[FFmpeg-devel] [PATCH] fix MSVC compilation errors

Aaron Levinson alevinsn_dev at levland.net
Sun Dec 10 04:15:26 EET 2017


On 12/9/2017 1:18 AM, Hendrik Leppkes wrote:
> On Fri, Dec 8, 2017 at 8:49 AM, Mateusz <mateuszb at poczta.onet.pl> wrote:
>> W dniu 07.12.2017 o 22:58, Hendrik Leppkes pisze:
>>> Am 07.12.2017 20:40 schrieb "Mateusz" <mateuszb at poczta.onet.pl>:
>>>
>>> W dniu 07.12.2017 o 10:42, Hendrik Leppkes pisze:
>>>> On Thu, Dec 7, 2017 at 2:02 AM, Mateusz <mateuszb at poczta.onet.pl> wrote:
>>>>> After commit 3701d49 'error_resilience: remove avpriv_atomic usage'
>>>>> we have included windows.h in much more files and we should
>>>>> avoid conflicts with defines/function declarations.
>>>>>
>>>>> We should declare compatible variables for atomic compat wrappers
>>>>> that expect fixed size variables in atomic_compare_exchange* macro.
>>>>>
>>>>> Signed-off-by: Mateusz Brzostek <mateuszb at poczta.onet.pl>
>>>>> ---
>>>>>   libavcodec/jpegls.h   |  2 ++
>>>>>   libavcodec/mjpegdec.h |  2 ++
>>>>>   libavcodec/mss2.c     |  6 +++---
>>>>>   libavcodec/utils.c    | 12 ++++++++++++
>>>>>   libavformat/mxfenc.c  |  2 +-
>>>>>   5 files changed, 20 insertions(+), 4 deletions(-)
>>>>>
>>>>> diff --git a/libavcodec/jpegls.h b/libavcodec/jpegls.h
>>>>> index c8997c7861..6b89b2afa3 100644
>>>>> --- a/libavcodec/jpegls.h
>>>>> +++ b/libavcodec/jpegls.h
>>>>> @@ -32,6 +32,8 @@
>>>>>   #include "avcodec.h"
>>>>>   #include "internal.h"
>>>>>
>>>>> +#undef near /* This file uses struct member 'near' which in windows.h
>>> is defined as empty. */
>>>>> +
>>>>>   typedef struct JpeglsContext {
>>>>>       AVCodecContext *avctx;
>>>>>   } JpeglsContext;
>>>>> diff --git a/libavcodec/mjpegdec.h b/libavcodec/mjpegdec.h
>>>>> index c84a40aa6e..c36fba5f22 100644
>>>>> --- a/libavcodec/mjpegdec.h
>>>>> +++ b/libavcodec/mjpegdec.h
>>>>> @@ -39,6 +39,8 @@
>>>>>   #include "hpeldsp.h"
>>>>>   #include "idctdsp.h"
>>>>>
>>>>> +#undef near /* This file uses struct member 'near' which in windows.h
>>> is defined as empty. */
>>>>> +
>>>>>   #define MAX_COMPONENTS 4
>>>>>
>>>>>   typedef struct MJpegDecodeContext {
>>>>> diff --git a/libavcodec/mss2.c b/libavcodec/mss2.c
>>>>> index 9e7cc466de..3180af1d60 100644
>>>>> --- a/libavcodec/mss2.c
>>>>> +++ b/libavcodec/mss2.c
>>>>> @@ -464,9 +464,9 @@ static int decode_wmv9(AVCodecContext *avctx, const
>>> uint8_t *buf, int buf_size,
>>>>>       return 0;
>>>>>   }
>>>>>
>>>>> -typedef struct Rectangle {
>>>>> +struct Rectangle {
>>>>>       int coded, x, y, w, h;
>>>>> -} Rectangle;
>>>>> +};
>>>>>
>>>>>   #define MAX_WMV9_RECTANGLES 20
>>>>>   #define ARITH2_PADDING 2
>>>>> @@ -485,7 +485,7 @@ static int mss2_decode_frame(AVCodecContext *avctx,
