hlsdemux: replace uridownloader with a GstElement

The GstElement is directly linked into a ghost pad and
its buffers are pushed as received downstream. This way the
buffers are small enough and not a whole fragment that usually
causes extra latency and makes buffering harder

ext/hls/gsthlsdemux.c

@@ -47,6 +47,7 @@
 #else
 #include <gcrypt.h>
 #endif
+#include <gst/base/gsttypefindhelper.h>
 #include "gsthlsdemux.h"
 
 static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src_%u",
@@ -101,9 +102,11 @@ static void gst_hls_demux_stream_loop (GstHLSDemux * demux);
 static void gst_hls_demux_updates_loop (GstHLSDemux * demux);
 static void gst_hls_demux_stop (GstHLSDemux * demux);
 static void gst_hls_demux_pause_tasks (GstHLSDemux * demux);
+#if 0
 static gboolean gst_hls_demux_switch_playlist (GstHLSDemux * demux,
     GstFragment * fragment);
-static GstFragment *gst_hls_demux_get_next_fragment (GstHLSDemux * demux,
+#endif
+static gboolean gst_hls_demux_get_next_fragment (GstHLSDemux * demux,
     gboolean * end_of_playlist, GError ** err);
 static gboolean gst_hls_demux_update_playlist (GstHLSDemux * demux,
     gboolean update, GError ** err);
@@ -116,7 +119,7 @@ static gboolean gst_hls_demux_change_playlist (GstHLSDemux * demux,
     guint max_bitrate);
 
 #define gst_hls_demux_parent_class parent_class
-G_DEFINE_TYPE (GstHLSDemux, gst_hls_demux, GST_TYPE_ELEMENT);
+G_DEFINE_TYPE (GstHLSDemux, gst_hls_demux, GST_TYPE_BIN);
 
 static void
 gst_hls_demux_dispose (GObject * obj)
@@ -146,6 +149,8 @@ gst_hls_demux_dispose (GObject * obj)
   g_cond_clear (&demux->download_cond);
   g_mutex_clear (&demux->updates_timed_lock);
   g_cond_clear (&demux->updates_timed_cond);
+  g_mutex_clear (&demux->fragment_download_lock);
+  g_cond_clear (&demux->fragment_download_cond);
 
   G_OBJECT_CLASS (parent_class)->dispose (obj);
 }
@@ -226,6 +231,8 @@ gst_hls_demux_init (GstHLSDemux * demux)
   g_cond_init (&demux->download_cond);
   g_mutex_init (&demux->updates_timed_lock);
   g_cond_init (&demux->updates_timed_cond);
+  g_mutex_init (&demux->fragment_download_lock);
+  g_cond_init (&demux->fragment_download_cond);
 
   /* Updates task */
   g_rec_mutex_init (&demux->updates_lock);
@@ -238,6 +245,9 @@ gst_hls_demux_init (GstHLSDemux * demux)
   demux->stream_task =
       gst_task_new ((GstTaskFunction) gst_hls_demux_stream_loop, demux, NULL);
   gst_task_set_lock (demux->stream_task, &demux->stream_lock);
+  demux->src = gst_element_factory_make ("souphttpsrc", "hls-download-src");
+  gst_element_set_locked_state (demux->src, TRUE);
+  gst_bin_add (GST_BIN_CAST (demux), demux->src);
 
   demux->have_group_id = FALSE;
   demux->group_id = G_MAXUINT;
@@ -305,6 +315,7 @@ gst_hls_demux_change_state (GstElement * element, GstStateChange transition)
 
   switch (transition) {
     case GST_STATE_CHANGE_PAUSED_TO_READY:
+      gst_element_set_state (demux->src, GST_STATE_NULL);
       gst_hls_demux_stop (demux);
       gst_task_join (demux->updates_task);
       gst_task_join (demux->stream_task);
@@ -687,12 +698,129 @@ gst_hls_demux_stop (GstHLSDemux * demux)
     demux->stop_stream_task = TRUE;
     g_cond_signal (&demux->download_cond);
     g_mutex_unlock (&demux->download_lock);
+    g_mutex_lock (&demux->fragment_download_lock);
+    g_cond_signal (&demux->fragment_download_cond);
+    g_mutex_unlock (&demux->fragment_download_lock);
     gst_task_stop (demux->stream_task);
     g_rec_mutex_lock (&demux->stream_lock);
     g_rec_mutex_unlock (&demux->stream_lock);
   }
 }
 
