]> git.sesse.net Git - ffmpeg/commitdiff
avformat/hls: Fixes overwriting existing #EXT-X-PROGRAM-DATE-TIME value in HLS playlist
authorVignesh Ravichandran <vignesh.ravichandran02@gmail.com>
Tue, 1 Dec 2020 10:10:40 +0000 (15:40 +0530)
committerliuqi05 <liuqi05@kuaishou.com>
Tue, 8 Dec 2020 12:57:24 +0000 (20:57 +0800)
fix ticket: 8989

This is is due to the following behavior in the current code:
1. The initial_prog_date_time gets set to the current local time
2. The existing playlist (.m3u8) file gets parsed and the segments
   present are added to the variant stream
3. The new segment is created and added
4. The existing segments and the new segment are written to the
   playlist file. The initial_prog_date_time from point 1 is used
   for calculating "#EXT-X-PROGRAM-DATE-TIME" for the segments,
   which results in incorrect "#EXT-X-PROGRAM-DATE-TIME" values
   for existing segments
The following approach fixes this bug:
1. Add a new variable "discont_program_date_time" of type double
   to HLSSegment struct
2. Store the "EXT-X-PROGRAM-DATE-TIME" value from the existing
   segments in this variable
3. When writing to playlist file if "discont_program_date_time"
   is set, then use that value for "EXT-X-PROGRAM-DATE-TIME" else
   use the value present in vs->initial_prog_date_time

Signed-off-by: Vignesh Ravichandran <vignesh.ravichandran02@gmail.com>
Signed-off-by: liuqi05 <liuqi05@kuaishou.com>
libavformat/hlsenc.c

index cbfd8f7c0d41adfe08e7f451a1aa2ac14cee4609..9bce37460554c0c53dd2ec7a5070b3678572507b 100644 (file)
@@ -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 +1185,7 @@ static int parse_playlist(AVFormatContext *s, const char *url, VariantStream *vs
     char line[MAX_URL_SIZE];
     const char *ptr;
     const char *end;
+    double discont_program_date_time = 0;
 
     if ((ret = ffio_open_whitelist(&in, url, AVIO_FLAG_READ,
                                    &s->interrupt_callback, NULL,
@@ -1236,7 +1240,25 @@ 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)) {
+            struct tm program_date_time;
+            int y,M,d,h,m,s;
+            double ms;
+            if (sscanf(ptr, "%d-%d-%dT%d:%d:%d.%lf", &y, &M, &d, &h, &m, &s, &ms) != 7) {
+                ret = AVERROR_INVALIDDATA;
+                goto fail;
+            }
+
+            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);
         } 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");
         }