Hello, everyone.
I'd like to request a change in order of DVB segments to be in line with ETSI
300 743. Basically Region Composition Segment should come before CLUT segment.
This caused problems on legacy STBs namely Amino A110.
In the ETSI EN 300 743 V1.6.1 (2018-10) section 4.4 it is written:
The order of their listing here matches their ordering, when present, in a
display set:
display definition segment ...
page composition segment ...
region composition segment ...
disparity signalling segment ...
CLUT definition segment ...
alternative CLUT segment ...
object data segment ...
end of display set segment ...
It makes sense for this order to be implemented by ffmpeg.
I attached a patch, made using git format-patch.
Best regards
Alen
From eaa9addf0bcab40e17d67c699919e5610b341eab Mon Sep 17 00:00:00 2001
From: Alen Vrecko <alen.vre...@fora.si>
Date: Mon, 17 Feb 2020 15:47:05 +0100
Subject: [PATCH] Change Dvb segment order to be the same as in ETSI EN 300 743
spec.
Having CLUT before Region Composition Segment caused problems on legacy STBs i.e. Amino A110.
In any case, the spec assumes an order. In section 4.4. It is written: "The order of their listing (referring to segment types) here matches their ordering, when present, in a display set". I think ffmpeg should match the order.
---
libavcodec/dvbsub.c | 80 ++++++++++++++++++++++-----------------------
1 file changed, 40 insertions(+), 40 deletions(-)
diff --git a/libavcodec/dvbsub.c b/libavcodec/dvbsub.c
index a8d43d81d6..e76d3044b8 100644
--- a/libavcodec/dvbsub.c
+++ b/libavcodec/dvbsub.c
@@ -296,6 +296,46 @@ static int encode_dvb_subtitles(AVCodecContext *avctx,
bytestream_put_be16(&pseg_len, q - pseg_len - 2);
+ for (region_id = 0; region_id < h->num_rects; region_id++) {
+
+ /* region composition segment */
+
+ if (h->rects[region_id]->nb_colors <= 4) {
+ /* 2 bpp, some decoders do not support it correctly */
+ bpp_index = 0;
+ } else if (h->rects[region_id]->nb_colors <= 16) {
+ /* 4 bpp, standard encoding */
+ bpp_index = 1;
+ } else if (h->rects[region_id]->nb_colors <= 256) {
+ /* 8 bpp, standard encoding */
+ bpp_index = 2;
+ } else {
+ return -1;
+ }
+
+ *q++ = 0x0f; /* sync_byte */
+ *q++ = 0x11; /* segment_type */
+ bytestream_put_be16(&q, page_id);
+ pseg_len = q;
+ q += 2; /* segment length */
+ *q++ = region_id;
+ *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
+ bytestream_put_be16(&q, h->rects[region_id]->w); /* region width */
+ bytestream_put_be16(&q, h->rects[region_id]->h); /* region height */
+ *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
+ *q++ = region_id; /* clut_id == region_id */
+ *q++ = 0; /* 8 bit fill colors */
+ *q++ = 0x03; /* 4 bit and 2 bit fill colors */
+
+ bytestream_put_be16(&q, region_id); /* object_id == region_id */
+ *q++ = (0 << 6) | (0 << 4);
+ *q++ = 0;
+ *q++ = 0xf0;
+ *q++ = 0;
+
+ bytestream_put_be16(&pseg_len, q - pseg_len - 2);
+ }
+
if (h->num_rects) {
for (clut_id = 0; clut_id < h->num_rects; clut_id++) {
@@ -346,46 +386,6 @@ static int encode_dvb_subtitles(AVCodecContext *avctx,
}
}
- for (region_id = 0; region_id < h->num_rects; region_id++) {
-
- /* region composition segment */
-
- if (h->rects[region_id]->nb_colors <= 4) {
- /* 2 bpp, some decoders do not support it correctly */
- bpp_index = 0;
- } else if (h->rects[region_id]->nb_colors <= 16) {
- /* 4 bpp, standard encoding */
- bpp_index = 1;
- } else if (h->rects[region_id]->nb_colors <= 256) {
- /* 8 bpp, standard encoding */
- bpp_index = 2;
- } else {
- return -1;
- }
-
- *q++ = 0x0f; /* sync_byte */
- *q++ = 0x11; /* segment_type */
- bytestream_put_be16(&q, page_id);
- pseg_len = q;
- q += 2; /* segment length */
- *q++ = region_id;
- *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
- bytestream_put_be16(&q, h->rects[region_id]->w); /* region width */
- bytestream_put_be16(&q, h->rects[region_id]->h); /* region height */
- *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
- *q++ = region_id; /* clut_id == region_id */
- *q++ = 0; /* 8 bit fill colors */
- *q++ = 0x03; /* 4 bit and 2 bit fill colors */
-
- bytestream_put_be16(&q, region_id); /* object_id == region_id */
- *q++ = (0 << 6) | (0 << 4);
- *q++ = 0;
- *q++ = 0xf0;
- *q++ = 0;
-
- bytestream_put_be16(&pseg_len, q - pseg_len - 2);
- }
-
if (h->num_rects) {
for (object_id = 0; object_id < h->num_rects; object_id++) {
--
2.21.1
_______________________________________________
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".
