A-Law Compressed Sound Format
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What is an AL file?
An AL file is an audio file saved in the A-Law Compressed Sound (A-Law) format, an audio format that features the standard A-Law audio compression algorithm. It typically stores a recorded voice message, most likely delivered via telephone.
The Consultative Committee for International Telegraphy and Telephony (CCITT) originally developed the A-Law format. However, the Telecommunication Standardization Sector of the International Telecommunication Union (ITU-T) superseded the CCITT. The A-Law format is one version of the G.711 audio codec, with the other being Mu-Law, also written as µ-Law.
Much of the world, including Europe, uses the A-Law compression algorithm in 8-bit pulse code modulation (PCM) digital communications, most notably voice transmission via telephones. However, North America and Japan use Mu-Law.
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. Also, A-Law compression is used in place of Mu-Law for international calls between two countries (where one country already is using A-Law) because it provides a smaller dynamic range with less distortion.
NOTE: AL files may also use the .alaw file extension (.ALAW files).
How to open an AL file
You can open an AL file with Apple QuickTime Player in macOS.