/*
 * GStreamer
 * Copyright (C) 2016 Vivia Nikolaidou <vivia@toolsonair.com>
 * Copyright (C) 2019 Sebastian Dröge <sebastian@centricular.com>
 *
 * gsttimecodestamper.c
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

/**
 * SECTION:element-timecodestamper
 * @title: timecodestamper
 * @short_description: Attach a timecode into incoming video frames
 *
 * This element attaches a timecode into every incoming video frame. It starts
 * counting from the stream time of each segment start, which it converts into
 * a timecode.
 *
 * ## Example launch line
 * |[
 * gst-launch-1.0 videotestsrc ! timecodestamper ! autovideosink
 * ]|
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "gsttimecodestamper.h"

#include <gst/gst.h>
#include <gst/video/video.h>
#include <gst/audio/audio.h>
#include <stdlib.h>
#include <string.h>

#define ABSDIFF(a,b) (((a) > (b)) ? ((a) - (b)) : ((b) - (a)))

GST_DEBUG_CATEGORY_STATIC (timecodestamper_debug);
#define GST_CAT_DEFAULT timecodestamper_debug

/* GstTimeCodeStamper properties */
enum
{
  PROP_0,
  PROP_SOURCE,
  PROP_SET,
  PROP_DROP_FRAME,
  PROP_POST_MESSAGES,
  PROP_SET_INTERNAL_TIMECODE,
  PROP_RTC_MAX_DRIFT,
  PROP_RTC_AUTO_RESYNC,
  PROP_TIMECODE_OFFSET
};

#define DEFAULT_SOURCE GST_TIME_CODE_STAMPER_SOURCE_INTERNAL
#define DEFAULT_SET GST_TIME_CODE_STAMPER_SET_KEEP
#define DEFAULT_DROP_FRAME FALSE
#define DEFAULT_POST_MESSAGES FALSE
#define DEFAULT_SET_INTERNAL_TIMECODE NULL
#define DEFAULT_RTC_MAX_DRIFT 250000000
#define DEFAULT_RTC_AUTO_RESYNC TRUE
#define DEFAULT_TIMECODE_OFFSET 0

static GstStaticPadTemplate gst_timecodestamper_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-raw")
    );

static GstStaticPadTemplate gst_timecodestamper_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-raw")
    );

static GstStaticPadTemplate gst_timecodestamper_ltc_template =
GST_STATIC_PAD_TEMPLATE ("ltc_sink",
    GST_PAD_SINK,
    GST_PAD_REQUEST,
    GST_STATIC_CAPS ("audio/x-raw,format=U8,rate=[1,max],channels=1")
    );

static void gst_timecodestamper_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_timecodestamper_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);
static void gst_timecodestamper_dispose (GObject * object);
static gboolean gst_timecodestamper_sink_event (GstBaseTransform * trans,
    GstEvent * event);
static GstFlowReturn gst_timecodestamper_transform_ip (GstBaseTransform *
    vfilter, GstBuffer * buffer);
static gboolean gst_timecodestamper_stop (GstBaseTransform * trans);

static void gst_timecodestamper_update_drop_frame (GstTimeCodeStamper *
    timecodestamper);

G_DEFINE_TYPE (GstTimeCodeStamper, gst_timecodestamper,
    GST_TYPE_BASE_TRANSFORM);

GType
gst_timecodestamper_source_get_type (void)
{
  static GType type = 0;
  static const GEnumValue values[] = {
    {GST_TIME_CODE_STAMPER_SOURCE_INTERNAL,
          "Use internal timecode counter, starting at zero or value set by property",
        "internal"},
    {GST_TIME_CODE_STAMPER_SOURCE_ZERO,
        "Always use zero", "zero"},
    {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_RTC,
        "Timecode from real time clock", "rtc"},
    {0, NULL, NULL},
  };

  if (!type) {
    type = g_enum_register_static ("GstTimeCodeStamperSource", values);
  }
  return type;
}

