WIP: dashdemux: Implement skipping propertydash-skip

NOTE/FIXME: This is not meant to be exposed/controllable. It's just
exposed for debugging purposes so far

When dealing with key-trick-mode use-cases, there are cases where we
want to be able to throttle the amount of keyframes downloaded. To do
that we use a "skipping" property, which specifies by how many keyframes
we should advance every-time.

The default value of 1 means we advance by 1 every time (i.e. get all
keyframes). 2 would only get 1 out of 2, etc...

2 files changed, 59 insertions, 8 deletions

diff --git a/ext/dash/gstdashdemux.c b/ext/dash/gstdashdemux.c
index 2b29a1de8..44f8bf37c 100644
--- a/ext/dash/gstdashdemux.c
+++ b/ext/dash/gstdashdemux.c
@@ -190,6 +190,7 @@ enum
   PROP_BANDWIDTH_USAGE,
   PROP_MAX_BITRATE,
   PROP_PRESENTATION_DELAY,
+  PROP_INCREMENT_VALUE,
   PROP_LAST
 };
 
@@ -198,6 +199,7 @@ enum
 #define DEFAULT_BANDWIDTH_USAGE         0.8     /* 0 to 1     */
 #define DEFAULT_MAX_BITRATE        24000000     /* in bit/s  */
 #define DEFAULT_PRESENTATION_DELAY     NULL     /* zero */
+#define DEFAULT_INCREMENT_VALUE           1     /* read everything */
 
 /* Clock drift compensation for live streams */
 #define SLOW_CLOCK_UPDATE_INTERVAL  (1000000 * 30 * 60) /* 30 minutes */
@@ -428,6 +430,12 @@ gst_dash_demux_class_init (GstDashDemuxClass * klass)
           DEFAULT_PRESENTATION_DELAY,
           G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 
+  g_object_class_install_property (gobject_class, PROP_INCREMENT_VALUE,
+      g_param_spec_uint ("increment-value", "Increment Value",
+          "(DEBUG) By how much to increment when advancing in key-frame mode",
+          1, G_MAXUINT, DEFAULT_INCREMENT_VALUE,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
   gst_element_class_add_static_pad_template (gstelement_class,
       &gst_dash_demux_audiosrc_template);
   gst_element_class_add_static_pad_template (gstelement_class,
@@ -494,6 +502,8 @@ gst_dash_demux_init (GstDashDemux * demux)
   demux->max_bitrate = DEFAULT_MAX_BITRATE;
   demux->default_presentation_delay = DEFAULT_PRESENTATION_DELAY;
 
+  demux->increment_value = DEFAULT_INCREMENT_VALUE;
+
   g_mutex_init (&demux->client_lock);
 
   gst_adaptive_demux_set_stream_struct_size (GST_ADAPTIVE_DEMUX_CAST (demux),
@@ -521,6 +531,9 @@ gst_dash_demux_set_property (GObject * object, guint prop_id,
       g_free (demux->default_presentation_delay);
       demux->default_presentation_delay = g_value_dup_string (value);
       break;
+    case PROP_INCREMENT_VALUE:
+      demux->increment_value = g_value_get_uint (value);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -550,6 +563,9 @@ gst_dash_demux_get_property (GObject * object, guint prop_id, GValue * value,
       else
         g_value_set_string (value, demux->default_presentation_delay);
       break;
+    case PROP_INCREMENT_VALUE:
+      g_value_set_uint (value, demux->increment_value);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -670,6 +686,10 @@ gst_dash_demux_setup_all_streams (GstDashDemux * demux)
           stream);
     }
 
+    /* FIXME : HARDCODED VALUES FOR DEBUGGIN */
+    stream->increment_value = stream->increment_leftover =
+        demux->increment_value;
+
     gst_isoff_sidx_parser_init (&stream->sidx_parser);
     if (gst_mpd_client_has_isoff_ondemand_profile (demux->client))
       stream->sidx_adapter = gst_adapter_new ();
@@ -1240,11 +1260,11 @@ gst_dash_demux_stream_has_next_sync_sample (GstAdaptiveDemuxStream * stream)
       && GST_ADAPTIVE_DEMUX (stream->demux)->
       segment.flags & GST_SEGMENT_FLAG_TRICKMODE_KEY_UNITS) {
     if (stream->demux->segment.rate > 0.0) {
-      if (dashstream->current_sync_sample + 1 <
+      if (dashstream->current_sync_sample + dashstream->increment_leftover <
           dashstream->moof_sync_samples->len)
         return TRUE;
     } else {
-      if (dashstream->current_sync_sample >= 1)
+      if (dashstream->current_sync_sample >= dashstream->increment_leftover)
         return TRUE;
     }
   }
@@ -1259,7 +1279,8 @@ gst_dash_demux_stream_has_next_subfragment (GstAdaptiveDemuxStream * stream)
 
