Re: [asterisk-users] local channels and g729a voice quality
On 18-01-12 04:57, Roi Stork wrote: Hi, I wasn't aware of the difference in quality between landline and mobile phones, or that cellphones use a low bit rate. I did a test again, landline voice quality is better. From what you observed, how much drop in quality do I expect when switching from ulaw to g729 for a normal mobile-to-mobile call? Afaik mobile to mobile uses the gsm codec (in gsm country, no idea about cdma etc.). IMHO gsm is not bad but certainly not as good as ulaw/alaw. Read up on MOS: https://en.wikipedia.org/wiki/Mean_opinion_score Regards, Patrick -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] local channels and g729a voice quality
Hi, I wasn't aware of the difference in quality between landline and mobile phones, or that cellphones use a low bit rate. I did a test again, landline voice quality is better. >From what you observed, how much drop in quality do I expect when switching from ulaw to g729 for a normal mobile-to-mobile call? On Tue, Jan 17, 2012 at 9:37 PM, Steve Underwood wrote: > On 01/16/2012 03:59 PM, Roi Stork wrote: >> >> Hi, >> >> We noticed a very sharp drop in voice quality when using digium g729a >> codec. The problem seems to happen if the A channel (caller's channel) >> is a landline/mobile number contacted using the same outgoing provider >> (as a local channel). It sounds like listening to a mono speaker on >> low volume. > > You have conflated two very different things there - landline calls and > cellular calls. A land line to a VoIP user by G.729A should sounds pretty > good. A cellphone to a VoIP user by G.729A should sound *far* worse. > Converting between two different low bit rate codecs really hits the > quality, and all cellphone calls are low bit rate. > >> If I use a softphone that is directly registered to our asterisk box >> the audio quality improves, the words come out more clearer and >> louder. > > You are conflating two things again. Quality and volume are largely > independent issues. > >> I also asked my provider to test call me using their Cisco as5300 >> system and g729 codec and compared it with ulaw. The difference is >> unnoticable. > > Try that again. If you really can't hear the difference you should check > carefully that the system is working as you think it is. If it is, maybe you > should consult a doctor. G.729A is considerably poorer than ulaw. > > Steve > > > > -- > _ > -- Bandwidth and Colocation Provided by http://www.api-digital.com -- > New to Asterisk? Join us for a live introductory webinar every Thurs: > http://www.asterisk.org/hello > > asterisk-users mailing list > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] local channels and g729a voice quality
On 01/16/2012 03:59 PM, Roi Stork wrote: Hi, We noticed a very sharp drop in voice quality when using digium g729a codec. The problem seems to happen if the A channel (caller's channel) is a landline/mobile number contacted using the same outgoing provider (as a local channel). It sounds like listening to a mono speaker on low volume. You have conflated two very different things there - landline calls and cellular calls. A land line to a VoIP user by G.729A should sounds pretty good. A cellphone to a VoIP user by G.729A should sound *far* worse. Converting between two different low bit rate codecs really hits the quality, and all cellphone calls are low bit rate. If I use a softphone that is directly registered to our asterisk box the audio quality improves, the words come out more clearer and louder. You are conflating two things again. Quality and volume are largely independent issues. I also asked my provider to test call me using their Cisco as5300 system and g729 codec and compared it with ulaw. The difference is unnoticable. Try that again. If you really can't hear the difference you should check carefully that the system is working as you think it is. If it is, maybe you should consult a doctor. G.729A is considerably poorer than ulaw. Steve -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] local channels and g729a voice quality
On 16/01/12 07:59, Roi Stork wrote: I also asked my provider to test call me using their Cisco as5300 system and g729 codec and compared it with ulaw. The difference is unnoticable. ^^ this doesn't make any sense, the difference *should* be very much noticeable. g729 is a lower quality codec (in terms of audio quality). -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
[asterisk-users] local channels and g729a voice quality
Hi, We noticed a very sharp drop in voice quality when using digium g729a codec. The problem seems to happen if the A channel (caller's channel) is a landline/mobile number contacted using the same outgoing provider (as a local channel). It sounds like listening to a mono speaker on low volume. If I use a softphone that is directly registered to our asterisk box the audio quality improves, the words come out more clearer and louder. I also asked my provider to test call me using their Cisco as5300 system and g729 codec and compared it with ulaw. The difference is unnoticable. -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
