avformat/subtitles: make dropping duplicate events optional

libavformat/subtitles.c

@@ -204,7 +204,8 @@ void ff_subtitles_queue_finalize(void *log_ctx, FFDemuxSubtitlesQueue *q)
         if (q->subs[i].duration == -1 && i < q->nb_subs - 1)
             q->subs[i].duration = q->subs[i + 1].pts - q->subs[i].pts;
 
-    drop_dups(log_ctx, q);
+    if (!q->keep_duplicates)
+        drop_dups(log_ctx, q);
 }
 
 int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)

libavformat/subtitles.h

@@ -105,6 +105,7 @@ typedef struct {
     int allocated_size;     ///< allocated size for subs
     int current_sub_idx;    ///< current position for the read packet callback
     enum sub_sort sort;     ///< sort method to use when finalizing subtitles
+    int keep_duplicates;    ///< set to 1 to keep duplicated subtitle events
 } FFDemuxSubtitlesQueue;
 
 /**