Although a compressor/limiter can be used to decrease dynamic range like you suggest, what you're describing is an Automatic Gain Control (AGC). PJSIP does have the speex AGC available, although you'll have to write the API to enable it yourself. You should also be aware that the speex echo canceler (and possibly the built-in echo suppressor) can be very confused by the non-linearity added by compression/AGC. It may create an unacceptable amount of residual echo, if the filter can converge at all. If you use an AGC or compressor/limiter along with an echo canceler, make certain that the filter is part of the pre-processor chain, before the echo canceler. I believe the speex AGC is in the correct spot, so it may be worth experimenting with. ~Loren Keagle On Tue, Oct 14, 2008 at 5:07 AM, Gr?gory BLANC <gblanc at netceler.com> wrote: > Hello, > > I've a question about a specific signal processing called "compressor / > limiter". It is an equipment (hardware) often use with musical instruments > (guitar for example) to control sound sent to speakers, to not damage them > and always have a good sound. > I want to use it with an application that I begin to develop, based on the > wonderfull PJSip (thanks Benny & Nanang for this jewel that is PJSip). This > app is used to call between many persons (like Skype for example). The > compressor/limiter will be used to control and ajust sound volume and have > always the same, whatever is the person, the environment where the person > is, the equipment used, etc... > Is there in PJSip a signal processing like this ? > > Thanks in advance, > > Greg > > _______________________________________________ > Visit our blog: http://blog.pjsip.org > > pjsip mailing list > pjsip at lists.pjsip.org > http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org >
