[XviD-devel] Dev-API-4 : Possibility to mark a defined area of the encoded picture as 'BLACK=0' , to encode BlackBars with absolute minimum of bitrate ?

[Christoph Lampert]

On Sun, 27 Jul 2003, ChristianHJW wrote:

> 
> Hi,
> 
> sorry if i am too dumb to look this up from the specs, but does 
> dev-api-4 allow apps to tell XviD to set certain areas of the picture 
> internally to 'BLACK', such that these macroblocks are just written as 
> '0' from the encoder ?

No, that's not part of dev-api-4. 
I though about it, too, a while ago, but adding such a feature to not
encode certain regions would need very big internal changes: At the
moment, all macroblock loops start at 0 and run till the end of the
picture. Those would have to be change to start and stop at arbitrary
positions and special cases would have to be added to treat the remaining
blocks.
That doesn't sound like much work, but since these loops are spread over 
all files, it would surely produce some unwanted side effects and new
bugs... 
On the other hand, completely black macroblocks are processed very fast
in ME and marked as SKIP. So if avisynth or whatever application creates
the black bars, XviD slows down only a little. 

gruel