>>> void *data, int *got_frame,
>>>>>
>>>>>       int keyframe, has_wmv9, has_mv, is_rle, is_555, ret;
>>>>>
>>>>> -    Rectangle wmv9rects[MAX_WMV9_RECTANGLES], *r;
>>>>> +    struct Rectangle wmv9rects[MAX_WMV9_RECTANGLES], *r;
>>>>>       int used_rects = 0, i, implicit_rect = 0, av_uninit(wmv9_mask);
>>>>>
>>>>>       if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)
>>>>> diff --git a/libavcodec/utils.c b/libavcodec/utils.c
>>>>> index baf09119fe..70a0764714 100644
>>>>> --- a/libavcodec/utils.c
>>>>> +++ b/libavcodec/utils.c
>>>>> @@ -1943,7 +1943,13 @@ int av_lockmgr_register(int (*cb)(void **mutex,
>>> enum AVLockOp op))
>>>>>
>>>>>   int ff_lock_avcodec(AVCodecContext *log_ctx, const AVCodec *codec)
>>>>>   {
>>>>> +#if !defined(COMPAT_ATOMICS_DUMMY_STDATOMIC_H) &&
>>> !defined(COMPAT_ATOMICS_PTHREAD_STDATOMIC_H) && \
>>>>> +    !defined(COMPAT_ATOMICS_SUNCC_STDATOMIC_H) &&
>>> !defined(COMPAT_ATOMICS_WIN32_STDATOMIC_H)
>>>>>       _Bool exp = 0;
>>>>> +#else
>>>>> +    atomic_bool exp = 0;
>>>>> +#endif
>>>>> +
>>>>>       if (codec->caps_internal & FF_CODEC_CAP_INIT_THREADSAFE ||
>>> !codec->init)
>>>>>           return 0;
>>>>>
>>>>> @@ -1969,7 +1975,13 @@ int ff_lock_avcodec(AVCodecContext *log_ctx,
>>> const AVCodec *codec)
>>>>>
>>>>>   int ff_unlock_avcodec(const AVCodec *codec)
>>>>>   {
>>>>> +#if !defined(COMPAT_ATOMICS_DUMMY_STDATOMIC_H) &&
>>> !defined(COMPAT_ATOMICS_PTHREAD_STDATOMIC_H) && \
>>>>> +    !defined(COMPAT_ATOMICS_SUNCC_STDATOMIC_H) &&
>>> !defined(COMPAT_ATOMICS_WIN32_STDATOMIC_H)
>>>>>       _Bool exp = 1;
>>>>> +#else
>>>>> +    atomic_bool exp = 1;
>>>>> +#endif
>>>>> +
>>>>>       if (codec->caps_internal & FF_CODEC_CAP_INIT_THREADSAFE ||
>>> !codec->init)
>>>>>           return 0;
>>>>>
>>>>
>>>> These ifdefs here are very ugly, and as mentioned in another mail, the
>>>> atomics in those two functions arent even required - all access to
>>>> those variables is supposed to be protected by the lockmgr anyway.
>>>> So it would be easier to just remove any atomic nature of those
>>>> variables (or at the very lease replace the compare_exchange with a
>>>> store to solve this problem at hand).
>>>
>>> I'm not sure but are you proposed to revert commit
>>> https://github.com/FFmpeg/FFmpeg/commit/590136e78da3d091ea99ab5432543d
>>> 47a559a461
>>>
>>>
>>> Basically, yes. Atomics are not needed for this variable, as access to it
>>> should be serialized anyways.
>>
>> OK for me. I've sent smaller patch (only near/Rectangle stuff).
>>
> 
> LGTM.

This patch doesn't apply anymore to the latest code base due to changes 
to mxfenc.c.


More information about the ffmpeg-devel mailing list