[FFmpeg-devel] [PATCH] avformat/hls: Fixes #EXT-X-PROGRAM-DATE-TIME value of existing segments from getting over written with new value when appending new segments to an existing playlist file

[Vignesh Ravichandran]

Signed-off-by: Vignesh Ravichandran <vignesh.ravichandran02 at gmail.com>
---
 libavformat/hlsenc.c | 35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
index cbfd8f7c0d..030a2d3b97 100644
--- a/libavformat/hlsenc.c
+++ b/libavformat/hlsenc.c
@@ -88,6 +88,7 @@ typedef struct HLSSegment {
     char iv_string[KEYSIZE*2 + 1];
 
     struct HLSSegment *next;
+    double discont_program_date_time;
 } HLSSegment;
 
 typedef enum HLSFlags {
@@ -1124,6 +1125,7 @@ static int hls_append_segment(struct AVFormatContext *s, HLSContext *hls,
     en->keyframe_size     = vs->video_keyframe_size;
     en->next     = NULL;
     en->discont  = 0;
+    en->discont_program_date_time = 0;
 
     if (vs->discontinuity) {
         en->discont = 1;
@@ -1148,7 +1150,8 @@ static int hls_append_segment(struct AVFormatContext *s, HLSContext *hls,
 
     if (hls->max_nb_segments && vs->nb_entries >= hls->max_nb_segments) {
         en = vs->segments;
-        vs->initial_prog_date_time += en->duration;
+        if (!en->next->discont_program_date_time && !en->discont_program_date_time)
+            vs->initial_prog_date_time += en->duration;
         vs->segments = en->next;
         if (en && hls->flags & HLS_DELETE_SEGMENTS &&
 #if FF_API_HLS_WRAP
@@ -1182,6 +1185,8 @@ static int parse_playlist(AVFormatContext *s, const char *url, VariantStream *vs
     char line[MAX_URL_SIZE];
     const char *ptr;
     const char *end;
+    int is_discont_detected = 0;
+    double discont_program_date_time = 0;
 
     if ((ret = ffio_open_whitelist(&in, url, AVIO_FLAG_READ,
                                    &s->interrupt_callback, NULL,
@@ -1211,6 +1216,7 @@ static int parse_playlist(AVFormatContext *s, const char *url, VariantStream *vs
         } else if (av_strstart(line, "#EXT-X-DISCONTINUITY", &ptr)) {
             is_segment = 1;
             vs->discontinuity = 1;
+            is_discont_detected = 1;
         } else if (av_strstart(line, "#EXTINF:", &ptr)) {
             is_segment = 1;
             vs->duration = atof(ptr);
@@ -1236,7 +1242,23 @@ static int parse_playlist(AVFormatContext *s, const char *url, VariantStream *vs
                     av_strlcpy(vs->iv_string, ptr, sizeof(vs->iv_string));
                 }
             }
-
+        } else if (av_strstart(line, "#EXT-X-PROGRAM-DATE-TIME:", &ptr) && is_discont_detected) {
+            struct tm program_date_time;
+            int y,M,d,h,m,s;
+            double ms;
+            sscanf(ptr, "%d-%d-%dT%d:%d:%d.%lf", &y, &M, &d, &h, &m, &s, &ms);
+
+            program_date_time.tm_year = y - 1900;
+            program_date_time.tm_mon = M - 1;
+            program_date_time.tm_mday = d;
+            program_date_time.tm_hour = h;
+            program_date_time.tm_min = m;
+            program_date_time.tm_sec = s;
+            program_date_time.tm_isdst = -1;
+
+            discont_program_date_time = mktime(&program_date_time);
+            discont_program_date_time += (double)(ms / 1000);
+            is_discont_detected = 0;
         } else if (av_strstart(line, "#", NULL)) {
             continue;
         } else if (line[0]) {
@@ -1250,8 +1272,9 @@ static int parse_playlist(AVFormatContext *s, const char *url, VariantStream *vs
                 is_segment = 0;
                 new_start_pos = avio_tell(vs->avf->pb);
                 vs->size = new_start_pos - vs->start_pos;
-                vs->initial_prog_date_time -= vs->duration; // this is a previously existing segment
                 ret = hls_append_segment(s, hls, vs, vs->duration, vs->start_pos, vs->size);
+                vs->last_segment->discont_program_date_time = discont_program_date_time;
+                discont_program_date_time += vs->duration;
                 if (ret < 0)
                     goto fail;
                 vs->start_pos = new_start_pos;
@@ -1572,7 +1595,11 @@ static int hls_window(AVFormatContext *s, int last, VariantStream *vs)
         ret = ff_hls_write_file_entry(byterange_mode ? hls->m3u8_out : vs->out, en->discont, byterange_mode,
                                       en->duration, hls->flags & HLS_ROUND_DURATIONS,
                                       en->size, en->pos, hls->baseurl,
-                                      en->filename, prog_date_time_p, en->keyframe_size, en->keyframe_pos, hls->flags & HLS_I_FRAMES_ONLY);
+                                      en->filename,
+                                      en->discont_program_date_time ? &en->discont_program_date_time : prog_date_time_p,
+                                      en->keyframe_size, en->keyframe_pos, hls->flags & HLS_I_FRAMES_ONLY);
+        if (en->discont_program_date_time)
+            en->discont_program_date_time -= en->duration;
         if (ret < 0) {
             av_log(s, AV_LOG_WARNING, "ff_hls_write_file_entry get error\n");
         }
-- 
2.24.2 (Apple Git-127)