queue2: Fix average input rate calculation on small input range

When dealing with small-ish input data coming into queue2, such as
adaptivedemux fragments, we would never take into account the last
<200ms of data coming in.

The problem is that usually on TCP connection the download rate
gradually increases (i.e. the rate is lower at the beginning of a
download than it is later on). Combined with small download time (less
than a second) we would end up with a computed average input rate
which was sometimes up to 30-50% off from the *actual* average input
rate for that fragment.

In order to fix this, force the average input rate calculation when
we receive an EOS so that we take into account that final window
of data.

https://bugzilla.gnome.org/show_bug.cgi?id=768649

1 files changed, 8 insertions, 6 deletions

diff --git a/plugins/elements/gstqueue2.c b/plugins/elements/gstqueue2.c
index 35c98cebc7..5e55ba2945 100644
--- a/plugins/elements/gstqueue2.c
+++ b/plugins/elements/gstqueue2.c
@@ -274,7 +274,7 @@ static gboolean gst_queue2_is_empty (GstQueue2 * queue);
 static gboolean gst_queue2_is_filled (GstQueue2 * queue);
 
 static void update_cur_level (GstQueue2 * queue, GstQueue2Range * range);
-static void update_in_rates (GstQueue2 * queue);
+static void update_in_rates (GstQueue2 * queue, gboolean force);
 static void gst_queue2_post_buffering (GstQueue2 * queue);
 
 typedef enum
@@ -1036,7 +1036,7 @@ update_buffering (GstQueue2 * queue)
   /* Ensure the variables used to calculate buffering state are up-to-date. */
   if (queue->current)
     update_cur_level (queue, queue->current);
-  update_in_rates (queue);
+  update_in_rates (queue, FALSE);
 
   if (!get_buffering_percent (queue, NULL, &percent))
     return;
@@ -1085,7 +1085,7 @@ reset_rate_timer (GstQueue2 * queue)
 #define AVG_OUT(avg,val) ((avg) * 3.0 + (val)) / 4.0
 
 static void
-update_in_rates (GstQueue2 * queue)
+update_in_rates (GstQueue2 * queue, gboolean force)
 {
   gdouble elapsed, period;
   gdouble byte_in_rate;
@@ -1100,7 +1100,7 @@ update_in_rates (GstQueue2 * queue)
       g_timer_elapsed (queue->in_timer, NULL);
 
   /* recalc after each interval. */
-  if (queue->last_in_elapsed + RATE_INTERVAL < elapsed) {
+  if (force || queue->last_in_elapsed + RATE_INTERVAL < elapsed) {
     period = elapsed - queue->last_in_elapsed;
 
     GST_DEBUG_OBJECT (queue,
@@ -2129,7 +2129,7 @@ gst_queue2_locked_enqueue (GstQueue2 * queue, gpointer item,
     /* apply new buffer to segment stats */
     apply_buffer (queue, buffer, &queue->sink_segment, size, TRUE);
     /* update the byterate stats */
-    update_in_rates (queue);
+    update_in_rates (queue, FALSE);
 
     if (!QUEUE_IS_USING_QUEUE (queue)) {
       /* FIXME - check return value? */
@@ -2155,7 +2155,7 @@ gst_queue2_locked_enqueue (GstQueue2 * queue, gpointer item,
     apply_buffer_list (queue, buffer_list, &queue->sink_segment, TRUE);
 
     /* update the byterate stats */
-    update_in_rates (queue);
+    update_in_rates (queue, FALSE);
 
     if (!QUEUE_IS_USING_QUEUE (queue)) {
       gst_buffer_list_foreach (buffer_list, buffer_list_create_write, queue);
@@ -2171,6 +2171,8 @@ gst_queue2_locked_enqueue (GstQueue2 * queue, gpointer item,
          * filled and we can read all data from the queue. */
         GST_DEBUG_OBJECT (queue, "we have EOS");
         queue->is_eos = TRUE;
+        /* Force updating the input bitrate */
+        update_in_rates (queue, TRUE);
         break;
       case GST_EVENT_SEGMENT:
         apply_segment (queue, event, &queue->sink_segment, TRUE);