+static GstFlowReturn
+_src_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
+{
+  GstPad *srcpad = (GstPad *) parent;
+  GstHLSDemux *demux = (GstHLSDemux *) GST_PAD_PARENT (srcpad);
+  GstFlowReturn ret;
+  GstCaps *caps;
+
+  /* We actually need to do this every time we switch bitrate */
+  if (G_UNLIKELY (demux->do_typefind)) {
+    caps = gst_type_find_helper_for_buffer (NULL, buffer, NULL);
+    if (G_UNLIKELY (!caps)) {
+      GST_ELEMENT_ERROR (demux, STREAM, TYPE_NOT_FOUND,
+          ("Could not determine type of stream"), (NULL));
+      gst_buffer_unref (buffer);
+      return GST_FLOW_NOT_NEGOTIATED;
+    }
+
+    if (!demux->input_caps || !gst_caps_is_equal (caps, demux->input_caps)) {
+      gst_caps_replace (&demux->input_caps, caps);
+      GST_INFO_OBJECT (demux, "Input source caps: %" GST_PTR_FORMAT,
+          demux->input_caps);
+      demux->do_typefind = FALSE;
+    }
+    gst_pad_set_caps (srcpad, caps);
+    gst_caps_unref (caps);
+  }
+
+  if (demux->discont) {
+    GST_DEBUG_OBJECT (demux, "Marking fragment as discontinuous");
+    GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DISCONT);
+    demux->discont = FALSE;
+  } else if (demux->starting_fragment && demux->segment.rate < 0) {
+    /* Set DISCONT flag for every buffer in reverse playback mode
+     * as each fragment for its own has to be reversed */
+    GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DISCONT);
+  } else {
+    GST_BUFFER_FLAG_UNSET (buffer, GST_BUFFER_FLAG_DISCONT);
+  }
+
+  demux->starting_fragment = FALSE;
+
+  GST_DEBUG_OBJECT (demux, "set fragment pts=%" GST_TIME_FORMAT,
+      GST_TIME_ARGS (demux->current_timestamp));
+
+  GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
+  GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
+  GST_BUFFER_PTS (buffer) = demux->current_timestamp;
+
+  demux->segment.position = GST_BUFFER_TIMESTAMP (buffer);
+#if 0
+  if (demux->segment.rate > 0)
+    demux->segment.position += GST_BUFFER_DURATION (buf);
+#endif
+
+  if (demux->need_segment) {
+    /* And send a newsegment */
+    GST_DEBUG_OBJECT (demux, "Sending segment event: %"
+        GST_SEGMENT_FORMAT, &demux->segment);
+    gst_pad_push_event (demux->srcpad, gst_event_new_segment (&demux->segment));
+    demux->need_segment = FALSE;
+  }
+
+  ret = gst_proxy_pad_chain_default (pad, parent, buffer);
+
+  if (ret != GST_FLOW_OK) {
+    if (ret == GST_FLOW_NOT_LINKED || ret < GST_FLOW_EOS) {
+      GST_ELEMENT_ERROR (demux, STREAM, FAILED, (NULL),
+          ("stream stopped, reason %s", gst_flow_get_name (ret)));
+      gst_pad_push_event (demux->srcpad, gst_event_new_eos ());
+    } else {
+      GST_DEBUG_OBJECT (demux, "stream stopped, reason %s",
+          gst_flow_get_name (ret));
+    }
+    gst_hls_demux_pause_tasks (demux);
+  }
+
+  /* avoid having the source handle the same error again */
+  ret = GST_FLOW_OK;
+
+  return ret;
+}
+
+static gboolean
+_src_event (GstPad * pad, GstObject * parent, GstEvent * event)
+{
+  GstPad *srcpad = GST_PAD_CAST (parent);
+  GstHLSDemux *demux = (GstHLSDemux *) GST_PAD_PARENT (srcpad);;
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_EOS:
+      g_cond_signal (&demux->fragment_download_cond);
+      break;
+    default:
+      break;
+  }
+
+  return TRUE;
+}
+
+static gboolean
+_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
+{
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_ALLOCATION:
+      return FALSE;
+      break;
+    default:
+      break;
+  }
+
+  return gst_pad_query_default (pad, parent, query);
+}
+
 static void
 switch_pads (GstHLSDemux * demux, GstCaps * newcaps)
 {
@@ -700,14 +828,35 @@ switch_pads (GstHLSDemux * demux, GstCaps * newcaps)
   GstEvent *event;
   gchar *stream_id;
   gchar *name;
+  GstPad *target;
+  GstPadTemplate *tmpl;
+  GstProxyPad *internal_pad;
 
