How to convert a .M4S file online
Three steps, all tab.
Open your file
Drop your .M4S file and every video, audio and subtitle track inside is listed with its codec, resolution, frame rate and language.
Preview
See frames from across your .M4S file before you convert, even when your browser can't play the codec inside.
Convert
Pick MP4, WEBM or MP3, or repack to MKV without re-encoding. Play the result right here, then download it.
What is a .M4S file?
Everything worth knowing about MPEG-DASH Video Segment.
An M4S file is a short video or audio fragment generated by MPEG-DASH adaptive streaming. You find these files in your browser's temporary cache after watching video on YouTube, Netflix, or similar services. A single .m4s file is not playable on its own. Use ffmpeg or yt-dlp to reassemble all segments into one MP4.
Programs that open .M4S files
- Windows
- VLC media player, FFmpeg, yt-dlp
- macOS
- VLC media player, FFmpeg
- Linux
- VLC media player, FFmpeg
| Full name | MPEG-DASH Video Segment |
|---|---|
| Developer | MPEG / ISO/IEC (ISO 14496-12) |
| First released | 2012 (MPEG-DASH standard ISO/IEC 23009-1 published) |
| Category | Audio & Video |
| MIME type | video/iso.segment |
Related viewers
Other free tools to open and preview your files.
Is my .M4S file uploaded to a server?
No. Your .M4S file is converted for you. The converted file is created in memory,.
Why is conversion slower than desktop software?
Browsers give web pages a single CPU core for this kind of work and no hardware video encoder. Short clips convert in seconds; for long 4K films a desktop app like HandBrake is faster. Use Start and Length to convert just the part you need.
Which output format should I pick?
MP4 plays on every phone, TV and browser. WEBM is an open format that's great for the web. MP3 keeps only the sound. MKV (no re-encode) is instant and lossless, but only changes the container.
Can I keep all audio tracks and subtitles?
The MKV (no re-encode) option copies every track as-is. MP4 and WEBM keep the first video and audio track, which is what most players use.
Why can't some files be converted?
Files protected with DRM (for example purchased iTunes .m4p songs or some .wmv rentals) are encrypted. We can show what's inside, but nobody can convert them without the key.
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