Wav is just a standard file format, the size is decided by the contents. The first format is PCM which is 8000 bytes samples per sec The second is GSM which is compressed voice - so in short you changed the file format, but is was and still is GSM inside. To convert from PCM to GSM you need an application that can do so - WavePad etc. can be recommended. Jan -----Original Message----- From: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] On Behalf Of Wes Sent: 24. juni 2011 23:26 To: FreeSWITCH Users Help Subject: [Freeswitch-users] .wav vs .gsm file sizes for recording calls. In my tests, if I record a call in .wav format, a 10 second file is about 177,000 bytes, while a 10 second .gsm file is 17,000 bytes. I then used sox to convert the .gsm file to a .wav file, and it stayed at around 17,000 bytes. So, is the default recording format for .wav using a higher sample rate? vs the default conversion format for the sox tool? checking the file type using "file" I see that the larger one is: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, mono 8000 Hz and the wav created by sox via the default conversion from .gsm is: RIFF (little-endian) data, WAVE audio, GSM 6.10, mono 8000 Hz So apparently the larger wav file is 16 bit... how are these recording parameters controlled? Can I set it to record directly into the smaller wav format? Or will I have to run sox on every file... _______________________________________________ Join us at ClueCon 2011, Aug 9-11, Chicago http://www.cluecon.com 877-7-4ACLUE FreeSWITCH-users mailing list FreeSWITCH-users@lists.freeswitch.org http://lists.freeswitch.org/mailman/listinfo/freeswitch-users UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users http://www.freeswitch.org