Audio distortion in Linux

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Hi,
    I have tried gcc 3.4.x. The signal seems ok. pjsip 1.0.2 with
libresample.

[root at webhost bin]# gcc -v
Reading specs from /usr/lib/gcc/i386-redhat-linux/3.4.6/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --enable-shared --enable-threads=posix
--disable-checking --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-java-awt=gtk
--host=i386-redhat-linux
Thread model: posix
gcc version 3.4.6 20060404 (Red Hat 3.4.6-10)

2009/3/27 Benny Prijono <bennylp at teluu.com>

> 2009/3/27 Gang Liu <gangban.lau at gmail.com>
>
>> We used a CMedia USB device as audio input device when we did resample
>> test before.
>>
>> MP3 player ---- line connect -- > USB --- 44khz ---> pjmedia app(the same
>> code as I published at google code)
>>
>> ---> PCMU stream ---> remote
>>
>> All at local LAN.
>> We used wireshark to capture G.711 stream.
>> And then compare this file again the orignal file and the 8khz file
>> converted by audacity.
>> It seems some high frequency was cut by pjmedia resampling. the quality
>> not good as audacity resampling. If change to 8khz, don't do resample
>> anymore, audio signal showed by audacity was OK. Also we tried Realtek
>> HD audio input of dell desktop pc.
>>
>>
>
> As I understand it, G.711 is not really a lossless compression codec, so
> some signal will be lost. Also the above involves analog connectivity too.
> So it's not a fair comparison IMO.
>
> For apple to apple comparison of the resample, use wav to wav resampling
> using pjsua method like I posted previously.
>
> cheers
>  Benny
>
>
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>
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