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

[bernhard.gerlach at stud.tu-ilmenau.de]

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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