[FFmpeg-user] Scene detection

[Peter B.]

Roger Pack wrote:
> It apperas that libx264 does some scene cut detection internally, to
> look for i-frames,
>
> I wonder why 2 pass is so much better then...
>   
I think because 2-pass is not only about when to put i-frames, but
rather how to distribute the available encoding bandwidth among the
video in an optimized way.

Example:
2 scenes in a video:
  1) several minutes of almost no motion: low bandwidth requirement
  2) a short scene with lots of motion: high bandwidth requirement

With 2-pass encoding, the codec is able to decide to save some bits in
the low-motion sequences in order to use them later on in high-motion
scenes.

At least this is how I understood its purpose...

Pb