak of any of those things which Christ has not accomplished through me, in word and deed, to make the Gentiles obedient in mighty signs and wonders by the power of the Spirit of God, so that from Jerusalem and roundabout to Lyrichem, I have fully preached the gospel of Christ. And so I have made it my aim to preach the gospel, not where Christ was named, lest I should build on another man's foundation. But as it is written, to whom he was not announced, they shall see. And those who have not heard shall understand. Iman, thank you. So in verses 14 to 21, Paul is basically shifting his whole thought to sharing some of his personal thoughts, and then he goes on to speak about his personal plans. So verse 14, he's confident that the believers at Rome are full of goodness, full of knowledge, they're able to admonish one another, and hence he's asking them to be there to encourage, motivate, inspire each other to do the things that he has spoken or he has admonished or he has asked them to do so far in the letter that he has written to them. And then in verses 15 to verse 21, basically the things that he's already stated, Paul is saying that it would be challenging for some of their thinking, especially on how they relate to each other and how they treat and serve each other. But Paul says, you know, I've been bold in telling you, you know, all of these things. And I have told you, even though, you know, you might question my authority, I've not established a church there, I've not visited you, I've not imparted into your lives, I've not taught you and all of those things. You might think that I don't have any right, but he's saying I have the boldness in telling you because I know the grace of God over my life. So he's saying this boldness is coming, not because, you know, I have the authority because I'm your spiritual father or, you know, I have led you to Christ or I have built up the church at Rome or I have, you know, come there imparted and taught to you. He knows that he's not done any of these things, but he's saying he has the boldness in telling them because he knows the grace of God over his life. So what do we learn from this, you know, when we know the grace of God over our life or in our life, we can move boldly in this grace, you know, or we can operate powerfully or boldly in the grace of God over our life or in our life. It does not mean that, you know, we can be arrogant, proud or think that, you know, we are better than others. It means that, you know, when we serve God, we're called to serve God in a certain area. We have a certain function that God has given to us. You know, when we know the grace of God in that area, you know, we can move boldly in that grace. We can operate powerfully and boldly in that grace. We can serve people boldly and, you know, whatever area of function that God has called us to, whether it's the ministry of the word or praying for people or whatever, you know, we can be powerful and bold in the grace that God has given to us. And what is the grace of God that was given to Paul? He talks about this in verses 16 onwards. He says that the grace of God has made him a minister to the Gentiles. Yes. And he says he can minister the gospel of God to the Gentiles. And he says that even as he does this, you know, the gospel is brought with great power because it is a power of the Holy Spirit that is working in and through him. And he says because he has the grace of God over his life, you know, to minister the gospel, he says therefore he can speak boldly about the things of God that God has worked in and through him. And he can speak about what God has spoken through him. Okay. Then he begins to talk about how God has brought the Gentiles to faith in Christ Jesus through faith and through deeds that is through science miracles and wonders.  Elkrim is the modern day Albena. And, you know, he says that he has proclaimed the gospel from Jerusalem to Elkrim through the power of the Holy Spirit. And he says he has been able to do this because of the grace of God that was given to him. Okay. So God's grace on Paul's life is to preach the gospel in the places where the gospel has not been preached before, you know, so that he can establish the work of God. So he's basically an apostle. So he's preaching the gospel where the gospel has not been preached before, and he can establish to work there. And he says, you know, because of the grace of God, he can preach the gospel where the gospel has not been preached. And he says, and hence he does not have to build on someone else's foundation. So Paul is describing the grace of God in his life. And he says that whatever he's doing, he's doing it boldly because of the grace of God that is there in his life. And how does he know that? Because, you know, he has proved it through his ministry and all the things that he has done. He's saying all the things that have accomplished, all that he mentions about is because he says it's the grace of God over his life. Okay. Another thing we can learn is that as we move in the grace of God in our life, you know, you're exercising it, you're practicing it in your living.   And we studied this when God calls us to a specific function in the body of Christ, you know, he gives us the grace. You know, grace is the divine enablement, the divine character, the divine favor. He enables us, you know, gives us the divine favor, the divine enablement, the divine character that we need to fulfill the function that he has given us. So he gives us the grace and the gifts that we need to fulfill the function that he has called us to. So, you know, when we exercise, practice, you know, God's calling and we fulfill it, we live it out. You know, we do go about doing our ministry. All of this is basically proving the grace of God over our lives.  Okay. So in Paul's case, the grace of God was to minister the gospel to the Gentiles from Jerusalem to Illicrim very boldly, unashamedly, which signs miracles and wonders and basically to bring the Gentiles in this area to the obedience to Jesus Christ and to establish the work there, which was not done before. There was no work done, but he had established God's work there and led the Gentiles to the faith, to the obedience to Christ Jesus. And, you know, and he says that he's, he has pired near the ministry here in these places, you know, and he has not worked on other people's foundation, but he has done what, you know, God has called him to do. So he says that he's speaking of things that Christ has established in his own life.  