GSM Player
Play raw GSM 06.10 voice files directly in your browser. Powered by FFmpeg WebAssembly. Open .gsm recordings from phone systems and voicemail without installing a codec.
Drop your audio file here
or click to browse
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What is GSM Player?
The GSM Player plays raw .gsm voice files in your browser. Choose a file, wait for the FFmpeg decoder to load, and press play. The tool decodes GSM 06.10 speech, which is stored as 8 kHz mono audio, and plays it with standard controls.
How does GSM Player work?
GSM 06.10, also called GSM full rate, is a speech codec from digital mobile telephony. It stores audio as 33-byte frames, each holding 160 samples of 8 kHz mono sound, which gives a bitrate of 13 kb/s. A raw .gsm file is a plain run of these frames with no header.
Browsers cannot decode GSM, so this tool loads FFmpeg compiled to WebAssembly, decodes the frames with its gsm decoder, and converts the result to 16-bit PCM at 44.1 kHz for the player. The 8 kHz sampling rate limits the audio to about 4 kHz of bandwidth, which is enough for speech and little else.
Key Features
- Decodes raw GSM 06.10 frames with the FFmpeg gsm decoder
- Opens .gsm voice recordings
- Handles 8 kHz mono speech at 13 kb/s
- Output is 16-bit PCM at 44.1 kHz
- Play, pause, and seek controls
- Decoding runs in WebAssembly on your device
Common Use Cases
Listen to a voicemail export
Play a .gsm message exported from a phone system or voicemail archive.
Check a call recording
Confirm that a recorded call file contains audible speech before you share it.
Open a legacy telephony file
Play a .gsm file from an old voice application on a machine with no GSM codec.
Test an encoder's output
Listen to the frames an encoder produced to hear whether the speech survived compression.
How to Use This Tool
Choose a GSM file
Click the upload area or drop a .gsm file onto it.
Wait for the decoder
The first file loads the FFmpeg WebAssembly binary from a CDN. It stays loaded for the rest of the session.
Press play
Start playback to hear the decoded speech.
Pause or seek
Use the player controls to stop, resume, or move to a different point in the recording.
Pro Tips
- 1
Expect a narrow, telephone-like sound. GSM 06.10 keeps only speech bandwidth, so music sounds thin.
- 2
A raw .gsm file has no header, so FFmpeg assumes 8 kHz mono. Files that hold other audio will not play correctly.
- 3
Each 33-byte frame covers 20 milliseconds, so a file's length in seconds is its size in bytes divided by 1,650.
- 4
Use the AMR Player for .amr voice notes from Android phones, which use a different codec.
Frequently Asked Questions
How do I play a GSM file?
Open the GSM Player in a browser, choose the .gsm file, and press play. FFmpeg decodes the audio in WebAssembly, so no codec or media player is needed.
What is GSM 06.10?
It is the full-rate speech codec used in GSM mobile networks. It compresses 8 kHz mono speech to 13 kb/s in 33-byte frames.
Why does a GSM file sound muffled?
The codec samples at 8 kHz, so frequencies above about 4 kHz are not stored. That range covers speech but cuts the upper part of music and background sound.
What is the difference between GSM and AMR?
Both are telephony speech codecs. AMR is a later codec with adjustable bitrates, and it is decoded by a different path than raw GSM 06.10.
Is my GSM recording uploaded anywhere?
No. The decoder runs in your browser, so the recording stays on your device.