Reference

GSM (audio)

GSM audio is a speech codec from the GSM mobile-phone standard, designed to compress voice into a very small, low-bitrate stream. It is used for voicemail, VoIP, and telephony where bandwidth matters more than fidelity.

Files & formatsGeneral

GSM (audio)

Also known as: GSM audio, .gsm file, GSM 06.10, full-rate GSM

Speech codec from the GSM mobile standard
Very small files; voice-only, not for music
Common in voicemail and VoIP systems

Built for voice calls

The GSM full-rate codec (GSM 06.10) was created to carry speech over mobile networks using minimal bandwidth. It models the human voice rather than general audio, so it is efficient for talking but poor for music.

You will encounter .gsm files in voicemail systems, PBX/VoIP setups, and some legacy recordings.

Playing and converting

FFmpeg, Audacity, and many telephony tools handle GSM audio. Since it is speech-optimized and low quality by design, converting to MP3 or WAV mainly improves compatibility, not fidelity.

Related terms

Keep reading the reference.

Files & formatsWAVWAV (WAVE) is an uncompressed audio format that stores raw PCM sound at full quality. That makes it ideal for editing and mastering, but the files are large — far bigger than MP3 or AAC for the same audio.General Files & formatsMP3MP3 is a lossy audio format that shrinks music files by discarding sound details most people cannot hear. It is the most universally compatible audio format, though newer codecs like AAC achieve similar quality in smaller files.General Files & formatsAMRAMR (Adaptive Multi-Rate) is a lossy audio format optimized for speech, used by older phones for voice recordings, voicemail, and MMS. It compresses voice very aggressively, so files are extremely small — but it sounds poor for music because it is tuned only for the human voice.General

Act on it

Guides and tools for this topic.

Convert audio to MP3