Make h264 parser 50% faster.

Originally committed as revision 16286 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h264_parser.c

@@ -44,6 +44,15 @@ int ff_h264_find_frame_end(H264Context *h, const uint8_t *buf, int buf_size)
 
     for(i=0; i<buf_size; i++){
         if(state==7){
+#ifdef HAVE_FAST_UNALIGNED
+#    ifdef HAVE_FAST_64BIT
+            while(i<buf_size && !((~*(uint64_t*)(buf+i) & (*(uint64_t*)(buf+i) - 0x0101010101010101ULL)) & 0x8080808080808080ULL))
+                i+=8;
+#    else
+            while(i<buf_size && !((~*(uint32_t*)(buf+i) & (*(uint32_t*)(buf+i) - 0x01010101U)) & 0x80808080U))
+                i+=4;
+#    endif
+#endif
             for(; i<buf_size; i++){
                 if(!buf[i]){
                     state=2;