From 920a55532c50a9326c37a7b0af5a3175f6f42693 Mon Sep 17 00:00:00 2001
From: George Kiagiadakis <george.kiagiadakis@collabora.com>
Date: Sat, 2 Nov 2013 15:21:08 +0200
Subject: [PATCH] rtprtxsend: keep important buffer information in a private
 structure

This is to avoid mapping a buffer every time we need to read a seqnum
or a timestamp.
---
 gst/rtpmanager/gstrtprtxsend.c | 66 +++++++++++++++++++++-------------
 1 file changed, 42 insertions(+), 24 deletions(-)

diff --git a/gst/rtpmanager/gstrtprtxsend.c b/gst/rtpmanager/gstrtprtxsend.c
index 3da8d7690a..cf3410d0dd 100644
--- a/gst/rtpmanager/gstrtprtxsend.c
+++ b/gst/rtpmanager/gstrtprtxsend.c
@@ -91,6 +91,20 @@ static void gst_rtp_rtx_send_finalize (GObject * object);
 
 G_DEFINE_TYPE (GstRtpRtxSend, gst_rtp_rtx_send, GST_TYPE_ELEMENT);
 
+typedef struct
+{
+  guint16 seqnum;
+  guint32 timestamp;
+  GstBuffer *buffer;
+} BufferQueueItem;
+
+static void
+buffer_queue_item_free (BufferQueueItem * item)
+{
+  gst_buffer_unref (item->buffer);
+  g_free (item);
+}
+
 static void
 gst_rtp_rtx_send_class_init (GstRtpRtxSendClass * klass)
 {
@@ -149,7 +163,7 @@ static void
 gst_rtp_rtx_send_reset (GstRtpRtxSend * rtx, gboolean full)
 {
   g_mutex_lock (&rtx->lock);
-  g_queue_foreach (rtx->queue, (GFunc) gst_buffer_unref, NULL);
+  g_queue_foreach (rtx->queue, (GFunc) buffer_queue_item_free, NULL);
   g_queue_clear (rtx->queue);
   g_list_foreach (rtx->pending, (GFunc) gst_buffer_unref, NULL);
   g_list_free (rtx->pending);
@@ -233,26 +247,18 @@ typedef struct
 /* traverse queue history and try to find the buffer that the
  * requested seqnum */
 static void
-push_seqnum (GstBuffer * buffer, RTXData * data)
+push_seqnum (BufferQueueItem * item, RTXData * data)
 {
   GstRtpRtxSend *rtx = data->rtx;
-  GstRTPBuffer rtpbuffer = GST_RTP_BUFFER_INIT;
-  guint16 seqnum;
 
   if (data->found)
     return;
 
-  if (!gst_rtp_buffer_map (buffer, GST_MAP_READ, &rtpbuffer))
-    return;
-
-  seqnum = gst_rtp_buffer_get_seq (&rtpbuffer);
-  gst_rtp_buffer_unmap (&rtpbuffer);
-
   /* data->seqnum comes from the request */
-  if (seqnum == data->seqnum) {
+  if (item->seqnum == data->seqnum) {
     data->found = TRUE;
-    GST_DEBUG_OBJECT (rtx, "found %" G_GUINT16_FORMAT, seqnum);
-    rtx->pending = g_list_prepend (rtx->pending, gst_buffer_ref (buffer));
+    GST_DEBUG_OBJECT (rtx, "found %" G_GUINT16_FORMAT, item->seqnum);
+    rtx->pending = g_list_prepend (rtx->pending, gst_buffer_ref (item->buffer));
   }
 }
 
@@ -431,42 +437,54 @@ gst_rtp_rtx_send_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
   GstFlowReturn ret = GST_FLOW_ERROR;
   GList *pending = NULL;
   GstRTPBuffer rtp = GST_RTP_BUFFER_INIT;
-  guint seqnum = 0;
+  BufferQueueItem *item;
+  guint16 seqnum;
+  guint32 ssrc, rtptime;
+
+  rtx = GST_RTP_RTX_SEND (parent);
+
+  /* read the information we want from the buffer */
+  gst_rtp_buffer_map (buffer, GST_MAP_READ, &rtp);
+  seqnum = gst_rtp_buffer_get_seq (&rtp);
+  ssrc = gst_rtp_buffer_get_ssrc (&rtp);
+  rtptime = gst_rtp_buffer_get_timestamp (&rtp);
+  gst_rtp_buffer_unmap (&rtp);
 
   g_mutex_lock (&rtx->lock);
 
-  /* retrievemaster stream ssrc */
-  gst_rtp_buffer_map (buffer, GST_MAP_READ, &rtp);
-  rtx->master_ssrc = gst_rtp_buffer_get_ssrc (&rtp);
-  seqnum = gst_rtp_buffer_get_seq (&rtp);
-  gst_rtp_buffer_unmap (&rtp);
-
+  /* retrieve master stream ssrc */
+  rtx->master_ssrc = ssrc;
   /* check if our initial aux ssrc is equal to master */
   if (rtx->rtx_ssrc == rtx->master_ssrc)
     choose_ssrc (rtx);
 
   /* add current rtp buffer to queue history */
-  g_queue_push_head (rtx->queue, gst_buffer_ref (buffer));
+  item = g_new0 (BufferQueueItem, 1);
+  item->seqnum = seqnum;
+  item->timestamp = rtptime;
+  item->buffer = gst_buffer_ref (buffer);
+  g_queue_push_head (rtx->queue, item);
 
   /* remove oldest packets from history if they are too many */
   if (rtx->max_size_packets) {
     while (g_queue_get_length (rtx->queue) > rtx->max_size_packets)
-      gst_buffer_unref (g_queue_pop_tail (rtx->queue));
+      buffer_queue_item_free (g_queue_pop_tail (rtx->queue));
   }
 
   /* within lock, get packets that have to be retransmited */
   pending = rtx->pending;
   rtx->pending = NULL;
 
-  /* assume we will succeed to retransmit those packets */
+  /* update statistics - assume we will succeed to retransmit those packets */
   rtx->num_rtx_packets += g_list_length (pending);
 
   /* transfer payload type while holding the lock */
   rtx->rtx_payload_type = rtx->rtx_payload_type_pending;
 
+  /* no need to hold the lock to push rtx packets */
   g_mutex_unlock (&rtx->lock);
 
-  /* no need to hold the lock to push rtx packets */
+  /* retransmit requested packets */
   g_list_foreach (pending, (GFunc) do_push, rtx);
   g_list_foreach (pending, (GFunc) gst_buffer_unref, NULL);
   g_list_free (pending);