[FFmpeg-trac] #2852(avcodec:new): dcadec internal default downmix is not normalised and reduces stereo separation by cross mixing L* and R*.
FFmpeg
trac at avcodec.org
Sat Nov 30 01:18:20 CET 2013
#2852: dcadec internal default downmix is not normalised and reduces stereo
separation by cross mixing L* and R*.
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Reporter: AndyF | Owner:
Type: defect | Status: new
Priority: normal | Component: avcodec
Version: git-master | Resolution:
Keywords: dca | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Comment (by AndyF):
It's fixed WRT the cross mixing.
It seems that it's now partially normalised - probably enough not to clip
too bad on real world content that doesn't max all channels equally, but
it's currently louder than -ac2 or the same content but an ac3 version
downmixed like : -drc_scale 0 -request_channels 2 .
This applies to streams that hit the default table and those that have
metadata - I haven't really had enough time to look properly, I suspect
for the metadata case post mix gain adjustment should be decoded and
applied.
I see commits to do with including LFE, but it doesn't seem to be included
in the mix currently (not that I would want that to be default) what are
the plans for this eg, default off and a new option?
I added some debugging so I can see the metadata if present and do have a
stream with LFE non zero.
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Ticket URL: <https://trac.ffmpeg.org/ticket/2852#comment:4>
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