[Ffmpeg-devel] [PATCH] AC-3 encoder volume
Justin Ruggles
justinruggles
Sun Mar 18 22:51:19 CET 2007
Hi everyone,
This bug has been bothering me for a while. The AC-3 encoder is
producing output with too high volume, which even results in clipping in
many cases.
The attached patch fixes the problem and updates regressions. Here is a
little history. Revision 5281 changed v-8 to v-9. Revision 7160
changed v-9 to v-10. But after that change I've found the resulting
file to be noticeably too loud when played.
To avoid basing the argument on my ears, I've attached a comparison I
did with a mono clip of a 1kHz tone at 85% of full dynamic range. The
screen shot shows 3 different files in Audacity. The top box is the
original file, offset by 256 samples to account for the AC-3 delay. The
middle box is the results from encoding _without_ the patch, then
decoding with a52dec. The bottom box is the results from encoding
_with_ the patch, then decoding with a52dec.
Thanks,
Justin
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