Revert ffmpeg related changes from "thread-safe VideoWriter and VideoCapture"

This reverts commit 4abf0b3193.

Changes are reverted because they break build of proxy dlls on Windows

modules/highgui/src/cap_ffmpeg.cpp

@@ -57,32 +57,11 @@ static CvCreateVideoWriter_Plugin icvCreateVideoWriter_FFMPEG_p = 0;
 static CvReleaseVideoWriter_Plugin icvReleaseVideoWriter_FFMPEG_p = 0;
 static CvWriteFrame_Plugin icvWriteFrame_FFMPEG_p = 0;
 
-static cv::Mutex _icvInitFFMPEG_mutex;
-
-class icvInitFFMPEG
+static void
+icvInitFFMPEG(void)
 {
-public:
-    static void Init()
-    {
-        cv::AutoLock al(_icvInitFFMPEG_mutex);
-        static icvInitFFMPEG init;
-    }
-
-private:
-    #if defined WIN32 || defined _WIN32
-    HMODULE icvFFOpenCV;
-
-    ~icvInitFFMPEG()
-    {
-        if (icvFFOpenCV)
-        {
-            FreeLibrary(icvFFOpenCV);
-            icvFFOpenCV = 0;
-        }
-    }
-    #endif
-
-    icvInitFFMPEG()
+    static int ffmpegInitialized = 0;
+    if( !ffmpegInitialized )
     {
     #if defined WIN32 || defined _WIN32
         const char* module_name = "opencv_ffmpeg"
@@ -92,7 +71,7 @@ private:
         #endif
             ".dll";
 
-        icvFFOpenCV = LoadLibrary( module_name );
+        static HMODULE icvFFOpenCV = LoadLibrary( module_name );
         if( icvFFOpenCV )
         {
             icvCreateFileCapture_FFMPEG_p =
@@ -138,8 +117,10 @@ private:
         icvReleaseVideoWriter_FFMPEG_p = (CvReleaseVideoWriter_Plugin)cvReleaseVideoWriter_FFMPEG;
         icvWriteFrame_FFMPEG_p = (CvWriteFrame_Plugin)cvWriteFrame_FFMPEG;
     #endif
+
+        ffmpegInitialized = 1;
     }
-};
+}
 
 
 class CvCapture_FFMPEG_proxy : public CvCapture
@@ -174,9 +155,9 @@ public:
     }
     virtual bool open( const char* filename )
     {
-        icvInitFFMPEG::Init();
         close();
 
+        icvInitFFMPEG();
         if( !icvCreateFileCapture_FFMPEG_p )
             return false;
         ffmpegCapture = icvCreateFileCapture_FFMPEG_p( filename );
@@ -209,6 +190,7 @@ CvCapture* cvCreateFileCapture_FFMPEG_proxy(const char * filename)
 #endif
 }
 
+
 class CvVideoWriter_FFMPEG_proxy : public CvVideoWriter
 {
 public:
@@ -226,8 +208,8 @@ public:
     }
     virtual bool open( const char* filename, int fourcc, double fps, CvSize frameSize, bool isColor )
     {
-        icvInitFFMPEG::Init();
         close();
+        icvInitFFMPEG();
         if( !icvCreateVideoWriter_FFMPEG_p )
             return false;
         ffmpegWriter = icvCreateVideoWriter_FFMPEG_p( filename, fourcc, fps, frameSize.width, frameSize.height, isColor );