Bug of x264 10bit or of ffdshow?

Hello, I hope the x264 devs are reading. :) I can't say if the following is a bug of ffdshow or x264: A x264 I444 10bit video doesn't look right, red is rather orange. Here I made a bug report for it for ffdshow, there you can also download a (totally legal) sample: The problem is that ffdshow either chooses the wrong YCbCr specification (709 instead of 601) or x264 10bit does something wrong. If encoded with --colormatrix fcc ffdshow chooses the right YCbCr specification. Now, is it a problem of ffdshow or x264 10bit?

Doesn't really sound like a bug to me. If there is no info about the matrix in the file, players have to guess. Ffdshow chooses BT.709 for files with your characteristics, and that is neither wrong nor right - it's really just a guess. If you need the player to know the matrix used, you have to include that info in the file (with --colormatrix, like you already found out). On a side note, I'm wondering if the high bitdepth BT.601 conversions are implemented correctly in the common programs, because there were problems with the corresponding BT.709 ones, pointed out by cyberbeing (IIRC) for x264 and ffdshow. Maybe it would be safer to convert the 8 bit sources to BT.709 with Colormatrix() before doing any high bitdepth work for the time being?

By default, ffdshow outputs yuv IIRC, that would mean that the colormatrix guessing is left to the video renderer, which also decides according to resolution. The renderer probably won't receive the header's information, no?

Nope, madvr get the flag right for my x264 768p game encode.

I suffered this a while ago. Feeding Fraps RGB to x264 and encoding to 4:4:4 resulted in wrong colors, it happened with 8 bit too. Tried everything about color matrixes, levels, etc. with no success. Pure green wasn't pure green, pure red wasn't pure red, and so on. Just like in those screenshots.

Nope, didn't found a solution. At that point it was just an experiment. My intention was to open a thread like this when I finally needed to do an actual encode. In my case flags were properly set, but played with everything and still got wrong colors unfortunately.

--colormatrix bt470bg works great, with LAV Decoder and ffdshow too. But just like with ffdshow I have to set output CS to RGB in the LAV Decoder settings or colors look wrong with I444. Also RGB output level must be set to PC, otherwise I420 DXVA videos are too bright with LAV. But techninally everything works.