[FFmpeg-devel] QTRLE encode performance

Malcolm Bechard malcolm.bechard at gmail.com
Fri Feb 8 20:26:05 CET 2013

I've recently changed my app's encoder from quicktime for windows to
ffmpeg's libraries.
Surprisingly the performance for encoding a lossless QTRLE file is
significantly worse in ffmpeg. With Quicktime I was able to encode a
1280x720 60FPS movie in realtime (so, less than 16ms a frame to encode).
With ffmpeg my calls to avcodec_encode_video() take ~150ms a frame. Even
the ffmpeg.exe command line can only do about 15FPS at this resolution
(although it is curious that it's faster than my avcodec_encode_video()

So I'm interested contributing and speeding this up. Before I get started
does anyone have any insight they can share on the current state of the
encoder? For example:
1. Do we know how the quicktime encoder is so fast? Is it using some sort
of hardware feature in windows?
2. I don't know the algorithm well yet, but is there any inherent reason
why I can't multithread it (which is my most likely approach).

Thanks for any insight you can offer.


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