diff --git a/docs/plugin_matrix.rst b/docs/plugin_matrix.rst
index b2fb70c8..11841b25 100644
--- a/docs/plugin_matrix.rst
+++ b/docs/plugin_matrix.rst
@@ -122,7 +122,8 @@ nrk                     - tv.nrk.no          Yes   Yes   Streams may be geo-rest
                         - radio.nrk.no
 ntv                     ntv.ru               Yes   No
 okru                    ok.ru                Yes   Yes
-olympicchannel          olympicchannel.com   Yes   Yes   Only non-premium content is available.
+olympicchannel          - olympicchannel.com Yes   Yes   Only non-premium content is available.
+                        - olympics.com
 oneplusone              1plus1.video         Yes   No
 onetv                   1tv.ru               Yes   No    Streams may be geo-restricted to Russia.
 openrectv               openrec.tv           Yes   Yes
diff --git a/src/streamlink/plugins/olympicchannel.py b/src/streamlink/plugins/olympicchannel.py
index 7ea41a80..d91924ff 100644
--- a/src/streamlink/plugins/olympicchannel.py
+++ b/src/streamlink/plugins/olympicchannel.py
@@ -1,58 +1,67 @@
-import json
 import logging
 import re
+from html import unescape as html_unescape
 from time import time
 from urllib.parse import urljoin, urlparse
 
 from streamlink.plugin import Plugin
 from streamlink.plugin.api import validate
 from streamlink.stream import HLSStream
+from streamlink.utils import parse_json
 
 log = logging.getLogger(__name__)
 
 
 class OlympicChannel(Plugin):
-    _url_re = re.compile(r"https?://(\w+\.)olympicchannel.com/../(?P<type>live|video|original-series|films)/?(?:\w?|[-\w]+)")
-    _tokenizationApiDomainUrl = """"tokenizationApiDomainUrl" content="/OcsTokenization/api/v1/tokenizedUrl">"""
-    _live_api_path = "/OcsTokenization/api/v1/tokenizedUrl?url={url}&domain={netloc}&_ts={time}"
-
+    _url_re = re.compile(r"https?://(\w+\.)?(?:olympics|olympicchannel)\.com/(?:[\w-]+/)?../.+")
+    _token_api_path = "/tokenGenerator?url={url}&domain={netloc}&_ts={time}"
     _api_schema = validate.Schema(
-        validate.text,
-        validate.transform(lambda v: json.loads(v)),
-        validate.url()
+        validate.transform(parse_json),
+        [{
+            validate.optional("src"): validate.url(),
+            validate.optional("srcType"): "HLS",
+        }],
+        validate.transform(lambda v: v[0].get("src")),
+    )
+    _data_url_re = re.compile(r'data-content-url="([^"]+)"')
+    _data_content_re = re.compile(r'data-d3vp-plugin="THEOplayer"\s*data-content="([^"]+)"')
+    _data_content_schema = validate.Schema(
+        validate.any(
+            validate.all(
+                validate.transform(_data_url_re.search),
+                validate.any(None, validate.get(1)),
+            ),
+            validate.all(
+                validate.transform(_data_content_re.search),
+                validate.any(None, validate.get(1)),
+            ),
+        ),
+        validate.any(None, validate.transform(html_unescape)),
     )
-    _video_url_re = re.compile(r""""video_url"\scontent\s*=\s*"(?P<value>[^"]+)""")
-    _video_url_schema = validate.Schema(
-        validate.contains(_tokenizationApiDomainUrl),
-        validate.transform(_video_url_re.search),
-        validate.any(None, validate.get("value")),
-        validate.url()
+    _stream_schema = validate.Schema(
+        validate.transform(parse_json),
+        validate.url(),
     )
 
     @classmethod
     def can_handle_url(cls, url):
         return cls._url_re.match(url)
 
-    def _get_vod_streams(self):
-        stream_url = self.session.http.get(self.url, schema=self._video_url_schema)
-        return HLSStream.parse_variant_playlist(self.session, stream_url)
+    def _get_streams(self):
+        api_url = self.session.http.get(self.url, schema=self._data_content_schema)
+        if api_url and (api_url.startswith("/") or api_url.startswith("http")):
+            api_url = urljoin(self.url, api_url)
+            stream_url = self.session.http.get(api_url, schema=self._api_schema, headers={"Referer": self.url})
+        elif api_url and api_url.startswith("[{"):
+            stream_url = self._api_schema.validate(api_url)
+        else:
+            return
 