-  GST_DEBUG ("Switching pads (oldpad:%p) with caps: %" GST_PTR_FORMAT, oldpad,
+  GST_DEBUG_OBJECT (demux,
+      "Switching pads (oldpad:%p) with caps: %" GST_PTR_FORMAT, oldpad,
       newcaps);
 
+  target = gst_element_get_static_pad (demux->src, "src");
+
   /* First create and activate new pad */
   name = g_strdup_printf ("src_%u", demux->srcpad_counter++);
-  demux->srcpad = gst_pad_new_from_static_template (&srctemplate, name);
+  tmpl = gst_static_pad_template_get (&srctemplate);
+  demux->srcpad = gst_ghost_pad_new_from_template (name, target, tmpl);
+  gst_object_unref (tmpl);
   g_free (name);
+  gst_object_unref (target);
+
+  /* set up our internal pad to drop all events from
+   * the http src we don't care about. On the chain function
+   * we just push the buffer forward, but this way hls can get
+   * the flow return from downstream */
+  internal_pad = gst_proxy_pad_get_internal (GST_PROXY_PAD (demux->srcpad));
+  gst_pad_set_chain_function (GST_PAD_CAST (internal_pad), _src_chain);
+  gst_pad_set_event_function (GST_PAD_CAST (internal_pad), _src_event);
+  /* need to set query otherwise deadlocks happen with allocation queries */
+  gst_pad_set_query_function (GST_PAD_CAST (internal_pad), _src_query);
+  gst_object_unref (internal_pad);
+
   gst_pad_set_event_function (demux->srcpad,
       GST_DEBUG_FUNCPTR (gst_hls_demux_src_event));
   gst_pad_set_query_function (demux->srcpad,
@@ -752,54 +901,28 @@ switch_pads (GstHLSDemux * demux, GstCaps * newcaps)
 }
 
 static gboolean
-gst_hls_demux_configure_src_pad (GstHLSDemux * demux, GstFragment * fragment)
+gst_hls_demux_configure_src_pad (GstHLSDemux * demux, GstCaps * bufcaps)
 {
-  GstCaps *bufcaps = NULL, *srccaps = NULL;
+  GstCaps *srccaps = NULL;
-  GstBuffer *buf = NULL;
   /* Figure out if we need to create/switch pads */
   if (G_LIKELY (demux->srcpad))
     srccaps = gst_pad_get_current_caps (demux->srcpad);
-  if (fragment) {
-    bufcaps = gst_fragment_get_caps (fragment);
-    if (G_UNLIKELY (!bufcaps)) {
-      if (srccaps)
-        gst_caps_unref (srccaps);
-      return FALSE;
-    }
-    buf = gst_fragment_get_buffer (fragment);
-  }
 
-  if (G_UNLIKELY (!srccaps || demux->discont || (buf
+  if (G_UNLIKELY (!srccaps || demux->discont)) {
-              && GST_BUFFER_IS_DISCONT (buf)))) {
     switch_pads (demux, bufcaps);
     demux->need_segment = TRUE;
-    demux->discont = FALSE;
-    if (buf)
-      GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DISCONT);
   }
   if (bufcaps)
     gst_caps_unref (bufcaps);
   if (G_LIKELY (srccaps))
     gst_caps_unref (srccaps);
 