And secondly, you know, when you know the grace of God over your life, you can move in it very, very boldly. So this is what he's talking about in these verses, you know, verses 15 to verse 21. He's talking about the grace of God over his life and what the grace of God has accomplished him to do. And because of this, you know, he can boldly speak and write and admonish and tell other believers how they need to live their lives, how they need to fulfill their calling and their function that God has given to them. And then in verses 22, verse 33, he talks about or shares about his travel plans. Okay. Any questions? Any questions?  Even as you fulfill God's function, the grace of God is operative, His gifts are operative.  And also, you know, you can also move boldly because of the grace of God that is over your lives. Okay. We'll stop here. I will post the last assessment, assessment for tomorrow. Is that fine? Okay. And I'll give you a week's time to do the last assessment so maybe you can, you know, post it, submit it, sorry, next Tuesday or Wednesday. Okay. And I think we'll finish class by Friday. Yeah. Okay. Thank you everyone for joining class and see you on Friday. Thank you. Thank you, Pastor. Thank you, Roselyne.


Making the school beautiful. A small class project. This is an example of a class project. The class made the school beautiful. The problem was the plant containers were ugly. They didn't have any plants in them. The first thing we did was get plants. We asked for donations from businesses. Some students had extra plants at home. We didn't have to pay for any plants. Next, we prepared the containers. We put in fresh dirt. We even involved our children. Then we planted the new plants. The school looked much better. Everyone at the school enjoyed the beautiful plants. The end.


Give a very warm welcome to Christoph Engelmann and Anton Schlesinger. Yes, thank you. This is a bit intimidating, large space. Hello everybody. The topic of this talk is a new audio format called MQA, Master Quality Authenticated. And as the title of our talk suggests, it's more than just an audio format. And in order to explain how we arrived at the title, the clever stealth DRM Trojan, we have a lot of ground to cover and our talk is structured as you see here. So I'm going to talk a little bit about audio files and audio files. Then Anton here is going to examine some of the claims that are being made about Master Quality Authenticated. Then we will move on to 24 bits, got some room to spare to have a look where they actually hide their DRM. And finally we're going to make some remarks why we think MQA is actually quite clever. So wait. So it's good to be back here. Some of you may know me already as I've spoken at the conferences a couple of times before and mostly on policy related issues on identification, digital identification and authentication related issues. This time I have to make a confession. I am an audiophile and I believe that this cable sounds different than this cable. So I should be a millionaire. As some of you may know, the James Randi Educational Foundation had offered a million dollars to anybody who was able to identify the difference between two audio interconnects like these ones. And it controlled a big testing. Here is a 10 year old report on this challenge. Of course, nobody managed to find these differences and win the million dollar. And I'm pretty sure I would fail at the test too. But in my own experience, if I put one of these cables in the system for a week or two and then the other cable for another week, there will be some preference that emerges. And I cannot explain that, but I guess if you ask me to ABX a mattress, the subtle differences in texture and softness won't be noticed by me by just laying down on them. But if I get to sleep on each of these mattresses for a week or so, I might develop some sort of preference. I make this point here and I'm sure Anton, who is more on the objective side of things when it comes to audiophilia, will be skeptical about it. But what I want to illustrate is that we are talking about a market that operates and exploits the limits of perceptibility and where environmental and habitual factors play a role in what you sense and what you notice. And I believe that certain markets have developed around those perceptible limits and exploit something like long tail phenomena in the distribution of perceptibility among humans. In other words, in a saturated consumer electronics market, there are a certain class of devices which offer just noticeable differences and these can be commercially attractive and command premium prices. To illustrate this point further, let me ask you, who of you here is a gamer? Quite a few. Okay, so how many of you have a 240 Hertz monitor? Oh, two. Okay. How many of you have a high polling rate mouse? Quite a few more. Do you believe this makes a difference in your gaming experience? Okay, these are all objectivists here, skeptical people. Okay, values like 240 Hertz refresh rates are astonishingly high. And if you tell somebody 20 years ago that people are able to discern 60 Hertz refresh rates from 100 Hertz refresh rate or 240 Hertz, they'd have told you that the latency of the human visual system is far exceeded at this rate and everything about 60 Hertz is moot. Yet Apple now sells you 120 Hertz iPad and the difference is perceptible for many. It turns out that peripheral factors like head movement, haptic interaction with the screen and so forth, modify certain thresholds of visibility. In the VR context, this created big headaches and anybody who follows John Carmich's Twitter feed will know that he continuously is surprised that some of his subjects are very sensitive towards visual artifacts that normal users don't notice. So it's very easy to make fun about audio files into $2,000 Ethernet cables. This is one of these and notice the small error there. That's probably there because packets otherwise would get confused which way to go. So these kinds of gadgets and their many, many examples of those, of