# AudioTrackInfo

URL: https://www.caprid.com/docs/reference/typescript/caprid/moq-media/interfaces/audiotrackinfo/

Defined in: [catalog.ts:42](https://github.com/caprids/relay-sdks/blob/main/ts/packages/moq-media/src/catalog.ts#L42)

The audio track [buildMsfCatalog](https://www.caprid.com/docs/reference/typescript/caprid/moq-media/functions/buildmsfcatalog/) advertises. Unset fields default to Opus, 48 kHz, stereo.

## Properties

### altGroup?

```ts
altGroup?: number;
```

Defined in: [catalog.ts:64](https://github.com/caprids/relay-sdks/blob/main/ts/packages/moq-media/src/catalog.ts#L64)

Alternate group (msf-01 §5.2.12): tracks sharing one are alternate versions of the same content, such as simulcast
layers, and a viewer subscribes to one of them. Members share a role and a render group.

***

### bitrate?

```ts
bitrate?: number;
```

Defined in: [catalog.ts:52](https://github.com/caprids/relay-sdks/blob/main/ts/packages/moq-media/src/catalog.ts#L52)

Bits per second.

***

### channelConfig?

```ts
channelConfig?: string;
```

Defined in: [catalog.ts:50](https://github.com/caprids/relay-sdks/blob/main/ts/packages/moq-media/src/catalog.ts#L50)

Channel config string (§5.2.21), e.g. `'2'` or `'5.1'`.

***

### codec?

```ts
codec?: string;
```

Defined in: [catalog.ts:46](https://github.com/caprids/relay-sdks/blob/main/ts/packages/moq-media/src/catalog.ts#L46)

WebCodecs registry codec string, e.g. `'opus'`.

***

### initData?

```ts
initData?: Uint8Array<ArrayBufferLike>;
```

Defined in: [catalog.ts:54](https://github.com/caprids/relay-sdks/blob/main/ts/packages/moq-media/src/catalog.ts#L54)

Decoder init data, e.g. an AAC AudioSpecificConfig — Opus carries none.

***

### name?

```ts
name?: string;
```

Defined in: [catalog.ts:44](https://github.com/caprids/relay-sdks/blob/main/ts/packages/moq-media/src/catalog.ts#L44)

Track name. Default [AUDIO\_TRACK](https://www.caprid.com/docs/reference/typescript/caprid/moq-media/variables/audio_track/).

***

### renderGroup?

```ts
renderGroup?: number;
```

Defined in: [catalog.ts:59](https://github.com/caprids/relay-sdks/blob/main/ts/packages/moq-media/src/catalog.ts#L59)

Render group (msf-01 §5.2.11): tracks sharing one play together on one timeline. Default 1; give a second source,
such as a screen share and its audio, its own.

***

### samplerate?

```ts
samplerate?: number;
```

Defined in: [catalog.ts:48](https://github.com/caprids/relay-sdks/blob/main/ts/packages/moq-media/src/catalog.ts#L48)

Output sample rate (§5.2.20). Always 48000 for Opus.