Hello again, maybe this is somewhat OT, but I really hope there is someone who can answer:
I'm doing analysis of MPEG(2) headers and while having some data of a PS stream (PAL 25fps, 720x576) I get stuck with some data bytes according to ISO/IEC 13818-1 (2000). Here are some pieces of the header data part in question: 1: 00 00 01 e0 => video stream 2: 07 dc 31 00 03 de 91 11.00 03 8a 31 3: 00 00 01 b3 2d 02 40 33.24 9f 23 69 10 11 11 12 ... => sequence header The problem is at line 2: After the 16 bit length field PES_packet_length of 0x7dc I get 16 bits of flags (0x3100) and a length byte for the options following PES_header_data_length which is 0x03. The data alignment flag is 0, so I have to use a standard start code for the next sequence after PES_header_data_length + the value in there. When I do this I point after the 11 in line 1 and get 0x00038a31 and that is of course wrong. It should continue with line 3 at 0x000001b3. I'm 4 Bytes in offset less than that. How's that? The flags say that the scrambling value is '11' which is user defined, no off. Is there some header scrambling in place? At another place in the same stream I've found a '00' scrambling value, an alignment flag of '1' so that I have to jump to a one byte start code after the header ... which is also garbage (a 0x46 that matches no stream in this file) and I have '01' as PTS_DTS_flag which is undefined to ISO of 2000. Are there major updates to the specification that say different things as of my interpretation? Or am I totally wrong with my assumptions? Cheers, Konran _______________________________________________ libav-user mailing list [email protected] https://lists.mplayerhq.hu/mailman/listinfo/libav-user