-  if (demux->need_segment) {
-    /* And send a newsegment */
-    GST_DEBUG_OBJECT (demux, "Sending segment event: %"
-        GST_SEGMENT_FORMAT, &demux->segment);
-    gst_pad_push_event (demux->srcpad, gst_event_new_segment (&demux->segment));
-    demux->need_segment = FALSE;
-  }
-  if (buf)
-    gst_buffer_unref (buf);
   return TRUE;
 }
 
 static void
 gst_hls_demux_stream_loop (GstHLSDemux * demux)
 {
-  GstFragment *fragment;
-  GstBuffer *buf;
-  GstFlowReturn ret;
   gboolean end_of_playlist;
   GError *err = NULL;
 
@@ -827,9 +950,7 @@ gst_hls_demux_stream_loop (GstHLSDemux * demux)
   }
 
   demux->next_download = g_get_monotonic_time ();
-  if ((fragment =
+  if (!gst_hls_demux_get_next_fragment (demux, &end_of_playlist, &err)) {
-          gst_hls_demux_get_next_fragment (demux, &end_of_playlist,
-              &err)) == NULL) {
     if (demux->stop_stream_task) {
       g_clear_error (&err);
       goto pause_task;
@@ -914,45 +1035,20 @@ gst_hls_demux_stream_loop (GstHLSDemux * demux)
     gst_m3u8_client_advance_fragment (demux->client, demux->segment.rate > 0);
 
     if (demux->stop_updates_task) {
-      g_object_unref (fragment);
       goto pause_task;
     }
   }
 
   if (demux->stop_updates_task) {
-    g_object_unref (fragment);
     goto pause_task;
   }
-
+#if 0
-  if (!gst_hls_demux_configure_src_pad (demux, fragment)) {
-    g_object_unref (fragment);
-    goto type_not_found;
-  }
-
-  buf = gst_fragment_get_buffer (fragment);
-
-  GST_DEBUG_OBJECT (demux, "Pushing buffer %" GST_TIME_FORMAT,
-      GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)));
-
-  /* Set DISCONT flag for every buffer in reverse playback mode
-   * as each fragment for its own has to be reversed */
-  if (demux->segment.rate < 0) {
-    GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DISCONT);
-  }
-
-  demux->segment.position = GST_BUFFER_TIMESTAMP (buf);
-  if (demux->segment.rate > 0)
-    demux->segment.position += GST_BUFFER_DURATION (buf);
-
-  ret = gst_pad_push (demux->srcpad, buf);
-  if (ret != GST_FLOW_OK)
-    goto error_pushing;
 
   /* try to switch to another bitrate if needed */
   gst_hls_demux_switch_playlist (demux, fragment);
-  g_object_unref (fragment);
+#endif
 
-  GST_DEBUG_OBJECT (demux, "Pushed buffer");
+  GST_DEBUG_OBJECT (demux, "Finished pushing fragment");
 
   return;
 
@@ -967,29 +1063,6 @@ end_of_playlist:
     return;
   }
 
-type_not_found:
-  {
-    GST_ELEMENT_ERROR (demux, STREAM, TYPE_NOT_FOUND,
-        ("Could not determine type of stream"), (NULL));
-    gst_hls_demux_pause_tasks (demux);
-    return;
-  }
-
-error_pushing:
-  {
-    g_object_unref (fragment);
-    if (ret == GST_FLOW_NOT_LINKED || ret < GST_FLOW_EOS) {
-      GST_ELEMENT_ERROR (demux, STREAM, FAILED, (NULL),
-          ("stream stopped, reason %s", gst_flow_get_name (ret)));
-      gst_pad_push_event (demux->srcpad, gst_event_new_eos ());
-    } else {
-      GST_DEBUG_OBJECT (demux, "stream stopped, reason %s",
-          gst_flow_get_name (ret));
-    }
-    gst_hls_demux_pause_tasks (demux);
-    return;
-  }
-
 pause_task:
   {
     GST_DEBUG_OBJECT (demux, "Pause task");
@@ -1252,8 +1325,8 @@ gst_hls_demux_update_playlist (GstHLSDemux * demux, gboolean update,
 
