On Thu, 11 Oct 2001, Billy Biggs wrote: > No, I don't think it can output 4:2:0 packed. So, you're saying we > can just edit the DMA program to not SKIP every other line (which is > pretty wrong if the image is composed of two fields)? That would be There are two DMA programs, one for the top and one for the bottom field. You would have the top program send the first line to chroma plane line 1, skip the second line of the field, send the third line to the chomra plane line 3, skip, line 5, skip, line 7, etc. The bottom program would send the first line to chroma line 2, skip the next, then line 4, etc. > nice, if you can also have it perform some averaging of chroma. Nope, no averaging. You'll need to get 4:2:2 and downsample yourself if you want that. The data from the video scaler portion of the chip comes out one line at a time to the DMA engine. There isn't any kind of line store and average circuity. > Ideally I think of it like this: Let o == chroma + luma sample, x == > luma sample. So, for 4:2:0 encoding, we get this: > 1: o x o x o x o x > 2: o x o x o x o x > 3: o x o x o x o x > 4: o x o x o x o x That looks like 4:2:2 to me.
