Timbra
Select the audio track for transcription
Select which (audio) track to use as a source
Live streams may contain multiple audio tracks, and you can select which audio track to use. If you want to transcribe multiple audio tracks, refer to the multi-track audio feature.
HLS source
By default, Timbra uses the primary audio track from the HLS stream as the source for transcription.
If you would like Timbra to transcribe a different audio source, open your live project and select More actions ⋯ > Edit project. Under the HLS stream check, choose the track you want under Select an audio track to transcribe. To use a specific playlist instead, select Show transcription URL and enter its URL in Selected audio track URL.

You’ll need to restart the captioning process to pick up the captions.
RTMP/SRT source
If your RTMP or SRT contains multiple audio streams, you can provide a Packet Identifier (PID) to select the audio track to transcribe. Select More actions ⋯ > Edit project, expand Advanced options and use PID for audio stream.

Use cases
You can use this feature to:
- Select the source language in a multilingual stream
- Select the correct audio track in a stream with multiple encoding variants or backups
- Select a non-default audio track, for example an audio track without music, or the Audio Description track
- Fail over to a backup audio stream
