[FFmpeg-devel] QTRLE encode performance

[Alexis Ballier]

2013/2/8 Alex Beregszaszi <alex at rtfs.hu>:
>> I don't know the quicktime encoder, but you should probably check the
>> filesize for the same color depth: ffmpeg's qtrle encoder is optimal
>> (in terms of output size), so it's likely a non-optimal heuristic is
>> much faster.
>
> If it is technically possible it would be nice to change qtlreenc to use
> ff_rle_encode and optimise/multithread the latter to benefit other encoders
> using RLE.

It's not exactly rle as in the ff_rle_encode sense: you can repeat n
times a pixel or have n raw pixels (which is what ff_rle_encode does
afaik) but also skip n pixels, meaning the pixels will be the same as
those from the previous frame.

Also, it's probably way much harder to parallelize the rle encoder
than cutting each frame into # of theads parts of (# of lines / # of
threads) lines and encode them in parallel.

Alexis.