On Tue, Dec 6, 2022 at 10:56 AM Nicolas Gaullier <nicolas.gaullier@cji.paris> wrote:
> >As the title says, is this at all possible? My concern is mostly with > mpeg2 and h264 that have content of one type but encoded/marked as another. > In a general manner, amongst other things, interlaced encoding involves > interlaced DCT, so this is not possible because it is not a simple "mark". > In some very limited scenarios, it is possible to tag interlaced content > as progressive-segmented frame (PsF). Take mpeg2/h264: I have never seen > any implementation (neither encoder or decoder) of the flags that actually > allow to mark progressive content, so PsF is pure theory here. So today, > for example, only "progressive sequence" mpeg2 is considered progressive : > you have to transcode. > > >Most notably content that has progressive video but stored interlaced. > "encoded" rather than "stored", but yes, it is indeed very commonplace. > Nevertheless, be very very carefull, it is also very very commonplace to > have interlaced branding/finishing on progressive content, so it can end up > with 1 hours of pure progressive content with 3x period of 10s where an > interlaced title appear or disappear in a corner... This is why > deinterlacing filters are both so useful and so tricky. > > IIRC there was/are some bitstream filters that can change stored flags at bitstream level. > Nicolas > _______________________________________________ > 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". > _______________________________________________ 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".