Insert dummy chapter if first chapter does not start at beginning of video

util/parse_chapters.c

@@ -10,20 +10,28 @@ void parse_chapters(AVFormatContext *ctx, char *s, int64_t duration)
 	int i;
 	duration = av_rescale_q(duration, AV_TIME_BASE_Q, CHAPTER_TIME_BASE);
 	for (p = jenter(s), i = 0; p; p = jnext(p), i ++);
-	ctx->chapters = xmalloc(sizeof(AVChapter *)*i);
-	ctx->nb_chapters = i;
-	for (p = jenter(s), i = 0; p; p = jnext(p), i ++)
+	ctx->chapters = xmalloc(sizeof(AVChapter *)*(i+1));
+	for (p = jenter(s), i = 0; p; i ++)
 	{
 		ctx->chapters[i] = malloc(sizeof(AVChapter));
 		memset(ctx->chapters[i], 0, sizeof(AVChapter));
 		ctx->chapters[i]->id = i;
 		ctx->chapters[i]->time_base = CHAPTER_TIME_BASE;
+		if (!i && jint(jlookup(p, "time"), -1))
+		{
+			/* Insert dummy chapter starting at time 0 (otherwise ffmpeg glitches) */
+			ctx->chapters[i]->start = 0;
+			av_dict_set(&ctx->chapters[i]->metadata, "title", "Intro", 0);
+			continue;
+		}
 		ctx->chapters[i]->start = jint(jlookup(p, "time"), 0);
-		av_dict_set(&ctx->chapters[i]->metadata, "title", jstr(jlookup(p, "text"), "EMPTY"), 0);
 		if (i)
 			ctx->chapters[i-1]->end = ctx->chapters[i]->start;
+		av_dict_set(&ctx->chapters[i]->metadata, "title", jstr(jlookup(p, "text"), "EMPTY"), 0);
+		p = jnext(p);
 	}
+	ctx->nb_chapters = i;
 	if (ctx->nb_chapters)
-		ctx->chapters[i-1]->end = duration;
+		ctx->chapters[ctx->nb_chapters-1]->end = duration;
 }