And unless you are directly connecting to the cell phone provider you are going to be converted to ULAW/ALAW to traverse the PSTN. So there is no advantage going to a native GSM codec only to have it expanded out to G711 and then back to GSM codec. On Tue, Jun 30, 2009 at 10:05 PM, Steve Underwood <steveu@coppice.org>wrote:
Edmar Cruz wrote:
So what codec supports mobile phones?
The main codecs used by mobile phones are: GSM FR The original GSM code, largely replaced by later codecs (some VoIP stuff uses this) GSM HR The half rate codec for GSM GSM EFR A later improved full rate codec that largely replaced GSM FR on GSM networks AMR-NB The current start of the art narrowband codec for GSM and UMTS networks AMR-WB The wide band codec for UMTS, though most networks seem to block it EVRC The main codec for the CDMA networks
Each of these codecs sounds pretty respectable, and G.729 sounds pretty respectable. However, if you transcode from one to another the result can be pretty bad.
Steve
_______________________________________________ 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
-- -Rupa