[FFmpeg-devel] Added HW H.264 and HEVC encoding for AMD GPUs based on AMF SDK

[Mironov, Mikhail]

> -----Original Message-----
> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> Of Mark Thompson
> Sent: November 8, 2017 10:15 AM
> To: ffmpeg-devel at ffmpeg.org
> Subject: Re: [FFmpeg-devel] Added HW H.264 and HEVC encoding for AMD
> GPUs based on AMF SDK
> 
> On 06/11/17 22:46, Michael Niedermayer wrote:
> > ...
> > In file included from src/libavcodec/amfenc.h:24:0,
> >                  from src/libavcodec/amfenc.c:27:
> > src/compat/amd/amfsdkenc.h:191:23: error: no previous prototype for
> > ‘AMFConstructRect’ [-Werror=missing-prototypes]  AMF_INLINE struct
> AMFRect AMFConstructRect(amf_int32 left, amf_int32 top, amf_int32 right,
> amf_int32 bottom)
> >                        ^
> > src/compat/amd/amfsdkenc.h:203:23: error: no previous prototype for
> > ‘AMFConstructSize’ [-Werror=missing-prototypes]  AMF_INLINE struct
> AMFSize AMFConstructSize(amf_int32 width, amf_int32 height)
> >                        ^
> > src/compat/amd/amfsdkenc.h:215:24: error: no previous prototype for
> > ‘AMFConstructPoint’ [-Werror=missing-prototypes]  AMF_INLINE struct
> AMFPoint AMFConstructPoint(amf_int32 x, amf_int32 y)
> >                         ^
> > src/compat/amd/amfsdkenc.h:227:23: error: no previous prototype for
> > ‘AMFConstructRate’ [-Werror=missing-prototypes]  AMF_INLINE struct
> AMFRate AMFConstructRate(amf_uint32 num, amf_uint32 den)
> >                        ^
> > src/compat/amd/amfsdkenc.h:239:24: error: no previous prototype for
> > ‘AMFConstructRatio’ [-Werror=missing-prototypes]  AMF_INLINE struct
> AMFRatio AMFConstructRatio(amf_uint32 num, amf_uint32 den)
> >                         ^
> > In file included from src/libavcodec/amfenc.h:24:0,
> >                  from src/libavcodec/amfenc.c:27:
> > src/compat/amd/amfsdkenc.h:275:24: error: no previous prototype for
> > ‘AMFConstructColor’ [-Werror=missing-prototypes]  AMF_INLINE struct
> AMFColor AMFConstructColor(amf_uint8 r, amf_uint8 g, amf_uint8 b,
> amf_uint8 a)
> >                         ^
> > In file included from src/libavcodec/amfenc.h:24:0,
> >                  from src/libavcodec/amfenc.c:27:
> > src/compat/amd/amfsdkenc.h:293:45: error: no previous prototype for
> ‘amf_variant_alloc’ [-Werror=missing-prototypes]
> >      AMF_INLINE void* AMF_CDECL_CALL amf_variant_alloc(amf_size count)
> >                                              ^
> > src/compat/amd/amfsdkenc.h:297:44: error: no previous prototype for
> ‘amf_variant_free’ [-Werror=missing-prototypes]
> >      AMF_INLINE void AMF_CDECL_CALL amf_variant_free(void* ptr)
> >                                             ^
> > cc1: some warnings being treated as errors
> > make: *** [libavcodec/amfenc.o] Error 1
> 
> This is showing an error in the AMF C API.
> 
> AMF_INLINE is defined at <https://github.com/GPUOpen-
> LibrariesAndSDKs/AMF/blob/master/amf/public/include/core/Platform.h#L9
> 9> as just "__inline__" (i.e. "inline"), so these functions are all inline without
> a storage class specifier.  But, no external definition actually exists anywhere,
> so if the compiler doesn't inline all instances you will fail to link.
> 
> (The behaviour is not the same in C++, where external versions are
> generated anyway in this case and then the multiple instances collapsed
> together later by invoking the ODR.)
> 
> Trivial test case (gcc defaults to not inlining anything when no optimisation
> options are given):
> 
> $ cat amf-inline.c
> #include "Platform.h"
> 
> int main(void)
> {
>     AMFSize size;
>     size = AMFConstructSize(123, 456);
>     return 0;
> }
> $ gcc -std=c99 amf-inline.c
> In file included from amf-inline.c:1:0:
> Platform.h: In function ‘AMFCompareGUIDs’:
> Platform.h:421:16: warning: implicit declaration of function ‘memcmp’ [-
> Wimplicit-function-declaration]
>          return memcmp(&guid1, &guid2, sizeof(guid1)) == 0;
>                 ^
> /tmp/ccMCUBTW.o: In function `main':
> amf-inline.c:(.text+0x13): undefined reference to `AMFConstructSize'
> collect2: error: ld returned 1 exit status $ gcc -c -std=c99 amf-inline.c In file
> included from amf-inline.c:1:0:
> Platform.h: In function ‘AMFCompareGUIDs’:
> Platform.h:421:16: warning: implicit declaration of function ‘memcmp’ [-
> Wimplicit-function-declaration]
>          return memcmp(&guid1, &guid2, sizeof(guid1)) == 0;
>                 ^
> $ nm amf-inline.o
>                  U AMFConstructSize
> 0000000000000000 T main
> $ gcc -O1 -std=c99 amf-inline.c
> In file included from amf-inline.c:1:0:
> Platform.h: In function ‘AMFCompareGUIDs’:
> Platform.h:421:16: warning: implicit declaration of function ‘memcmp’ [-
> Wimplicit-function-declaration]
>          return memcmp(&guid1, &guid2, sizeof(guid1)) == 0;
>                 ^
> $
> 
> I think AMF_INLINE should for these functions instead be "static inline"
> (though I didn't look at all uses, so there may be others where this isn't true).


Yes, this is the issue. I found that in most of the functions "static" was added 
but not to these few. And my debug script build had a different issue so I didn’t catch it.
I've added "static". Please use amfenc.h header from the next patch. GitHub AMF headers 
will be updated together with other changes.

> 
> - Mark
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Thanks,
Mikhail