fre 2024-07-12 klockan 12:51 -0700 skrev Pierre-Anthony Lemieux: > On Thu, Jul 11, 2024 at 10:28 PM Tomas Härdin <g...@haerdin.se> wrote: > > > > > + if (s->in_tile_headers == 1 && s->isHT && (!s- > > > > Ccap15_b11)) > > > + av_log(s->avctx, AV_LOG_WARNING, "COD marker is > > > found in HOMOGENEOUS HT set\n"); > > > > How bad is this and the other markers being present in this case? > > At the very least, it means that signaling is inconsistent within the > codestream since the standard states that: > """ > The HOMOGENEOUS set is the set of HTJ2K codestreams where: > • none of the functional marker segments, e.g., COD, COC, RGN, QCD, > QCC, and POC, are present in any > tile-part header; and > • no PPT marker segment is present. > """ > > The point of signalling that a codestream is "HOMOGENEOUS" is to > allow > decoders to configure themselves solely based on information > retrieved > entirely from the main header. > > Since, AFAIK, FFMPEG does not rely on the HOMOGENEOUS to short- > circuit > configuration, incorrect HOMOGENEOUS signalling will likely not > impact > FFMPEG.
It could happen that information in tile headers contradict information in the main header, right? In such a case it sounds like we can't be sure which decode is the correct one. Much like with broken MXF files I think we should error out because of the potential ambiguity, to discourage broken encoders from proliferating. Else we'll have to deal with them perpetually /Tomas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
