hlsdemux2: Add parsing of partial segments

Add partial segments to each media segment, and potentially create a trailing dummy segment if there are partial segments at the end of the playlist Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3883>
2024-12-18 14:26:43 +00:00 · 2022-06-08 01:35:44 +10:00 · 2022-06-08 01:35:44 +10:00 · 07f51396af
commit 07f51396af
parent fac7177354
2 changed files with 233 additions and 6 deletions
--- a/subprojects/gst-plugins-good/ext/adaptivedemux2/hls/m3u8.c
+++ b/subprojects/gst-plugins-good/ext/adaptivedemux2/hls/m3u8.c
@ -112,10 +112,32 @@ gst_m3u8_media_segment_unref (GstM3U8MediaSegment * self)
    g_free (self->key);
    if (self->datetime)
      g_date_time_unref (self->datetime);
+    if (self->partial_segments)
+      g_ptr_array_free (self->partial_segments, TRUE);
    g_free (self);
  }
 }

+GstM3U8PartialSegment *
+gst_m3u8_partial_segment_ref (GstM3U8PartialSegment * part)
+{
+  g_assert (part != NULL && part->ref_count > 0);
+
+  g_atomic_int_add (&part->ref_count, 1);
+  return part;
+}
+
+void
+gst_m3u8_partial_segment_unref (GstM3U8PartialSegment * part)
+{
+  g_return_if_fail (part != NULL && part->ref_count > 0);
+
+  if (g_atomic_int_dec_and_test (&part->ref_count)) {
+    g_free (part->uri);
+    g_free (part);
+  }
+}
+
 static GstM3U8InitFile *
 gst_m3u8_init_file_new (gchar * uri, gint64 size, gint64 offset)
 {
@ -343,6 +365,7 @@ gst_hls_media_playlist_new (const gchar * uri, const gchar * base_uri)
  m3u8->version = 1;
  m3u8->type = GST_HLS_PLAYLIST_TYPE_UNDEFINED;
  m3u8->targetduration = GST_CLOCK_TIME_NONE;
+  m3u8->partial_targetduration = GST_CLOCK_TIME_NONE;
  m3u8->media_sequence = 0;
  m3u8->discont_sequence = 0;
  m3u8->endlist = FALSE;
@ -377,6 +400,8 @@ gst_hls_media_playlist_dump (GstHLSMediaPlaylist * self)

  GST_DEBUG ("targetduration   : %" GST_TIME_FORMAT,
      GST_TIME_ARGS (self->targetduration));
+  GST_DEBUG ("partial segment targetduration   : %" GST_TIME_FORMAT,
+      GST_TIME_ARGS (self->partial_targetduration));
  GST_DEBUG ("media_sequence   : %" G_GINT64_FORMAT, self->media_sequence);
  GST_DEBUG ("discont_sequence : %" G_GINT64_FORMAT, self->discont_sequence);

@ -398,6 +423,7 @@ gst_hls_media_playlist_dump (GstHLSMediaPlaylist * self)

    GST_DEBUG ("  sequence:%" G_GINT64_FORMAT " discont_sequence:%"
        G_GINT64_FORMAT, segment->sequence, segment->discont_sequence);
+    GST_DEBUG ("    partial only: %s", segment->partial_only ? "YES" : "NO");
    GST_DEBUG ("    stream_time : %" GST_STIME_FORMAT,
        GST_STIME_ARGS (segment->stream_time));
    GST_DEBUG ("    duration    :  %" GST_TIME_FORMAT,
@ -412,6 +438,25 @@ gst_hls_media_playlist_dump (GstHLSMediaPlaylist * self)
    }
    GST_DEBUG ("    uri         : %s %" G_GUINT64_FORMAT " %" G_GINT64_FORMAT,
        segment->uri, segment->offset, segment->size);
+
+    GST_DEBUG ("    is gap      : %s", segment->is_gap ? "YES" : "NO");
+
+    if (segment->partial_segments != NULL) {
+      guint part_idx;
+      for (part_idx = 0; part_idx < segment->partial_segments->len; part_idx++) {
+        GstM3U8PartialSegment *part =
+            g_ptr_array_index (segment->partial_segments, part_idx);
+        GST_DEBUG ("    partial segment %u:", part_idx);
+        GST_DEBUG ("      uri         : %s %" G_GUINT64_FORMAT " %"
+            G_GINT64_FORMAT, part->uri, part->offset, part->size);
+        GST_DEBUG ("      stream_time : %" GST_STIME_FORMAT,
+            GST_STIME_ARGS (part->stream_time));
+        GST_DEBUG ("      duration    : %" GST_TIME_FORMAT,
+            GST_TIME_ARGS (part->duration));
+        GST_DEBUG ("      is gap      : %s", part->is_gap ? "YES" : "NO");
+        GST_DEBUG ("      independent : %s", part->independent ? "YES" : "NO");
+      }
+    }
  }
 #endif
 }
@ -479,6 +524,62 @@ gst_hls_media_playlist_postprocess_pdt (GstHLSMediaPlaylist * self)
  }
 }

