Currently there is no clear way for users to play, decode, and convert many of the audio files provided with Asterisk at http://downloads.asterisk.org/pub/telephony/asterisk/releases/. These files are only provided in the GSM audio file format. Why doesn’t Digium provide any documentation on this format? How are we supposed to import this into Audacity? I saw instructions to use “Import”–>“Raw”, but there are numerous options for importing a raw file. I assume I’m supposed to select encoding “GSM 6.10” and 1 channel (mono), but what “byte order” and sample rate must we select? Are users expected to simply guess this through trial and error? As an open-source project, all file formats that are used, especially ambiguous ones, should be fully documented. There are “readme” files with the archives but they contain no information on the “GSM” file format or how to read or open them. Can Digium please provide some kind of official documentation on what file format is being used here and exactly how this supposed to be imported into Audacity, with the exact options you’re supposed to use?
In addition, http://downloads.asterisk.org/pub/telephony/sounds/ contains other Asterisk sounds in the “GSM”, “ALAW”, “G722”, “SIREN7”, “SIREN14”, “SLN16”, and “WAV” file extensions. Can we please also have documentation for all of these formats? For example, what kind of WAV file is being used? What open-source software can be used to open these formats? Can Audacity be used for all of them? If not, what is the recommended open-source software?