GType
gst_timecodestamper_set_get_type (void)
{
  static GType type = 0;
  static const GEnumValue values[] = {
    {GST_TIME_CODE_STAMPER_SET_NEVER,
        "Never set timecodes", "never"},
    {GST_TIME_CODE_STAMPER_SET_KEEP,
        "Keep upstream timecodes and only set if no upstream timecode", "keep"},
    {GST_TIME_CODE_STAMPER_SET_ALWAYS,
        "Always set timecode and remove upstream timecode", "always"},
    {0, NULL, NULL},
  };

  if (!type) {
    type = g_enum_register_static ("GstTimeCodeStamperSet", values);
  }
  return type;
}

static void
gst_timecodestamper_class_init (GstTimeCodeStamperClass * klass)
{
  GObjectClass *gobject_class = (GObjectClass *) klass;
  GstElementClass *element_class = (GstElementClass *) klass;
  GstBaseTransformClass *trans_class = (GstBaseTransformClass *) klass;

  GST_DEBUG_CATEGORY_INIT (timecodestamper_debug, "timecodestamper", 0,
      "timecodestamper");
  gst_element_class_set_static_metadata (element_class, "Timecode stamper",
      "Filter/Video", "Attaches a timecode meta into each video frame",
      "Vivia Nikolaidou <vivia@toolsonair.com>");

  gobject_class->set_property = gst_timecodestamper_set_property;
  gobject_class->get_property = gst_timecodestamper_get_property;
  gobject_class->dispose = gst_timecodestamper_dispose;

  g_object_class_install_property (gobject_class, PROP_SOURCE,
      g_param_spec_enum ("source", "Timecode Source",
          "Choose from what source the timecode should be taken",
          GST_TYPE_TIME_CODE_STAMPER_SOURCE,
          DEFAULT_SOURCE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_SET,
      g_param_spec_enum ("set", "Timecode Set",
          "Choose whether timecodes should be overridden or not",
          GST_TYPE_TIME_CODE_STAMPER_SET,
          DEFAULT_SET, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_DROP_FRAME,
      g_param_spec_boolean ("drop-frame", "Drop Frame",
          "Use drop-frame timecodes for 29.97 and 59.94 FPS",
          DEFAULT_DROP_FRAME, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_POST_MESSAGES,
      g_param_spec_boolean ("post-messages", "Post element message",
          "Post element message containing the current timecode",
          DEFAULT_POST_MESSAGES, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_SET_INTERNAL_TIMECODE,
      g_param_spec_boxed ("set-internal-timecode",
          "Set Internal Timecode",
          "If set, take this timecode as the internal timecode for the first "
          "frame and increment from it. Only the values itself and daily jam are taken, "
          "flags and frame rate are always determined by timecodestamper "
          "itself. If unset (and to-now is also not set), the internal timecode will "
          "start at 0 with the daily jam being the current real-time clock time",
          GST_TYPE_VIDEO_TIME_CODE,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_RTC_MAX_DRIFT,
      g_param_spec_uint64 ("rtc-max-drift",
          "RTC Maximum Offset",
          "Maximum number of nanoseconds the RTC clock is allowed to drift from "
          "the video before it is resynced",
          0, G_MAXUINT64, DEFAULT_RTC_MAX_DRIFT,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_RTC_AUTO_RESYNC,
      g_param_spec_boolean ("rtc-auto-resync",
          "RTC Auto Resync",
          "If true and RTC timecode is used, it will be automatically "
          "resynced if it drifts, otherwise it will only be initialised once",
          DEFAULT_RTC_AUTO_RESYNC, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_TIMECODE_OFFSET,
      g_param_spec_int ("timecode-offset",
          "Timecode Offset",
          "Add this offset in frames to internal or RTC timecode, "
          "useful if there is an offset between the timecode source and video",
          G_MININT, G_MAXINT, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_timecodestamper_sink_template));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_timecodestamper_src_template));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_timecodestamper_ltc_template));

  trans_class->sink_event = GST_DEBUG_FUNCPTR (gst_timecodestamper_sink_event);
  trans_class->stop = GST_DEBUG_FUNCPTR (gst_timecodestamper_stop);

  trans_class->transform_ip =
      GST_DEBUG_FUNCPTR (gst_timecodestamper_transform_ip);
}