-    def _get_live_streams(self):
-        video_url = self.session.http.get(self.url, schema=self._video_url_schema)
-        parsed = urlparse(video_url)
-        api_url = urljoin(self.url, self._live_api_path.format(url=video_url,
+        parsed = urlparse(stream_url)
+        api_url = urljoin(self.url, self._token_api_path.format(url=stream_url,
                           netloc="{0}://{1}".format(parsed.scheme, parsed.netloc), time=int(time())))
-        stream_url = self.session.http.get(api_url, schema=self._api_schema)
+        stream_url = self.session.http.get(api_url, schema=self._stream_schema, headers={"Referer": self.url})
         return HLSStream.parse_variant_playlist(self.session, stream_url)
 
-    def _get_streams(self):
-        match = self._url_re.match(self.url)
-        type_of_stream = match.group('type')
-
-        if type_of_stream == 'live':
-            return self._get_live_streams()
-        elif type_of_stream in ('video', 'original-series', 'films'):
-            return self._get_vod_streams()
-
 
 __plugin__ = OlympicChannel
diff --git a/src/streamlink/plugins/twitch.py b/src/streamlink/plugins/twitch.py
index 4b067620..4ef7f1d1 100644
--- a/src/streamlink/plugins/twitch.py
+++ b/src/streamlink/plugins/twitch.py
@@ -15,6 +15,7 @@ from streamlink.stream import HLSStream, HTTPStream
 from streamlink.stream.hls import HLSStreamReader, HLSStreamWorker, HLSStreamWriter
 from streamlink.stream.hls_playlist import M3U8, M3U8Parser, load as load_hls_playlist
 from streamlink.utils.times import hours_minutes_seconds
+from streamlink.utils.url import update_qsd
 
 log = logging.getLogger(__name__)
 
@@ -346,47 +347,89 @@ class TwitchAPI:
         ))
 
     def clips(self, clipname):
-        query = """{{
-            clip(slug: "{clipname}") {{
-                broadcaster {{
-                    displayName
-                }}
-                title
-                game {{
-                    name
-                }}
-                videoQualities {{
-                    quality
-                    sourceURL
-                }}
-            }}
-        }}""".format(clipname=clipname)
-
-        return self.call_gql({"query": query}, schema=validate.Schema(
-            {"data": {
-                "clip": validate.any(None, validate.all({
-                    "broadcaster": validate.all({"displayName": validate.text}, validate.get("displayName")),
-                    "title": validate.text,
-                    "game": validate.all({"name": validate.text}, validate.get("name")),
-                    "videoQualities": [validate.all({
-                        "quality": validate.all(
-                            validate.text,
-                            validate.transform(lambda q: "{0}p".format(q))
-                        ),
-                        "sourceURL": validate.url()
-                    }, validate.union((
-                        validate.get("quality"),
-                        validate.get("sourceURL")
-                    )))]
-                }, validate.union((
-                    validate.get("broadcaster"),
-                    validate.get("title"),
-                    validate.get("game"),
-                    validate.get("videoQualities")
-                ))))
-            }},
-            validate.get("data"),
-            validate.get("clip")
+        queries = [
+            {
+                "operationName": "VideoAccessToken_Clip",
+                "extensions": {
+                    "persistedQuery": {
+                        "version": 1,
+                        "sha256Hash": "36b89d2507fce29e5ca551df756d27c1cfe079e2609642b4390aa4c35796eb11"
+                    }
+                },
+                "variables": {"slug": clipname}
+            },
+            {
+                "operationName": "ClipsView",
+                "extensions": {
+                    "persistedQuery": {
+                        "version": 1,
+                        "sha256Hash": "4480c1dcc2494a17bb6ef64b94a5213a956afb8a45fe314c66b0d04079a93a8f"
+                    }
+                },
+                "variables": {"slug": clipname}
+            },
+            {
+                "operationName": "ClipsTitle",
+                "extensions": {
+                    "persistedQuery": {
+                        "version": 1,
+                        "sha256Hash": "f6cca7f2fdfbfc2cecea0c88452500dae569191e58a265f97711f8f2a838f5b4"
+                    }
+                },
+                "variables": {"slug": clipname}
+            }
+        ]
+
+        return self.call_gql(queries, schema=validate.Schema(
+            [
+                validate.all(
+                    {"data": {
+                        "clip": validate.all({
+                            "playbackAccessToken": validate.all({
+                                "__typename": "PlaybackAccessToken",
+                                "signature": str,
+                                "value": str
+                            }, validate.union((
+                                validate.get("signature"),
+                                validate.get("value")
+                            ))),
+                            "videoQualities": [validate.all({
+                                "frameRate": validate.any(int, float),
+                                "quality": str,
+                                "sourceURL": validate.url()
+                            }, validate.union((
+                                validate.transform(lambda q: f"{q['quality']}p{int(q['frameRate'])}"),
+                                validate.get("sourceURL")
+                            )))]
+                        }, validate.union((
+                            validate.get("playbackAccessToken"),
+                            validate.get("videoQualities")
+                        )))
+                    }},
+                    validate.get("data"),
+                    validate.get("clip")
+                ),
+                validate.all(
+                    {"data": {
+                        "clip": validate.all({
+                            "broadcaster": validate.all({"displayName": str}, validate.get("displayName")),
+                            "game": validate.all({"name": str}, validate.get("name"))
+                        }, validate.union((
+                            validate.get("broadcaster"),
+                            validate.get("game")
+                        )))
+                    }},
+                    validate.get("data"),
+                    validate.get("clip")
+                ),
+                validate.all(
+                    {"data": {
+                        "clip": validate.all({"title": str}, validate.get("title"))
+                    }},
+                    validate.get("data"),
+                    validate.get("clip")
+                )
+            ]
         ))
 
