From 9dfb7b411ea6b0d0c5e627178427d8cd1ca43b73 Mon Sep 17 00:00:00 2001
From: Wojciech Kapsa <wojciech.kapsa@medvc.eu>
Date: Fri, 7 Oct 2022 08:30:05 +0200
Subject: [PATCH] decklink: reset calculation of
 gst_decklink_video_src_update_time_mapping on no_signal. When the HDMI cable
 was disconnected for a long time, the calculation took too much time. SDI
 cable works fine.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3168>
---
 .../sys/decklink/gstdecklinkvideosrc.cpp      | 31 ++++++++++++++++++-
 .../sys/decklink/gstdecklinkvideosrc.h        |  1 +
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/subprojects/gst-plugins-bad/sys/decklink/gstdecklinkvideosrc.cpp b/subprojects/gst-plugins-bad/sys/decklink/gstdecklinkvideosrc.cpp
index 2385a2339a..e0b6fd49de 100644
--- a/subprojects/gst-plugins-bad/sys/decklink/gstdecklinkvideosrc.cpp
+++ b/subprojects/gst-plugins-bad/sys/decklink/gstdecklinkvideosrc.cpp
@@ -154,6 +154,8 @@ GST_DEBUG_CATEGORY_STATIC (gst_decklink_video_src_debug);
 #define ABSDIFF(x, y) ( (x) > (y) ? ((x) - (y)) : ((y) - (x)) )
 #endif
 
+#define NO_SIGNL_RESET_COUNT (10)
+
 enum
 {
   PROP_0,
@@ -671,6 +673,23 @@ gst_decklink_video_src_start (GstDecklinkVideoSrc * self)
   return TRUE;
 }
 
+static void
+gst_decklink_reset_time_mapping(GstDecklinkVideoSrc * self)
+{
+    self->window_fill = 0;
+    self->window_filled = FALSE;
+    self->window_skip = 1;
+    self->window_skip_count = 0;
+    self->current_time_mapping.xbase = 0;
+    self->current_time_mapping.b = 0;
+    self->current_time_mapping.num = 1;
+    self->current_time_mapping.den = 1;
+    self->next_time_mapping.xbase = 0;
+    self->next_time_mapping.b = 0;
+    self->next_time_mapping.num = 1;
+    self->next_time_mapping.den = 1;
+}
+
 static void
 gst_decklink_video_src_update_time_mapping (GstDecklinkVideoSrc * self,
     GstClockTime capture_time, GstClockTime stream_time)
@@ -811,6 +830,9 @@ gst_decklink_video_src_got_frame (GstElement * element,
     return;
   }
 
+  if (no_signal)
+    self->no_signal_count++;
+
   if (self->drop_no_signal_frames && no_signal) {
     CaptureFrame f;
     memset (&f, 0, sizeof (f));
@@ -823,6 +845,13 @@ gst_decklink_video_src_got_frame (GstElement * element,
     return;
   }
 
+  if (!no_signal) {
+    if (self->no_signal_count > NO_SIGNL_RESET_COUNT) {
+      gst_decklink_reset_time_mapping(self);
+    }
+    self->no_signal_count = 0;
+  }
+
   gst_decklink_video_src_update_time_mapping (self, capture_time, stream_time);
   if (self->output_stream_time) {
     timestamp = stream_time;
@@ -1709,4 +1738,4 @@ gst_decklink_video_src_change_state (GstElement * element,
 out:
 
   return ret;
-}
+}
\ No newline at end of file
diff --git a/subprojects/gst-plugins-bad/sys/decklink/gstdecklinkvideosrc.h b/subprojects/gst-plugins-bad/sys/decklink/gstdecklinkvideosrc.h
index 5e9876687c..879911b26c 100644
--- a/subprojects/gst-plugins-bad/sys/decklink/gstdecklinkvideosrc.h
+++ b/subprojects/gst-plugins-bad/sys/decklink/gstdecklinkvideosrc.h
@@ -69,6 +69,7 @@ struct _GstDecklinkVideoSrc
   guint64 processed;
   guint64 dropped;
   guint64 first_stream_time;
+  guint64 no_signal_count;
 
   GstVideoInfo info;
   GstDecklinkVideoFormat video_format;