static void
gst_timecodestamper_init (GstTimeCodeStamper * timecodestamper)
{
  timecodestamper->ltcpad = NULL;

  timecodestamper->tc_source = GST_TIME_CODE_STAMPER_SOURCE_INTERNAL;
  timecodestamper->tc_set = GST_TIME_CODE_STAMPER_SET_KEEP;
  timecodestamper->drop_frame = DEFAULT_DROP_FRAME;
  timecodestamper->post_messages = DEFAULT_POST_MESSAGES;
  timecodestamper->set_internal_tc = NULL;
  timecodestamper->rtc_max_drift = DEFAULT_RTC_MAX_DRIFT;
  timecodestamper->rtc_auto_resync = DEFAULT_RTC_AUTO_RESYNC;
  timecodestamper->timecode_offset = 0;

  timecodestamper->internal_tc = NULL;
  timecodestamper->last_tc = NULL;
  timecodestamper->rtc_tc = NULL;
}

static void
gst_timecodestamper_dispose (GObject * object)
{
  GstTimeCodeStamper *timecodestamper = GST_TIME_CODE_STAMPER (object);

  if (timecodestamper->ltc_daily_jam) {
    g_date_time_unref (timecodestamper->ltc_daily_jam);
    timecodestamper->ltc_daily_jam = NULL;
  }

  if (timecodestamper->internal_tc != NULL) {
    gst_video_time_code_free (timecodestamper->internal_tc);
    timecodestamper->internal_tc = NULL;
  }

  if (timecodestamper->set_internal_tc != NULL) {
    gst_video_time_code_free (timecodestamper->set_internal_tc);
    timecodestamper->set_internal_tc = NULL;
  }

  if (timecodestamper->last_tc != NULL) {
    gst_video_time_code_free (timecodestamper->last_tc);
    timecodestamper->last_tc = NULL;
  }

  if (timecodestamper->rtc_tc != NULL) {
    gst_video_time_code_free (timecodestamper->rtc_tc);
    timecodestamper->rtc_tc = NULL;
  }

  G_OBJECT_CLASS (gst_timecodestamper_parent_class)->dispose (object);
}

static void
gst_timecodestamper_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstTimeCodeStamper *timecodestamper = GST_TIME_CODE_STAMPER (object);

  GST_OBJECT_LOCK (timecodestamper);
  switch (prop_id) {
    case PROP_SOURCE:
      timecodestamper->tc_source = (GstTimeCodeStamperSource)
          g_value_get_enum (value);
      break;
    case PROP_SET:
      timecodestamper->tc_set = (GstTimeCodeStamperSet)
          g_value_get_enum (value);
      break;
    case PROP_DROP_FRAME:
      timecodestamper->drop_frame = g_value_get_boolean (value);
      gst_timecodestamper_update_drop_frame (timecodestamper);
      break;
    case PROP_POST_MESSAGES:
      timecodestamper->post_messages = g_value_get_boolean (value);
      break;
    case PROP_SET_INTERNAL_TIMECODE:{
      if (timecodestamper->set_internal_tc)
        gst_video_time_code_free (timecodestamper->set_internal_tc);
      timecodestamper->set_internal_tc = g_value_dup_boxed (value);

      /* Reset the internal timecode on the next opportunity if a new
       * timecode was set here. If none was set we just continue counting
       * from the previous one */
      if (timecodestamper->set_internal_tc && timecodestamper->internal_tc) {
        gst_video_time_code_free (timecodestamper->internal_tc);
        timecodestamper->internal_tc = NULL;
      }
      break;
    }
    case PROP_RTC_MAX_DRIFT:
      timecodestamper->rtc_max_drift = g_value_get_uint64 (value);
      break;
    case PROP_RTC_AUTO_RESYNC:
      timecodestamper->rtc_auto_resync = g_value_get_boolean (value);
      break;
    case PROP_TIMECODE_OFFSET:
      timecodestamper->timecode_offset = g_value_get_int (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }

  GST_OBJECT_UNLOCK (timecodestamper);
}

static void
gst_timecodestamper_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  GstTimeCodeStamper *timecodestamper = GST_TIME_CODE_STAMPER (object);

