[MPlayer-dev-eng] Colorspace conversion and image buffer format

[Roberto Togni]

Hi all.

I'm writing a native decoder for HuffYUV (fourcc HFYU).
Image format can be RGB, RGBA (RGB plus alpha channel) and YUY2 (it 
will use new output format selection when it will be available).

I have some question about colorspaces:
- what about RGBA? Should I store it as RGB32, using the 4th byte as A, 
or shoud I ignore alpha channel?
- what's the best way to output YV12 using YUY2 as source? should I 
convert it "on the fly" averaging U (and V) every 2 rows or it's better 
to store the image into a temporary buffer and use yuy2toyv12() 
function from rgb2rgb.c? What's the best way to do it if input is 
interlaced?


Another question about buffer format:
image buffer will be MP_TEMP (every frame is independent from others).
Do I have to use MP_IMGFLAG_READABLE if I need to read from buffer 
during decompression (I need to access previous pixel and top pixel 
from previous row)?
Other flags used are MP_IMGFLAG_YUV for YUY2 case and also 
MP_IMGFLAG_PLANAR for YV12 case.

Ciao,
  Roberto