2017-04-12 0:55 GMT+10:00 Andy Shaules <[email protected]>: > On 4/10/2017 4:37 PM, YIRAN LI wrote: > > > > 2017-04-10 7:16 GMT+10:00 bowljoman <[email protected]>: > >> >> sorry if this client top posts, but to answer, you can do 1 of 2 things. >> assume it is different and insert it before returning to the unprocessed >> clip. or you can check if they are different by doing a comparison. >> >> >> Thanks for your suggestion. Let's say if original H.264 video stream has > AVCC bitstream, no matter you encode 1st part with Annex-b or AVCC, as long > as it's different from orginal format, I won't be able to do codec copy > using readpacket/writepacket, right? > > Thanks > > >> Sent from my T-Mobile 4G LTE Device >> >> -------- Original message -------- >> From: YIRAN LI <[email protected]> >> Date: 4/7/17 3:15 PM (GMT-08:00) >> To: "This list is about using libavcodec, libavformat, libavutil, >> libavdevice and libavfilter." <[email protected]>, FFmpeg user >> questions <[email protected]> >> Subject: [Libav-user] re-encoding and transcode (codec copy) on same >> file. >> >> Hi guys, >> >> I'm investigating if it's possible to do editing and transcode on same >> file. >> >> I mean use -vcodec copy, we can readout packets and write them directly >> into output file without re-encoding. But if it's possible, for example if >> I have a 2 mins video, re-encode 1st min because there're some effects >> applied to that region but copy 2nd part? >> >> My concern is, for example we know H.264 has extradata, if I re-encode >> first part but keep 2nd part, how if new extradata is different from old >> extradta? >> >> Anyone have suggestion on this? and any other possible problems doing >> this? >> >> Thanks >> >> _______________________________________________ >> Libav-user mailing list >> [email protected] >> http://ffmpeg.org/mailman/listinfo/libav-user >> >> > > > _______________________________________________ > Libav-user mailing > [email protected]http://ffmpeg.org/mailman/listinfo/libav-user > > It doesnt matter what the inputs are. just convert them to one or the > other type. the final stream can be assembled with all avc or avcc packets. > choose one or the other. >
Thanks for reply. I did some research yesterday and I think no matter packets in the file is in starting code (annex-b) or size (avcc) mode, I can always detect and convert it to another mode. The problem is, if I re-encode a part and keep another part, how can I guarantee the SPS/PPS values for 2 parts are same? If they are different, even if they are in packets (in-band) instead of in global header, is such a file standard compliant ? Thanks > > _______________________________________________ > Libav-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/libav-user > >
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