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Jean-Marc Valin
2007-Oct-25 17:24 UTC
[Speex-dev] Obtaining loudness information in 1.2beta2
I'm in favor of the idea, but not of the current implementation. There are two problems: 1) The st->loudness parameter doesn't represent the amplitude of the signal, but the amplitude^5 (fifth power). That makes it hard to use 2) The call returns a float, but it should really be an int (spx_int32_t) so that it can work easily with fixed-point code There's a last minor thing: instead of SPEEX_PREPROCESS_GET_LOUDNESS, it should be called SPEEX_PREPROCESS_GET_AGC_LOUDNESS. If you can send me a patch that addresses these issues, I'll gladly apply it. Jean-Marc Mihai Balea wrote:> Hi all, > > I'm working on a project called iaxclient > (http://sourceforge.net/projects/iaxclient). > We use speex for the majority of our audio processing, including voice > compression and processing. > One of the features of iaxclient is Analog AGC, which drives the > hardware mixer levels based on signal loudness. Up until 1.2beta1, we > were able to access the internals of the SpeexPreprocessState structure > to get loudness information, but, of course, that is no longer possible > with 1.2beta2. I would like to propose an addition to the preprocessor > control interface that exposes that parameter. I'm attaching a patch > that contains the proposed change. > > I'm looking forward to any comments and suggestions. > > Cheers, > Mihai > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Speex-dev mailing list > Speex-dev@xiph.org > http://lists.xiph.org/mailman/listinfo/speex-dev
What would be a good parameter to return that would better represent the loudness of the signal? As for the your other comments, I'll make the necessary changes and resubmit. Thanks, Mihai On Oct 25, 2007, at 7:45 PM, Jean-Marc Valin wrote:> I'm in favor of the idea, but not of the current implementation. There > are two problems: > 1) The st->loudness parameter doesn't represent the amplitude of the > signal, but the amplitude^5 (fifth power). That makes it hard to use > 2) The call returns a float, but it should really be an int > (spx_int32_t) so that it can work easily with fixed-point code > > There's a last minor thing: instead of > SPEEX_PREPROCESS_GET_LOUDNESS, it > should be called SPEEX_PREPROCESS_GET_AGC_LOUDNESS. If you can send > me a > patch that addresses these issues, I'll gladly apply it. > > Jean-Marc > > Mihai Balea wrote: >> Hi all, >> >> I'm working on a project called iaxclient >> (http://sourceforge.net/projects/iaxclient). >> We use speex for the majority of our audio processing, including >> voice >> compression and processing. >> One of the features of iaxclient is Analog AGC, which drives the >> hardware mixer levels based on signal loudness. Up until >> 1.2beta1, we >> were able to access the internals of the SpeexPreprocessState >> structure >> to get loudness information, but, of course, that is no longer >> possible >> with 1.2beta2. I would like to propose an addition to the >> preprocessor >> control interface that exposes that parameter. I'm attaching a patch >> that contains the proposed change. >> >> I'm looking forward to any comments and suggestions. >> >> Cheers, >> Mihai >> >> >> >> --------------------------------------------------------------------- >> --- >> >> _______________________________________________ >> Speex-dev mailing list >> Speex-dev@xiph.org >> http://lists.xiph.org/mailman/listinfo/speex-dev > >-------------- next part -------------- A non-text attachment was scrubbed... Name: smime.p7s Type: application/pkcs7-signature Size: 2411 bytes Desc: not available Url : http://lists.xiph.org/pipermail/speex-dev/attachments/20071025/d7bf79a1/smime-0001.bin
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