[FFmpeg-user] Compression is a lot smaller

Moritz Barsnick barsnick at gmx.net
Wed Aug 19 15:51:34 EEST 2020

On Mon, Aug 17, 2020 at 13:54:33 +0200, Cecil Westerhof wrote:
> > The input doesn't look uncompressed to me.
> I do not have much knowledge of video formats, but this was really
> shot with a Sony. Maybe that the Sony compresses the video itself?
> It is a HDR-CX320.

You won't see use of uncompressed video on storage, especially with
modern resolutions and bit-depths. The storage just cannot handle it.

So the recorder has a HW chip which does compression on the fly.

> 454 -> 415
> 503 -> 230
> 490 -> 254
> 462 -> 157
> 497 -> 197
> 454 -> 174

Assuming the camera used the same settings for each recording:
Compression results (size reduction) depend on the content as well. The
Sony may be compressing nearly static videos inefficiently, while
ffmpeg/x264 optimized those well. At the same time, Sony may be
compressing videos with movement, shakiness, or even noise, quite well,
and ffmpeg cannot improve on that.

This is just speculation, but could be an explanation.

It might be interesting to look at the original and resulting
bandwidths as well (i.e. video size in relation to duration).


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