  GST_OBJECT_LOCK (timecodestamper);
  switch (prop_id) {
    case PROP_SOURCE:
      g_value_set_enum (value, timecodestamper->tc_source);
      break;
    case PROP_SET:
      g_value_set_enum (value, timecodestamper->tc_set);
      break;
    case PROP_DROP_FRAME:
      g_value_set_boolean (value, timecodestamper->drop_frame);
      break;
    case PROP_POST_MESSAGES:
      g_value_set_boolean (value, timecodestamper->post_messages);
      break;
    case PROP_SET_INTERNAL_TIMECODE:
      g_value_set_boxed (value, timecodestamper->set_internal_tc);
      break;
    case PROP_RTC_MAX_DRIFT:
      g_value_set_uint64 (value, timecodestamper->rtc_max_drift);
      break;
    case PROP_RTC_AUTO_RESYNC:
      g_value_set_boolean (value, timecodestamper->rtc_auto_resync);
      break;
    case PROP_TIMECODE_OFFSET:
      g_value_set_int (value, timecodestamper->timecode_offset);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
  GST_OBJECT_UNLOCK (timecodestamper);
}

static gboolean
gst_timecodestamper_stop (GstBaseTransform * trans)
{
  GstTimeCodeStamper *timecodestamper = GST_TIME_CODE_STAMPER (trans);

  gst_video_info_init (&timecodestamper->vinfo);

  if (timecodestamper->internal_tc != NULL) {
    gst_video_time_code_free (timecodestamper->internal_tc);
    timecodestamper->internal_tc = NULL;
  }

  if (timecodestamper->rtc_tc != NULL) {
    gst_video_time_code_free (timecodestamper->rtc_tc);
    timecodestamper->rtc_tc = NULL;
  }

  if (timecodestamper->last_tc != NULL) {
    gst_video_time_code_free (timecodestamper->last_tc);
    timecodestamper->last_tc = NULL;
  }

  return TRUE;
}

/* Must be called with object lock */
static void
gst_timecodestamper_update_drop_frame (GstTimeCodeStamper * timecodestamper)
{
  if (timecodestamper->drop_frame && timecodestamper->vinfo.fps_d == 1001 &&
      (timecodestamper->vinfo.fps_n == 30000 ||
          timecodestamper->vinfo.fps_n == 60000)) {
    if (timecodestamper->internal_tc)
      timecodestamper->internal_tc->config.flags |=
          GST_VIDEO_TIME_CODE_FLAGS_DROP_FRAME;
    if (timecodestamper->rtc_tc)
      timecodestamper->rtc_tc->config.flags |=
          GST_VIDEO_TIME_CODE_FLAGS_DROP_FRAME;
  } else {
    if (timecodestamper->internal_tc)
      timecodestamper->internal_tc->config.flags &=
          ~GST_VIDEO_TIME_CODE_FLAGS_DROP_FRAME;
    if (timecodestamper->rtc_tc)
      timecodestamper->rtc_tc->config.flags &=
          ~GST_VIDEO_TIME_CODE_FLAGS_DROP_FRAME;
  }
}

static void
gst_timecodestamper_update_timecode_framerate (GstTimeCodeStamper *
    timecodestamper, const GstVideoInfo * vinfo, GstVideoTimeCode * timecode)
{
  guint64 nframes;
  GstClockTime time;
  GDateTime *jam = NULL;
  GstVideoTimeCodeFlags tc_flags = 0;

  if (!timecode)
    return;

  if (timecodestamper->vinfo.interlace_mode !=
      GST_VIDEO_INTERLACE_MODE_PROGRESSIVE)
    tc_flags |= GST_VIDEO_TIME_CODE_FLAGS_INTERLACED;

  if (timecodestamper->drop_frame && timecodestamper->vinfo.fps_d == 1001 &&
      (timecodestamper->vinfo.fps_n == 30000 ||
          timecodestamper->vinfo.fps_n == 60000))
    tc_flags |= GST_VIDEO_TIME_CODE_FLAGS_DROP_FRAME;

