From deeb3917a5723b5e120786b98555c332fb45a814 Mon Sep 17 00:00:00 2001
From: "Jan Alexander Steffens (heftig)" <jan.steffens@ltnglobal.com>
Date: Wed, 9 Sep 2020 15:12:53 +0200
Subject: [PATCH] flvmux: Move stream skipping to
 GstAggregatorPadClass.skip_buffer

Besides looking like the correct place to put this, it allows us to drop
the entire aggregator queue. The old implementation only dropped at most
one buffer for each call of aggregate.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/722>
---
 gst/flv/gstflvmux.c | 84 ++++++++++++++++++++++++---------------------
 1 file changed, 45 insertions(+), 39 deletions(-)

diff --git a/gst/flv/gstflvmux.c b/gst/flv/gstflvmux.c
index b691712c37..82324ecbe1 100644
--- a/gst/flv/gstflvmux.c
+++ b/gst/flv/gstflvmux.c
@@ -134,6 +134,8 @@ static gboolean gst_flv_mux_are_all_pads_eos (GstFlvMux * mux);
 static GstFlowReturn gst_flv_mux_update_src_caps (GstAggregator * aggregator,
     GstCaps * caps, GstCaps ** ret);
 static guint64 gst_flv_mux_query_upstream_duration (GstFlvMux * mux);
+static GstClockTime gst_flv_mux_segment_to_running_time (const GstSegment *
+    segment, GstClockTime t);
 
 static GstFlowReturn
 gst_flv_mux_pad_flush (GstAggregatorPad * pad, GstAggregator * aggregator)
@@ -147,6 +149,47 @@ gst_flv_mux_pad_flush (GstAggregatorPad * pad, GstAggregator * aggregator)
   return GST_FLOW_OK;
 }
 
+static gboolean
+gst_flv_mux_skip_buffer (GstAggregatorPad * apad, GstAggregator * aggregator,
+    GstBuffer * buffer)
+{
+  GstFlvMuxPad *fpad = GST_FLV_MUX_PAD_CAST (apad);
+  GstFlvMux *mux = GST_FLV_MUX_CAST (aggregator);
+  GstClockTime t;
+
+  if (!mux->skip_backwards_streams)
+    return FALSE;
+
+  if (fpad->drop_deltas) {
+    if (GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_DELTA_UNIT)) {
+      GST_INFO_OBJECT (fpad, "Waiting for keyframe, dropping %" GST_PTR_FORMAT,
+          buffer);
+      return TRUE;
+    } else {
+      /* drop-deltas is set and the buffer isn't delta, drop flag */
+      fpad->drop_deltas = FALSE;
+    }
+  }
+
+  if (GST_CLOCK_TIME_IS_VALID (GST_BUFFER_DTS_OR_PTS (buffer))) {
+    t = gst_flv_mux_segment_to_running_time (&apad->segment,
+        GST_BUFFER_DTS_OR_PTS (buffer));
+
+    if (t < (GST_MSECOND * mux->last_dts)) {
+      GST_WARNING_OBJECT (fpad,
+          "Timestamp %" GST_TIME_FORMAT " going backwards from last used %"
+          GST_TIME_FORMAT ", dropping %" GST_PTR_FORMAT,
+          GST_TIME_ARGS (t), GST_TIME_ARGS (GST_MSECOND * mux->last_dts),
+          buffer);
+      /* Look for non-delta buffer */
+      fpad->drop_deltas = TRUE;
+      return TRUE;
+    }
+  }
+
+  return FALSE;
+}
+
 static void
 gst_flv_mux_pad_class_init (GstFlvMuxPadClass * klass)
 {
@@ -156,6 +199,8 @@ gst_flv_mux_pad_class_init (GstFlvMuxPadClass * klass)
   gobject_class->finalize = gst_flv_mux_pad_finalize;
 
   aggregatorpad_class->flush = GST_DEBUG_FUNCPTR (gst_flv_mux_pad_flush);
+  aggregatorpad_class->skip_buffer =
+      GST_DEBUG_FUNCPTR (gst_flv_mux_skip_buffer);
 }
 
 static void
@@ -1853,7 +1898,6 @@ static GstFlvMuxPad *
 gst_flv_mux_find_best_pad (GstAggregator * aggregator, GstClockTime * ts,
     gboolean timeout)
 {
-  GstFlvMux *mux = GST_FLV_MUX (aggregator);
   GstFlvMuxPad *best = NULL;
   GstClockTime best_ts = GST_CLOCK_TIME_NONE;
   GstIterator *pads;
@@ -1866,7 +1910,6 @@ gst_flv_mux_find_best_pad (GstAggregator * aggregator, GstClockTime * ts,
     switch (gst_iterator_next (pads, &padptr)) {
       case GST_ITERATOR_OK:{
         GstAggregatorPad *apad = g_value_get_object (&padptr);
-        GstFlvMuxPad *fpad = GST_FLV_MUX_PAD (apad);
         GstClockTime t = GST_CLOCK_TIME_NONE;
         GstBuffer *buffer;
 
@@ -1880,46 +1923,9 @@ gst_flv_mux_find_best_pad (GstAggregator * aggregator, GstClockTime * ts,
           break;
         }
 
-        if (fpad->drop_deltas) {
-          if (mux->skip_backwards_streams
-              && GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_DELTA_UNIT)) {
-            GST_INFO_OBJECT (apad,
-                "Dropped buffer %" GST_PTR_FORMAT " until keyframe", buffer);
-            gst_buffer_unref (buffer);
-            gst_aggregator_pad_drop_buffer (apad);
-            if (!timeout) {
-              gst_object_replace ((GstObject **) & best, NULL);
-              best_ts = GST_CLOCK_TIME_NONE;
-              done = TRUE;
-            }
-            break;
-          } else {
-            /* drop-deltas is set and the buffer isn't delta, drop flag */
-            fpad->drop_deltas = FALSE;
-          }
-        }
-
         if (GST_CLOCK_TIME_IS_VALID (GST_BUFFER_DTS_OR_PTS (buffer))) {
           t = gst_flv_mux_segment_to_running_time (&apad->segment,
               GST_BUFFER_DTS_OR_PTS (buffer));
-
-          if (mux->skip_backwards_streams
-              && (t < (GST_MSECOND * mux->last_dts))) {
-            GST_WARNING_OBJECT (mux,
-                "Timestamp %" GST_TIME_FORMAT " going "
-                "backwards from last known %" GST_TIME_FORMAT ", dropping",
-                GST_TIME_ARGS (t), GST_TIME_ARGS (GST_MSECOND * mux->last_dts));
-            gst_buffer_unref (buffer);
-            gst_aggregator_pad_drop_buffer (apad);
-            /* Look for non-delta buffer */
-            fpad->drop_deltas = TRUE;
-            if (!timeout) {
-              gst_object_replace ((GstObject **) & best, NULL);
-              best_ts = GST_CLOCK_TIME_NONE;
-              done = TRUE;
-            }
-            break;
-          }
         }
 
         if (!GST_CLOCK_TIME_IS_VALID (best_ts) ||