+static GstM3U8PartialSegment *
+gst_m3u8_parse_partial_segment (gchar * data, const gchar * base_uri)
+{
+  gchar *v, *a;
+  gboolean have_duration = FALSE;
+  GstM3U8PartialSegment *part = g_new0 (GstM3U8PartialSegment, 1);
+
+  part->ref_count = 1;
+  part->stream_time = GST_CLOCK_STIME_NONE;
+  part->size = -1;
+
+  while (data != NULL && parse_attributes (&data, &a, &v)) {
+    if (strcmp (a, "URI") == 0) {
+      g_free (part->uri);
+      part->uri = uri_join (base_uri, v);
+    } else if (strcmp (a, "DURATION") == 0) {
+      if (!time_from_double_in_string (v, NULL, &part->duration)) {
+        GST_WARNING ("Can't read EXT-X-PART duration");
+        goto malformed_line;
+      }
+      have_duration = TRUE;
+    } else if (strcmp (a, "INDEPENDENT") == 0) {
+      part->independent = g_ascii_strcasecmp (v, "yes") == 0;
+    } else if (strcmp (a, "GAP") == 0) {
+      part->is_gap = g_ascii_strcasecmp (v, "yes") == 0;
+    } else if (strcmp (a, "BYTERANGE") == 0) {
+      if (int64_from_string (v, &v, &part->size)) {
+        goto malformed_line;
+      }
+      if (*v == '@' && !int64_from_string (v + 1, &v, &part->offset)) {
+        goto malformed_line;
+      }
+    }
+  }
+
+  if (part->uri == NULL || !have_duration) {
+    goto required_attributes_missing;
+  }
+
+  return part;
+
+required_attributes_missing:
+  {
+    GST_WARNING
+        ("EXT-X-PART description is missing required URI or DURATION attributes");
+    gst_m3u8_partial_segment_unref (part);
+    return NULL;
+  }
+malformed_line:
+  {
+    GST_WARNING ("Invalid EXT-X-PART entry in playlist");
+    gst_m3u8_partial_segment_unref (part);
+    return NULL;
+  }
+}
+
 /* Parse and create a new GstHLSMediaPlaylist */
 GstHLSMediaPlaylist *
 gst_hls_media_playlist_parse (gchar * data, const gchar * uri,
@ -487,7 +588,7 @@ gst_hls_media_playlist_parse (gchar * data, const gchar * uri,
  gchar *input_data = data;
  GstHLSMediaPlaylist *self;
  gint val;
-  GstClockTime duration;
+  GstClockTime duration, partial_duration;
  gchar *title, *end;
  gboolean discontinuity = FALSE;
  gchar *current_key = NULL;
@ -499,6 +600,7 @@ gst_hls_media_playlist_parse (gchar * data, const gchar * uri,
  GDateTime *date_time = NULL;
  GstM3U8InitFile *last_init_file = NULL;
  GstM3U8MediaSegment *previous = NULL;
+  GPtrArray *partial_segments = NULL;
  gboolean is_gap = FALSE;

  GST_LOG ("uri: %s", uri);
@ -523,6 +625,7 @@ gst_hls_media_playlist_parse (gchar * data, const gchar * uri,
  self->last_data = g_strdup (data);

  duration = 0;
+  partial_duration = 0;
  title = NULL;
  data += 7;
  while (TRUE) {
@ -552,17 +655,22 @@ gst_hls_media_playlist_parse (gchar * data, const gchar * uri,
        data = NULL;
        date_time = NULL;
        duration = 0;
+        partial_duration = 0;
        g_free (title);
        title = NULL;
        discontinuity = FALSE;
        size = offset = -1;
        is_gap = FALSE;
+        if (partial_segments != NULL) {
+          g_ptr_array_free (partial_segments, TRUE);
+          partial_segments = NULL;
+        }
        goto next_line;
      }
      if (data != NULL) {
        GstM3U8MediaSegment *file;
        /* We can finally create the segment */
-        /* The disconinuity sequence number is only stored if the header has
+        /* The discontinuity sequence number is only stored if the header has
         * EXT-X-DISCONTINUITY-SEQUENCE present.  */
        file =
            gst_m3u8_media_segment_new (data, title, duration, mediasequence++,
@ -593,8 +701,12 @@ gst_hls_media_playlist_parse (gchar * data, const gchar * uri,
        if (last_init_file)
          file->init_file = gst_m3u8_init_file_ref (last_init_file);

+        file->partial_segments = partial_segments;
+        partial_segments = NULL;
+
        date_time = NULL;       /* Ownership was passed to the segment */
        duration = 0;
+        partial_duration = 0;
        title = NULL;           /* Ownership was passed to the segment */
        discontinuity = FALSE;
        size = offset = -1;
@ -763,6 +875,36 @@ gst_hls_media_playlist_parse (gchar * data, const gchar * uri,
        }
      } else if (g_str_has_prefix (data_ext_x, "GAP:")) {
        is_gap = TRUE;
+      } else if (g_str_has_prefix (data_ext_x, "PART:")) {
+        GstM3U8PartialSegment *part = NULL;
+
+        part =
+            gst_m3u8_parse_partial_segment (data + strlen ("#EXT-X-PART:"),
+            self->base_uri ? self->base_uri : self->uri);
+        if (part == NULL)
+          goto next_line;
+
+        if (partial_segments == NULL) {
+          partial_segments = g_ptr_array_new_full (2,
+              (GDestroyNotify) gst_m3u8_partial_segment_unref);
+        }
+        g_ptr_array_add (partial_segments, part);
+        partial_duration += part->duration;
+
+      } else if (g_str_has_prefix (data_ext_x, "PART-INF:")) {
+        gchar *v, *a;
+
+        data += strlen ("#EXT-X-PART-INF:");
+
+        while (data != NULL && parse_attributes (&data, &a, &v)) {
+          if (strcmp (a, "PART-TARGET") == 0) {
+            if (!time_from_double_in_string (v, NULL,
+                    &self->partial_targetduration)) {
+              GST_WARNING ("Invalid PART-TARGET");
+              goto next_line;
+            }
+          }
+        }
      } else {
        GST_LOG ("Ignored line: %s", data);
      }
@ -777,6 +919,59 @@ gst_hls_media_playlist_parse (gchar * data, const gchar * uri,
    data = g_utf8_next_char (end);      /* skip \n */
  }

+  /* If there are trailing partial segments at the end,
+   * create a dummy segment to hold them */
+  if (partial_segments != NULL) {
+    GstM3U8MediaSegment *file;
+    GST_DEBUG ("Creating dummy segment for trailing partial segments");
+
+    /* The discontinuity sequence number is only stored if the header has
+     * EXT-X-DISCONTINUITY-SEQUENCE present.  */
+    file =
+        gst_m3u8_media_segment_new (NULL, title, partial_duration,
+        mediasequence++, dsn, size, offset);
+
+    file->partial_only = TRUE;
+
+    self->duration += partial_duration;
+
+    file->is_gap = is_gap;
+
+    /* set encryption params */
+    if (current_key != NULL) {
+      file->key = g_strdup (current_key);
+      if (have_iv) {
+        memcpy (file->iv, iv, sizeof (iv));
+      } else {
+        /* An EXT-X-KEY tag with a KEYFORMAT of "identity" that does
+         * not have an IV attribute indicates that the Media Sequence
+         * Number is to be used as the IV when decrypting a Media
+         * Segment, by putting its big-endian binary representation
+         * into a 16-octet (128-bit) buffer and padding (on the left)
+         * with zeros. */
+        guint8 *iv = file->iv + 12;
+        GST_WRITE_UINT32_BE (iv, file->sequence);
+      }
+    }
+
+    file->datetime = date_time;
+    file->discont = discontinuity;
+    if (last_init_file)
+      file->init_file = gst_m3u8_init_file_ref (last_init_file);
+
+    file->partial_segments = partial_segments;
+    partial_segments = NULL;
+
+    date_time = NULL;           /* Ownership was passed to the partial segment */
+    duration = 0;
+    partial_duration = 0;
+    title = NULL;               /* Ownership was passed to the partial segment */
+    discontinuity = FALSE;
+    size = offset = -1;
+    g_ptr_array_add (self->segments, file);
+    previous = file;
+  }
+
  /* Clean up date that wasn't freed / handed to a segment */
  g_free (current_key);
  current_key = NULL;
@ -1445,7 +1640,7 @@ gst_hls_media_playlist_is_live (GstHLSMediaPlaylist * m3u8)
  return is_live;
 }

-gchar *
+static gchar *
 uri_join (const gchar * uri1, const gchar * uri2)
 {
  gchar *uri_copy, *tmp, *ret = NULL;
@ -1617,7 +1812,7 @@ gst_hls_rendition_stream_type_get_name (GstHLSRenditionStreamType mtype)
  return nicks[mtype];
 }

