From 7ad49b423e9391362bf26e310c230e64b290f068 Mon Sep 17 00:00:00 2001
From: Devata <devatadev@pm.me>
Date: Mon, 21 Aug 2023 01:46:33 +0800
Subject: [PATCH] fix for ext-discontinuity

---
 libavformat/hls.c | 42 +++++++++++++++++++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 3 deletions(-)

diff --git a/libavformat/hls.c b/libavformat/hls.c
index acaebed..2439c7c 100644
--- a/libavformat/hls.c
+++ b/libavformat/hls.c
@@ -66,7 +66,9 @@ enum KeyType {
 };
 
 struct segment {
+    int64_t previous_duration;
     int64_t duration;
+    int64_t start_time;
     int64_t url_offset;
     int64_t size;
     char *url;
@@ -716,7 +718,7 @@ static int parse_playlist(HLSContext *c, const char *url,
                           struct playlist *pls, AVIOContext *in)
 {
     int ret = 0, is_segment = 0, is_variant = 0;
-    int64_t duration = 0;
+    int64_t duration = 0, previous_duration1 = 0, previous_duration = 0, total_duration = 0;
     enum KeyType key_type = KEY_NONE;
     uint8_t iv[16] = "";
     int has_iv = 0;
@@ -874,6 +876,8 @@ static int parse_playlist(HLSContext *c, const char *url,
         } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
             if (pls)
                 pls->finished = 1;
+        } else if (av_strstart(line, "#EXT-X-DISCONTINUITY", &ptr)) {
+            previous_duration = previous_duration1;
         } else if (av_strstart(line, "#EXTINF:", &ptr)) {
             is_segment = 1;
             duration   = atof(ptr) * AV_TIME_BASE;
@@ -903,6 +907,14 @@ static int parse_playlist(HLSContext *c, const char *url,
                     ret = AVERROR(ENOMEM);
                     goto fail;
                 }
+                
+                previous_duration1 += duration;
+                seg->previous_duration = previous_duration;
+                seg->start_time = total_duration;
+                total_duration += duration;
+                seg->duration = duration;
+                seg->key_type = key_type;
+                
                 if (has_iv) {
                     memcpy(seg->iv, iv, sizeof(iv));
                 } else {
@@ -949,8 +961,9 @@ static int parse_playlist(HLSContext *c, const char *url,
                                     " set to default value to 1ms.\n", seg->url);
                     duration = 0.001 * AV_TIME_BASE;
                 }
-                seg->duration = duration;
-                seg->key_type = key_type;
+                // seg->duration = duration;
+                // seg->key_type = key_type;
+
                 dynarray_add(&pls->segments, &pls->n_segments, seg);
                 is_segment = 0;
 
@@ -2257,6 +2270,29 @@ static int hls_read_packet(AVFormatContext *s, AVPacket *pkt)
                                             ist->time_base,
                                             AV_TIME_BASE_Q);
 
+        if (c->playlists[minplaylist]->finished) {
+            struct playlist *pls = c->playlists[minplaylist];
+            int seq_no = pls->cur_seq_no - pls->start_seq_no;
+            if (seq_no < pls->n_segments && s->streams[pkt->stream_index]) {
+                struct segment *seg = pls->segments[seq_no];
+                int64_t pred = av_rescale_q(seg->previous_duration,
+                                            AV_TIME_BASE_Q,
+                                            s->streams[pkt->stream_index]->time_base);
+                int64_t max_ts = av_rescale_q(seg->start_time + seg->duration,
+                                              AV_TIME_BASE_Q,
+                                              s->streams[pkt->stream_index]->time_base);
+                /* EXTINF duration is not precise enough */
+                max_ts += 2 * AV_TIME_BASE;
+                if (s->start_time > 0) {
+                    max_ts += av_rescale_q(s->start_time,
+                                           AV_TIME_BASE_Q,
+                                           s->streams[pkt->stream_index]->time_base);
+                }
+                if (pkt->dts != AV_NOPTS_VALUE && pkt->dts + pred < max_ts) pkt->dts += pred;
+                if (pkt->pts != AV_NOPTS_VALUE && pkt->pts + pred < max_ts) pkt->pts += pred;
+            }
+        }
+
         /* There may be more situations where this would be useful, but this at least
          * handles newly probed codecs properly (i.e. request_probe by mpegts). */
         if (ist->codecpar->codec_id != st->codecpar->codec_id) {