Mark Filipak wrote: > Thank you for your summary, Oliver. That has really, really helped. As you > know, H.264 is > prescriptive, not descriptive, which makes understanding it very difficult. > > It also lacks the strings: "I[- ]frame" "P[- ]frame" "B[- ]frame" "I[- > ]picture" "P[- ]picture" "B[- > ]picture" and "GOP.+".
Well, reading the standard document itself is probably not a very good idea, unless you're already an expert and about to implement your own software from scratch. But there are heaps of secondary literature. Just use the internet search engine of your choice -- it's actually difficult *not* to find useful information. BTW, terms like "I-frame" are generic for video compression, not specific to H.264 or even MPEG. The standard itself might not call it like that, but the concept is there. > I've taken my 40 second clip of a Criterion mastered video and am trying to > parse it. The TS packets > are 192 bytes. TS packets are 188 bytes maximum. It would have been helpful if you had included a hexdump of the first few packets of your file. > What are the 4 bytes, 0..3, that precede the 0x47 sync byte? I can't find > any documentation on them. > What can you tell me? My guess is that you actually have a so-called M2TS file. These are used on Blu-ray disks, some DV cameras and similar equipment that uses AVCHD. In that case, each TS packet is preceded by 4 bytes that contain 2 bits of copy permission flags and 30 bits ATS (arrival time stamp) with 27 MHz resolution. Note that the ATS restarts every 40 seconds, and it's *not* related to the DTS/PTS of the actual video. The reason for that is that the MPEG-TS format is actually intended to be used for broadcast at constant bitrates, but it's not optimized for storage, such as on Blu-ray. Therefore, M2TS uses a variable bitrate. In order to reconstruct a transport stream that is suitable for broadcast, the additional ATS information is required. It can be ignored for ordinary playback. Best regards -- Oliver _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
