MMX2 yuv420p10 → yuv444p scaler produces vertical undithered(?) lines with GCC 4.6
|Reported by:||Martin Herkt||Owned by:||Michael Niedermayer|
|Version:||git||Keywords:||yuv420p10, yuv444p, mmx2|
|Blocking:||Reproduced by developer:||no|
|Analyzed by developer:||no|
I know this might be a PITA to reproduce since it only happens with GCC 4.6, but I’ll report it anyway.
Background: I’ve been trying to play yuv420p10 video with my patched MPlayer2 builds for Windows (http://mplayer2.srsfckn.biz/mplayer2-high-bit-depth-latest.7z).
MPlayer2 apparently chooses the yuv420p10 → yuv444p scaler by default.
That is probably fine, but there’s a problem: The MMX2 version of that scaler seems to break with GCC 4.6.0, causing vertical lines of what seems to be undithered luma (can’t tell for sure since I didn’t actually investigate that in detail, but I’ll attach a screenshot).
The C version works fine.
This can be reproduced with for example:
ffmpeg -i test10bit.mkv -pix_fmt yuv444p -vcodec ffv1 out.mkv