     def stream_metadata(self, channel):
@@ -662,12 +705,12 @@ class Twitch(Plugin):
 
     def _get_clips(self):
         try:
-            (self.author, self.title, self.category, streams) = self.api.clips(self.clip_name)
+            (((sig, token), streams), (self.author, self.category), self.title) = self.api.clips(self.clip_name)
         except (PluginError, TypeError):
             return
 
         for quality, stream in streams:
-            yield quality, HTTPStream(self.session, stream)
+            yield quality, HTTPStream(self.session, update_qsd(stream, {"sig": sig, "token": token}))
 
     def _get_streams(self):
         if self.video_id:
diff --git a/src/streamlink/utils/url.py b/src/streamlink/utils/url.py
index 7776c648..bc967126 100644
--- a/src/streamlink/utils/url.py
+++ b/src/streamlink/utils/url.py
@@ -1,24 +1,38 @@
+import re
 from collections import OrderedDict
 from urllib.parse import parse_qsl, quote_plus, urlencode, urljoin, urlparse, urlunparse
 
 
-def update_scheme(current, target):
+_re_uri_implicit_scheme = re.compile(r"""^[a-z0-9][a-z0-9.+-]*://""", re.IGNORECASE)
+
+
+def update_scheme(current: str, target: str) -> str:
     """
-    Take the scheme from the current URL and applies it to the
-    target URL if the target URL startswith // or is missing a scheme
+    Take the scheme from the current URL and apply it to the
+    target URL if the target URL starts with // or is missing a scheme
     :param current: current URL
     :param target: target URL
     :return: target URL with the current URLs scheme
     """
     target_p = urlparse(target)
+
+    if (
+        # target URLs with implicit scheme and netloc including a port: ("http://", "foo.bar:1234") -> "http://foo.bar:1234"
+        # urllib.parse.urlparse has incorrect behavior in py<3.9, so we'll have to use a regex here
+        # py>=3.9: urlparse("127.0.0.1:1234") == ParseResult(scheme='127.0.0.1', netloc='', path='1234', ...)
+        # py<3.9 : urlparse("127.0.0.1:1234") == ParseResult(scheme='', netloc='', path='127.0.0.1:1234', ...)
+        not _re_uri_implicit_scheme.search(target) and not target.startswith("//")
+        # target URLs without scheme and netloc: ("http://", "foo.bar/foo") -> "http://foo.bar/foo"
+        or not target_p.scheme and not target_p.netloc
+    ):
+        return f"{urlparse(current).scheme}://{urlunparse(target_p)}"
+
+    # target URLs without scheme but with netloc: ("http://", "//foo.bar/foo") -> "http://foo.bar/foo"
     if not target_p.scheme and target_p.netloc:
-        return "{0}:{1}".format(urlparse(current).scheme,
-                                urlunparse(target_p))
-    elif not target_p.scheme and not target_p.netloc:
-        return "{0}://{1}".format(urlparse(current).scheme,
-                                  urlunparse(target_p))
-    else:
-        return target
+        return f"{urlparse(current).scheme}:{urlunparse(target_p)}"
+
+    # target URLs with scheme
+    return target
 