  nframes = gst_video_time_code_frames_since_daily_jam (timecode);
  time =
      gst_util_uint64_scale (nframes, GST_SECOND * timecodestamper->vinfo.fps_d,
      timecodestamper->vinfo.fps_n);
  jam =
      timecode->config.latest_daily_jam ? g_date_time_ref (timecode->
      config.latest_daily_jam) : NULL;
  gst_video_time_code_clear (timecode);
  gst_video_time_code_init (timecode, timecodestamper->vinfo.fps_n,
      timecodestamper->vinfo.fps_d, jam, tc_flags, 0, 0, 0, 0, 0);
  if (jam)
    g_date_time_unref (jam);

  nframes =
      gst_util_uint64_scale (time, vinfo->fps_n, GST_SECOND * vinfo->fps_d);
  gst_video_time_code_add_frames (timecode, nframes);
}

/* Must be called with object lock */
static void
gst_timecodestamper_update_framerate (GstTimeCodeStamper * timecodestamper,
    const GstVideoInfo * vinfo)
{
  /* Nothing changed */
  if (vinfo->fps_n == timecodestamper->vinfo.fps_n &&
      vinfo->fps_d == timecodestamper->vinfo.fps_d)
    return;

  gst_timecodestamper_update_timecode_framerate (timecodestamper, vinfo,
      timecodestamper->internal_tc);
  gst_timecodestamper_update_timecode_framerate (timecodestamper, vinfo,
      timecodestamper->last_tc);
  gst_timecodestamper_update_timecode_framerate (timecodestamper, vinfo,
      timecodestamper->rtc_tc);
}

static gboolean
gst_timecodestamper_sink_event (GstBaseTransform * trans, GstEvent * event)
{
  gboolean ret = FALSE;
  GstTimeCodeStamper *timecodestamper = GST_TIME_CODE_STAMPER (trans);

  GST_DEBUG_OBJECT (trans, "received event %" GST_PTR_FORMAT, event);
  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_SEGMENT:
    {
      GstSegment segment;

      gst_event_copy_segment (event, &segment);
      if (segment.format != GST_FORMAT_TIME) {
        GST_ERROR_OBJECT (timecodestamper, "Invalid segment format");
        gst_event_unref (event);
        return FALSE;
      }
      break;
    }
    case GST_EVENT_CAPS:
    {
      GstCaps *caps;
      GstVideoInfo info;

      GST_OBJECT_LOCK (timecodestamper);
      gst_event_parse_caps (event, &caps);
      if (!gst_video_info_from_caps (&info, caps)) {
        GST_OBJECT_UNLOCK (timecodestamper);
        gst_event_unref (event);
        return FALSE;
      }
      if (info.fps_n == 0) {
        GST_WARNING_OBJECT (timecodestamper,
            "Non-constant frame rate found. Refusing to create a timecode");
        GST_OBJECT_UNLOCK (timecodestamper);
        gst_event_unref (event);
        return FALSE;
      }

      gst_timecodestamper_update_framerate (timecodestamper, &info);
      timecodestamper->vinfo = info;
      GST_OBJECT_UNLOCK (timecodestamper);
      break;
    }
    default:
      break;
  }
  ret =
      GST_BASE_TRANSFORM_CLASS (gst_timecodestamper_parent_class)->sink_event
      (trans, event);
  return ret;
}

static gboolean
remove_timecode_meta (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
{
  if (meta && *meta && (*meta)->info->api == GST_VIDEO_TIME_CODE_META_API_TYPE) {
    *meta = NULL;
  }

  return TRUE;
}

static GstFlowReturn
gst_timecodestamper_transform_ip (GstBaseTransform * vfilter,
    GstBuffer * buffer)
{
  GstTimeCodeStamper *timecodestamper = GST_TIME_CODE_STAMPER (vfilter);
  GstClockTime running_time, base_time, clock_time;
  GstClock *clock;
  GstClockTime clock_time_now;
  GDateTime *dt_now, *dt_frame;
  GstVideoTimeCode *tc = NULL;
  gboolean free_tc = FALSE;
  GstVideoTimeCodeMeta *tc_meta;
  GstFlowReturn flow_ret = GST_FLOW_OK;
  GstVideoTimeCodeFlags tc_flags = 0;

  if (timecodestamper->vinfo.fps_n == 0 || timecodestamper->vinfo.fps_d == 0
      || !GST_BUFFER_PTS_IS_VALID (buffer)) {
    gst_buffer_unref (buffer);
    return GST_FLOW_NOT_NEGOTIATED;
  }

