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# MPEG-4 elementary stream descriptor atom  ('esds')

A required extension to the audio sample description for MPEG-4 audio.

## Overview

This atom contains an elementary stream descriptor, which is defined in ISO/IEC FDIS 14496.

## Topics

### Data fields

[`Size`](/documentation/quicktime-file-format/MPEG-4_elementary_sound_stream_descriptor_atom/Size)

An unsigned 32-bit integer holding the size of the elementary stream descriptor atom.

[`Type`](/documentation/quicktime-file-format/MPEG-4_elementary_sound_stream_descriptor_atom/Type)

An unsigned 32-bit field.

[`Version`](/documentation/quicktime-file-format/MPEG-4_elementary_sound_stream_descriptor_atom/Version)

An unsigned 32-bit integer set to zero.

[`Elementary stream descriptor`](/documentation/quicktime-file-format/MPEG-4_elementary_sound_stream_descriptor_atom/Elementary_stream_descriptor)

An elementary stream descriptor for MPEG-4 audio.


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