Replace hard-coded SEI type constants with symbolic names

Patch by Ivan Schreter ( schreter gmx net )

Originally committed as revision 17064 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h264.c

@@ -6865,11 +6865,11 @@ static int decode_sei(H264Context *h){
         }while(get_bits(&s->gb, 8) == 255);
 
         switch(type){
-        case 1: // Picture timing SEI
+        case SEI_TYPE_PIC_TIMING: // Picture timing SEI
             if(decode_picture_timing(h) < 0)
                 return -1;
             break;
-        case 5:
+        case SEI_TYPE_USER_DATA_UNREGISTERED:
             if(decode_unregistered_user_data(h, size) < 0)
                 return -1;
             break;

libavcodec/h264.h

@@ -111,6 +111,15 @@ enum {
     NAL_AUXILIARY_SLICE=19
 };
 
+/**
+ * SEI message types
+ */
+typedef enum {
+    SEI_TYPE_PIC_TIMING              =  1, ///< picture timing
+    SEI_TYPE_USER_DATA_UNREGISTERED  =  5, ///< unregistered user data
+    SEI_TYPE_RECOVERY_POINT          =  6  ///< recovery point (frame # to decoder sync)
+} SEI_Type;
+
 /**
  * pic_struct in picture timing SEI message
  */