Extract text from ADPCM audio files (G721)
To convert G721 audio files to another format, you need Audacity or other Audio software.
To convert other file formats to the "ADPCM Audio File" file type, you need software like Audacity or a similar tool.
The .g721 file contains audio encoded with the G.721 Adaptive Differential Pulse Code Modulation (ADPCM) standard. Originally developed by the International Telecommunication Union (ITU), this 32 kbit/s codec was heavily used in early digital telephony, VoIP infrastructure, and legacy voice recording systems.
To play these files today, you typically need command-line tools like FFmpeg or SoX. Alternatively, you can use Audacity by importing the file as raw audio data. Read more about the history of the format on the G.726 Wikipedia page, which superseded G.721.
You must convert .g721 files because they are practically unusable in modern workflows. They are obsolete, highly specialized, and not supported by standard media players like Windows Media Player, Apple QuickTime, or mobile browsers. Furthermore, these files frequently lack standard audio headers. Without a header, most software cannot determine the correct sample rate or bit rate to play the audio back without distortion.
We recommend converting .g721 files to WAV for uncompressed archiving, or MP3 and FLAC for everyday playback. Converting to WAV retains the exact original quality of the voice recording while adding a standard header that modern players understand.
Converting this format is difficult because the lack of a file header means the converter simply sees a stream of raw bytes. Automated online converters routinely fail here because they expect a recognized container format.
Convert.Guru analyzes your G721 file, detects the exact format, and lets you read the text inside.
If you want to convert G721 file to , you can use Audacity or similar software from the "Digital telephony audio storage" category. In the File menu, look for Save As… or Export….
To convert files to G721, try Audacity or another comparable tool in the "Digital telephony audio storage" category.
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our G721 converter.