gstreamer/sys/decklink/gstdecklinkvideosrc.cpp

/* GStreamer
 * Copyright (C) 2011 David Schleef <ds@entropywave.com>
 * Copyright (C) 2014 Sebastian Dröge <sebastian@centricular.com>
 * Copyright (C) 2015 Florian Langlois <florian.langlois@fr.thalesgroup.com>
 *
 * 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 Street, Suite 500,
 * Boston, MA 02110-1335, USA.
 */

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

#include "gstdecklinkvideosrc.h"
#include <string.h>

GST_DEBUG_CATEGORY_STATIC (gst_decklink_video_src_debug);
#define GST_CAT_DEFAULT gst_decklink_video_src_debug

#define DEFAULT_MODE (GST_DECKLINK_MODE_AUTO)
#define DEFAULT_CONNECTION (GST_DECKLINK_CONNECTION_AUTO)
#define DEFAULT_BUFFER_SIZE (5)
#define DEFAULT_OUTPUT_STREAM_TIME (FALSE)
#define DEFAULT_SKIP_FIRST_TIME (0)
#define DEFAULT_DROP_NO_SIGNAL_FRAMES (FALSE)
#define DEFAULT_OUTPUT_CC (FALSE)

#ifndef ABSDIFF
#define ABSDIFF(x, y) ( (x) > (y) ? ((x) - (y)) : ((y) - (x)) )
#endif

enum
{
  PROP_0,
  PROP_MODE,
  PROP_CONNECTION,
  PROP_DEVICE_NUMBER,
  PROP_BUFFER_SIZE,
  PROP_VIDEO_FORMAT,
  PROP_TIMECODE_FORMAT,
  PROP_OUTPUT_STREAM_TIME,
  PROP_SKIP_FIRST_TIME,
  PROP_DROP_NO_SIGNAL_FRAMES,
  PROP_SIGNAL,
  PROP_HW_SERIAL_NUMBER,
  PROP_OUTPUT_CC
};

typedef struct
{
  IDeckLinkVideoInputFrame *frame;
  GstClockTime timestamp, duration;
  GstClockTime stream_timestamp;
  GstClockTime stream_duration;
  GstClockTime hardware_timestamp;
  GstClockTime hardware_duration;
  GstDecklinkModeEnum mode;
  BMDPixelFormat format;
  GstVideoTimeCode *tc;
  gboolean no_signal;
} CaptureFrame;

static void
capture_frame_clear (CaptureFrame * frame)
{
  frame->frame->Release ();
  if (frame->tc)
    gst_video_time_code_free (frame->tc);
  memset (frame, 0, sizeof (*frame));
}

typedef struct
{
  IDeckLinkVideoInputFrame *frame;
  IDeckLinkInput *input;
} VideoFrame;

static void
video_frame_free (void *data)
{
  VideoFrame *frame = (VideoFrame *) data;

  frame->frame->Release ();
  frame->input->Release ();
  g_free (frame);
}

static void gst_decklink_video_src_set_property (GObject * object,
    guint property_id, const GValue * value, GParamSpec * pspec);
static void gst_decklink_video_src_get_property (GObject * object,
    guint property_id, GValue * value, GParamSpec * pspec);
static void gst_decklink_video_src_finalize (GObject * object);

static GstStateChangeReturn
gst_decklink_video_src_change_state (GstElement * element,
    GstStateChange transition);

static gboolean gst_decklink_video_src_set_caps (GstBaseSrc * bsrc,
    GstCaps * caps);
static GstCaps *gst_decklink_video_src_get_caps (GstBaseSrc * bsrc,
    GstCaps * filter);
static gboolean gst_decklink_video_src_query (GstBaseSrc * bsrc,
    GstQuery * query);
static gboolean gst_decklink_video_src_unlock (GstBaseSrc * bsrc);
static gboolean gst_decklink_video_src_unlock_stop (GstBaseSrc * bsrc);

static GstFlowReturn gst_decklink_video_src_create (GstPushSrc * psrc,
    GstBuffer ** buffer);

static gboolean gst_decklink_video_src_open (GstDecklinkVideoSrc * self);
static gboolean gst_decklink_video_src_close (GstDecklinkVideoSrc * self);

static gboolean gst_decklink_video_src_stop (GstDecklinkVideoSrc * self);

static void gst_decklink_video_src_start_streams (GstElement * element);