   if (dashstream->sidx_parser.status == GST_ISOFF_SIDX_PARSER_FINISHED) {
     if (stream->demux->segment.rate > 0.0) {
-      if (sidx->entry_index + 1 < sidx->entries_count)
+      if (sidx->entry_index + dashstream->increment_leftover <
+          sidx->entries_count)
         return TRUE;
     } else {
       if (sidx->entry_index >= 1)
@@ -1275,15 +1296,28 @@ gst_dash_demux_stream_advance_sync_sample (GstAdaptiveDemuxStream * stream)
   GstDashDemuxStream *dashstream = (GstDashDemuxStream *) stream;
   gboolean fragment_finished = FALSE;
 
+  GST_DEBUG_OBJECT (stream->pad,
+      "Advancing sync sample #%d/#%d leftover:%d",
+      dashstream->current_sync_sample,
+      dashstream->moof_sync_samples->len, dashstream->increment_leftover);
+
   if (dashstream->moof_sync_samples
       && GST_ADAPTIVE_DEMUX (stream->demux)->
       segment.flags & GST_SEGMENT_FLAG_TRICKMODE_KEY_UNITS) {
     if (stream->demux->segment.rate > 0.0) {
-      dashstream->current_sync_sample++;
+      if (dashstream->current_sync_sample == -1)
+        dashstream->current_sync_sample = dashstream->increment_leftover;
+      else
+        dashstream->current_sync_sample += dashstream->increment_leftover;
       if (dashstream->current_sync_sample >= dashstream->moof_sync_samples->len) {
         fragment_finished = TRUE;
-      }
+        dashstream->increment_leftover =
+            dashstream->current_sync_sample -
+            dashstream->moof_sync_samples->len + 1;
+      } else
+        dashstream->increment_leftover = dashstream->increment_value;
     } else {
+      /* FIXME : REVERSE INCREMENT HANDLING !! */
       if (dashstream->current_sync_sample == -1) {
         dashstream->current_sync_sample =
             dashstream->moof_sync_samples->len - 1;
@@ -1297,8 +1331,9 @@ gst_dash_demux_stream_advance_sync_sample (GstAdaptiveDemuxStream * stream)
   }
 
   GST_DEBUG_OBJECT (stream->pad,
-      "Advancing sync sample #%d fragment_finished:%d",
-      dashstream->current_sync_sample, fragment_finished);
+      "Advanced sync sample #%d/#%d fragment_finished:%d",
+      dashstream->current_sync_sample,
+      dashstream->moof_sync_samples->len, fragment_finished);
 
   if (!fragment_finished)
     stream->discont = TRUE;
@@ -2365,12 +2400,17 @@ gst_dash_demux_handle_isobmff_buffer (GstAdaptiveDemux * demux,
           GST_ADAPTIVE_DEMUX (stream->demux)->
           segment.flags & GST_SEGMENT_FLAG_TRICKMODE_KEY_UNITS) {
 
-        if (dash_stream->first_sync_sample_after_moof) {
+        if (dash_stream->first_sync_sample_after_moof &&
+            dash_stream->increment_value == dash_stream->increment_leftover) {
           /* If we're here, don't throw away data but collect sync
            * sample while we're at it below. We're doing chunked
            * downloading so might need to adjust the next chunk size for
            * the remainder */
           dash_stream->current_sync_sample = 0;
+          GST_DEBUG ("current #%d / %d (skip %d)",
+              dash_stream->current_sync_sample,
+              dash_stream->moof_sync_samples->len,
+              dash_stream->increment_leftover);
         } else {
           gst_adapter_clear (dash_stream->isobmff_adapter);
         }
diff --git a/ext/dash/gstdashdemux.h b/ext/dash/gstdashdemux.h
index e32b7b4a8..7678c0355 100644
--- a/ext/dash/gstdashdemux.h
+++ b/ext/dash/gstdashdemux.h
@@ -96,6 +96,13 @@ struct _GstDashDemuxStream
 
   guint64 moof_average_size, first_sync_sample_average_size;
   gboolean first_sync_sample_after_moof, first_sync_sample_always_after_moof;
+
+  /* By how much we should advance for the next sync_sample.
+   * Default is 1, which means we advance normally */
+  guint32 increment_value;
+  /* Actual value used for increments, gets resetted to increment_value
+   * once it reaches 0 */
+  guint32 increment_leftover;
 };
 
 /**
@@ -128,6 +135,10 @@ struct _GstDashDemux
 
   gboolean trickmode_no_audio;
   gboolean allow_trickmode_key_units;
+
+  /* By how much we should advance for the next sync_sample.
+   * Default is 1, which means we advance normally */
+  guint32 increment_value;
 };
 
 struct _GstDashDemuxClass