M4S Video — A .m4s file is a M4S Video. It is a video format used to store movies and animation, typically with video and audio tracks.
Quick facts
What is .m4s
A .m4s file is a M4S Video. It is a video format used to store movies and animation, typically with video and audio tracks.
In the mime-db registry it maps to video/iso.segment. When serving .m4s over HTTP, set the Content-Type header as shown in Developer info below.
Related entities: it maps to video/iso.segment — and is delivered over HTTP via the Content-Type header.
How to open .m4s files
Developer info
When served over HTTP, responses should set the following header:
Content-Type: video/iso.segment
Common software that reads/writes .m4s:
Relation chain
Related extensions
Related MIME types
Common uses
How to edit .m4s files
How to create .m4s files
Frequently asked questions
Common options include VLC, MPV, HandBrake. You can also open many of these files with built-in viewers or a browser.
Create a new file in any text editor or the app that owns the format and save it with the .m4s extension.
video/iso.segment is the media type identifier used for .m4s files during network transfer (for example in the HTTP Content-Type header).
Sources & standards
Updated 2026-08-18
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