[FFmpeg-trac] #2699(avfilter:new): automate lossless normalisation

FFmpeg trac at avcodec.org
Wed Jun 26 11:03:53 CEST 2013


#2699: automate lossless normalisation
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             Reporter:  feelart      |                    Owner:
                 Type:  enhancement  |                   Status:  new
             Priority:  normal       |                Component:  avfilter
              Version:  git-master   |               Resolution:
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by feelart):

 Sorry, I meant

 volumedetect helps to find out how much you'll change the volume, using
 vol switch (http://www.ffmpeg.org/ffmpeg-filters.html#volume)

 To my best knowledge, vol filter does not provide/attempt a lossless
 normalisation.
 Lossless normalisation is possible on mp3 & aac, for other codecs I do not
 know.

 Instead of having 3 CLI:
 1/ first volumedetect
 2/ then vol (don't think you can pipe vol with the right normalisation
 factor from volumedetect directly on the CLI)
 3/ run your other instructions

 It would be nice to have a single CLI such as:

 {{{
 ffmpeg -i src.mp4 -vf
 "crop=in_w-24*32:in_h-5*32:17*32:3*32,hqdn3d,lut=y=val*0.65" -c:v libx264
 -crf 28 -preset slower -a:llnorm -c:a libmp3lame -ac 1 -ar 32000 -aq 0
 -async 1
 videoStreamProcessedSoundLosslesslyNormalisedThenConvertedToMp3.mp4
 }}}

 You might find strange to make a lossless normalisation, then a sound
 convertion, but lossless convertion is lossless and convertion might be an
 user request.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2699#comment:2>
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