static int read_packet(AVFormatContext *s, AVPacket *pkt) { FilmstripDemuxContext *film = s->priv_data; AVStream *st = s->streams[0]; if (s->pb->eof_reached) return AVERROR(EIO); pkt->dts = avio_tell(s->pb) / (st->codec->width * (st->codec->height + film->leading) * 4); pkt->size = av_get_packet(s->pb, pkt, st->codec->width * st->codec->height * 4); avio_skip(s->pb, st->codec->width * film->leading * 4); if (pkt->size < 0) return pkt->size; pkt->flags |= AV_PKT_FLAG_KEY; return 0; }