100l (document buffer padding requirements)

Originally committed as revision 1866 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/utils.c

@@ -343,9 +343,15 @@ int avcodec_encode_video(AVCodecContext *avctx, uint8_t *buf, int buf_size,
     return ret;
 }
 
-/* decode a frame. return -1 if error, otherwise return the number of
-   bytes used. If no frame could be decompressed, *got_picture_ptr is
-   zero. Otherwise, it is non zero */
+/** 
+ * decode a frame. 
+ * @param buf bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE larger then the actual read bytes
+ * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
+ * @param buf_size the size of the buffer in bytes
+ * @param got_picture_ptr zero if no frame could be decompressed, Otherwise, it is non zero
+ * @return -1 if error, otherwise return the number of
+ * bytes used. 
+ */
 int avcodec_decode_video(AVCodecContext *avctx, AVFrame *picture, 
                          int *got_picture_ptr,
                          uint8_t *buf, int buf_size)