[theora-dev] [theora in hardware] Contents of YUV_BUFFER_ENTRY

Arthur Valadares arthur00 at gmail.com
Tue Jul 25 09:57:38 PDT 2006

Thanks for the help, it took me a while to understand everything you said,
but after a little reading (especially the 7.9.1 you recommended) i think i
got it. I still have a question about the definition you sent, it doesn`t
fit with what i`m reading on the code:

recon_pixel_index_table gives the offset for the pixel in the
> lower-right of the given fragment (remember Theora stores the image from
> bottom to top internally). Be careful, as the fragments are not arranged

 Please look at this part of the code: (imagine PlaneFragOffset = 0 for

> PixelIndex = pbi->recon_pixel_index_table[PlaneFragOffset];
> SrcPtr1 = &DestReconPtr[ PixelIndex ];
> DestPtr1 = &DestReconPtr[ PixelIndex - PlaneBorderWidth ];
> PixelIndex = pbi->recon_pixel_index_table[PlaneFragOffset +
> LineFragments - 1] +
> SrcPtr2 = &DestReconPtr[ PixelIndex ];
> DestPtr2 = &DestReconPtr[ PixelIndex + 1 ];
 it seems that recon_pixel_index returns the lower LEFT pixel. I noticed how
he sets the first pixelindex as pbi->recon_pixel_index_table[PlaneFragOffset].
If that is the lower left pixel, it makes sense, since this code is suposed
to copy the first pixel on the left over to the MV edges. It then gets the
destination pointer as the lower left - 16 (left edge border)

On the second pixelindex, it does PixelIndex =
pbi->recon_pixel_index_table[PlaneFragOffset +LineFragments - 1] + (HFRAGPIXELS
- 1) which makes sense again if it returns the lower left pixel, so this
could be interpreted as 1) get the lower left pixel on the fragment that
represents the last fragment on the line and 2) Add the number of pixels on
a fragment to make it go from the lower left to the lower right, and then
set the destination as +1, which would be just by it`s side to fill the
right edge border

Correct me if im wrong on my interpretation, but it seems to me that it fits

Arthur Valadares
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