[FFmpeg-devel] [PATCH] RoQ video encoder (take 4)
Thu Jun 14 13:44:55 CEST 2007
Michael Niedermayer wrote:
> IIRC theres a used count and if its 0 we drop a codebook
> so if we just consider codebooks with a small used value (like 1)
> for droping then there shouldnt be much reindexing needed
I still would imagine that would be difficult, a good codebook generator
produces very even distribution.
One thing that may be more viable, especially at low bitrates: Drop the
entire codebook. The contents of the codebook are preserved whether a
codebook update occurs or not, so if one frame is similar enough to the
previous, it can potentially just reuse the codebooks. The cost of
encoding a codebook is about 2000 bytes.
> codebook size estimation probably would have to be done after decidng
> the macroblock types ...
> which might lead to a iterative loop of codebook generation and macroblock
> type decission)
Deciding the macroblock types requires being indexed. It's a
chicken-and-egg problem I decided to sidestep completely. Thresholding
never quite worked when I tried it, though that's probably the best option.
> not fast but i suspect these cases are rare
Depends on the target bitrate. Sharp scene changes can also cause
potentially cause drastic increases in size when targetting quality.
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