使用 ffmpeg 构建 opencv 时出错

Question

我按照这个article安装了ffmpeg。 ffmpeg 安装没问题。 现在我用 ffmpeg 支持构建 opencv，但我有一些错误。 错误是

/home/coie/Softwares/Libraries/opencv-2.4.13.3/modules/highgui/src/cap_ffmpeg_impl.hpp:1484:21: error: ‘CODEC_FLAG_GLOBAL_HEADER’ was not declared in this scope
         c->flags |= CODEC_FLAG_GLOBAL_HEADER;
                     ^
/home/coie/Softwares/Libraries/opencv-2.4.13.3/modules/highgui/src/cap_ffmpeg_impl.hpp: In function ‘int icv_av_write_frame_FFMPEG(AVFormatContext*, AVStream*, uint8_t*, uint32_t, AVFrame*)’:
/home/coie/Softwares/Libraries/opencv-2.4.13.3/modules/highgui/src/cap_ffmpeg_impl.hpp:1512:30: error: ‘AVFMT_RAWPICTURE’ was not declared in this scope
     if (oc->oformat->flags & AVFMT_RAWPICTURE) {
                              ^
/home/coie/Softwares/Libraries/opencv-2.4.13.3/modules/highgui/src/cap_ffmpeg_impl.hpp: In member function ‘void CvVideoWriter_FFMPEG::close()’:
/home/coie/Softwares/Libraries/opencv-2.4.13.3/modules/highgui/src/cap_ffmpeg_impl.hpp:1686:35: error: ‘AVFMT_RAWPICTURE’ was not declared in this scope
         if( (oc->oformat->flags & AVFMT_RAWPICTURE) == 0 )
                                   ^
/home/coie/Softwares/Libraries/opencv-2.4.13.3/modules/highgui/src/cap_ffmpeg_impl.hpp: In member function ‘bool CvVideoWriter_FFMPEG::open(const char*, int, double, int, int, bool)’:
/home/coie/Softwares/Libraries/opencv-2.4.13.3/modules/highgui/src/cap_ffmpeg_impl.hpp:1920:32: error: ‘AVFMT_RAWPICTURE’ was not declared in this scope
     if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
                                ^
In file included from /home/coie/Softwares/Libraries/opencv-2.4.13.3/modules/highgui/src/cap_ffmpeg.cpp:45:0:
/home/coie/Softwares/Libraries/opencv-2.4.13.3/modules/highgui/src/cap_ffmpeg_impl.hpp: In static member function ‘static AVStream* OutputMediaStream_FFMPEG::addVideoStream(AVFormatContext*, AVCodecID, int, int, int, double, AVPixelFormat)’:
/home/coie/Softwares/Libraries/opencv-2.4.13.3/modules/highgui/src/cap_ffmpeg_impl.hpp:2214:25: error: ‘CODEC_FLAG_GLOBAL_HEADER’ was not declared in this scope
             c->flags |= CODEC_FLAG_GLOBAL_HEADER;
                         ^
modules/highgui/CMakeFiles/opencv_highgui.dir/build.make:230: recipe for target 'modules/highgui/CMakeFiles/opencv_highgui.dir/src/cap_ffmpeg.cpp.o' failed
make[2]: *** [modules/highgui/CMakeFiles/opencv_highgui.dir/src/cap_ffmpeg.cpp.o] Error 1
CMakeFiles/Makefile2:2349: recipe for target 'modules/highgui/CMakeFiles/opencv_highgui.dir/all' failed

可能出了什么问题？

Answer 1

我的解决方案是使用 grep -r 从 FFmpeg grep 缺少的定义（总共 2 个），这会导致在 libavcodec/avcodec.h 中找到以下代码：

#define AV_CODEC_FLAG_GLOBAL_HEADER (1 << 22)
#define CODEC_FLAG_GLOBAL_HEADER AV_CODEC_FLAG_GLOBAL_HEADER
#define AVFMT_RAWPICTURE 0x0020

复制粘贴到：

opencv-3.3.0/modules/videoio/src/cap_ffmpeg_impl.hpp

编译，即使使用最新的源代码也能正常工作

Answer 2

在 opencv:0/2.4 中没有 modules/videoio 目录！为了让旧版本（2.4.13-r3）在 gentoo（4.1.3）上使用最新的 media-video/ffmpeg 进行编译，我必须将上述更改添加到 modules/highgui/src/cap_ffmpeg_api.hpp 补丁：

--- opencv-2.4.13/modules/highgui/src/cap_ffmpeg_api.hpp        2019-05-27 13:28:05.736339890 +0200
+++ opencv-2.4.13-new/modules/highgui/src/cap_ffmpeg_api.hpp    2019-05-27 13:27:48.787198507 +0200
@@ -12,6 +12,10 @@
 #define OPENCV_FFMPEG_API
 #endif

+#define AV_CODEC_FLAG_GLOBAL_HEADER (1 << 22)
+#define CODEC_FLAG_GLOBAL_HEADER 
AV_CODEC_FLAG_GLOBAL_HEADER
+#define AVFMT_RAWPICTURE 0x0020
+
 enum
 {
     CV_FFMPEG_CAP_PROP_POS_MSEC=0,

（即我使用该内容创建了路径和文件 /etc/portage/patches/media-libs/opencv-2.4.13-r3/old-ffmpeg.patch。） 为了保护 gentoo，我应该提一下，新的 media-libs/opencv:0/3.4.1 也可用，旧的 media-video/ffmpeg-3.4.5 也是可用的，所以我也可以选择屏蔽掉版本或提交错误供开发人员为我执行此操作...

Answer 3

CODEC_FLAG_GLOBAL_HEADER 最简单的更改是将其更改为 AV_CODEC_FLAG_GLOBAL_HEADER，它已在较新的版本中重新定义。

注意前面的“AV_”