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Old 16th July 2020, 20:21   #8  |  Link
tebasuna51
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Join Date: Feb 2005
Location: Spain
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Quote:
Originally Posted by richardpl View Post
Nope, amerge is causing that.
I don't understand what is the problem, but we can live with that.

Quote:
Let me repeat again you need to specify pcm_s24le/be encoder to get 24bit output.
Sorry, I checked (the four first channels are bitidentical between the 7.1 and the 5.1 obtained) than the final output preserve the precission from the source adding at the end -c:a pcm_s24le

Quote:
Otherwise default encoder is 16 bit PCM.
That's is my problem, I can't understand for what the default is downsample.

But ok, that is my final command line recommended to downsample 7.1 -> 5.1 with ffmpeg:
Code:
FFMPEG -i 8v341.dts -filter_complex "asplit [f][s]; \
  [f] pan=3.1|c0=c0|c1=c1|c2=c2|c3=c3 [r]; \
  [s] pan=stereo|c0=0.5*c4+0.5*c6|c1=0.5*c5+0.5*c7, \
  compand=attacks=0:decays=0:points=-90/-84|-10/-4|-6/-2|-0/-0.3, \
  aformat=channel_layouts=stereo [d]; \
  [r][d] amerge [a]" -map "[a]" -c:a pcm_s24le zz51.wav
Of course the output can be other format (FLAC, AAC, EAC3, AC3,...)
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Last edited by tebasuna51; 16th July 2020 at 20:25.
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