Media Processing
M4S Converter
A local M4S to MP4 tool for Android, iOS, and HarmonyOS with batch scan, audio-video merge, and gallery save.
Android
iOS
HarmonyOS
A local M4S to MP4 tool for Android, iOS, and HarmonyOS with batch scan, audio-video merge, and gallery save.
Turn .m4s, video.m4s, or audio.m4s fragments into more portable MP4 or audio results.
Merge separate audio.m4s and video.m4s files into one synchronized MP4, with manual select and batch pairing.
Authorize a scan scope, discover local M4S files, batch pair multiple audio-video sets, and manage the pending queue.
Available on Android, iOS, and HarmonyOS — one experience across all your devices.
Keep conversion records, customize output naming, and save MP4 results to the system gallery.
Process authorized local video and audio files on device without uploading personal files.
M4S Converter focuses on separated M4S fragments: when video.m4s has no sound, the app helps find matching audio.m4s files, pair them locally, and export standard MP4 files.
When a video fragment has picture but no audio, pair it with the matching audio.m4s before exporting MP4.
Scan local M4S files and reduce the manual work of matching multiple audio.m4s and video.m4s sets.
Create standard MP4 files on device and save them for playback or gallery management.
Files are processed locally. Only convert files you own or have permission to use.
Choose it when video.m4s plays without sound and the matching audio.m4s is available locally.
Choose it when several audio.m4s and video.m4s fragments need to be paired and exported as MP4 on Android.
Use FFmpeg for command-line automation, custom codec options, or desktop batch scripts.
Do not use it to process files you do not own or do not have permission to convert.
Best for: Android users fixing no-sound video.m4s and pairing local M4S fragments
Strength: Local scan, batch pairing, MP4 export, and gallery saving without upload
Limit: Focused on M4S fragments, not a universal video downloader
Best for: Occasional small files
Strength: No app install
Limit: Requires upload and is weaker for privacy or batch pairing
Best for: Technical users and desktop automation
Strength: Powerful and scriptable
Limit: Command-line setup is harder for ordinary phone workflows
Some sources store picture and sound separately as video.m4s and audio.m4s. The video fragment alone may not contain audio.
Yes. It is designed around local scanning and batch pairing of matching M4S fragments.
No. The workflow is designed for on-device processing.
No. If the matching audio fragment is missing, the exported MP4 may still have no sound.
A local M4S to MP4 tool for Android, iOS, and HarmonyOS with batch scan, audio-video merge, and gallery save.
Download for Android