course, give ample ground to make fun of audio files. But that's not what we want to do here today. Instead, we want to look at master quality authenticated this new format as a development in the audiophile world that deals with these aforementioned limits of perceptibility and in a clever way exploits them to create and legitimize a new distribution channel for audio content. And we furthermore believe that these developments have possible repercussions outside of the audiophile world and might affect music consumers and producers and that is you. And labels and the way music is distributed in profound ways. So again, MQA stands for Master Quality Authenticated on Promises Studio Sound at Home. This is the MQA website or this is some page on the website. Join the revolution and recorded music. And there's a lot of, a lot to unpack in this statement master and quality and authenticated. To give you a little bit an idea why I'm talking about this, as I already said, I'm an audiophile, but I also sometimes spend time on the other side of music, namely in music production. I used to manage a metal band or co-manage a metal band called President Evil. We call it the Stiles Donut Trash. This is a great record. You just shouldn't look at the waveforms because it clips all the way through and has a DR of three for those people who know what that means. We toured with ministry and so forth. On the other side of things, I'm also interested in acoustic music. This is me at the Hansa Studio in Berlin, where among others David Bowie, Depeche Mode, and you too have recorded albums. And we recorded this album by Beatrix Becker, which is piano and clarinet music and cello music and a wonderful record. So coming back to MQA, you will understand that as an audiophile and as somebody who likes to be in studios, I'm somewhat familiar with music production distribution and their marketing claims of studio sound and take me into the studio and so forth, of course raise an eyebrow with me. And furthermore, somebody tells me or promises that they want to authenticate a digital file. It not only raises my eyebrows, my professional curiosity is peaked. I have given talks here about the history of authentication media and I publish on this issues on the questions of media of authentication. So all things authenticating of interest to me and MQA promises something like that. So what they say is it sound like what the engineers heard and they're going to authenticate that on your playback device. Everybody with basic knowledge of intellectual property enforcement and digital rights management by now should be a little bit skeptic about their claims. As we're going to show, this is rightly so, but the devil's in the details and MQA offers an interesting and clever design of how to bring digital rights management back into music and the music distribution context as some of you may know the music industry has tried to do that several times and always failed to implement and sell digital rights management to consumers. And most distribution channels these days and most files come without DRM. So this again is the website of MQA and you can see how they explain authentication and they have this interesting term provenance. And there's the important thing is here the blue and green light that will light that will go on on your device. If an MQA file is played on this device and authenticated and they promise sound like in the studio. So in order to understand what they mean by quality in the acronym, it's important to go back a little bit in history and give you a background about digital audio. So what is quality? In the 1980s digital audio was introduced that means for the introduced to the consumer. Here you see the CD as advertised by Sony. I think this ad is from 1984. The underlying format of the CD is Red Book Audio where you have a signal that's sampled at 16 bit worth of 44k, 44,000 times a second. And with 16 bit we have a dynamic range of 65,000 values to represent the difference between the most silent and loudest signal in the format. And with 44k we can represent frequencies up to 22 kilohertz. This is about 10% higher than what humans was very good and that usually means very young ears can hear. Most music today is recorded and distributed in this format. The Audio World Standardized in 44,1k, the Video Broadcasting World Standardized in 48k and those of you who have surround systems DVD or Blu-ray based will be familiar with the 48k sampling rate. So in the 1990s we see another step. We see music production becoming fully digital with digital audio workstations. The first 20 and 24 bit converters arrive in the studios. We see higher sampling rates. So this is one of these converters from the 90s. The little 24 indicates that it can do 24 bits. And there was also an attempt to sell these higher resolutions to the consumer in the late 90s with a little bit different format. This is the SACD introduced by Sony in 99. It's a different encoding scheme called GSD. It offers 120 decibels of dynamic range and in its initial form went up to 30 kilohertz, so way above human hearing range. But as many of you know, this failed in the market. And there's of course an interesting backstory to this too because the SACD was introduced in the very moment the patterns for the CD expired. And Sony tried to push a new format into the market and have a new pattern and licensing regime to generate revenue. So why did the SACD and the supposedly higher quality fail? Not only because people couldn't really hear it. On the turn of the 2000s we had MP3 and MP3 pretty much owned the market. And Steve Jobs put it best when he said convenience beats quality. And as you know, he turned around Apple basically with the iPod, which could hold in its initial form, I don't know, 5000 songs or something. And Steve Jobs knew what he was talking about. He was actually an audiophile with a system worth north of 50K in his home and supposedly only listened to vinyl. This together with Snapstar basically killed the music market and especially the market for high resolution audio as these formats are called that exceed the red book standard. Audio files to come back to our storyline here, of course fought holy wars against MP3 and any form of lossy compression. They deemed the format as inferior