[FFmpeg-devel] [PATCH] libtheora hard-coded at quality 0

[Henrik Gulbrandsen]

OK, folks: I have a small series of patches to offer. I will try to give
you enough information to reproduce the problems, but feel free to shout
in case I forget some vital configuration detail. To make things easy,
let's start with one of the easy fixes...

For FFmpeg configured with --enable-libtheora, the quality parameter in
libavcodec/libtheoraenc.c has been given as the (fixed) value 0 for the
quality range 0-63. As can be expected, this has a certain detrimental
effect for Ogg Theora movies encoded with FFmpeg. It may be particularly
obvious for a static image, as in these movies encoded before and after
the patch, which simply modifies the quality to a more reasonable 48:

    http://www.gulbra.net/ffmpeg-devel/movies/libtheora_quality_0.ogv

    http://www.gulbra.net/ffmpeg-devel/movies/libtheora_quality_48.ogv

Notice the pulsing artifacts in the first movie, presumably caused by
something like regularly appearing low-quality intra frames...

/Henrik

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