Hello, I am working on a VoIP audio conference. I want that all mixed sources have the same volume before being mixing so that when the speaker changes, participants will keep hearing the same level of volume. Do I need a AGC algorithm? All the AGC algorithms that I found on the Internet are about using AGC for a single source, could anybody explain to me how to use AGC for a conference. Thank you _____________________________________ Do you know a company who employs DSP engineers? Is it already listed at http://dsprelated.com/employers.php ?
AGC in audio conference
Started by ●March 27, 2007
Reply by ●March 27, 20072007-03-27
hech1 wrote:> I am working on a VoIP audio conference. I want that all mixed sources > have the same volume before being mixing so that when the speaker changes, > participants will keep hearing the same level of volume. > > Do I need a AGC algorithm?It depends. The AGC may or may not be required. The good AGC is not very simple either. The interaction between the AGC and the EC is another interesting story. So, if it works OK without the AGC, leave it alone.> All the AGC algorithms that I found on the Internet are about using AGC > for a single source, could anybody explain to me how to use AGC for a > conference.Here is the situation: one participant is speaking and the others are listening. The AGC will raise the noise from each of the participants to the equal level, those noises will be added together, so nobody can hear anything. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●March 27, 20072007-03-27
Thank you very much Vladimir, So what do you suggest instead of the AGC. I found on the Internet other techniques like volume compressors but I am not sure. Actually, i don't really have experience in signal processing but I want to provide a good quality of the conference streams to all participants. Now participants are complaining about the variation of the volume when differents speakers speak using different equipements. Thank you> > >hech1 wrote: > >> I am working on a VoIP audio conference. I want that all mixed sources >> have the same volume before being mixing so that when the speakerchanges,>> participants will keep hearing the same level of volume. >> >> Do I need a AGC algorithm? > >It depends. The AGC may or may not be required. The good AGC is not very>simple either. The interaction between the AGC and the EC is another >interesting story. So, if it works OK without the AGC, leave it alone. > >> All the AGC algorithms that I found on the Internet are about usingAGC>> for a single source, could anybody explain to me how to use AGC for a >> conference. > >Here is the situation: one participant is speaking and the others are >listening. The AGC will raise the noise from each of the participants to>the equal level, those noises will be added together, so nobody can hear>anything. > > >Vladimir Vassilevsky > >DSP and Mixed Signal Design Consultant > >http://www.abvolt.com >_____________________________________ Do you know a company who employs DSP engineers? Is it already listed at http://dsprelated.com/employers.php ?
Reply by ●March 28, 20072007-03-28
hech1 wrote: You can try to put the AGC (or compressor, which is basically the same thing) at the system outputs rather then the inputs. However it will require a lot of tweaking to achieve a decent result, especially if you are unfamiliar with this stuff. It also depends on the architecture of the system. The goals are the AGC should not pump up the noise (which is very annoing), and it should not squash the sound. Also, the AGC should not be confused by random clicks or pops, and it should be efficient. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com> Thank you very much Vladimir, > > So what do you suggest instead of the AGC. I found on the Internet other > techniques like volume compressors but I am not sure. Actually, i don't > really have experience in signal processing but I want to provide a good > quality of the conference streams to all participants. Now participants > are complaining about the variation of the volume when differents speakers > speak using different equipements. > > Thank you > > >> >>hech1 wrote: >> >> >>>I am working on a VoIP audio conference. I want that all mixed sources >>>have the same volume before being mixing so that when the speaker > > changes, > >>>participants will keep hearing the same level of volume. >>> >>>Do I need a AGC algorithm? >> >>It depends. The AGC may or may not be required. The good AGC is not very > > >>simple either. The interaction between the AGC and the EC is another >>interesting story. So, if it works OK without the AGC, leave it alone. >> >> >>>All the AGC algorithms that I found on the Internet are about using > > AGC > >>>for a single source, could anybody explain to me how to use AGC for a >>>conference. >> >>Here is the situation: one participant is speaking and the others are >>listening. The AGC will raise the noise from each of the participants to > > >>the equal level, those noises will be added together, so nobody can hear > > >>anything. >> >> >>Vladimir Vassilevsky >> >>DSP and Mixed Signal Design Consultant >> >>http://www.abvolt.com >>