[MPlayer-G2-dev] impostor yv12

[Ivan Kalvachev]

Hello,
I had send few patches and few mails to xvid people
regarding their handling of YV12 format.
In short they claimed that it is reversed and they swaped the UV
planes. I had tracked a bug in DSHOW and VfW handling of
IYUV - they had mapped it to yv12, while IYUV is the same as I420.
Few weaks ago I checked the image.c routines and noticed that
the thing are unchanged, but later i found out that the VfW/DShow issues
have been sorted.

So,
In short the YV12 format is not the format that mplayer claims it is.
YV12 is in fact YVU / YCrCb /, that is in no way the default MPEG standart
color format. As you know in MPEG 0,1,2,3 blocks are Y, Cb is #4 block, Cr
is #5 block.
Yes, I know that all code over mplayer-g1 use IMGFMT_YV12 as YUV, but in
fact this format is the I420 or IYUV format. The real conversion is done
at vo_xv (in draw_slice around line 488). Same for vo_directx and probably
all that support planar formats. I should say that now I see the reason
mplayer to have always U as plane[1] and V as plane[2].

Well, I don't want to change all IMGFMT_YV12 to I420, or to IMGFMT_YUV,
as it is a too global change. But we should make G2 in the right way.
Of cource if it is not already done.

Best Regards
   Ivan Kalvachev
  iive