{"action":"created","issue":{"url":"https://api.github.com/repos/Dash-Industry-Forum/dash.js/issues/888","labels_url":"https://api.github.com/repos/Dash-Industry-Forum/dash.js/issues/888/labels{/name}","comments_url":"https://api.github.com/repos/Dash-Industry-Forum/dash.js/issues/888/comments","events_url":"https://api.github.com/repos/Dash-Industry-Forum/dash.js/issues/888/events","html_url":"https://github.com/Dash-Industry-Forum/dash.js/issues/888","id":116921198,"number":888,"title":"the usage of   PlayList metrics","user":{"login":"Samsoso94","id":15844424,"avatar_url":"https://avatars.githubusercontent.com/u/15844424?v=3","gravatar_id":"","url":"https://api.github.com/users/Samsoso94","html_url":"https://github.com/Samsoso94","followers_url":"https://api.github.com/users/Samsoso94/followers","following_url":"https://api.github.com/users/Samsoso94/following{/other_user}","gists_url":"https://api.github.com/users/Samsoso94/gists{/gist_id}","starred_url":"https://api.github.com/users/Samsoso94/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Samsoso94/subscriptions","organizations_url":"https://api.github.com/users/Samsoso94/orgs","repos_url":"https://api.github.com/users/Samsoso94/repos","events_url":"https://api.github.com/users/Samsoso94/events{/privacy}","received_events_url":"https://api.github.com/users/Samsoso94/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-11-14T12:02:33Z","updated_at":"2015-11-17T10:36:57Z","closed_at":null,"body":"Hi,\r\nI'm new to dash.js(1.5.1) and trying to  to understand the  metrics PlayList  Can you please explain the used of   PlayList.mstart and PlayList.trace.mstart in dash.js.I found from:PlayList.js\r\nthis.start = null;      // Real-Time | Timestamp of the user action that starts the playback stream...\r\nthis.mstart = null;     // Media-Time | Presentation time at which playout was requested by the user...\r\nand from PlayList.Trace function():\r\n   L1 * start            - Real-Time | The time at which the first sample was rendered.\r\n   L2* mstart           - Media-Time | The presentation time of the first sample rendered.\r\n\r\nCan you please explain the meaning of the line *L1,L2 in dash.js,and i also see the issue #865\r\nI really appreciate any help you can provide."},"comment":{"url":"https://api.github.com/repos/Dash-Industry-Forum/dash.js/issues/comments/157331871","html_url":"https://github.com/Dash-Industry-Forum/dash.js/issues/888#issuecomment-157331871","issue_url":"https://api.github.com/repos/Dash-Industry-Forum/dash.js/issues/888","id":157331871,"user":{"login":"bbcrddave","id":5390145,"avatar_url":"https://avatars.githubusercontent.com/u/5390145?v=3","gravatar_id":"","url":"https://api.github.com/users/bbcrddave","html_url":"https://github.com/bbcrddave","followers_url":"https://api.github.com/users/bbcrddave/followers","following_url":"https://api.github.com/users/bbcrddave/following{/other_user}","gists_url":"https://api.github.com/users/bbcrddave/gists{/gist_id}","starred_url":"https://api.github.com/users/bbcrddave/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/bbcrddave/subscriptions","organizations_url":"https://api.github.com/users/bbcrddave/orgs","repos_url":"https://api.github.com/users/bbcrddave/repos","events_url":"https://api.github.com/users/bbcrddave/events{/privacy}","received_events_url":"https://api.github.com/users/bbcrddave/received_events","type":"User","site_admin":false},"created_at":"2015-11-17T10:36:57Z","updated_at":"2015-11-17T10:36:57Z","body":"These metrics are defined in the MPEG-DASH specification [1] in section D.4.6.\r\n\r\nI'm not really sure what exactly you are asking, but here's a short explanation. Please clarify if this does not answer your question.\r\n\r\nA PlayList metric represents a period of continuous playback and is made up of one top level `PlayList`, which should be created when playback begins, and a list of trace entries which are created when something changes which is not the end of the session (representation switch for example).\r\n\r\nIn JS, we don't have control over the decoder or the ability to get very accurate timing back from it, so we assume that `start` and `mstart` are the times we requested.\r\n\r\nNote that the current implementation is not 100% spec compliant and it will probably change in a future release.\r\n\r\n[1] http://standards.iso.org/ittf/PubliclyAvailableStandards/index.html"}}