# Music media Store note-based audio data, such as MIDI data, in QuickTime movies. ## Overview Music media is used to store note-based audio data, such as MIDI data, in QuickTime movies. It has a media type of `'musi'`. ## Music sample description The music sample description uses the standard sample description header, as described in [`Sample description atom`](/documentation/quicktime-file-format/Sample_description_atom). The data format field in the sample description is always set to `'musi'`. The music media handler adds an additional 32-bit integer field to the sample description containing flags. Currently no flags are defined, and this field should be set to `0`. Following the flags field, there may be appended data in the QuickTime music format. This data consists of part-to-instrument mappings in the form of General events containing note requests. One note request event should be present for each part that will be used in the sample data. ## Music Sample Data The sample data for music samples consists entirely of data in the QuickTime music format. Typically, up to 30 seconds of notes are grouped into a single sample. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)