[Speex-dev] speex-1.2beta1 AEC garbles up audio unless compiled with --enable-fixed-point

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Tue Oct 3 14:22:02 PDT 2006

You may have triggered an instability problem. Can you upload your files
somewhere so I can have a look at them?


Andras Kadinger a écrit :
> Greetings everyone,
> I was about to compare AEC performance between 1.1.12 and 1.2beta1 when
> I noticed something.
> If I configure (and compile) speex-1.1.12 with
> ./configure --enable-shared=no --enable-static=yes
> it compiles and works as expected: I can run a mic and speaker signal
> through testecho, it runs in a reasonable amount of time (about 23 secs
> for 3 minutes of audio) and I get back good audio.
> If I configure (and compile) speex-1.2beta1 with
> ./configure --enable-shared=no --enable-static=yes
> it compiles, but with the same input files testecho runs very long (say
> about 21-24 minutes, probably data-dependent), and the output audio is
> garbled up.
> It does the same with --enable-sse.
> But with --enable-fixed-point, AEC returns to normal.
> This is happening on a Gentoo stable (1.12.4) system, gcc 4.1.1, glibc
> 2.4, processor is "Intel(R) Pentium(R) 4 CPU 3.00GHz" (with
> HyperThreading disabled).
> My data is real-world audio captured from a physical speaker and mic
> setup in a room, by the left and right channels of the same soundcard
> input, and is sampled at 32 kHz. 1.2beta1 AEC without
> --enable-fixed-point garbles the audio up whether I claim it is sampled
> at 8 kHz or 32 kHz in testecho.c, it just does so differently. I can't
> hear anything of my original audio, instead I hear a very loud
> (full-scale), regularly repeating noise. When I look at the waveform, it
> looks a bit like 1/x for x>0, where overflowed samples values are not
> clipped but wrapped back down; that is, the first few dozen samples are
> wildly swinging between -32768 and 32767, later slow down but still
> full-scale, even later the sample values asymptotically approach zero
> from above; then suddenly the cycle begins again. (I can provide samples
> of input and output on request.)
> Is anyone else seeing anything like this?
> Thanks in advance.
> Best Regards,
> Andras Kadinger
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