long-term prediction

Writable

other

scheme employed in order to reduce the amount of data sent between the mobile station (MS) and base transceiver station (BTS)

Identify it

Extensions	`.gsm`
Wikidata	`Q4047883`

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To	With	Fidelity	Command and losses
FLAC (Free Lossless Audio Codec) 1.2.1	FFmpeg	Partial	`ffmpeg -i in.gsm out.flac` Audio track only: the video is dropped.
Waveform Audio	FFmpeg	Partial	`ffmpeg -i in.gsm out.wav` Audio track only: the video is dropped.
Matroska 1-4	FFmpeg	Lossy	`ffmpeg -i in.gsm out.mkv` Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container.
MPEG 1/2 Audio Layer 3	FFmpeg	Lossy	`ffmpeg -i in.gsm out.mp3` Lossy re-encoding.
MPEG-4 Part 14	FFmpeg	Lossy	`ffmpeg -i in.gsm out.mp4` Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container.
Ogg	FFmpeg	Lossy	`ffmpeg -i in.gsm out.ogg` Lossy re-encoding.
WebM	FFmpeg	Lossy	`ffmpeg -i in.gsm out.webm` Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container.

From Converters (FFmpeg, ImageMagick, Pandoc, LibreOffice), Wikidata. Updated 2026-10-20.