  /* Collect all the current times */
  base_time = gst_element_get_base_time (GST_ELEMENT (timecodestamper));
  clock = gst_element_get_clock (GST_ELEMENT (timecodestamper));
  if (clock) {
    clock_time_now = gst_clock_get_time (clock);
    gst_object_unref (clock);
  } else {
    clock_time_now = GST_CLOCK_TIME_NONE;
  }

  dt_now = g_date_time_new_now_local ();

  running_time =
      gst_segment_to_running_time (&vfilter->segment, GST_FORMAT_TIME,
      GST_BUFFER_PTS (buffer));

  if (clock_time_now != GST_CLOCK_TIME_NONE) {
    gdouble seconds_diff;

    clock_time = running_time + base_time;
    if (clock_time_now > clock_time) {
      seconds_diff = (clock_time_now - clock_time) / -1000000000.0;
    } else {
      seconds_diff = (clock_time - clock_time_now) / 1000000000.0;
    }
    dt_frame = g_date_time_add_seconds (dt_now, seconds_diff);
  } else {
    /* If we have no clock we can't really know the time of the frame */
    dt_frame = g_date_time_ref (dt_now);
  }

  GST_DEBUG_OBJECT (timecodestamper,
      "Handling video frame with running time %" GST_TIME_FORMAT,
      GST_TIME_ARGS (running_time));

  tc_meta = gst_buffer_get_video_time_code_meta (buffer);

  /* Update all our internal timecodes as needed */
  GST_OBJECT_LOCK (timecodestamper);

  if (timecodestamper->vinfo.interlace_mode !=
      GST_VIDEO_INTERLACE_MODE_PROGRESSIVE)
    tc_flags |= GST_VIDEO_TIME_CODE_FLAGS_INTERLACED;

  if (timecodestamper->drop_frame && timecodestamper->vinfo.fps_d == 1001 &&
      (timecodestamper->vinfo.fps_n == 30000 ||
          timecodestamper->vinfo.fps_n == 60000))
    tc_flags |= GST_VIDEO_TIME_CODE_FLAGS_DROP_FRAME;

  /* If we don't have an internal timecode yet then either a new one was just
   * set via the property or we just started. Initialize it here, otherwise
   * increment it by one */
  if (!timecodestamper->internal_tc) {
    gchar *tc_str;

    if (timecodestamper->set_internal_tc)
      timecodestamper->internal_tc =
          gst_video_time_code_new (timecodestamper->vinfo.fps_n,
          timecodestamper->vinfo.fps_d,
          timecodestamper->set_internal_tc->config.latest_daily_jam,
          tc_flags,
          timecodestamper->set_internal_tc->hours,
          timecodestamper->set_internal_tc->minutes,
          timecodestamper->set_internal_tc->seconds,
          timecodestamper->set_internal_tc->frames,
          timecodestamper->set_internal_tc->field_count);
    else
      timecodestamper->internal_tc =
          gst_video_time_code_new (timecodestamper->vinfo.fps_n,
          timecodestamper->vinfo.fps_d, dt_frame, tc_flags, 0, 0, 0, 0, 0);

    tc_str = gst_video_time_code_to_string (timecodestamper->internal_tc);
    GST_DEBUG_OBJECT (timecodestamper, "Initialized internal timecode to %s",
        tc_str);
    g_free (tc_str);
  } else {
    gchar *tc_str;

    gst_video_time_code_increment_frame (timecodestamper->internal_tc);
    tc_str = gst_video_time_code_to_string (timecodestamper->internal_tc);
    GST_DEBUG_OBJECT (timecodestamper, "Incremented internal timecode to %s",
        tc_str);
    g_free (tc_str);
  }

