---
title: Timed metadata sample description
framework: quicktime-file-format
role: collectionGroup
role_heading: API Collection
path: quicktime-file-format/timed_metadata_sample_descriptions
---

# Timed metadata sample description

An atom that defines how to interpret timed metadata media samples.

## Overview

Overview The timed metadata sample description contains information that defines how to interpret timed metadata media samples. This sample description is based on the standard sample description header, as described in Sample description atom ('stsd'). The metadata sample description is a derived sample description format which describes metadata values represented in atoms. It may also include other atoms not holding metadata values. Zero, one, or more values may be carried in a metadata sample description for a particular time. The data format field contains the format of the timed metadata media, which is set to 'mebx'. note: Other forms of timed metadata media are not described here. They would be indicated by an alternative type code in the place of ‘mebx’. The metadata sample description must contain a metadata key table atom and optionally contains a bit rate atom following the standard sample description atom header, defined below. Other atoms may be introduced in the future.

## Topics

### Describing timed metadata

- [Metadata key table atom ('keys')](quicktime-file-format/metadata_key_table_atom.md)
- [Bit rate atom ('btrt')](quicktime-file-format/bit_rate_atom.md)
- [Metadata key atom](quicktime-file-format/metadata_key_atom.md)
- [Metadata key declaration atom ('keyd')](quicktime-file-format/metadata_key_declaration_atom.md)
- [Metadata datatype definition atom ('dtyp')](quicktime-file-format/metadata_datatype_definition_atom.md)
- [Metadata locale atom ('loca')](quicktime-file-format/metadata_locale_atom.md)

## See Also

### Storing timed metadata media

- [Overview of timed metadata](quicktime-file-format/overview_of_timed_metadata.md)
- [Timed metadata sample data format](quicktime-file-format/timed_metadata_sample_data_format.md)
- [Constant-size timed metadata sample data](quicktime-file-format/constant-size_timed_metadata_sample_data.md)
- [Combining multiple streams of metadata into the same track](quicktime-file-format/combining_multiple_streams_of_metadata_into_the_same_track.md)
- [Movie-level relationships among tracks](quicktime-file-format/movie-level_relationships_among_tracks.md)