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Parameter | Values available | Description |
---|---|---|
Audio parameters | ||
codec | opus mpeg4-generic speex ulaw | Audio codec to use |
bitrate | Depends on quality required and bandwidth available | Audio bitrate, bps |
rate | 8000 11025 12000 16000 22050 24000 32000 44100 48000 | Audio sample rate, kHz |
channels | 1 2 | Audio channels number |
Video parameters | ||
codec | h264 mpv vp8 | Video codec to use |
bitrate | Depends on quality required and bandwidth available | Video bitrate, kbps |
width | Depends on quality required and bandwidth available | Picture width |
height | Depends on quality required and bandwidth available | Picture height |
codeImpl | FF OPENH264 | Video codec used, FF by default |
gop | Depends on quality required and bandwidth available | Key frames frequency (GOP) |
fps | Depends on quality required and bandwidth available | Frames frequency per second |
quality | Depends on quality required and bandwidth available | Video quality |
preset | ultrafast superfast veryfast faster fast medium slow slower veryslow placebo | FF preset, ultrafast by default |
profile | 66 (Baseline) 77 (Main) 88 (Extended) 100 (High) | FF profile, 66 (Baseline) by default |
level | Depends on required quality | FF level, 3.1 by default |
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The settings above should be applied to Transcoder nodes.be applied to Transcoder nodes.
Multi channels audio support
Since build 5.2.773, audio transcoding by profile with certain number of channels (1 - mono, 2 - stereo) is supported
Code Block | ||||
---|---|---|---|---|
| ||||
profiles:
-240p:
audio:
codec : mpeg4-generic
rate : 48000
channels: 1
video:
height : 240
bitrate : 300
gop : 50
codec : h264 |
A channels number in a profile should be equal to channels number in original audio track for subscriber on Edge server to play stereo sound when stream with stereo sound is published, i.e.
Code Block | ||||
---|---|---|---|---|
| ||||
profiles:
-240p:
audio:
codec : mpeg4-generic
rate : 48000
channels: 2 |
If profile codec, samplerate and channels number are equal to original audio track parameters, the track will be passed to Edge server without transcoding
Transcoding profile management using REST API
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By default, this interval is 60 seconds. It is recommended to reduce this parameter to 1 second for Transcoder nodes to distribute the streams to another nodes.
Transcoder
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threshold reached state setup
Since build 5.2.640 Transcoder node threshold reached state can be set with the following parameter, GROUP_CONNECTIONS_ALLOWED by default
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Code Block | ||||
---|---|---|---|---|
| ||||
profiles: -240p: audio: codec : opus rate : 48000 video: height : 240 bitrate : 400 gop : 50 fps : 25 codec : h264 codecImpl : OPENH264 |
2. Encoding quality settings cannot be applied if OpenH264 is used
Symptoms: picture quality is not changing when using different quality
values in transcoding profile
Solution: do not use OpenH264 encoder because it does not support CRF
Code Block | ||||
---|---|---|---|---|
| ||||
profiles:
-240p:
audio:
...
video:
...
quality: 10
codecImpl : FF |