 
 def url_equal(first, second, ignore_scheme=False, ignore_netloc=False, ignore_path=False, ignore_params=False,

diff --git a/tests/plugins/test_olympicchannel.py b/tests/plugins/test_olympicchannel.py
index c859a4d0..39d4dc1a 100644
--- a/tests/plugins/test_olympicchannel.py
+++ b/tests/plugins/test_olympicchannel.py
@@ -11,10 +11,16 @@ class TestPluginCanHandleUrlOlympicChannel(PluginCanHandleUrl):
         "https://www.olympicchannel.com/en/live/video/detail/olympic-ceremonies-channel/",
         "https://www.olympicchannel.com/de/video/detail/stefanidi-husband-coach-krier-relationship/",
         "https://www.olympicchannel.com/de/original-series/detail/body/body-season-season-1/episodes/"
-        + "treffen-sie-aaron-wheelz-fotheringham-den-paten-des-rollstuhl-extremsports/",
+        "treffen-sie-aaron-wheelz-fotheringham-den-paten-des-rollstuhl-extremsports/",
+        "https://olympics.com/en/sport-events/2021-fiba-3x3-olympic-qualifier-graz/?"
+        "slug=final-day-fiba-3x3-olympic-qualifier-graz",
+        "https://olympics.com/en/video/spider-woman-shauna-coxsey-great-britain-climbing-interview",
+        "https://olympics.com/en/original-series/episode/how-fun-fuels-this-para-taekwondo-world-champion-unleash-the-new",
+        "https://olympics.com/tokyo-2020/en/news/videos/tokyo-2020-1-message",
     ]
 
     should_not_match = [
         "https://www.olympicchannel.com/en/",
-        "https://www.olympicchannel.com/en/channel/olympic-channel/",
+        "https://www.olympics.com/en/",
+        "https://olympics.com/tokyo-2020/en/",
     ]
diff --git a/tests/test_utils_url.py b/tests/test_utils_url.py
index 9f283316..f5b725fd 100644
--- a/tests/test_utils_url.py
+++ b/tests/test_utils_url.py
@@ -9,6 +9,9 @@ def test_update_scheme():
     assert update_scheme("http://other.com/bar", "//example.com/foo") == "http://example.com/foo", "should become http"
     assert update_scheme("https://other.com/bar", "http://example.com/foo") == "http://example.com/foo", "should remain http"
     assert update_scheme("https://other.com/bar", "example.com/foo") == "https://example.com/foo", "should become https"
+    assert update_scheme("http://", "127.0.0.1:1234/foo") == "http://127.0.0.1:1234/foo", "implicit scheme with IPv4+port"
+    assert update_scheme("http://", "foo.bar:1234/foo") == "http://foo.bar:1234/foo", "implicit scheme with hostname+port"
+    assert update_scheme("http://", "foo.1+2-bar://baz") == "foo.1+2-bar://baz", "correctly parses all kinds of schemes"
 
 
 def test_url_equal():

plugins.twitch: clips 404 - require access token
<!--
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USE THE TEMPLATE. Otherwise your bug report may be rejected.

First, see the contribution guidelines:
https://github.com/streamlink/streamlink/blob/master/CONTRIBUTING.md#contributing-to-streamlink

Bugs are the result of broken functionality within Streamlink's main code base. Use the plugin issue template if your report is about a broken plugin.

Also check the list of open and closed bug reports:
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Please see the text preview to avoid unnecessary formatting errors.
-->


## Bug Report

<!-- Replace the space character between the square brackets with an x in order to check the boxes -->
- [x] This is a bug report and I have read the contribution guidelines.
- [x] I am using the latest development version from the master branch.


