From: softworkz <softwo...@hotmail.com>
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 flawed condition prevented proper fallback to using the default
resolution for the decoding context.
Signed-off-by: softworkz <softwo...@hotmail.com>
---
libavcodec/dvbsubdec.c | 51 +++++++++++++++++++++++++-----------------
1 file changed, 30 insertions(+), 21 deletions(-)
diff --git a/libavcodec/dvbsubdec.c b/libavcodec/dvbsubdec.c
index c864ba3fb6..4df350574d 100644
--- a/libavcodec/dvbsubdec.c
+++ b/libavcodec/dvbsubdec.c
@@ -34,7 +34,7 @@
#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)
@@ -1450,8 +1450,12 @@ 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_segment = 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");
@@ -1496,34 +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",
@@ -1536,13 +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 && got_end_display) {
+
+ 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-codebot
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