ffmpeg v2.1 提示错误

ommon.h(30) : fatal error C1189: #error :  missing -D__STDC_CONSTANT_MACROS / #define __STDC_CONSTANT_MACROS

原因：

FFmpeg is written in C99, thus some features may not be compilable or usable in C++.

Anyway, for most purposes, including FFmpeg headers in a C++ application should be rather straightforward.

First, to include the FFmpeg headers within your C++ application you need to explicitly state that you are including C code. You can do this by encompassing your FFmpeg includes usingextern "C", like in:

extern "C" {
#include <libavutil/imgutils.h>
#include <libavcodec/avcodec.h>
#include <libswscale/swscale.h>
}

Second, you may need to append -D__STDC_CONSTANT_MACROS to your CXXFLAGS flags, if the compiler complains about ’UINT64_C’ was not declared in this scope.

 

解决办法：

extern "C"
{
#ifdef __cplusplus
#define __STDC_CONSTANT_MACROS

#endif

}

 

编译又提示错误：

错误二： error C3861: “UINT64_C”: 找不到标识符
解决方法：在common.h中添加如下代码：

#ifndef INT64_C
#define INT64_C(c) (c ## LL)
#define UINT64_C(c) (c ## ULL)
#endif

 

ffmpeg v2.1 的api和v1.2.1api对比，修改了几个地方：

1）v1.2.1  frame = avcodec_alloc_frame();

v.2.1 frame = av_frame_alloc();

 

2)v.1.2.1  avcodec_free_frame(&frame);

v.2.1    av_frame_free(&frame);