- Using Multiple Audio Tracks with Kaltura Live +
- Requirements for Kaltura Multi-Audio Tracks
- Mapping Audio Suffixes and Languages
- How to Setup Multi-audio for Kaltura Live+
- How to Test Multi-audio for Live+
- Known Limitations
Kaltura supports multiple audio/language tracks for Live+ streaming. Multiple audio tracks are used to provide live streaming with several audio tracks, typically in different languages and provide a better user-experience for multi-lingual audiences.
Instead of creating multiple live streams, each with a video and a different audio language, one video stream with multi-audio tracks can be created and used to simplify the setup and reduce the bandwidth and processing costs.
Switching between audio tracks is done in the player (both Web and Mobile) by simply choosing the preferred language from the audio menu.
The following components are required to configure multiple audios for Kaltura Live+ Streaming:
- Multiple audio sources - If you are streaming a live event, you will need translators that will record different languages in realtime during your live event. If you are simulating a live event, you will need several audio tracks.
- An encoder that can send separate RTMP feeds for each track:
- The video track and all audio tracks should use different RTMP stream names.
- Each track should have a separate RTMP connection.
The audio and video tracks should be broadcasted separately.
Audios that are interleaved (included ) with videos will be discarded.
The following lists the audio suffixes and languages for mapping multi-audio and multi-language streaming:
- English - 1000
- Spanish - 1001
- French - 1002
- German - 1003
- Portuguese - 1004
- Chinese - 1005
- Arabic - 1006
- Hindi - 1007
- Russian - 1008
- Japanese -1009
For example, if you are broadcasting in English, Spanish and French:
All the video and audio tracks will all have the same RTMP endpoint prefix:
The video track stream name will have and "_1" suffix (e.g. 1_g5gun4of_1)
The English audio track stream name will have a "_1000" suffix (e.g. 1_g5gun4of_1000)
The Spanish audio track stream name will have a "_1001" suffix (e.g. 1_g5gun4of_1001)
The French audio track stream name will have a "_1002" suffix (e.g. 1_g5gun4of_1002)
- Your Kaltura account has to be setup with Live+ (The multi-audio tracks feature is not supported for Kaltura Pass-through streaming).
- KMC - The selected Transcoding Profile for your live entry must be configured to select all the languages' flavors that are being used by your partner. See How to Configure the Transcoding Settings.
- Encoder - Define each track (video/audio) to stream to its dedicated endpoint. Make sure to start broadcasting your video and all audio tracks all together, not one after the other.
- Enable the "Audio Selector" in the player to be able to switch between audios/languages. See How to Configure the Audio Selector in the Kaltura Player.
- Select the Settings tab and then select Transcoding Settings.
The Transcoding Flavors window is displayed showing the flavors you selected for the Default Transcoding profile and the Live Transcoding Profiles.
The list of Live Transcoding Profiles is displayed if they have been created. See How to Set Transcoding Profiles for Live Streaming for additional information.
- Click Add new to create a transcoding profile for multiple audio tracks or edit an existing multi-audio profile.
- Enter a Name and Description and Save.
- Choose the Flavors tab and select the video flavors.
- Choose the relevant audio languages (flavors 100 and onward).
- Click Save. The new transcoding profile for multi-audio is created.
- After the transcoding profile is created for multiple audio tracks, create a new live entry and assign the transcoding profile you created to it.
- Start broadcasting your video and multiple audio streams.
- Preview the broadcast in your player.
- If the player is not showing multiple audio, download the master manifest (.m3u8) and check if the audio group is defined there.
An example of how multi- audio looks on the manifest:
- Multi-audio does not work with seamless fail-over. Regular primary/backup failover works.
- Downloading a recording with multi-audio tracks will result in downloading the video with the first audio track. This is a general known multi-audio VOD limitation and is not related to Kaltura Live+.
The packager supports up to 32 tracks in total. A track may be – audio/video/subtitles.
For example, if there are 16 audio tracks + 6 video tracks + 12 subtitles, the total of 34 tracks exceeds the limit and is not supported.
Additional audio languages are kept in separate files and can be downloaded as such. We currently do not have a feature for downloading all videos and audios into a single file.
Different flavors (SD/HD etc.) are counted as video tracks. If the source is high quality, there will be 6 tracks when using the Kaltura default set.