Wave File Compression Codecs Compared
Audio Compression Manager
This is a reference to compare the audio quality and compression bitrates of the different wave compression codecs available for ".wav" and ".dct" files using the audio compression manager including PCM, GSM, ADPCM, CELP, SBC, TrueSpeech and MPEG Layer-3.
Note: The Audio Compression Manager (ACM) is used for recording to .wav (wave) or .dct (dictation) files. For other file formats, please start with the
Sound File Formats page.
The ACM is used by:
The audio file compression formats listed on this page are low bitrate speech formats. Higher bitrate music and broadcast voice formats are not listed.
You can listen to samples of each audio format by clicking on the "Sample" link.
Format
Bitrate
1 min =
Sample
8,000Hz u-Law
* toll quality telephone 64kbs 468.8k 8kulaw.wav
8,000Hz GSM6.10
* cell phone quality 13kbs 102.5k 8kgsm.wav
8000Hz Lernout & Hauspie SBC 12k 12.0kbs 87.9k 8ksbc12.wav
8,000Hz Lernout & Hauspie CELP 4.8kbs 35k 8kcelp.wav
Comments
The above are wave files - even if they have the mp3 codec they will have the ".wav" or ".dct" extension. For a broader overview of other file formats, please see the
Sound File Formats page.
Recommended Codec
NCH Swift Sound currently recommends GSM6.10 8000Hz for voice recording.
Problem Formats
The ACM codec shipped with Windows 2000/XP called "Microsoft G.723.1" has a bug which means it cannot be used for encoding / recording. Please do not attempt to use this format.
Discussion Forum
If you have any questions in ACM codecs or are generally interested please see the
Sound Formats Discussion Forum.
Software that Support ACM
A number of the NCH Swift Sound professional audio software applications include the Audio Compression Manager: