hlsdemux2: Parse EXT-X-SKIP tag

Parse the attributes from the EXT-X-SKIP tag

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3883>

subprojects/gst-plugins-good/ext/adaptivedemux2/hls/m3u8.c

@@ -66,6 +66,9 @@ gst_hls_media_playlist_unref (GstHLSMediaPlaylist * self)
     if (self->preload_hints != NULL)
       g_ptr_array_free (self->preload_hints, TRUE);
 
+    if (self->removed_date_ranges != NULL)
+      g_strfreev (self->removed_date_ranges);
+
     g_free (self->last_data);
     g_mutex_clear (&self->lock);
     g_free (self);
@@ -479,6 +482,17 @@ gst_hls_media_playlist_dump (GstHLSMediaPlaylist * self)
 
   GST_DEBUG ("can block reloads: %s", self->can_block_reload ? "YES" : "NO");
 
+  GST_DEBUG ("skipped segments: %d", self->skipped_segments);
+
+  if (self->num_removed_date_ranges && self->removed_date_ranges) {
+    GST_DEBUG ("Removed date ranges: %u", self->num_removed_date_ranges);
+    gchar **cur = self->removed_date_ranges;
+    while (*cur != NULL) {
+      GST_DEBUG ("  ID: %s", *cur);
+      cur++;
+    }
+  }
+
   GST_DEBUG ("Segments : %d", self->segments->len);
   for (idx = 0; idx < self->segments->len; idx++) {
     GstM3U8MediaSegment *segment = g_ptr_array_index (self->segments, idx);
@@ -762,6 +776,37 @@ malformed_line:
   }
 }
 
+/* Parse EXT-X-SKIP */
+static void
+parse_skip_tag (GstHLSMediaPlaylist * self, gchar * data)
+{
+  gchar *v, *a;
+
+  while (data != NULL && parse_attributes (&data, &a, &v)) {
+    if (strcmp (a, "SKIPPED-SEGMENTS") == 0) {
+      if (!int_from_string (v, NULL, &self->skipped_segments)
+          || self->skipped_segments < 0) {
+        GST_WARNING ("Can't read skipped segments from EXT-X-SKIP value");
+        self->skipped_segments = 0;
+        goto malformed_line;
+      }
+    } else if (strcmp (a, "RECENTLY-REMOVED-DATERANGES") == 0) {
+      gchar **removed_date_ranges = g_strsplit (v, "\t", -1);
+
+      g_strfreev (self->removed_date_ranges);
+      self->removed_date_ranges = removed_date_ranges;
+      self->num_removed_date_ranges = g_strv_length (removed_date_ranges);
+    }
+  }
+
+  return;
+malformed_line:
+  {
+    GST_WARNING ("Invalid EXT-X-SKIP entry in playlist");
+    return;
+  }
+}
+
 /* Parse and create a new GstHLSMediaPlaylist */
 GstHLSMediaPlaylist *
 gst_hls_media_playlist_parse (gchar * data,
@@ -1106,6 +1151,9 @@ gst_hls_media_playlist_parse (gchar * data,
               (GDestroyNotify) gst_m3u8_preload_hint_unref);
         }
         g_ptr_array_add (self->preload_hints, hint);
+      } else if (g_str_has_prefix (data_ext_x, "SKIP:")) {
+        data += strlen ("#EXT-X-SKIP:");
+        parse_skip_tag (self, data);
       } else {
         GST_LOG ("Ignored line: %s", data);
       }

subprojects/gst-plugins-good/ext/adaptivedemux2/hls/m3u8.h

@@ -142,6 +142,11 @@ struct _GstHLSMediaPlaylist
   GstClockTime part_hold_back;  /* Part-Hold-Back value, if provided (or CLOCK_TIME_NONE */
   gboolean can_block_reload;    /* TRUE if CAN-BLOCK-RELOAD was YES */
 
+  /* Delta playlist info from EXT-X-SKIP tag */
+  gint skipped_segments;
+  gint num_removed_date_ranges;
+  gchar **removed_date_ranges;
+
   /*< private > */
   GMutex lock;
 

subprojects/gst-plugins-good/tests/check/elements/hlsdemux_m3u8.c

@@ -259,6 +259,30 @@ midRoll273.mp4\n\
 #EXT-X-PRELOAD-HINT:TYPE=PART,URI=\"midRoll274.1.mp4\"\n\
 #EXT-X-RENDITION-REPORT:URI=\"/1M/LL-HLS.m3u8\",LAST-MSN=274,LAST-PART=1";
 
+static const gchar *SKIP_PLAYLIST = "#EXTM3U\n\
+#EXT-X-VERSION:7\n\
+#EXT-X-TARGETDURATION:4\n\
+#EXT-X-PART-INF:PART-TARGET=2\n\
+#EXT-X-SKIP:SKIPPED-SEGMENTS=2,RECENTLY-REMOVED-DATERANGES=\"splice-6FFFFFF0\tsplice-6FFFFFF1\"\n\
+#EXTINF:4.00008,\n\
+fileSequence270.mp4\n\
+#EXT-X-PART:DURATION=2.00004,INDEPENDENT=YES,URI=\"filePart271.0.mp4\"\n\
+#EXT-X-PART:DURATION=2.00004,URI=\"filePart271.1.mp4\"\n\
+#EXTINF:4.00008,\n\
+fileSequence271.mp4\n\
+#EXT-X-PART:DURATION=2.00004,INDEPENDENT=YES,URI=\"filePart272.0.mp4\"\n\
+#EXT-X-PART:DURATION=0.50001,URI=\"filePart272.1.mp4\"\n\
+#EXTINF:2.50005,\n\
+fileSequence272.mp4\n\
+#EXT-X-DISCONTINUITY\n\
+#EXT-X-PART:DURATION=2.00004,INDEPENDENT=YES,URI=\"midRoll273.0.mp4\"\n\
+#EXT-X-PART:DURATION=2.00004,URI=\"midRoll273.1.mp4\"\n\
+#EXTINF:4.00008,\n\
+midRoll273.mp4\n\
+#EXT-X-PART:DURATION=2.00004,INDEPENDENT=YES,URI=\"midRoll274.0.mp4\"\n\
+#EXT-X-PRELOAD-HINT:TYPE=PART,URI=\"midRoll274.1.mp4\"\n\
+#EXT-X-RENDITION-REPORT:URI=\"/1M/LL-HLS.m3u8\",LAST-MSN=274,LAST-PART=1";
+
 static GstHLSMediaPlaylist *
 load_m3u8 (const gchar * data)
 {
@@ -920,6 +944,24 @@ GST_START_TEST (test_low_latency_playlist)
 }
 
 GST_END_TEST;
+
+GST_START_TEST (test_playlist_skip)
+{
+  GstHLSMediaPlaylist *pl;
+
+  pl = load_m3u8 (SKIP_PLAYLIST);
+  fail_unless (pl != NULL);
+
+  assert_equals_int (pl->skipped_segments, 2);
+  assert_equals_int (pl->num_removed_date_ranges, 2);
+  fail_unless (g_strcmp0 (pl->removed_date_ranges[0], "splice-6FFFFFF0") == 0);
+  fail_unless (g_strcmp0 (pl->removed_date_ranges[1], "splice-6FFFFFF1") == 0);
+
+  gst_hls_media_playlist_unref (pl);
+}
+
+GST_END_TEST;
+
 static Suite *
 hlsdemux_suite (void)
 {
@@ -955,6 +997,7 @@ hlsdemux_suite (void)
   tcase_add_test (tc_m3u8, test_stream_inf_tag);
   tcase_add_test (tc_m3u8, test_map_tag);
   tcase_add_test (tc_m3u8, test_low_latency_playlist);
+  tcase_add_test (tc_m3u8, test_playlist_skip);
   return s;
 }