[Mp4-tech] Question about mismatch between faad output and reference wave.

[Zhang, Ying S]

I use "faad.exe -b 2 -o outfilename infilename" to generate some 24bit
pcm wave file.
The output wave files seem quite different with reference stream.
The maximum absolute value is much higher than 2-14 relative to full
scale.
I don't know what's wrong with that. The audio signal sounds alike.
I calculate the each sample doing:
"
Sample = ((*(mmioinfoRef.pchNext+2))<<16)&0xFF0000 +
(((*(mmioinfoRef.pchNext+1))<<8)&0xFF00)+(*mmioinfoRef.pchNext&0xFF);
if(Sample>>23 ==1)  Sample |= 0xFF000000;
"
Do I use the wrong configuration in faad.exe or do I calculate the
sample value wrong? 
Or the difference is reasonable?
For example, I use al_sbr_s_32_1.mp4 as input and the maximum absolute
value is 2492181 while RMS is about 41.5 which is acceptable.
Can any one give some hint?
Thanks!
Best Regards,
 Zhang Ying  
iNet: 8-752-1572
Tel:  +86-21-52574545-1572
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