ffmpeg | branch: master | softworkz <softwo...@hotmail.com> | Fri Dec 3 15:15:27 2021 +0100| [edd28770be8b37edb35747426cb0510b83893c09] | committer: softworkz
avcodec/dvbsubdec: Fix conditions for fallback to default resolution The previous code expected a segment of type CLUT definition to exist in order to accept a set of segments to be complete. This was an incorrect assumption as the presence of a CLUT segment is not mandatory. (version 1.6.1 of the spec is probably a bit more clear about this than earlier versions: https://www.etsi.org/deliver/etsi_en/ 300700_300799/300743/01.06.01_20/en_300743v010601a.pdf) The incorrect condition prevented proper fallback to using the default resolution for the decoding context. This also adds variables and moves the fallback check to the outside for better clarity. Signed-off-by: softworkz <softwo...@hotmail.com> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=edd28770be8b37edb35747426cb0510b83893c09 --- libavcodec/dvbsubdec.c | 50 +++++++++++++++++++++++++++++--------------------- 1 file changed, 29 insertions(+), 21 deletions(-) diff --git a/libavcodec/dvbsubdec.c b/libavcodec/dvbsubdec.c index 4553c45b3d..cbb16e501a 100644 --- a/libavcodec/dvbsubdec.c +++ b/libavcodec/dvbsubdec.c @@ -35,7 +35,7 @@ #define DVBSUB_CLUT_SEGMENT 0x12 #define DVBSUB_OBJECT_SEGMENT 0x13 #define DVBSUB_DISPLAYDEFINITION_SEGMENT 0x14 -#define DVBSUB_DISPLAY_SEGMENT 0x80 +#define DVBSUB_END_DISPLAY_SEGMENT 0x80 #define cm (ff_crop_tab + MAX_NEG_CROP) @@ -1451,8 +1451,11 @@ static int dvbsub_decode(AVCodecContext *avctx, AVSubtitle *sub, int segment_length; int i; int ret = 0; - int got_segment = 0; - int got_dds = 0; + int got_page = 0; + int got_region = 0; + int got_object = 0; + int got_end_display = 0; + int got_displaydef = 0; ff_dlog(avctx, "DVB sub packet:\n"); @@ -1497,34 +1500,28 @@ static int dvbsub_decode(AVCodecContext *avctx, AVSubtitle *sub, switch (segment_type) { case DVBSUB_PAGE_SEGMENT: ret = dvbsub_parse_page_segment(avctx, p, segment_length, sub, got_sub_ptr); - got_segment |= 1; + got_page = 1; break; case DVBSUB_REGION_SEGMENT: ret = dvbsub_parse_region_segment(avctx, p, segment_length); - got_segment |= 2; + got_region = 1; break; case DVBSUB_CLUT_SEGMENT: ret = dvbsub_parse_clut_segment(avctx, p, segment_length); if (ret < 0) goto end; - got_segment |= 4; break; case DVBSUB_OBJECT_SEGMENT: ret = dvbsub_parse_object_segment(avctx, p, segment_length); - got_segment |= 8; + got_object = 1; break; case DVBSUB_DISPLAYDEFINITION_SEGMENT: ret = dvbsub_parse_display_definition_segment(avctx, p, segment_length); - got_dds = 1; + got_displaydef = 1; break; - case DVBSUB_DISPLAY_SEGMENT: + case DVBSUB_END_DISPLAY_SEGMENT: ret = dvbsub_display_end_segment(avctx, p, segment_length, sub, got_sub_ptr); - if (got_segment == 15 && !got_dds && !avctx->width && !avctx->height) { - // Default from ETSI EN 300 743 V1.3.1 (7.2.1) - avctx->width = 720; - avctx->height = 576; - } - got_segment |= 16; + got_end_display = 1; break; default: ff_dlog(avctx, "Subtitling segment type 0x%x, page id %d, length %d\n", @@ -1537,13 +1534,24 @@ static int dvbsub_decode(AVCodecContext *avctx, AVSubtitle *sub, p += segment_length; } - // Some streams do not send a display segment but if we have all the other - // segments then we need no further data. - if (got_segment == 15) { - av_log(avctx, AV_LOG_DEBUG, "Missing display_end_segment, emulating\n"); - dvbsub_display_end_segment(avctx, p, 0, sub, got_sub_ptr); - } + // Even though not mandated by the spec, we're imposing a minimum requirement + // for a useful packet to have at least one page, region and object segment. + if (got_page && got_region && got_object) { + + if (!got_displaydef && !avctx->width && !avctx->height) { + // Default from ETSI EN 300 743 V1.3.1 (7.2.1) + avctx->width = 720; + avctx->height = 576; + } + + // Some streams do not send an end-of-display segment but if we have all the other + // segments then we need no further data. + if (!got_end_display) { + av_log(avctx, AV_LOG_DEBUG, "Missing display_end_segment, emulating\n"); + dvbsub_display_end_segment(avctx, p, 0, sub, got_sub_ptr); + } + } end: if (ret < 0) { return ret; _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
