Coffey, Michael
2007-May-22 12:18 UTC
[Speex-dev] Clicking Problems with slightly clipped audio
It appears that both the echo canceller and the noise reducer (NR) introduce rather severe clicking artifacts when presented with audio that has slightly overloaded the A/D converters. I am talking about speech that sounds just slightly distorted, due to clipping, when simply played back. If I pass that speech through the echo canceller or the noise reducer, it acquires really loud clicks and/or scratchiness in high amplitude sections. Granted, it would be best if I could avoid any clipping in the first place. A problem, though, is that we can not control end user behavior and it is quite common for them to have their audio settings slightly out of adjustment. I've found a workaround, which is to divide everything by two before sending it to the AEC or NR. Is this a known problem? Would it be helpful for me to send a couple of .wav files to illustrate? Thanks again for the great contributions. -Michael -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.xiph.org/pipermail/speex-dev/attachments/20070522/436c4d07/attachment.htm
Jean-Marc Valin
2007-May-22 17:18 UTC
[Speex-dev] Clicking Problems with slightly clipped audio
Floating-point or fixed-point? if fixed-point, could you compile with --enable-fixed-point-debug (or defining FIXED_DEBUG) and report any error message? Jean-Marc Coffey, Michael a ?crit :> It appears that both the echo canceller and the noise reducer (NR) > introduce rather severe clicking artifacts when presented with audio > that has slightly overloaded the A/D converters. I am talking about > speech that sounds just slightly distorted, due to clipping, when simply > played back. If I pass that speech through the echo canceller or the > noise reducer, it acquires really loud clicks and/or scratchiness in > high amplitude sections. > > > > Granted, it would be best if I could avoid any clipping in the first > place. A problem, though, is that we can not control end user behavior > and it is quite common for them to have their audio settings slightly > out of adjustment. > > > > I've found a workaround, which is to divide everything by two before > sending it to the AEC or NR. > > > > Is this a known problem? Would it be helpful for me to send a couple of > .wav files to illustrate? > > > > Thanks again for the great contributions. > > > > -Michael > > > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Speex-dev mailing list > Speex-dev@xiph.org > http://lists.xiph.org/mailman/listinfo/speex-dev
marzullo maio
2007-May-23 07:43 UTC
[Speex-dev] Clicking Problems with slightly clipped audio
I've the same problem using the FIXED_POINT version. Platforms: ARM HTC tytn with WM 5.0 and ARM i-mate jasjar WM 5.0 The same problem on both devices. If you need i could record what i hear on my device. Dividing by 2 worked well for me. Adding the following C++ lines before feeding the encoder with PCM apparently solved the problem: void Encoder::normalizeRange(spx_int16_t* audioBuf) { DWORD i; for(i = 0; i < SAMPLES_PER_BLOCK; ++i) *audioBuf++ = (*audioBuf >> 1); // +- 8192 } Anyway i think this is the dirty solution but at least it works. I can't low the microphone gain on my devices and cannot use AGC since it isn't converted to FIXED_POINT yet, so i've no choice other than that dirty solution. Asking on xda developers, nobody has found a way to lower the mic gain. Even the OEM is keeping it secret. I'll switch to develop for linux pda as soon as i can. Bye. "Coffey, Michael" <mcoffey@avistar.com> ha scritto: st1\:*{behavior:url(#default#ieooui) } It appears that both the echo canceller and the noise reducer (NR) introduce rather severe clicking artifacts when presented with audio that has slightly overloaded the A/D converters. I am talking about speech that sounds just slightly distorted, due to clipping, when simply played back. If I pass that speech through the echo canceller or the noise reducer, it acquires really loud clicks and/or scratchiness in high amplitude sections. Granted, it would be best if I could avoid any clipping in the first place. A problem, though, is that we can not control end user behavior and it is quite common for them to have their audio settings slightly out of adjustment. I?ve found a workaround, which is to divide everything by two before sending it to the AEC or NR. Is this a known problem? Would it be helpful for me to send a couple of .wav files to illustrate? Thanks again for the great contributions. -Michael _______________________________________________ Speex-dev mailing list Speex-dev@xiph.org http://lists.xiph.org/mailman/listinfo/speex-dev --------------------------------- --------------------------------- L'email della prossima generazione? Puoi averla con la nuova Yahoo! Mail -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.xiph.org/pipermail/speex-dev/attachments/20070523/e149b47b/attachment.htm
Jean-Marc Valin
2007-May-24 06:53 UTC
[Speex-dev] Clicking Problems with slightly clipped audio
Actually, could you upload the input audio file somewhere so I can have a look at it? Jean-Marc Coffey, Michael a ?crit :> It appears that both the echo canceller and the noise reducer (NR) > introduce rather severe clicking artifacts when presented with audio > that has slightly overloaded the A/D converters. I am talking about > speech that sounds just slightly distorted, due to clipping, when simply > played back. If I pass that speech through the echo canceller or the > noise reducer, it acquires really loud clicks and/or scratchiness in > high amplitude sections. > > > > Granted, it would be best if I could avoid any clipping in the first > place. A problem, though, is that we can not control end user behavior > and it is quite common for them to have their audio settings slightly > out of adjustment. > > > > I've found a workaround, which is to divide everything by two before > sending it to the AEC or NR. > > > > Is this a known problem? Would it be helpful for me to send a couple of > .wav files to illustrate? > > > > Thanks again for the great contributions. > > > > -Michael > > > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Speex-dev mailing list > Speex-dev@xiph.org > http://lists.xiph.org/mailman/listinfo/speex-dev