and argued that it destroys a generation's hearing and even inside brain damage. And I was actually surprised that Douglas Rushkoff made this argument too MP3 is bad for you. And he asked down there will the next generation of music listeners be able to hear reality the same way we did. So the idea is that we somehow lose contact to reality if we are exposed to lossy formats. But however, audiophiles to abandoned physical media and things like these standalone digital audio converters found the way in their systems or streaming amplifiers that either via USB or Ethernet allow you to stream music from local networks or from the Internet into your system. And these converters you can see here it offers DSD which is at the SACD format and 1624 bits and higher sampling rates allowed access to high resolution, higher bit rate files. So this is important because we come back to this in the context of MQA. And of course you can ask about the benefit of these kinds of devices and the audibility of resolutions higher than 16 bit and 44 1K. Again, I think there might be individuals that actually hear differences. Let's jump to the current decade, 2010s. I think we are actually in a golden age for audiophiles because music comes basically into the house more or less at very low prices via streaming. And furthermore, they can actually buy lossless files in resolutions up to 24 bit and 192 KHz in online stores like this one is the French company Kubos. And you can see that some of the contemporary current records are actually offered in these formats. So you can buy the new Burke record in high-res audio. I actually haven't looked at what resolution I guess 2496 or something like that. And Kubos will even stream at that resolution over the Internet. There is this little website where you can compare the different offerings. You just enter some band or some music and it will list you the availability of these files at different resolutions. So again, in essence, the 2010s are kind of a golden decade for audiophiles. They got ducks and streamers in their homes and could play the files at the same resolution as they recorded mixed and mastered in the studios in their homes. And it is this context basically that the master quality authenticated format was launched and promoted in 2014. There was a big launch event at the chart at this high-rise in London. Looks a little bit like this tower in Middle-earth where Zauron resides. And they claimed a revolutionary advance in audio and to deliver studio sound at home. But not only that, and that's where the story gets interesting. The inventors credit as Peter Craven and Bob Stewart. You already saw Stewart on the picture. Where is it? It comes back later. They backed their claims over the paper that was published in the Proceedings of the Audio Engineering Society. And they say that MQA builds on advances in neuroscience. And they also sometimes say advances in the sampling theory beyond Shannon Nyquist. Which are strong claims to make. So if you go to the MQA website, you will find this explanation in the FAQ. How does it work? And it says MQA is based entirely on science. Specifically it's based on new findings in neuroscience that have told us that the resolution of timing information is critical to our hearing and our ear-brain interaction. So if you look in this paper published in the AAS Proceedings, and look specifically at the neuroscience works cited there, I think it's seven or something like that. There's only one paper that actually deals with humans. The other papers, Test Hearing with Mongolian Gabriel and Barn Olds. And it's probably another mistake to believe that these animals have a very different auditory system than we have. And that their hearing exceeds our hearing when it comes to high frequencies. So building on these neuroscientific advances, they claim to correct for the time domain errors in the digital audio chain. Namely, errors introduced in analog digital converters. So when you record an analog signal in the studio and convert it to digital, and they say that these would create temporal blur. This is what they here say. There's a problem with digital. It's called blurring. It's also from the website. And this temporal blur is basically the main marketing mantra of MQA. And their quality argument, the argument that it sounds better, rests to a large part on this claim not only to bring the studio sound to the home, but by reducing what they call temporal blur. Their format, their format, so they claim contains mechanisms to cope and correct these temporal inefficiencies present in all digital systems where an analog digital or digital analog conversion takes place and remove that temporal blur. And reviewers in the audiophile press called these innovations revolutionary and claimed them not only to be audible, but to lift music to a whole new level. This is from audiophile online publication, The Absolute Sound. They say let the revolution begin. And here they more or less compare Bob Stewart with Einstein. If you read this here, this caption is Lord Kelvin up there. There's nothing new to be discovered in physics now. All that remains is more and more precise measurement Lord Kelvin five years before Einstein's paper on relativity. And if you look deeper in the text, and I'm sorry for this, I know you can read that now. But they basically bring forward Thomas Kuhn revolution, the structure of scientific revolutions and talk about a paradigm shift in digital audio and even come up with the Copernican models of planting plotemies, worldview and so forth, right? So big things are happening audio right now. You probably haven't heard yet, but we're entering a new paradigm. And we are currently and the fact that we are standing here is actually an indicator of the scientific crisis because we belong to the old world view and think probably not, right? So there is of course a big debate happening in the audiophile world around claims like this. And much of this debate is happening on a website called computer audiophile. And there is specifically this threat, which was opened on January 2 this year. And it has a mass 250k views by now. It's really interesting because there's a couple of really reputable people publishing on this forum in this threat. They have many outspoken