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Supported codecs
WebRTC video:
WebRTC audio:
- Opus
Implementation basics
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In this case all the media traffic will pass through the WCS internal TURN server. This feature may be also used to wrap WebRTC traffic to TCP if the client has a bad channel, because WCS does not support TCP transport for SFU streams.
VP9 support
Since WCS build 5.2.1908 and SFU SDK build 2.0.
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268, VP9 codec is supported for SFU mediatraffic publishing and playback
Code Block | ||
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| ||
codecs=opus,alaw,ulaw,g729,speex16,g722,mpeg4-generic,telephone-event,h264,vp8,vp9,flv,mpv |
VP9 must be excluded for the cases when it is not supported by other party (SIP calls for instance)
Code Block | ||
---|---|---|
| ||
codecs_exclude_sip=mpeg4-generic,flv,mpv,h265,vp9
codecs_exclude_sip_rtmp=opus,g729,g722,mpeg4-generic,vp8,vp9,mpv,h265 |
It is necessary to exclude H264 and VP8 codecs for SFU to enable VP9
Code Block | ||
---|---|---|
| ||
codecs_exclude_sfu=alaw,ulaw,g729,speex16,g722,mpeg4-generic,telephone-event,h265,flv,mpv,vp8,h264,h265 |
VP9 codec allows to use SVC (Scalable Video Coding) at browser side by setting scalabilityMode
in encoding profile
Code Block | ||||
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| ||||
{
"room": {
...
},
"media": {
"audio": {
"tracks": [
]
},
"video": {
"tracks": [{
"source": "camera",
"width": 1280,
"height": 720,
"codec": "vp9",
"encodings": [
{
"rid": "nonsense",
"active": true,
"scalabilityMode": "L1T3"
}
]
}]
}
}
} |
In this example, a video track will be published in one resolution (L1) with 3 FPS layers (T3). A full scalability modes list is available here.
Known limits
1. It is not recommended to use Simulcast (using a number of encoding profiles) and SVC simultaneously because this may not be properly supported in a browser.
2. Only one spatial layer (L1) is available for screen sharing, other settings are ignored. The limit is hardcoded at WebRTC library level and applied in any browser.
Known issues
1. A stream captured from a screen window simulcast publishing will crash Chrome browser tab on minimizing this window
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