[FFmpeg-devel] [PATCH] avcodec/ccaption_dec: don't print multiple \pos tags per cue

[Marth64]

Currently, Closed Captions decoder prints multiple \pos ASS tags per line,
per cue. This is invalid behavior, because only the first \pos tag in a cue
is honored by ASS anyway. Don't write multiple \pos tags.

Signed-off-by: Marth64 <marth64 at proxyid.net>
---
 libavcodec/ccaption_dec.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c
index faf058ce97..9d4a93647c 100644
--- a/libavcodec/ccaption_dec.c
+++ b/libavcodec/ccaption_dec.c
@@ -456,7 +456,7 @@ static void roll_up(CCaptionSubContext *ctx)
 
 static int capture_screen(CCaptionSubContext *ctx)
 {
-    int i, j, tab = 0;
+    int i, j, tab = 0, seen_row = 0;
     struct Screen *screen = ctx->screen + ctx->active_screen;
     enum cc_font prev_font = CCFONT_REGULAR;
     enum cc_color_code prev_color = CCCOL_WHITE;
@@ -496,7 +496,11 @@ static int capture_screen(CCaptionSubContext *ctx)
 
             x = ASS_DEFAULT_PLAYRESX * (0.1 + 0.0250 * j);
             y = ASS_DEFAULT_PLAYRESY * (0.1 + 0.0533 * i);
-            av_bprintf(&ctx->buffer[bidx], "{\\an7}{\\pos(%d,%d)}", x, y);
+
+            if (!seen_row) {
+                av_bprintf(&ctx->buffer[bidx], "{\\an7}{\\pos(%d,%d)}", x, y);
+                seen_row = 1;
+            }
 
             for (; j < SCREEN_COLUMNS; j++) {
                 const char *e_tag = "", *s_tag = "", *c_tag = "", *b_tag = "";
-- 
2.34.1