critics. One of them is mastering engineer Brian Lucy, who has six Grammys and mastered among others Depeche Mode and Mary Manson and so forth. And he basically said that the available MQR files that you can buy now or stream via the title service were not created in mastering studios but encoded in an automatic way somewhere probably on the cloud. So the claim of MQA that you get the sound that the artist and the mastering engineer signed off on is definitely false for the MQA files available now. And we must presume that it remains false because there is no commercial converters available that include MQA encoding. So nobody running a studio can actually use this format right now. You have to send the files often in an encoding house where they get encoded and signed. So part of this controversy is a couple of people online who did deeper research. One of them is Akimago, a blogger, an anonymous blogger who actually set up an internet blind test MQR, if you're interested in that please look it up. It's actually pretty complicated what he does because since the encoders are not available, we cannot properly encode music in MQA. And in the past four years the company has not allowed anybody to basically send them files in order to create a proper comparison between MQA encoded files and files in PCM or any other format that you would have. So Akimago invented a pretty interesting way to work around this limitation. I can't go further into that if you want to take this test, look at this website. Another hacker that had a look at this is Mans Rohlgaard who is working on the SOX resampling package. And he has a GitLab site up where you find a filter coefficients of MQA and tools to actually look at the control stream of MQA. We will also list this later in the presentation once we put it up. So to wrap up my part so far, in 2017, 24-bit files as they're created in the studio, worked in the studio, are available for audio files. So they can actually listen to what's happening in the studio in a way. Of course there's other, you know, like the listening room and the playback change and so forth are other parameters affecting that, what they hear. But does that actually matter? Because most music, as all of you will know, gets consumed in lossy formats via Spotify or any other streaming service and listened on speakers like this. Mono Bluetooth speakers. So in this context now MQA promises lossless studio sound at home that is authenticated and they also promise a sound improvement via fixing the temporal blur supposedly happening in the AD and DA stages. So Anton, who actually works on these matters, will now investigate these technical claims a little further. Okay, there you go. Hi. So as Christoph introduced himself, I do the same. My background in digital audio. Christoph, it's changing slides by itself. Is there a way to press? All right. So my background in digital audio started in 1993 when I bought this CD player together with an amplifier and two HAKO speakers. And looking back at that time it was the only point in my life where I actually carefully listened to audio quality as a listener. I repeatedly listened to my favorite records, which were mostly dance music at that time again and again. The player did well and still makes the job today. Later on in 2000 I started studying at the TU Ilmenau close to Leipzig. And I heard the lectures of Karl-Heinz Brandenburg who led in the 90s group that developed the MP3 algorithm. And with that invention I later in the last decade I became a very convenient listener. I downloaded continuously and then in the current decade I'm streaming. So nevertheless, or of course, Onkyu wants to sell a system again to me and I'm inclined to do a purchase soon. But not the one that comes with MQA and why that is like that I'm going to show now. So apart from the DRM I do not appreciate the audio quality of MQA. And before we have a quick look at the audio technology, let me state the following. There's not much information out there from MQA on the algorithm itself. There are, Christoph mentioned it already, there are mainly two papers, convention papers of the AES. There are patents which of course hide the crucial parts and increase their freedom to operate so it's vague. But there's luckily a lot of information from engineers that looked into the details and did a reverse engineering. So MQA is an encoder decoder system nested in a container such as flag, free lossless audio coding, or Apple audio coding, or Apple lossless audio coding, ALEC, or the Microsoft Wave container. And thereby can be read and decoded by standard audio players in hardened software. Of course MQA wants to replace the entire audio chain, the entire audio chain of AD converters and DA converters. And wants to get royalties also from the streaming services. And the main approach is to reduce the file size such that you send a 24 or 22 bandwidth file over the internet. But nevertheless by unfolding is it, you can still have the high-resolution audio. So the MQA claims are there, it's lossless and it shall improve the audio quality. MQA is scalable, the more you pay, the more bandwidth you get. So from the sampling rate, 48 kilohertz, you can unfold it four times. And download prices are currently at 2L higher than for the original high-resolution audio. The 24-bit and sampled at 192 kilohertz files. Important to know, the end user does not own the file. This has implications. For example, if you do a loudness normalization on the file itself or room compensation, you lose the MQA license, so to say, and it's reduced to CD quality or below. So one of those claims in the AES paper, which is written at the bottom, is we advocate lossless compression, lossless processing and hierarchical up-down sampling. We highlight the quality and efficiency gains possible if the encoder and decoder are mutually aware and each match to their analog converters. So this is a bold claim and not based on evidence. So we look into that, lossless compression in audio means a redundancy removal and the possibility to reconstruct the original recording bit by bit, including the noise, whether the noise belongs to the music or not. Lossy compression removes information, be it audible or not. So it's MQA lossless. Shannon's entropy allows us to assess the