#define parent_class gst_decklink_video_src_parent_class
G_DEFINE_TYPE (GstDecklinkVideoSrc, gst_decklink_video_src, GST_TYPE_PUSH_SRC);

static void
gst_decklink_video_src_class_init (GstDecklinkVideoSrcClass * klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
  GstBaseSrcClass *basesrc_class = GST_BASE_SRC_CLASS (klass);
  GstPushSrcClass *pushsrc_class = GST_PUSH_SRC_CLASS (klass);
  GstCaps *templ_caps;

  gobject_class->set_property = gst_decklink_video_src_set_property;
  gobject_class->get_property = gst_decklink_video_src_get_property;
  gobject_class->finalize = gst_decklink_video_src_finalize;

  element_class->change_state =
      GST_DEBUG_FUNCPTR (gst_decklink_video_src_change_state);

  basesrc_class->get_caps = GST_DEBUG_FUNCPTR (gst_decklink_video_src_get_caps);
  basesrc_class->set_caps = GST_DEBUG_FUNCPTR (gst_decklink_video_src_set_caps);
  basesrc_class->query = GST_DEBUG_FUNCPTR (gst_decklink_video_src_query);
  basesrc_class->unlock = GST_DEBUG_FUNCPTR (gst_decklink_video_src_unlock);
  basesrc_class->unlock_stop =
      GST_DEBUG_FUNCPTR (gst_decklink_video_src_unlock_stop);

  pushsrc_class->create = GST_DEBUG_FUNCPTR (gst_decklink_video_src_create);

  g_object_class_install_property (gobject_class, PROP_MODE,
      g_param_spec_enum ("mode", "Playback Mode",
          "Video Mode to use for playback",
          GST_TYPE_DECKLINK_MODE, DEFAULT_MODE,
          (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS |
              G_PARAM_CONSTRUCT)));

  g_object_class_install_property (gobject_class, PROP_CONNECTION,
      g_param_spec_enum ("connection", "Connection",
          "Video input connection to use",
          GST_TYPE_DECKLINK_CONNECTION, DEFAULT_CONNECTION,
          (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS |
              G_PARAM_CONSTRUCT)));

  g_object_class_install_property (gobject_class, PROP_DEVICE_NUMBER,
      g_param_spec_int ("device-number", "Device number",
          "Output device instance to use", 0, G_MAXINT, 0,
          (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS |
              G_PARAM_CONSTRUCT)));

  g_object_class_install_property (gobject_class, PROP_BUFFER_SIZE,
      g_param_spec_uint ("buffer-size", "Buffer Size",
          "Size of internal buffer in number of video frames", 1,
          G_MAXINT, DEFAULT_BUFFER_SIZE,
          (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)));

  g_object_class_install_property (gobject_class, PROP_VIDEO_FORMAT,
      g_param_spec_enum ("video-format", "Video format",
          "Video format type to use for input (Only use auto for mode=auto)",
          GST_TYPE_DECKLINK_VIDEO_FORMAT, GST_DECKLINK_VIDEO_FORMAT_AUTO,
          (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS |
              G_PARAM_CONSTRUCT)));

  g_object_class_install_property (gobject_class, PROP_TIMECODE_FORMAT,
      g_param_spec_enum ("timecode-format", "Timecode format",
          "Timecode format type to use for input",
          GST_TYPE_DECKLINK_TIMECODE_FORMAT,
          GST_DECKLINK_TIMECODE_FORMAT_RP188ANY,
          (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS |
              G_PARAM_CONSTRUCT)));

  g_object_class_install_property (gobject_class, PROP_OUTPUT_STREAM_TIME,
      g_param_spec_boolean ("output-stream-time", "Output Stream Time",
          "Output stream time directly instead of translating to pipeline clock",
          DEFAULT_OUTPUT_STREAM_TIME,
          (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)));

  g_object_class_install_property (gobject_class, PROP_SKIP_FIRST_TIME,
      g_param_spec_uint64 ("skip-first-time", "Skip First Time",
          "Skip that much time of initial frames after starting", 0,
          G_MAXUINT64, DEFAULT_SKIP_FIRST_TIME,
          (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)));

  g_object_class_install_property (gobject_class, PROP_DROP_NO_SIGNAL_FRAMES,
      g_param_spec_boolean ("drop-no-signal-frames", "Drop No Signal Frames",
          "Drop frames that are marked as having no input signal",
          DEFAULT_DROP_NO_SIGNAL_FRAMES,
          (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)));

  g_object_class_install_property (gobject_class, PROP_SIGNAL,
      g_param_spec_boolean ("signal", "Input signal available",
          "True if there is a valid input signal available",
          FALSE, (GParamFlags) (G_PARAM_READABLE | G_PARAM_STATIC_STRINGS)));

