[FFmpeg-devel] [PATCH 3/6] lavc/pgssubdec: use the PTS from the presentation segment.

[Nicolas George]

According to the sample for trac ticket #1722, PGS subtitles
are decoded from several packets at the same DTS and varying PTS.
The PTS from the presentation segment seem to be the valid one;
in particular, clear subtitles are too early with the other PTS.

Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
---
 libavcodec/pgssubdec.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/libavcodec/pgssubdec.c b/libavcodec/pgssubdec.c
index 79ebb55..64d20df 100644
--- a/libavcodec/pgssubdec.c
+++ b/libavcodec/pgssubdec.c
@@ -67,6 +67,7 @@ typedef struct PGSSubContext {
     PGSSubPresentation presentation;
     uint32_t           clut[256];
     PGSSubPicture      pictures[UINT16_MAX];
+    int64_t            pts;
     int forced_subs_only;
 } PGSSubContext;
 
@@ -387,7 +388,11 @@ static int display_end_segment(AVCodecContext *avctx, void *data,
      *      not been cleared by a subsequent empty display command.
      */
 
+    if (ctx->pts == AV_NOPTS_VALUE) /* if no presentation segment to set it */
+        ctx->pts = sub->pts;
     memset(sub, 0, sizeof(*sub));
+    sub->pts = ctx->pts;
+    ctx->pts = AV_NOPTS_VALUE;
 
     // Blank if last object_count was 0.
     if (!ctx->presentation.object_count)
@@ -436,8 +441,10 @@ static int display_end_segment(AVCodecContext *avctx, void *data,
 static int decode(AVCodecContext *avctx, void *data, int *data_size,
                   AVPacket *avpkt)
 {
+    PGSSubContext *ctx = avctx->priv_data;
     const uint8_t *buf = avpkt->data;
     int buf_size       = avpkt->size;
+    AVSubtitle *sub    = data;
 
     const uint8_t *buf_end;
     uint8_t       segment_type;
@@ -482,6 +489,7 @@ static int decode(AVCodecContext *avctx, void *data, int *data_size,
             break;
         case PRESENTATION_SEGMENT:
             parse_presentation_segment(avctx, buf, segment_length);
+            ctx->pts = sub->pts;
             break;
         case WINDOW_SEGMENT:
             /*
-- 
1.7.10.4