[FFmpeg-devel] H.264 decoder calls fill_rectangle() with unaligned buffers

[Måns Rullgård]

Michael Niedermayer wrote:
> On Mon, Jul 14, 2008 at 02:58:18PM +0100, M?ns Rullg?rd wrote:
>>
>> Michael Niedermayer wrote:
>> > On Mon, Jul 14, 2008 at 12:36:47AM +0100, M?ns Rullg?rd wrote:
>> >> If STRIDE_ALIGN is set to 16, the H.264 decoder will call
>> >> fill_rectangle() with buffer addresses failing the alignment assert()
>> >> at the top of the function.  This obviously does no harm to this
>> >> function, so I'm not sure which is incorrect, the assert() or the
>> >> calling code.
>> >
>> > And i am not sure without knowing what that calling code is.
>>
>> Sorry, I forgot to mention.  It can happen with any of the
>> fill_rectangle(h->mv_cache[list][ scan8[0] ], 4, 4, 8, val, 4)
>> and similar calls where width*size > 8, for instance the one
>> on line 4784 of h264.c.
>
> I suspect you are missing a
> #define DECLARE_ALIGNED_8(t, v) DECLARE_ALIGNED(16, t, v)
> in dsputil.h where STRIDE_ALIGN is set to 16
>
> (yes DECLARE_ALIGNED_8 is not a good name i know, it should be
> renamed to DECLARE_ALIGNED_NATIVE or _MAX or so)

Or why not like this?

#define DECLARE_STRIDE_ALIGNED(t, v) DECLARE_ALIGNED(STRIDE_ALIGN, t, v)

Requiring essentially the same information to be repeated in several
places is only asking for trouble.

-- 
M?ns Rullg?rd
mans at mansr.com