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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 |
...
By default, maximum encoder threads quantity is set to 2.
The settings above should be applied to Transcoder nodes.should 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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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 |