.ALAW File Extension
A-Law Compressed Sound Format
| Developer | ITU-T |
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What is an ALAW file?
An ALAW file is an audio file saved in the A-Law Compressed Sound (A-Law) format, which saves data compressed with the standard A-Law audio compression algorithm in the G.711 audio codec. It typically stores a recorded voice message delivered via telephone. ALAW files more commonly use the .al file extension (.AL files).
More Information
The Consultative Committee for International Telegraphy and Telephony (CCITT) originally developed the A-Law format. Then, the Telecommunication Standardization Sector of the International Telecommunication Union (ITU-T) superseded the CCITT and now maintains the format.
The A-Law format is one of two versions of the G.711 audio codec. The other version is Mu-Law, also written as µ-Law. Most of the world, including Europe, uses the A-Law compression algorithm. However, North America and Japan use Mu-Law. Both compression algorithms are used in 8-bit pulse code modulation (PCM) digital communications.
The A-Law and Mu-Law compression algorithms are similar. They offer 2:1 bit compression and optimize the dynamic range of an analog audio signal for digitization. However, they provide different coding levels and bit inversion, and A-Law compression provides less dynamic range, resulting in more minor distortion. For this reason, calls between two countries using the two formats default to A-Law compression.
How to open an ALAW file
You can open an ALAW file with Apple QuickTime Player in macOS.