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

Beeblebrox zaphod at berentweb.com
Wed May 7 18:15:52 CEST 2014

As I had mentioned, I did a run on the previously tested 3.1G video file
> $ 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

* File size and video quality consistent with previously reported result.
* compand made a very nice job of pulling the outlying sound values to a
more standard volume range.
* The problem is, when the speaker starts to speak, there is a background
noise like a microphone being pulled over wool - a "crishhhhh" sound. It's
borderline; the speech can be understood but it's a major strain on the
ears. If that particular frequency were louder, speech would become

* Result of test #1: Overall success, but needs to be fine-tuned so that a
particular frequency (noise?) does not overwhelm audio.
* Cannot run test #2, as syntax needs conversion.


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