[FFmpeg-devel] [PATCH] H264 DXVA2 implementation

[Ramiro Polla]

On Sun, Jan 10, 2010 at 1:22 PM, Reimar D?ffinger
<Reimar.Doeffinger at gmx.de> wrote:
> On Sun, Jan 10, 2010 at 04:13:43PM +0100, Reimar D?ffinger wrote:
>> On Sun, Jan 10, 2010 at 04:08:50PM +0100, Jean-Baptiste Kempf wrote:
>> > On Sun, Jan 10, 2010 at 03:01:25PM +0000, M?ns Rullg?rd wrote :
>> > > >> > j-b pointed me to the vlc buildbot where this doesn't compile under
>> > > >> > "-std=c99" (which is set by default in FFmpeg). I'm no C guru and I'm
>> > > >> > quite tired right now, but it seems you can't use anonymous unions in
>> > > >> > your dxva2api.h, such as:
>> > > >> >
>> > > >> > typedef struct {
>> > > >> > ? ? union {
>> > > >> > ? ? ? ? struct {
>> > > >> > ? ? ? ? ? ? UCHAR Index7Bits ? ? : 7;
>> > > >> > ? ? ? ? ? ? UCHAR AssociatedFlag : 1;
>> > > >> > ? ? ? ? };
>> > > >> > ? ? ? ? UCHAR bPicEntry;
>> > > >> > ? ? };
>> > > >> > } DXVA_PicEntry_H264;
>> > > >>
>> > > >> WTF? ?How would you even begin to access those fields?
>> > > >
>> > > > It's a Microsoft/GNU extension.
>> > > > DXVA_PicEntry_H264.Index7Bits
>> > > > accesses right into the union/struct
>> > >
>> > > What's the point of that? ?Why not put them directly in the outer
>> > > struct if you don't want a name?
>> >
>> > Because that is how it is done in the Microsoft header Dxva2api.h.
>> > See:
>> > http://download.microsoft.com/download/5/f/c/5fc4ec5c-bd8c-4624-8034-319c1bab7671/DXVA_H264.pdf
>> > page 16, chapter 3.1 for reference.
>> >
>> > Our dxva2api.h tries to stay compatible with Microsoft headers like the
>> > other DirectX headers from Mingw/wine.
>>
>> That doesn't fully excuse sending a patch for review that seems to not even compile...
>
> And to say something constructive: I suggest adding check for a define that if set
> will remove the non-portable bitfields and (if any remain) name the remaining unions/structs

Or we could set -fms-extensions for that file, see
http://gcc.gnu.org/onlinedocs/gcc/C-Dialect-Options.html

Where can the microsoft version of this file be found? (as in what's
the smallest sdk or somesuch I have to download to get it)