Gerd Knorr wrote:
>
> > I have seen some mmx filters, and even some hardware, that requires the
> > lines to be DWORD or QWORD aligned.
>
> No problem with the common image sizes, lines will be aligned even
> without any padding:
>
> NTSC: 640 = 2^7 * 5
> PAL: 768 = 2^8 * 3
>
> The common DCT-based compression algorithms want image width be
> a multiple of 8 or 16 because the DCT blocks are 8x8 (luma needs
> to be 16 then because of chroma subsampling). That will give
> you qword aligned lines without padding too.
>
> > Granted, this is rare,
>
> ... and would be a problem only if you want to use image sizes
> like 389 * 251. Is this really a problem?
>
> Gerd
It probably isn't a problem, but I don't see any reason not to support
it - even if it is only for a few very specific applications. After all
- most of your changes are pretty much non backward compatible anyway,
so why not break the bytesperline thing as well, and keep the API as
universal as possible?
-justin
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