### Description

When running streamlink with a twitchclip URL it results in an 404 error

### Expected / Actual behavior

It shouldn't 404


### Reproduction steps / Explicit stream URLs to test

<!-- How can we reproduce this? Please note the exact steps below using the list format supplied. If you need more steps please add them. -->

1. run stramlink with a twitch clip URL
2. results in a 404 error


### Log output

<!--
DEBUG LOG OUTPUT IS REQUIRED for a bug report!
INCLUDE THE ENTIRE COMMAND LINE and make sure to **remove usernames and passwords**

Use the `--loglevel debug` parameter and avoid using parameters which suppress log output.
Debug log includes important details about your platform. Don't remove it.
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Don't post screenshots of the log output and instead copy the text from your terminal application.
-->

```
[cli][debug] OS:         Windows 10
[cli][debug] Python:     3.8.2
[cli][debug] Streamlink: 2.1.2+10.ge747226
[cli][debug] Requests(2.25.1), Socks(1.7.1), Websocket(1.0.1)
[cli][debug] Arguments:
[cli][debug]  url=https://clips.twitch.tv/GrossRamshacklePheasantPipeHype-vb-LdFjwD-kLo87L
[cli][debug]  stream=['best']
[cli][debug]  --loglevel=debug
[cli][debug]  --rtmpdump=D:\Program Files (x86)\Streamlink\rtmpdump\rtmpdump.exe
[cli][debug]  --ffmpeg-ffmpeg=D:\Program Files (x86)\Streamlink\ffmpeg\ffmpeg.exe
[cli][info] Found matching plugin twitch for URL https://clips.twitch.tv/GrossRamshacklePheasantPipeHype-vb-LdFjwD-kLo87L
[cli][info] Available streams: 360p (worst), 480p, 720p, 1080p (best)
[cli][info] Opening stream: 1080p (http)
[cli][error] Try 1/1: Could not open stream <HTTPStream('https://production.assets.clips.twitchcdn.net/AT-cm%7C1198016717.mp4')> (Could not open stream: Unable to open URL: https://production.assets.clips.twitchcdn.net/AT-cm%7C1198016717.mp4 (404 Client Error:  for url: https://production.assets.clips.twitchcdn.net/AT-cm%7C1198016717.mp4))
error: Could not open stream <HTTPStream('https://production.assets.clips.twitchcdn.net/AT-cm%7C1198016717.mp4')>, tried 1 times, exiting
```


### Additional comments, etc.

Twitch now needs a JWT in the URL for authentication. The page 404 if it isn't present. 
The JSON is just plaintext, but urlencoded and has the form:
{"authorization":{"forbidden":false,"reason":""},"clip_uri":"","device_id":str,"expires":int,"user_id":str,"version":2}
The signature appears to be sha1, but I couldn't figure out what exactly that were hashing as nothing I tried resulted in a valid hash.

[Love Streamlink? Please consider supporting our collective. Thanks!](https://opencollective.com/streamlink/donate)

tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_positive[https://olympics.com/en/sport-events/2021-fiba-3x3-olympic-qualifier-graz/?slug=final-day-fiba-3x3-olympic-qualifier-graz] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_positive[https://olympics.com/en/video/spider-woman-shauna-coxsey-great-britain-climbing-interview] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_positive[https://olympics.com/en/original-series/episode/how-fun-fuels-this-para-taekwondo-world-champion-unleash-the-new] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_positive[https://olympics.com/tokyo-2020/en/news/videos/tokyo-2020-1-message] tests/test_utils_url.py::test_update_scheme
tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_class_setup tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_positive[https://www.olympicchannel.com/en/video/detail/stefanidi-husband-coach-krier-relationship/] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_positive[https://www.olympicchannel.com/en/live/] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_positive[https://www.olympicchannel.com/en/live/video/detail/olympic-ceremonies-channel/] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_positive[https://www.olympicchannel.com/de/video/detail/stefanidi-husband-coach-krier-relationship/] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_positive[https://www.olympicchannel.com/de/original-series/detail/body/body-season-season-1/episodes/treffen-sie-aaron-wheelz-fotheringham-den-paten-des-rollstuhl-extremsports/] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_negative[https://www.olympicchannel.com/en/] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_negative[https://www.olympics.com/en/] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_negative[https://olympics.com/tokyo-2020/en/] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_negative[http://example.com/] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_negative[https://example.com/] tests/plugins/test_olympicchannel.py::TestPluginCanHandleUrlOlympicChannel::test_can_handle_url_negative[https://example.com/index.html] tests/test_utils_url.py::test_url_equal tests/test_utils_url.py::test_url_concat tests/test_utils_url.py::test_update_qsd