     GST_M3U8_CLIENT_LOCK (demux->client);
     last_sequence =
-        GST_M3U8_MEDIA_FILE (g_list_last (demux->client->current->files)->
+        GST_M3U8_MEDIA_FILE (g_list_last (demux->client->current->
-        data)->sequence;
+            files)->data)->sequence;
 
     if (demux->client->sequence >= last_sequence - 3) {
       GST_DEBUG_OBJECT (demux, "Sequence is beyond playlist. Moving back to %u",
@@ -1353,8 +1426,8 @@ retry_failover_protection:
     gst_m3u8_client_set_current (demux->client, previous_variant->data);
     /*  Try a lower bitrate (or stop if we just tried the lowest) */
     if (GST_M3U8 (previous_variant->data)->iframe && new_bandwidth ==
-        GST_M3U8 (g_list_first (demux->client->main->iframe_lists)->
+        GST_M3U8 (g_list_first (demux->client->main->iframe_lists)->data)->
-            data)->bandwidth)
+        bandwidth)
       return FALSE;
     else if (!GST_M3U8 (previous_variant->data)->iframe && new_bandwidth ==
         GST_M3U8 (g_list_first (demux->client->main->lists)->data)->bandwidth)
@@ -1369,6 +1442,7 @@ retry_failover_protection:
   return TRUE;
 }
 
+#if 0
 static gboolean
 gst_hls_demux_switch_playlist (GstHLSDemux * demux, GstFragment * fragment)
 {
@@ -1411,7 +1485,9 @@ gst_hls_demux_switch_playlist (GstHLSDemux * demux, GstFragment * fragment)
 
   return gst_hls_demux_change_playlist (demux, bitrate * demux->bitrate_limit);
 }
+#endif
 
+#if 0
 #ifdef HAVE_NETTLE
 static gboolean
 decrypt_fragment (GstHLSDemux * demux, gsize length,
@@ -1549,16 +1625,15 @@ decrypt_error:
   g_object_unref (encrypted_fragment);
   return ret;
 }
+#endif
 
-static GstFragment *
+static gboolean
 gst_hls_demux_get_next_fragment (GstHLSDemux * demux,
     gboolean * end_of_playlist, GError ** err)
 {
-  GstFragment *download;
   const gchar *next_fragment_uri;
   GstClockTime duration;
   GstClockTime timestamp;
-  GstBuffer *buf;
   gboolean discont;
   gint64 range_start, range_end;
   const gchar *key = NULL;
@@ -1570,74 +1645,43 @@ gst_hls_demux_get_next_fragment (GstHLSDemux * demux,
           &key, &iv, demux->segment.rate > 0)) {
     GST_INFO_OBJECT (demux, "This playlist doesn't contain more fragments");
     *end_of_playlist = TRUE;
-    return NULL;
+    return FALSE;
   }
 
-  GST_INFO_OBJECT (demux,
+  if (!gst_hls_demux_configure_src_pad (demux, NULL)) {
+    *end_of_playlist = FALSE;
+    return FALSE;
+  }
+
+  g_mutex_lock (&demux->fragment_download_lock);
+  GST_DEBUG_OBJECT (demux,
       "Fetching next fragment %s (range=%" G_GINT64_FORMAT "-%" G_GINT64_FORMAT
       ")", next_fragment_uri, range_start, range_end);
 
