# Multi-audio support

***

The Dolby OptiView platform supports multi-audio ingest and delivery with our HESP solution. This functionality is perfect for use cases such as live events where multiple languages or commentary may be required.

> **Caution**
>
> This functionality is **only** supported through the SRT Pull ingest method. Playback is **only** supported on web.

## Configuring multi-audio ingest and playback

To deliver multi audio SRT the following steps must be taken:

1. Within your dashboard configure your SRT listener endpoint.
2. Configure your expected incoming "Audio tracks" by specifying a language, label, and the expected PID.

![SRT Multi-audio example with PIDs](/pr-863/assets/images/srt-multi-audio-5be22752023aeb2bb30c3bd3b255f0ca.png)

3. Start the Channel and begin ingesting video and audio into the engine.
4. Your output will be available for playback on web only via the [channel alias](https://docs-preview.optiview.dolby.com/pr-863/theolive/v1/platform/multi-channel.md).
5. You can validate the audio tracks are being delivered via the demo player : `https://demo.theo.live/?channel=YOUR_CHANNEL_ID`

## Feature Compatibility and Limitations

* Audio must be encoded as AAC.
* Only stereo audio is supported.
* There is a limit of 12 audio tracks per channel.

#### Ingest

| RTMP Push | RTMP Pull | SRT Pull |
| --------- | --------- | -------- |
| No        | No        | Yes      |

#### Playback

| Web SDK | Android SDK | iOS SDK |
| ------- | ----------- | ------- |
| Yes     | No          | No      |