[FFmpeg-devel] [PATCH] Fix libavdevice/vfwcap.c for w32api-3.12

[Ramiro Polla]

Hello,

Note I have not tested what I'm writing here since I don't have a 
Windows box atm.

JonY wrote:
> HWND_MESSAGE is now present in w32api but only exposed when WINVER is at 
> least 0x0500.
> 
> I want to stress that vfwcap is still not buildable, it ends with 
> "error: WM_CAP_FIRSTA undeclared" when compiled with w32api-3.12.
> 
> Defines for WM_CAP_FIRSTA == WM_CAP_START, but was undef'ed for reasons 
> unknown in "vfw.h" soon after it was defined, currently awaiting 
> explaination from the MinGW team.

I screwed up when submitting the patch to MinGW. You probably have to 
remove the 3 #undefs in vfw.h which are not #undef INTERFACE.

> Do we support older w32api versions? Comments?

What happens with vfwcap.c the way it is and w32api-3.12?

> Index: libavdevice/vfwcap.c
> ===================================================================
> --- libavdevice/vfwcap.c	(revision 15290)
> +++ libavdevice/vfwcap.c	(working copy)
> @@ -19,6 +19,10 @@
>   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
>   */
>  
> +#if !defined (WINVER) || (WINVER < 0x0500)
> +#warning vfwcap requires Windows 2000/XP
> +#define WINVER 0x0500
> +#endif

I think there are other parts of FFmpeg that expect Windows to be 
2000/XP already (GetProcessTimes() IIRC). Besides this shouldn't be in 
compile-time since FFmpeg specifies all the CFLAGS to be used.

I haven't tested with Windows 98 for over a year now, and I don't think 
anyone cares about it anymore... I don't even know if it will refuse to 
run because of missing functions or just not work properly.

[...]
> @@ -27,6 +31,7 @@
>  
>  /* Defines for VFW missing from MinGW.
>   * Remove this when MinGW incorporates them. */
> +#if defined (__W32API_VERSION) && (__W32API_MAJOR_VERSION == 3) && (__W32API_MINOR_VERSION < 12)
>  #define WM_CAP_START                (0x0400)
>  #define WM_CAP_SET_CALLBACK_VIDEOSTREAM (WM_CAP_START + 6)
>  #define WM_CAP_DRIVER_CONNECT       (WM_CAP_START + 10)
> @@ -79,6 +84,7 @@
>      BOOL  fDisableWriteCache;
>      UINT  AVStreamMaster;
>  } CAPTUREPARMS;
> +#endif /* __W32API_VERSION < 3.12 */
>  /* End of missing MinGW defines */
>  
>  struct vfw_ctx {

Well, you say it doesn't work with 3.12, so I guess we should wait for 
3.13. In the meantime I still haven't figured out if we should just drop 
3.12 support or work around it somehow.

Ramiro Polla