  /* If we have a new timecode on the incoming frame, update our last known
   * timecode or otherwise increment it by one */
  if (tc_meta) {
    gchar *tc_str;

    if (timecodestamper->last_tc)
      gst_video_time_code_free (timecodestamper->last_tc);
    timecodestamper->last_tc = gst_video_time_code_copy (&tc_meta->tc);

    tc_str = gst_video_time_code_to_string (timecodestamper->last_tc);
    GST_DEBUG_OBJECT (timecodestamper, "Updated upstream timecode to %s",
        tc_str);
    g_free (tc_str);
  } else {
    gchar *tc_str;

    if (timecodestamper->last_tc) {
      gst_video_time_code_increment_frame (timecodestamper->last_tc);
    } else {
      /* We have no last known timecode so initialize with 0 here */
      timecodestamper->last_tc =
          gst_video_time_code_new (timecodestamper->vinfo.fps_n,
          timecodestamper->vinfo.fps_d, dt_frame, tc_flags, 0, 0, 0, 0, 0);
    }

    tc_str = gst_video_time_code_to_string (timecodestamper->last_tc);
    GST_DEBUG_OBJECT (timecodestamper, "Incremented upstream timecode to %s",
        tc_str);
    g_free (tc_str);
  }

  /* Update RTC-based timecode */
  {
    GstVideoTimeCode rtc_timecode_now;
    gchar *tc_str, *dt_str;

    /* Create timecode for the current frame time */
    memset (&rtc_timecode_now, 0, sizeof (rtc_timecode_now));
    gst_video_time_code_init_from_date_time_full (&rtc_timecode_now,
        timecodestamper->vinfo.fps_n, timecodestamper->vinfo.fps_d, dt_frame,
        tc_flags, 0);

    tc_str = gst_video_time_code_to_string (&rtc_timecode_now);
    dt_str = g_date_time_format (dt_frame, "%F %R %z");
    GST_DEBUG_OBJECT (timecodestamper,
        "Created RTC timecode %s for %s (%06u us)", tc_str, dt_str,
        g_date_time_get_microsecond (dt_frame));
    g_free (dt_str);
    g_free (tc_str);

    /* If we don't have an RTC timecode yet, directly initialize with this one */
    if (!timecodestamper->rtc_tc) {
      timecodestamper->rtc_tc = gst_video_time_code_copy (&rtc_timecode_now);
      tc_str = gst_video_time_code_to_string (timecodestamper->rtc_tc);
      GST_DEBUG_OBJECT (timecodestamper, "Initialized RTC timecode to %s",
          tc_str);
      g_free (tc_str);
    } else {
      GstClockTime rtc_now_time, rtc_tc_time;
      GstClockTime rtc_diff;

      /* Increment the old RTC timecode to this frame */
      gst_video_time_code_increment_frame (timecodestamper->rtc_tc);

      /* Otherwise check if we drifted too much and need to resync */
      rtc_tc_time =
          gst_video_time_code_nsec_since_daily_jam (timecodestamper->rtc_tc);
      rtc_now_time =
          gst_video_time_code_nsec_since_daily_jam (&rtc_timecode_now);
      if (rtc_tc_time > rtc_now_time)
        rtc_diff = rtc_tc_time - rtc_now_time;
      else
        rtc_diff = rtc_now_time - rtc_tc_time;

      if (timecodestamper->rtc_auto_resync
          && timecodestamper->rtc_max_drift != GST_CLOCK_TIME_NONE
          && rtc_diff > timecodestamper->rtc_max_drift) {
        gst_video_time_code_free (timecodestamper->rtc_tc);
        timecodestamper->rtc_tc = gst_video_time_code_copy (&rtc_timecode_now);
        tc_str = gst_video_time_code_to_string (timecodestamper->rtc_tc);
        GST_DEBUG_OBJECT (timecodestamper,
            "Updated RTC timecode to %s (%s%" GST_TIME_FORMAT " drift)", tc_str,
            (rtc_tc_time > rtc_now_time ? "-" : "+"), GST_TIME_ARGS (rtc_diff));
        g_free (tc_str);
      } else {
        /* Else nothing to do here, we use the current one */
        tc_str = gst_video_time_code_to_string (timecodestamper->rtc_tc);
        GST_DEBUG_OBJECT (timecodestamper,
            "Incremented RTC timecode to %s (%s%" GST_TIME_FORMAT " drift)",
            tc_str, (rtc_tc_time > rtc_now_time ? "-" : "+"),
            GST_TIME_ARGS (rtc_diff));
        g_free (tc_str);
      }
    }

    gst_video_time_code_clear (&rtc_timecode_now);
  }
  GST_OBJECT_UNLOCK (timecodestamper);

