CVS change done by Oded Shimon CVS Update of /cvsroot/mplayer/main/DOCS/tech In directory mail:/var2/tmp/cvs-serv6347 Modified Files: mpcf.txt Log Message: max_distance clarification Index: mpcf.txt =================================================================== RCS file: /cvsroot/mplayer/main/DOCS/tech/mpcf.txt,v retrieving revision 1.154 retrieving revision 1.155 diff -u -r1.154 -r1.155 --- mpcf.txt 25 Mar 2006 07:58:34 -0000 1.154 +++ mpcf.txt 25 Mar 2006 13:39:47 -0000 1.155 @@ -1,5 +1,5 @@ ======================================== -NUT Open Container Format DRAFT 20060312 +NUT Open Container Format DRAFT 20060322 ======================================== @@ -397,10 +397,14 @@ after the packet_header to the first byte of the next packet) max_distance - max distance of syncpoints, the distance may only be larger if - there is no more than a single frame between the two syncpoints. This can - be used by the demuxer to detect damaged frame headers if the damage - results in too long of a chain + max distance between startcodes. If p1 and p2 are the byte + positions of the first byte of two consecutive startcodes, then + p2-p1 MUST be less than or equal to max_distance unless the entire + span from p1 to p2 comprises a single packet or a syncpoint + followed by a single frame. This imposition places efficient upper + bounds on seek operations and allows for the detection of damaged + frame headers, should a chain of frame headers pass max_distance + without encountering any startcode. syncpoints SHOULD be placed immediately before a keyframe if the previous frame of the same stream was a non-keyframe, unless such @@ -415,7 +419,9 @@ max_pts_distance max absoloute difference of pts of new frame from last_pts in the - timebase of the stream, without a checksum after the frameheader + timebase of the stream, without a checksum after the frameheader. + A frame header MUST include a checksum if abs(pts-last_pts) is + strictly greater than max_pts_distance. Note that last_pts is not necessarily the pts of the last frame on the same stream, as it is altered by syncpoint timestamps. SHOULD NOT be higher than 1/timebase @@ -529,8 +535,10 @@ end presentation time of the final frame. An EOR set stream is unset by the first content frames. EOR can only be unset in streams with zero decode_delay . - FLAG_CHECKSUM MUST be set if the frame is larger than 2*max_distance or - its pts differs by more then max_pts_distance from the last frame + FLAG_CHECKSUM MUST be set if the frame's data_size is strictly greater than + 2*max_distance or the difference abs(pts-last_pts) is strictly greater than + max_pts_distance (where pts represents this frame's pts and last_pts is + defined as below). stream_id[frame_code] MUST be <250