[FFmpeg-devel] [PATCH]v308 and yuv4 encoders and decoders

Carl Eugen Hoyos cehoyos at ag.or.at
Fri Dec 30 19:50:47 CET 2011

Derek Buitenhuis <derek.buitenhuis <at> gmail.com> writes:

> So I checked libquicktime's source code. The part you copied the ^0x80
> from is yuv2.

I copied it from libavcodec/rawdec.c, the only thing I used the libquicktime
source for was to confirm that Y is 2x2. (Theoretically, it could be 4x1, or am
I misunderstanding?)

> yuv2 can have signed chroma (i.e. can have a negative
> value), and that's why it xors with 0x80. yuv4 has unsigned chroma, so
> I do not think you should be xoring with 0x80.

Did you test?

> Can you, say, compare output of libquicktime with your
> decoder/encoder?

I may be misunderstanding "compare" but without "^ 0x80", output looks very
broken to me.

Thank you for your help, Carl Eugen

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