-/* returns unquoted copy of string */
+/* returns copy of string with surrounding quotation marks removed */
 static gchar *
 gst_m3u8_unquote (const gchar * str)
 {
--- a/subprojects/gst-plugins-good/ext/adaptivedemux2/hls/m3u8.h
+++ b/subprojects/gst-plugins-good/ext/adaptivedemux2/hls/m3u8.h
@ -35,6 +35,7 @@ G_BEGIN_DECLS
 typedef struct _GstHLSMediaPlaylist GstHLSMediaPlaylist;
 typedef struct _GstHLSTimeMap GstHLSTimeMap;
 typedef struct _GstM3U8MediaSegment GstM3U8MediaSegment;
+typedef struct _GstM3U8PartialSegment GstM3U8PartialSegment;
 typedef struct _GstM3U8InitFile GstM3U8InitFile;
 typedef struct _GstHLSRenditionStream GstHLSRenditionStream;
 typedef struct _GstM3U8Client GstM3U8Client;
@ -43,6 +44,7 @@ typedef struct _GstHLSMasterPlaylist GstHLSMasterPlaylist;

 #define GST_HLS_MEDIA_PLAYLIST(m) ((GstHLSMediaPlaylist*)m)
 #define GST_M3U8_MEDIA_SEGMENT(f) ((GstM3U8MediaSegment*)f)
+#define GST_M3U8_PARTIAL_SEGMENT(p) ((GstM3U8PartialSegment*)p)

 #define GST_HLS_MEDIA_PLAYLIST_LOCK(m) g_mutex_lock (&m->lock);
 #define GST_HLS_MEDIA_PLAYLIST_UNLOCK(m) g_mutex_unlock (&m->lock);
@ -82,6 +84,8 @@ struct _GstHLSMediaPlaylist

  /* Media Playlist Tags */
  GstClockTime targetduration;  /* EXT-X-TARGETDURATION, default GST_CLOCK_TIME_NONE */
+  GstClockTime partial_targetduration;  /* EXT-X-PART-INF, default GST_CLOCK_TIME_NONE */
+
  gint64 media_sequence;	/* EXT-X-MEDIA-SEQUENCE, MSN of the first Media
 				   Segment in the playlist. */
  gint64 discont_sequence;	/* EXT-X-DISCONTINUITY-SEQUENCE. Default : 0 */
@ -127,6 +131,31 @@ GstHLSMediaPlaylist * gst_hls_media_playlist_ref (GstHLSMediaPlaylist * m3u8);

 void                  gst_hls_media_playlist_unref (GstHLSMediaPlaylist * m3u8);

+/**
+ * GstM3U8PartialSegment:
+ *
+ * Official term in RFC : "Partial Segment"
+ *
+ */
+struct _GstM3U8PartialSegment
+{
+  gboolean is_gap; /* TRUE if this part is a gap */
+  gboolean independent; /* TRUE if there is an I-frame in the partial segment */
+  gchar *uri;
+  gint64 offset, size;
+
+  GstClockTimeDiff stream_time;	/* Computed stream time */
+  GstClockTime duration;
+
+  gint ref_count;               /* ATOMIC */
+};
+
+GstM3U8PartialSegment *
+gst_m3u8_partial_segment_ref   (GstM3U8PartialSegment *part);
+
+void
+gst_m3u8_partial_segment_unref (GstM3U8PartialSegment *part);
+
 /**
 * GstM3U8MediaSegment:
 *
@ -137,6 +166,7 @@ void                  gst_hls_media_playlist_unref (GstHLSMediaPlaylist * m3u8);
 struct _GstM3U8MediaSegment
 {
  gboolean is_gap; /* TRUE if EXT-X-GAP was present for this segment */
+  gboolean partial_only; /* TRUE if this is the last segment in a playlist consisting of only EXT-X-PART and no full URL */

  gchar *title;
  GstClockTimeDiff stream_time;	/* Computed stream time */
@ -148,9 +178,12 @@ struct _GstM3U8MediaSegment
  gchar *key;
  guint8 iv[16];
  gint64 offset, size;
-  gint ref_count;               /* ATOMIC */
  GstM3U8InitFile *init_file;   /* Media Initialization (hold ref) */
  GDateTime *datetime;		/* EXT-X-PROGRAM-DATE-TIME */
+
+  GPtrArray *partial_segments; /* If there are Partial Segments for this Media Segment */
+
+  gint ref_count;               /* ATOMIC */
 };

 struct _GstM3U8InitFile
@ -170,7 +203,6 @@ gst_m3u8_media_segment_ref   (GstM3U8MediaSegment * mfile);
 void
 gst_m3u8_media_segment_unref (GstM3U8MediaSegment * mfile);

-
 gboolean
 gst_hls_media_playlist_has_same_data (GstHLSMediaPlaylist * m3u8,
 				      gchar   * playlist_data);