  GST_OBJECT_LOCK (timecodestamper);
  switch (timecodestamper->tc_source) {
    case GST_TIME_CODE_STAMPER_SOURCE_INTERNAL:
      tc = timecodestamper->internal_tc;
      break;
    case GST_TIME_CODE_STAMPER_SOURCE_ZERO:
      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_LAST_KNOWN:
      tc = timecodestamper->last_tc;
      break;
    case GST_TIME_CODE_STAMPER_SOURCE_RTC:
      tc = timecodestamper->rtc_tc;
      break;
  }

  switch (timecodestamper->tc_set) {
    case GST_TIME_CODE_STAMPER_SET_NEVER:
      break;
    case GST_TIME_CODE_STAMPER_SET_KEEP:
      if (!tc_meta && tc) {
        gchar *tc_str;

        if (timecodestamper->timecode_offset) {
          if (!free_tc) {
            tc = gst_video_time_code_copy (tc);
            free_tc = TRUE;
          }
          gst_video_time_code_add_frames (tc, timecodestamper->timecode_offset);
        }

        tc_str = gst_video_time_code_to_string (tc);
        GST_DEBUG_OBJECT (timecodestamper, "Storing timecode %s", tc_str);
        g_free (tc_str);

        gst_buffer_add_video_time_code_meta (buffer, tc);
      }
      break;
    case GST_TIME_CODE_STAMPER_SET_ALWAYS:
      gst_buffer_foreach_meta (buffer, remove_timecode_meta, NULL);
      if (tc) {
        gchar *tc_str;

        if (timecodestamper->timecode_offset) {
          if (!free_tc) {
            tc = gst_video_time_code_copy (tc);
            free_tc = TRUE;
          }
          gst_video_time_code_add_frames (tc, timecodestamper->timecode_offset);
        }

        tc_str = gst_video_time_code_to_string (tc);
        GST_DEBUG_OBJECT (timecodestamper, "Storing timecode %s", tc_str);
        g_free (tc_str);

        gst_buffer_add_video_time_code_meta (buffer, tc);
      }
      break;
  }

  GST_OBJECT_UNLOCK (timecodestamper);

  if (timecodestamper->post_messages && tc) {
    GstClockTime stream_time, running_time, duration;
    GstStructure *s;
    GstMessage *msg;

    running_time =
        gst_segment_to_running_time (&vfilter->segment, GST_FORMAT_TIME,
        GST_BUFFER_PTS (buffer));
    stream_time =
        gst_segment_to_stream_time (&vfilter->segment, GST_FORMAT_TIME,
        GST_BUFFER_PTS (buffer));
    duration =
        gst_util_uint64_scale_int (GST_SECOND, timecodestamper->vinfo.fps_d,
        timecodestamper->vinfo.fps_n);
    s = gst_structure_new ("timecodestamper", "timestamp", G_TYPE_UINT64,
        GST_BUFFER_PTS (buffer), "stream-time", G_TYPE_UINT64, stream_time,
        "running-time", G_TYPE_UINT64, running_time, "duration",
        G_TYPE_UINT64, duration, "timecode", GST_TYPE_VIDEO_TIME_CODE, tc,
        NULL);
    msg = gst_message_new_element (GST_OBJECT (timecodestamper), s);
    gst_element_post_message (GST_ELEMENT (timecodestamper), msg);
  }

  if (dt_now)
    g_date_time_unref (dt_now);
  if (dt_frame)
    g_date_time_unref (dt_frame);
  if (free_tc && tc)
    gst_video_time_code_free (tc);

  return flow_ret;
}