[Speex-dev] Noisy sound quality with Blackfin in WB-mode

Jean-Marc Valin Jean-Marc.Valin at USherbrooke.ca
Tue Oct 25 05:17:48 PDT 2005

Hi Bernhard,

Can you confirm I'm understanding everything correctly? You encode with
the same encoder and then decode with either A) blackfin assembly and
fixed-point or B) fixed-point only on Blackfin. Then A) sounds bad and
B) sounds good. If you do the same in narrowband, it sounds OK. Is that
correct? If that's the case, it's *probably* some kind of bug and/or
invalid assumption in the blackfin assembly. Could you check if that
happens on all wideband modes (and none of the narrowband modes)? Also,
testing with 1.1.10 would help (in case I broke something in svn).


Le lundi 24 octobre 2005 à 11:22 +0200,
bernhard.gerlach at stud.tu-ilmenau.de a écrit :
> Hello all,
> I'm testing the Speex codec for my diploma thesis on a BF-533 Blackfin under
> uCLinux (2005R3 RC3 release). I successfully compiled the Speex (1.1.11-svn)
> and I can encode/decode wav-files on my STAMP-board using the speexenc/speexdec
> sample apps. But I encountered that the decoded file sounds strange/noisy, when
> compiling with "--enable-blackfin-asm" + "--enable-fixed-point", while it was
> comparable to a PC/x86/Linux encoded/decoded file, when Speex was compiled with
> "--enable-fixed-point" only. The strange sound seems to occur only in 16 kHz
> WB-mode, not in NB-mode (I didn't test 32 kHz).
> I encoded using for WB-mode:
> # speexenc -w --quality 5 --comp 5 input-wav-16khz outputA.speex
> and for NB-mode
> # speexenc --quality 5 --comp 5 input-wav-8kHz outputB.speex
> I decoded with
> # speexdec outputA.speex
> # speexdec outputB.speex
> The decoded files can be downloaded at (156k each):
> http://www.stud.tu-ilmenau.de/~bege-mt/maennl1-16000-16-mono-speex-c5-q5-noblackfinopt-decoded.wav
> http://www.stud.tu-ilmenau.de/~bege-mt/maennl1-16000-16-mono-speex-c5-q5-blackfinopt-decoded.wav
> (Text is german, hope that doesn't matter...)
> Am I doing something wrong? Or is there a bug in the blackfin assembler code?
> Thanks for answers,
> Bernhard Gerlach
> Technical University Ilmenau
> Germany
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