MTS to GSM Converter
Processing entirely on your device — large files may take a moment.
AVCHD Video and GSM 06.10 Speech exist for different jobs: MTS is the raw AVCHD clip format Sony/Canon camcorders write — high-bitrate H.264 transport streams straight off the memory card. Convert GSM speech recordings to WAV or MP3.
This converter runs entirely in your browser using WebAssembly — your files never leave your device, nothing is uploaded, and there are no watermarks, sign-ups or queues. Drop in several files at once to convert them as a batch.
How MTS compares to GSM
| MTS | GSM | |
|---|---|---|
| Structure | MPEG-TS with AVCHD PAT/PMT | Raw GSM frames (33 bytes/20ms) |
| Types / schema | H.264 + AC-3/PCM | Lossy speech codec (RPE-LTP) |
| Compatibility | ffmpeg, VLC, Premiere | Asterisk, SoX, ffmpeg |
| Best for | Camcorder footage ingestion | Telephony recordings |
How to convert MTS to GSM
- 1
Select your files
Select your MTS video.
- 2
Convert instantly
The engine demuxes the container and encodes the audio track into your chosen format.
- 3
Download results
Download the GSM audio — the video track is simply dropped.
About the MTS format
MTS is what actually comes off a Sony or Canon AVCHD camcorder's memory card: high-bitrate H.264 transport streams with AC-3/PCM audio, often split across a BDMV folder structure. The video inside is excellent — the container is what edit software refuses to import.
Converting MTS to MP4 remuxes or re-encodes into a container every device opens. Stream-copy is possible when the H.264 profile is baseline-compatible; otherwise a light re-encode fixes compatibility without visible loss.
+ Strengths
- ✓Native camcorder quality (24-28 Mbps)
- ✓Audio in AC-3/PCM survives remux
- ✓ffmpeg handles the transport stream natively
! Limitations
- −AVCHD H.264 profiles not always stream-copyable
- −Interlaced variants need deinterlacing
- −60p modes confuse older editors
About the GSM format
GSM 06.10 is the speech codec of the original GSM mobile network — 13 kbit/s RPE-LTP that made digital cellphone calls possible in 1991 and still lives inside VoIP systems, old answering machines and Asterisk PBX recordings.
It is lossy speech, not music: converting GSM to WAV or MP3 preserves intelligibility perfectly while finally letting desktop players open the file without special codecs.
+ Strengths
- ✓Tiny bitrate for speech intelligibility
- ✓Ubiquitous in telephony systems
- ✓Decodes natively via ffmpeg
! Limitations
- −Speech-only quality — music falls apart
- −13 kbit/s artifacts are audible
- −8000 Hz sample rate only
Why convert MTS to GSM?
There is a concrete reason this conversion exists: AVCHD H.264 profiles not always stream-copyable GSM sidesteps that — Tiny bitrate for speech intelligibility If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this MTS to GSM converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for MTS to GSM?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
Will the audio track be kept?
Yes. The audio is carried over and re-encoded to the standard audio codec of GSM, staying in sync with the video. If your MTS file has multiple audio tracks, the first one is used.
Does converting MTS to GSM re-encode my video?
Yes. The video is decoded and re-encoded with the settings chosen by the quality slider, which is what allows the format and size to change. For an archival copy, keep higher quality; for sharing, lower quality gives a much smaller file.