maximum redundancy in an audio file that can be removed without information loss. So on a data set of music, Stefan Horto, a link is given to his paper, not the link, but the paper itself is given in the bottom of this slide, did a entropy optimization and flag compression and reached for a certain high resolution data rate, 50% of file size. So this is quite a lot and nevertheless MQA however has a data reduction of 57%. And it's obvious that this reduction, lowering the bit depths and changing the amplitude and phase response is a lossy process. This is also highlighted in the paper that I give here by Stefan Horto. So slide six, the next claim, MQA approach of recoding results in superior sound and significant lower data rate when compared to unstructured encoding and playback and has been enthusiastically supported in listening trials with a number of recording and mastering engineers, artists and producers. So this is a truly scientific wording that may give you an impression of the AS publications that we have as the resource. And we analyzed that. I quickly take you through the sampling process. On the left side you see two columns. In the top you see a drawing of the sampling scheme. 15 minutes, yes. So we start with a band limited analog time function and this is then multiplied in the time domain with a series of pulses. Then in the third line we have the multiplication. The right column shows you the frequency equivalent and the time discrete signal gets quantized with certain bit depths for high resolution audio. It's 24 bit per sample. And then if you put an analog low pass filter on the signal you can reconstruct the original analog signal bit by bit and at 24 bit practically equal to the original signal. What MQA changes is for example the B-spline kernel for a sparse sampling scheme. And this shall improve the temporal resolution. It's the highlight, Christoph already mentioned it. They highlight the detection of humans, the ability to detect transients with 10 microseconds and the kernel also shall match to the song. So a second point is they change the low pass filter for avoiding pre-ringing and for improving together with the kernel the time resolution, they call it de-blurring and compensation for signal distortions from the analog digital conversion during the recording process. So is it actually improving sound quality? The temporal resolution, I should start with a listening test that Christoph already mentioned. There was no preference towards MQA compared to high resolution audio. In fact in some situations standard high resolution audio was preferred. So in terms of temporal resolution is it improving audio sound quality? If you look at their claim it shall allow for the detection of events that are as short as 10 microseconds which would be a bandwidth of 100 megahertz. They call it de-blurring from a 48 kilohertz sample signal. This is questionable, so I don't think that's actually the case. The next point is, is it tuned to the song? At first they post to change the balance between time and frequency representation of their filters. Both are equivalent representations of a filter but if they use an adapter filter we don't know actually what is tuned to the song so there's information missing. In terms of the minimum phase filters to suppress pre-ringing minimum phase filters have their shortcomings. They change the frequency response, the amplitude and the phase response that has been also shown by Stefan Hotto. And in the last point that we want to make on that slide is the appetization in the time domain to avoid the ringing of the filters. The minimum phase filter has a ringing after the center of the filter and to improve also temporal resolution and to compensate for the signal change that is also a point Stefan Hotto looked at and he clearly shows that appetization, so windowing in fact is a low pass filter and not improving sound quality. So do we need MQA enhancement based on today's evidence from neuroscience? We heard we need a time resolution in that paper of six microseconds and it was referred to the binaural hearing and in fact we are able to discriminate interval time differences with just noticeable differences of 10 microseconds. Those differences are however based on a central auditory comparison of sound waves between the ears and because of the spatial nyquist limit only the fine structure of the frequency up to 1.3 kHz is analyzed and if we remember the binaural for example has of course ears that are closer together and that's why they can even detect differences that are smaller than in humans. So and from the media production side there's no need for an enhancement of audio from a scientific point as well as from an artistic point of view the artistic concept with all variables composition, performance, practice, etc. is captured on multi-channel files and the transmission chain has always been kept free from influences. Quote the music is the message and finally interpreted by the auditory system so we don't need a channel that is pre-processing what's going on in our head eventually. A general question, do we need HR audio, high-resolution audio based on today's evidence from Neuroscience for listening to music? And I have here a graph from Zwicker and Fassel on psychoacoustics so the audible threshold in quiet is this solid line and it shows clearly we are not able to listen beyond let's say 20 kilohertz. Moreover music has an amplitude spectrum with 1 over F so beyond 20 kilohertz the sound power is very faint and it's from my point of view I can hardly imagine that we are able to listen beyond 20 kilohertz. Nevertheless on the production side we use filters that perform interpolation and for that case it's good to have high-resolution audio. Another point is conservation of recordings so if we store music digitally then of course it's good to have a lot of samples such that we can interpolate once there are errors arising. So conclusion there is no evidence-based research that supports audio quality claims of MQA MQA is lossy because it reduces the bit depths and the frequency response we see a degradation of audio quality which in its current version might not always be audible the algorithm of MQA folding scheme is only vaguely described and it's disadvantages for high-resolution