-  download =
+  /* set up our source for download */
-      gst_uri_downloader_fetch_uri_with_range_and_referer (demux->downloader,
+  demux->current_timestamp = timestamp;
-      next_fragment_uri, demux->client->main ? demux->client->main->uri : NULL,
+  demux->starting_fragment = TRUE;
-      FALSE, range_start, range_end, err);
+  g_object_set (demux->src, "location", next_fragment_uri, NULL);
+  gst_element_set_state (demux->src, GST_STATE_READY);  /* TODO check return */
+  gst_element_send_event (demux->src, gst_event_new_seek (1.0, GST_FORMAT_BYTES,
+          (GstSeekFlags) GST_SEEK_FLAG_FLUSH, GST_SEEK_TYPE_SET, range_start,
+          GST_SEEK_TYPE_SET, range_end));
 
-  if (download == NULL)
+  gst_element_sync_state_with_parent (demux->src);
-    goto error;
 
+  /* wait for the fragment to be completely downloaded */
+  g_cond_wait (&demux->fragment_download_cond, &demux->fragment_download_lock);
+
+  g_mutex_unlock (&demux->fragment_download_lock);
+  gst_element_set_state (demux->src, GST_STATE_NULL);
+
+#if 0
   if (key) {
     download = gst_hls_demux_decrypt_fragment (demux, download, key, iv, err);
     if (download == NULL)
       goto error;
   }
+#endif
 
-  buf = gst_fragment_get_buffer (download);
+  return TRUE;
-
-  GST_DEBUG_OBJECT (demux, "set fragment pts=%" GST_TIME_FORMAT " duration=%"
-      GST_TIME_FORMAT, GST_TIME_ARGS (timestamp), GST_TIME_ARGS (duration));
-
-  GST_BUFFER_DURATION (buf) = duration;
-  GST_BUFFER_PTS (buf) = timestamp;
-  GST_BUFFER_DTS (buf) = GST_CLOCK_TIME_NONE;
-
-  /* We actually need to do this every time we switch bitrate */
-  if (G_UNLIKELY (demux->do_typefind)) {
-    GstCaps *caps = gst_fragment_get_caps (download);
-
-    if (G_UNLIKELY (!caps)) {
-      GST_ELEMENT_ERROR (demux, STREAM, TYPE_NOT_FOUND,
-          ("Could not determine type of stream"), (NULL));
-      gst_buffer_unref (buf);
-      g_object_unref (download);
-      goto error;
-    }
-
-    if (!demux->input_caps || !gst_caps_is_equal (caps, demux->input_caps)) {
-      gst_caps_replace (&demux->input_caps, caps);
-      /* gst_pad_set_caps (demux->srcpad, demux->input_caps); */
-      GST_INFO_OBJECT (demux, "Input source caps: %" GST_PTR_FORMAT,
-          demux->input_caps);
-      demux->do_typefind = FALSE;
-    }
-    gst_caps_unref (caps);
-  } else {
-    gst_fragment_set_caps (download, demux->input_caps);
-  }
-
-  if (discont) {
-    GST_DEBUG_OBJECT (demux, "Marking fragment as discontinuous");
-    GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DISCONT);
-  } else {
-    GST_BUFFER_FLAG_UNSET (buf, GST_BUFFER_FLAG_DISCONT);
-  }
-
-  /* The buffer ref is still kept inside the fragment download */
-  gst_buffer_unref (buf);
-
-  return download;
-
-error:
-  {
-    return NULL;
-  }
 }

ext/hls/gsthlsdemux.h

@@ -53,7 +53,7 @@ typedef struct _GstHLSDemuxClass GstHLSDemuxClass;
  */
 struct _GstHLSDemux
 {
-  GstElement parent;
+  GstBin parent;
 
   GstPad *sinkpad;
   GstPad *srcpad;
@@ -103,11 +103,18 @@ struct _GstHLSDemux
 
   /* Current download rate (bps) */
   gint current_download_rate;
+
+  /* fragment download tooling */
+  GstElement *src;
+  GMutex fragment_download_lock;
+  GCond fragment_download_cond;
+  GstClockTime current_timestamp;
+  gboolean starting_fragment;
 };
 
 struct _GstHLSDemuxClass
 {
-  GstElementClass parent_class;
+  GstBinClass parent_class;
 };
 
 GType gst_hls_demux_get_type (void);