From 96aa9b5633f08fdd9c699b0047e95133639213ba Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Wed, 23 Oct 2019 14:31:16 +0300
Subject: [PATCH] timecodestamper: Add last-known-or-zero mode

This uses the last known upstream timecode (counted up per frame), or
otherwise zero if none was known.

The normal last-known timestamp uses the internal timecode as fallback
if no upstream timecode was ever known.
---
 gst/timecode/gsttimecodestamper.c | 10 ++++++++++
 gst/timecode/gsttimecodestamper.h |  1 +
 2 files changed, 11 insertions(+)

diff --git a/gst/timecode/gsttimecodestamper.c b/gst/timecode/gsttimecodestamper.c
index c8bea0ff33..58b1780d7d 100644
--- a/gst/timecode/gsttimecodestamper.c
+++ b/gst/timecode/gsttimecodestamper.c
@@ -156,6 +156,9 @@ gst_timecodestamper_source_get_type (void)
     {GST_TIME_CODE_STAMPER_SOURCE_LAST_KNOWN,
           "Count up from the last known upstream timecode or internal if unknown",
         "last-known"},
+    {GST_TIME_CODE_STAMPER_SOURCE_LAST_KNOWN_OR_ZERO,
+          "Count up from the last known upstream timecode or zero if unknown",
+        "last-known-or-zero"},
     {GST_TIME_CODE_STAMPER_SOURCE_LTC,
         "Linear timecode from an audio device", "ltc"},
     {GST_TIME_CODE_STAMPER_SOURCE_RTC,
@@ -1164,6 +1167,13 @@ gst_timecodestamper_transform_ip (GstBaseTransform * vfilter,
       if (!tc)
         tc = timecodestamper->internal_tc;
       break;
+    case GST_TIME_CODE_STAMPER_SOURCE_LAST_KNOWN_OR_ZERO:
+      tc = timecodestamper->last_tc;
+      if (!tc) {
+        tc = gst_video_time_code_new (timecodestamper->vinfo.fps_n,
+            timecodestamper->vinfo.fps_d, NULL, tc_flags, 0, 0, 0, 0, 0);
+        free_tc = TRUE;
+      }
       break;
     case GST_TIME_CODE_STAMPER_SOURCE_LTC:
 #if HAVE_LTC
diff --git a/gst/timecode/gsttimecodestamper.h b/gst/timecode/gsttimecodestamper.h
index 43617f65d6..6450e9d9c0 100644
--- a/gst/timecode/gsttimecodestamper.h
+++ b/gst/timecode/gsttimecodestamper.h
@@ -49,6 +49,7 @@ typedef enum GstTimeCodeStamperSource
   GST_TIME_CODE_STAMPER_SOURCE_INTERNAL,
   GST_TIME_CODE_STAMPER_SOURCE_ZERO,
   GST_TIME_CODE_STAMPER_SOURCE_LAST_KNOWN,
+  GST_TIME_CODE_STAMPER_SOURCE_LAST_KNOWN_OR_ZERO,
   GST_TIME_CODE_STAMPER_SOURCE_LTC,
   GST_TIME_CODE_STAMPER_SOURCE_RTC,
 } GstTimeCodeStamperSource;