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

[Andras Kadinger]

I'll try to make some shorter samples later, but for now here are the 
ones I have tried with:

http://www.surfnonstop.com/~bandit/speex/1.2beta1_AEC_garble/

The original recordings are in mic.raw and spk.raw.

Jean-Marc Valin wrote:
> You may have triggered an instability problem. Can you upload your files
> somewhere so I can have a look at them?
>
> 	Jean-Marc
>
> 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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>>
>>