>Envoyé : mardi 26 mars 2024 16:10 > >This is a patch from my patch serie >https://patchwork.ffmpeg.org/project/ffmpeg/list/?series=10999 >Maybe it is easier to review it this way, independantly. >This patch shows some benefits by itself, but most importantly, it is required >for my patch serie to avoid any regression with some invalid streams. > >This patch is active in mpegts/h264 when the NAL Access Unit Delimiter is >missing the zero_byte (= a invalid stream case). >In such a case, if it happens that the last data byte from the previous frame >is a null byte, this byte is "kidnaped" to form the full NAL_AUD... >This is not good, but even worser, with my patch serie above applied, it means >that the start of the editunit is in the previous frame, which means the pts >has to be taken in it, which is not the expected behaviour in such a >missleading >scenario. > >Michael sent me a sample from the wild but it can't be shared, so here it is: >I have another sample of my own with NAL_AUD missing zero_byte similarly, but >it is missing the ending null byte, so I have patched/inserted the null byte >(I shrinked the adaptation field) to show how the code behave. > >Sample original (invalid NAL_AUDs): >https://0x0.st/Xs9Q.ts >Same sample modified to exhibit the issue (invalid NAL_AUDs + an available >null ending byte at 0x291F): >https://0x0.st/Xs9j.ts > >I use this simple command line and then compare the xml, it seems quite clear: >ffprobe xxx.ts -show_packets -show_data -print_format xml > >Nicolas Gaullier (1): > avcodec/h264_parser: fix start of packet for some broken streams > > libavcodec/h264_parser.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-)
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