Add convenience macros for 5.0/5.1 back speaker configurations.

Originally committed as revision 18339 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/avcodec.h

@@ -30,7 +30,7 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVCODEC_VERSION_MAJOR 52
-#define LIBAVCODEC_VERSION_MINOR 24
+#define LIBAVCODEC_VERSION_MINOR 25
 #define LIBAVCODEC_VERSION_MICRO  0
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
@@ -383,9 +383,10 @@ enum SampleFormat {
 #define CH_LAYOUT_QUAD              (CH_LAYOUT_STEREO|CH_BACK_LEFT|CH_BACK_RIGHT)
 #define CH_LAYOUT_5POINT0           (CH_LAYOUT_SURROUND|CH_SIDE_LEFT|CH_SIDE_RIGHT)
 #define CH_LAYOUT_5POINT1           (CH_LAYOUT_5POINT0|CH_LOW_FREQUENCY)
+#define CH_LAYOUT_5POINT0_BACK      (CH_LAYOUT_SURROUND|CH_BACK_LEFT|CH_BACK_RIGHT)
+#define CH_LAYOUT_5POINT1_BACK      (CH_LAYOUT_5POINT0_BACK|CH_LOW_FREQUENCY)
 #define CH_LAYOUT_7POINT1           (CH_LAYOUT_5POINT1|CH_BACK_LEFT|CH_BACK_RIGHT)
-#define CH_LAYOUT_7POINT1_WIDE      (CH_LAYOUT_SURROUND|CH_LOW_FREQUENCY|\
-                                          CH_BACK_LEFT|CH_BACK_RIGHT|\
+#define CH_LAYOUT_7POINT1_WIDE      (CH_LAYOUT_5POINT1_BACK|\
                                           CH_FRONT_LEFT_OF_CENTER|CH_FRONT_RIGHT_OF_CENTER)
 #define CH_LAYOUT_STEREO_DOWNMIX    (CH_STEREO_LEFT|CH_STEREO_RIGHT)