Media player/codec for call recording


(total Asterisk newbie here)

I’m trying to playback a call recording. I assume that it gets encoded with g7.11. Do you know what media player (or some codec pack) that I can install that will allow me to listen to the recording?


If your file extension is .wav (lowecase) it will be Windows WAV PCM and just about any media player will play it back (I use VLC). If its WAV (uppercase), it will be Windows WAV (headers) with GSM encoded audio, again can be played back with VLC. If its .gsm, it will be a raw GSM encoded stream. (Tricky to play back) If its .g729 you will need g729 to PCM decoder, then PCM to AU conversion (using perl script), then the AU file can be played back with… you guessed it VLC! :wink:


yeah, how can I playback .gsm then?

Is there some way to turn it into MP3?

The audio seems weird when I try VLC :smile:


I cannot remember how it did i once - I think i used QuickTime (but seriously it was a long time ago :open_mouth: )

Why not change the call recording format to .WAV or .wav (if you have the disk space)?

If the sound quality is poor remember that the GSM compression is lossy (meaning it will loose quality to obtain compression.). You can also expect the volume to be quite a bit lower. However, save your self s huge amount of disk space. I mean huge!! Uncompressed audio is no joke, yes the quality fine, but unless you are going to periodically delete the older recordings don’t use it. My suggestion is .WAV (also called wav49).


sox can convert raw GSM. There is also a tool built into Asterisk to convert between formats between which there is a codec path.

Using MP3 for telephone quality audio makes very little sense. Doing so for GSM audio makes even less sense, as the comptression strategies are completely different.


As david said, sox is a good native utility. You can also try using wave pad audio editor if you want to listen or edit gsm files. for conversion you can use switch sound file converter. Both are available in a single package called Switch. You can download windows based application from NCH site here : i personally use it and really like it.

Here is download link for linux based downloads.