Bug 927: Fix minor MT issues w/ libav/ffmpeg

Issue:
  [NULL @ 0x35bde60] insufficient thread locking around avcodec_open/close()

Decorating said libav functions w/ mutex lock/release.

Abstract impl. to either use pthread or JNI Monitor,
but using the latter to reduce dependencies (ming64 windows).

FFMPEGNatives is now an abstract class containing the
  'static final Object mutex_avcodec_openclose'

1 files changed, 15 insertions, 0 deletions

diff --git a/src/jogl/native/libav/ffmpeg_tool.h b/src/jogl/native/libav/ffmpeg_tool.h
index 97e60afce..66c3519e6 100644
--- a/src/jogl/native/libav/ffmpeg_tool.h
+++ b/src/jogl/native/libav/ffmpeg_tool.h
@@ -64,6 +64,15 @@ typedef struct SwrContext SwrContext;
 #include <stdio.h>
 #include <stdlib.h>
 
+// We use JNI Monitor Locking, since this removes the need 
+// to statically link-in pthreads on window ..
+//   #define USE_PTHREAD_LOCKING 1
+//
+#ifdef USE_PTHREAD_LOCKING
+    #include <pthread.h>
+    #error PTHREAD path not tested yet
+#endif
+
 #include <GL/gl.h>
 
 typedef void (APIENTRYP PFNGLTEXSUBIMAGE2DPROC) (GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const GLvoid *pixels);
@@ -148,6 +157,12 @@ typedef struct {
     PFNGLFLUSH procAddrGLFlush;
     PFNGLFINISH procAddrGLFinish;
 
+    #ifdef USE_PTHREAD_LOCKING
+        pthread_mutex_t  mutex_avcodec_openclose;
+    #else
+        jobject mutex_avcodec_openclose;
+    #endif
+
     AVFormatContext* pFormatCtx;
     int32_t          vid;
     AVStream*        pVStream;