audio are obviously disguised by marketing slogans like deblurring. Once an MQA infrastructure is established the audio quality can be easily scaled down MQA's description of kernel optimization for each track song alludes to a perceptual coding scheme which might eventually end up at mp3 quality. One thing to remember there are three high-resolution audio codecs that compress audio losslessly like FLAC. Internet bandwidth is not a big concern in the western world anymore it increases hence there's no need to fallossy audio coding and most of the music as Christoph already told us is still stored in CD quality if we upsample that information signal-to-noise ratio decreases. Okay, thanks. Alright, so thanks Anton. Okay, I showed that. Good, so the question is where is the DRM? Basically Anton already showed that MQA employs a clever encoding scheme and as far as we know because this is proprietary technology and we have to work with what we got and that is reverse engineering by some people online and some of the papers and other publications that MQA makes. This is again from the paper that Anton just mentioned from Stefan Hotto where he drew up the MQA encoding scheme and the important part, I don't have a laser pointer here but the DRM sample up there which you can see is 24 bits and as you can furthermore see it's divided into two parts the bassband is the audio bits and the subband is the data bits so basically what MQA does is using a 24-bit sample throwing away 8 bits of that more or less 8 bits of that audio information and bury other stuff basically in the noise floor that a 24-bit sample allows for give me a second so if you look at the history I just gave you on digital audio this is in a way back to square one because we had in 81 with the CD Redbook standard 16 bits at 441 kHz what we now would get with MQA is in their own words something to the extent of 15 to 17 bits of dynamic bandwidth sampled at 48 kHz everything above 48 kHz is encoded in a lossy compression scheme as Anton just showed this is this folding what they talk about how this actually is accomplished in detail we don't know it's I guess it's a pretty clever way because you have to basically get spectrum from 24 kHz to 96 kHz into just a few bits and bury that in the 6, 7, 8 bits that you get with MQA compression so in a way MQA acknowledges that the standard that Sony and Philips arrived at 16 bits 441 kHz is good enough for human hearing and all the information above 16 bit and above 44 or 48 kHz is more or less useless not audible we can do something else with that so what do you do what do you put there and it's a fairly complex sophisticated cryptographic scheme oh wait I forgot this one this is the blue light on the on one of these MQA decks that lights up when the file is authenticated an authentication to remind you of that that's a loaded term in the digital realm it promises to verify the origin of the data that so who is the sender and the integrity of the data under the conditions of open networks where data can be altered at any point in the transmission and these requirements can only be met via cryptographic means as the continuous reports on hacked cryptos indicate MQA has to come up with a workable and sufficiently secure system to make this possible and MQA partnered with the German data security company UTIMACO to create an authentication component for their format UTIMACO is a major purveyor of cryptographic products and well established in the banking sector in Europe and also in the healthcare sector and this is the website for UTIMACO it's a powerful interception data retention services which is nice to have and they offer these hardware security modules which is actually what MQA uses UTIMACO also published a white paper on MQA it's available on the website that's very sparse on details but it suggests that MQA entails a public key infrastructure and that hardware security modules like these ones shown here will be deployed in at least the MQA encoding houses and purportedly later on in the mastering studios so the converters in those mastering studios would need to have these hardware security modules in them or some sort of hardware security modules derived from these devices and UTIMACO was even so nice or is it to provide hardware security modules for dummies book on their site which apparently audio journalists so far haven't been able to find and these hardware security modules basically provide the means to embed the necessary keys in the MQA encoded files and the exact means of the scheme management schemes and the handling of the root of trust is unknown at this point MQA might outsource this to UTIMACO or might use this crypto service that do the key management okay I have to come to an end in-house so I like to ask the audience here is this DRM I don't hear anybody I guess that means yes okay so I'm asking this because MQA claims of course it's otherwise they say it's not DRM and here is from Ars Technica MQA has no DRM competent application outside of the studio we have no opinion on this beyond nothing noting that DRM is a futile exercise right and this is like a large part of the narrative and the online debate because MQA and all the people involved including the audio press keeps tuning this is not DRM because you can copy the files but copy protection is just one form of DRM the goal of DRM if you just look it up on Wikipedia for example this is the first thing you see is to manage the rights of a user with data and this means both in the restrictive and the permissive use cases so MQA permits copying but it restricts access to parts of the file namely the higher resolution parts so in DRM parlance that's conditional access and the access is only granted if you have an MQA capable digital audio converter which you have paid for of course so I guess what we can say is that MQA is something like a premium model right you get the file that you can play on any kind of converter or CD player you can burn on CD it actually would be playable but if you want access to the premium part of that file you have to buy a device also where it allows that good so why do they do that one more point and then I'm coming to end the firmware as it has been reverse engineer so far chose that they actually have provisions in place for