[FFmpeg-user] mpeg2 filesize reduction: reduce video, enhance audio, codec selection

Beeblebrox zaphod at berentweb.com
Wed May 7 16:44:11 CEST 2014

Hi Steve, & Thanks.

I have done some quick reading and compand seems to be what I am looking
for. Combined with SoX documentation, the values I came across
being suggested for voice normalization were:
* compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2 )from
ffmpeg documentation) and
* compand 0.1,0.3 -60,-60,-30,-15,-20,-12,-4,-8,-2,-7 -2
The best thing probably is to make some test runs. However, when combined
with previous command ($ ffmpeg -i video1.mpg -c:a libfdk_aac -af
'volume=1.8 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2'
-c:v libx264 -preset slow -crf 32 -f mp4 video1-out.mp4)

I get an error: " Unable to find a suitable output format for
compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2: Invalid

* What is the proper compand syntax?
* Do I need to make two runs (one for comapnd & audio only, second for -c:v
* What's the SoX fo ffmpeg translated compand values for example #2? I
assume "/" is to replace the commas (,) do the colons replace whitespace?
compand 0.1/0.3 -60/-60/-30/-15/-20/-12/-4/-8/-2/-7 -2 (or is it -7:-2?)

Thanks and Regards.

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