lavc/ccaption_dec: fix ASS tags

libavcodec/ccaption_dec.c

@@ -307,24 +307,24 @@ static int capture_screen(CCaptionSubContext *ctx)
                 if (prev_font != font[j]) {
                     switch (prev_font) {
                     case CCFONT_ITALICS:
-                        e_tag = "{/i0}";
+                        e_tag = "{\\i0}";
                         break;
                     case CCFONT_UNDERLINED:
-                        e_tag = "{/u0}";
+                        e_tag = "{\\u0}";
                         break;
                     case CCFONT_UNDERLINED_ITALICS:
-                        e_tag = "{/u0}{/i0}";
+                        e_tag = "{\\u0}{\\i0}";
                         break;
                     }
                     switch (font[j]) {
                     case CCFONT_ITALICS:
-                        s_tag = "{/i1}";
+                        s_tag = "{\\i1}";
                         break;
                     case CCFONT_UNDERLINED:
-                        s_tag = "{/u1}";
+                        s_tag = "{\\u1}";
                         break;
                     case CCFONT_UNDERLINED_ITALICS:
-                        s_tag = "{/u1}{/i1}";
+                        s_tag = "{\\u1}{\\i1}";
                         break;
                     }
                 }

tests/ref/fate/sub-cc

@@ -10,5 +10,5 @@ Style: Default,Arial,16,&Hffffff,&Hffffff,&H0,&H0,0,0,0,0,100,100,0,0,1,1,0,2,10
 
 [Events]
 Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
-Dialogue: 0,0:00:12.36,0:00:40.83,Default,,0,0,0,,({/i1} inaudible radio chatter{/i0} )
-Dialogue: 0,0:00:40.83,0:00:59.07,Default,,0,0,0,,({/i1} inaudible radio chatter{/i0} )\N>> Safety remains our number one
+Dialogue: 0,0:00:12.36,0:00:40.83,Default,,0,0,0,,({\i1} inaudible radio chatter{\i0} )
+Dialogue: 0,0:00:40.83,0:00:59.07,Default,,0,0,0,,({\i1} inaudible radio chatter{\i0} )\N>> Safety remains our number one