Provide old api if not provided by new libavcodec

src/Makefile.am

@@ -202,7 +202,9 @@ endif
 if BUILD_FFMPEG
 libmediastreamer_voip_la_SOURCES+=	videofilters/videoenc.c \
 					videofilters/videodec.c \
-					utils/swscale.h utils/ffmpeg-priv.h \
+					utils/swscale.h \
+					utils/ffmpeg-priv.h \
+					utils/ffmpeg-priv.c \
 					videofilters/h264dec.c \
 					videofilters/jpegwriter.c
 endif

src/utils/ffmpeg-priv.h

@@ -69,5 +69,14 @@ static inline int avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture,
 	return avcodec_decode_video(avctx,picture, got_picture_ptr,avpkt->data,avpkt->size);
 }
 #endif
-
+#if LIBAVCODEC_VERSION_INT > AV_VERSION_INT(52,25,0)
+#define CodecID AVCodecID
+#endif
+#if !FF_API_ALLOC_CONTEXT
+AVCodecContext *avcodec_alloc_context(void); 
+void avcodec_get_context_defaults(AVCodecContext *s);
+#endif
+#if !FF_API_AVCODEC_OPEN
+int avcodec_open(AVCodecContext *avctx, AVCodec *codec);
+#endif
 #endif /* FFMPEG_PRIV_H */