---
description: Dolby Digital (AC-3) audio codec definition, defining legal codec strings, decoder configs, and packet data formats.
---

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<VPBadge type="info" text="Audio codec" />

# AC-3 codec registration

## Description

The Dolby Digital (AC-3) audio codec, specified in [ETSI TS 102 366](https://www.etsi.org/deliver/etsi_ts/102300_102399/102366/01.04.01_60/ts_102366v010401p.pdf).

## Codec ID

```ts
'ac3'
```

## `EncodedPacket` data

The packet's data must be a sync frame (syntactic element `syncframe()`) as defined in Section 4.3 of [ETSI TS 102 366](https://www.etsi.org/deliver/etsi_ts/102300_102399/102366/01.04.01_60/ts_102366v010401p.pdf), beginning with the sync word `0x0B77`.

## `EncodedPacket` type

The packet's type is always `'key'`.

## `AudioDecoderConfig` codec string

```ts
'ac-3'
```

## `AudioDecoderConfig` description

`description` is not used for this codec.