[Ffmpeg-devel] calculating optimal bitrates
Thu Nov 23 11:09:19 CET 2006
Karl H. Beckers wrote:
> Hi all,
> am trying to find an algorithm for determining a good bitrate based on
> let's say a percentual quality I want to achieve (kinda like when saving
> jpegs) and would appreciate if anybody could comment on the validity of
> the lines along which I'm thinking.
> I thought I already had a tolerable algo and was struck by the fact that
> even at a 10% quality configured I was getting perfect results (with
> little movement ....).
You seem to make the assumption that compression only depends
on the amount of movement, while in fact it also depends on
the textural complexity of the frames. If your Intra frame is just
a solid color, it can be compressed losslessly using just a few bits.
On the other hand, if it includes noise and high-frequency content,
it might only be possible to compress it with losses of information.
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