copy protection there are provisions there to encrypt the files and with the SARTSA 20 cipher and there's also bridge transposition schemes in there why do they do this Jimmy Iovine just said Apple Music boss that the streaming services have a bad situation there's no margins they don't make any money so he's talking about titles, Spotify and so forth whereas Amazon sells Prime, Apple sells telephones and iPads and so forth so the problem is that you have to sell something else outside of your streaming service in order to make money which of course Apple is in good place Amazon is currently the biggest speaker company in the world with these kinds of devices and Google is catching up so our interpretation of what MQA is trying to do is it's trying to generate a new licensing stream for the music industry or specifically for MQA these elements of the music production distribution and consumption value chain would need MQA licenses the recording software and plug ins the recording mastering studios with new converters the artists would get their back catalogs remastered and would have to agree on that streaming services would have to sign up with them physical media manufacturers and if it comes to that and of course all the hyphen manufacturers and end customers also are looking at paying MQA okay I'll skip all this why is it clever and why is it stealth I think the encoding schemes that MQA employs make very clever use of the space afforded by 24-bit samples namely to stealthily introduce a DIM in the music production distribution and consumption value chain and they don't openly talk about it and they're actually very very difficult to find these elements and if you ask what to do Tuvat in this context of the conference here it would be worthwhile if people start to dig deeper on what MQA is actually doing okay I just stop here thank you so thank you very much for the talk we have now like five minutes for questioning and answering so please line up to the microphones and do we have a question from the internet no so microphone number one hello thanks for your talk you talked about the reverse engineering of the firmware so it somehow sounds that they wouldn't have these complicated hardware security modules in the DAX well it's a specific firmware in one product that has been reverse engineered from Blue Sound I don't know the security provisions of that but these hardware security modules won't be at this point part of the consumer products they will be part of the converters in the encoding house and the distribution context how the exact crypto works between the MQA files and the consumer DAX is not yet known there's some hints and indications you will find in these resources of how that works but the hardware security models would be employed in the production distribution part of the of the scheme okay thanks we have another question for microphone number four yeah thank you for your talk I have two questions one of them is do you think that this marketing concept will have any success at all and the second one is do you think that music encoding does evolve anywhere else than multi channel encoding instead of increasing sample rate and sample bits yeah thank you good questions I think this this is a good example of how not to market something because I cannot think of any product that has managed to create more doubt with both the consumers of this product and also hardware manufacturers and all kinds of other people who are involved in digital audio than MQA I think they went out with very bold claims tried to play the audio files with their easy easy suggestibility and were surprised by the competence in the audience so I don't think this will go anywhere in these terms what was your second question again about how the encoding of music evolves if we are going for more channels like 5 channels 8 channels maybe 16 channels at some point or do some people still try to increase the bit rate and frequency so it's probably a question for Anton I can only as an audio file answer this in the audio file market multi channel audio is dead it's stereo I mean for the consumers this is why I showed this bluetooth speaker everybody is happy with mono now and that doesn't seem to be a problem stereo files will have audio files will have stereo setups and multi channel setups create problems with rooms and calibration all kinds of things it might be different in the AV sector in more general terms I think audio is a solved problem 24 bits and 192 kHz should be enough the frontier now is room correction and face correction with speakers so that's where the real problems are and where there is actually real progress digital what do you call weichen crossovers yes digital crossovers these kinds of things thank you we can add micrometric coding is used in multi channel audio so you send one mono signal and then you can reproduce by parameters a room for a multi channel setup that's often used thanks I think we have time for another question do we another question for number one I went to three conferences on digital audio and computer music this year I didn't hear anybody mention this I think the story about the authenticity authentication what do you call it can you step a bit forward it's fabulous I wonder if do they make any claims that do like virtual analog models of the original converters this story is completely like crazy that actually is being mentioned in the MQA marketing model that they call it fingerprint the original analog digital converter and compensate for the deficiencies and errors this converter makes and that's one of the big claims that there is a device specific compensation embedded in the MQA file being called upon upon replay and hence a better quality experience for the listener but all the evidence so far shows that this is absolutely not true what we have is a pair song encoding just like you would have an mp3 or something else the encoder apparently analyzes the file the song or the track it makes certain provisions on how to fold the signal so how many bits get allocated on the dynamic range on a pair track basis so there is no authentication or fingerprinting or any kind of modeling of the analog part or the ad part in the chain thank you very much for the questioning and thanks again very much for the talk