> ## Documentation Index
> Fetch the complete documentation index at: https://gladia-95-fix-geo-speaker-diarization.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Multiple channels

> Transcribe multi-channel audio and tag utterances by channel

Gladia supports multi-channel audio for both pre-recorded files and live streams. Each utterance in the result includes a `channel` key corresponding to the source channel.

| Mode | Max channels | How to configure |
| - | - | - |
| Pre-recorded (async) | 2 (mono or stereo) | Detected automatically from the file |
| Live (realtime) | 8 | Set `channels` in the [init request](/api-reference/v2/live/init) |

## Pre-recorded

Pre-recorded transcription supports **up to 2 channels** (mono or stereo). If your audio file has two distinct channels, Gladia will detect and transcribe them automatically.

<Warning>
  Files with more than 2 channels are not supported for pre-recorded transcription.
</Warning>

<Warning>
  Sending an audio with two different channels (with different content) will be billed as two audios. If your audio has multiple channels with the same content, it will only be billed once.
</Warning>

## Live transcription

For live audio streams, you must supply the channel count in your [init request](/api-reference/v2/live/init). The `channels` value must be an integer from **1 to 8**.

```json theme={null}
{
  "channels": 2
}
```

Gladia's real-time API will automatically split the channels and transcribe them separately.

<Warning>
  Transcribing an audio stream with multiple channels is billed per channel. For example, an audio stream with 2 channels will be billed as double the audio duration, even if the channels are identical.
</Warning>

<Note>
  For a detailed guide on how to merge multiple audio tracks into a single multi-channel stream and send it over a WebSocket, see the [Sending multiple audio tracks over a single WebSocket](/chapters/live-stt/quickstart#merging-multiple-audio-tracks-into-one-multi-channel-websocket) section.
</Note>


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