From 9e585ffd4653b75ddf35f23fbf9295d40882e86f Mon Sep 17 00:00:00 2001
From: "Joshua M. Doe" <oss@nvl.army.mil>
Date: Wed, 15 Jan 2014 15:53:26 -0500
Subject: [PATCH] framelinksrc: don't push out an old buffer and report dropped
 frames

---
 sys/imperx/gstframelinksrc.c | 20 ++++++++++++++++++--
 sys/imperx/gstframelinksrc.h |  1 +
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/sys/imperx/gstframelinksrc.c b/sys/imperx/gstframelinksrc.c
index dc2931c..b0e8dd6 100644
--- a/sys/imperx/gstframelinksrc.c
+++ b/sys/imperx/gstframelinksrc.c
@@ -565,6 +565,7 @@ gst_framelinksrc_create (GstPushSrc * psrc, GstBuffer ** buf)
   GstFramelinkSrc *src = GST_FRAMELINK_SRC (psrc);
   VCECLB_Error err;
   VCECLB_FrameInfoEx pFrameInfo;
+  gboolean got_new_buffer = FALSE;
 
   /* Start acquisition if not already started */
   if (!src->acq_started) {
@@ -598,14 +599,29 @@ gst_framelinksrc_create (GstPushSrc * psrc, GstBuffer ** buf)
   }
   g_mutex_unlock (&src->mutex);
 #else
-  pFrameInfo.lpRawBuffer = NULL;
-  while (pFrameInfo.lpRawBuffer == NULL) {
+  while (!got_new_buffer) {
+    guint dropped_frames;
     err = VCECLB_GetLastBufferData (src->grabber, src->channel, &pFrameInfo);
     if (err != VCECLB_Err_Success) {
       GST_ELEMENT_ERROR (src, RESOURCE, FAILED,
           ("Failed to get last buffer (code %d)", err), (NULL));
       return GST_FLOW_ERROR;
     }
+
+    if (pFrameInfo.lpRawBuffer == NULL
+        || pFrameInfo.number == src->last_buffer_number)
+      continue;
+
+    got_new_buffer = TRUE;
+
+    dropped_frames = pFrameInfo.number - src->last_buffer_number - 1;
+    if (dropped_frames > 0) {
+      src->dropped_frame_count += dropped_frames;
+      GST_WARNING_OBJECT (src, "Dropped %d frames (%d total)", dropped_frames,
+          src->dropped_frame_count);
+    }
+    src->last_buffer_number = pFrameInfo.number;
+
   }
 
   /* TODO: check for missed frames by comparing pFrameInfo.number */
diff --git a/sys/imperx/gstframelinksrc.h b/sys/imperx/gstframelinksrc.h
index ad32b4d..321e1a3 100644
--- a/sys/imperx/gstframelinksrc.h
+++ b/sys/imperx/gstframelinksrc.h
@@ -40,6 +40,7 @@ struct _GstFramelinkSrc
 {
   GstPushSrc base_framelinksrc;
 
+  guint last_buffer_number;
   gint dropped_frame_count;
   gboolean acq_started;