  g_object_class_install_property (gobject_class, PROP_HW_SERIAL_NUMBER,
      g_param_spec_string ("hw-serial-number", "Hardware serial number",
          "The serial number (hardware ID) of the Decklink card",
          NULL, (GParamFlags) (G_PARAM_READABLE | G_PARAM_STATIC_STRINGS)));

  g_object_class_install_property (gobject_class, PROP_OUTPUT_CC,
      g_param_spec_boolean ("output-cc", "Output Closed Caption",
          "Extract and output CC as GstMeta (if present)",
          DEFAULT_OUTPUT_CC,
          (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)));

  templ_caps = gst_decklink_mode_get_template_caps (TRUE);
  gst_element_class_add_pad_template (element_class,
      gst_pad_template_new ("src", GST_PAD_SRC, GST_PAD_ALWAYS, templ_caps));
  gst_caps_unref (templ_caps);

  gst_element_class_set_static_metadata (element_class, "Decklink Video Source",
      "Video/Src", "Decklink Source", "David Schleef <ds@entropywave.com>, "
      "Sebastian Dröge <sebastian@centricular.com>");

  GST_DEBUG_CATEGORY_INIT (gst_decklink_video_src_debug, "decklinkvideosrc",
      0, "debug category for decklinkvideosrc element");
}

static void
gst_decklink_video_src_init (GstDecklinkVideoSrc * self)
{
  self->mode = DEFAULT_MODE;
  self->caps_mode = GST_DECKLINK_MODE_AUTO;
  self->caps_format = bmdFormat8BitYUV;
  self->connection = DEFAULT_CONNECTION;
  self->device_number = 0;
  self->buffer_size = DEFAULT_BUFFER_SIZE;
  self->video_format = GST_DECKLINK_VIDEO_FORMAT_AUTO;
  self->timecode_format = bmdTimecodeRP188Any;
  self->no_signal = FALSE;
  self->output_stream_time = DEFAULT_OUTPUT_STREAM_TIME;
  self->skip_first_time = DEFAULT_SKIP_FIRST_TIME;
  self->drop_no_signal_frames = DEFAULT_DROP_NO_SIGNAL_FRAMES;

  self->window_size = 64;
  self->times = g_new (GstClockTime, 4 * self->window_size);
  self->times_temp = self->times + 2 * self->window_size;
  self->window_fill = 0;
  self->window_skip = 1;
  self->window_skip_count = 0;

  gst_base_src_set_live (GST_BASE_SRC (self), TRUE);
  gst_base_src_set_format (GST_BASE_SRC (self), GST_FORMAT_TIME);

  g_mutex_init (&self->lock);
  g_cond_init (&self->cond);

  self->current_frames =
      gst_queue_array_new_for_struct (sizeof (CaptureFrame),
      DEFAULT_BUFFER_SIZE);
}

void
gst_decklink_video_src_set_property (GObject * object, guint property_id,
    const GValue * value, GParamSpec * pspec)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (object);

  switch (property_id) {
    case PROP_MODE:
      self->mode = (GstDecklinkModeEnum) g_value_get_enum (value);
      /* setting the default value for caps_mode here: if mode==auto then we
       * configure caps_mode from the caps, if mode!=auto we set caps_mode to
       * the same value as the mode. so self->caps_mode is essentially
       * self->mode with mode=auto filtered into whatever we got from the
       * negotiation */
      if (self->mode != GST_DECKLINK_MODE_AUTO)
        self->caps_mode = self->mode;
      break;
    case PROP_CONNECTION:
      self->connection = (GstDecklinkConnectionEnum) g_value_get_enum (value);
      break;
    case PROP_DEVICE_NUMBER:
      self->device_number = g_value_get_int (value);
      break;
    case PROP_BUFFER_SIZE:
      self->buffer_size = g_value_get_uint (value);
      break;
    case PROP_VIDEO_FORMAT:
      self->video_format = (GstDecklinkVideoFormat) g_value_get_enum (value);
      switch (self->video_format) {
        case GST_DECKLINK_VIDEO_FORMAT_8BIT_YUV:
        case GST_DECKLINK_VIDEO_FORMAT_10BIT_YUV:
        case GST_DECKLINK_VIDEO_FORMAT_8BIT_ARGB:
        case GST_DECKLINK_VIDEO_FORMAT_8BIT_BGRA:
          self->caps_format =
              gst_decklink_pixel_format_from_type (self->video_format);
        case GST_DECKLINK_VIDEO_FORMAT_AUTO:
          break;
        default:
          GST_ELEMENT_WARNING (GST_ELEMENT (self), CORE, NOT_IMPLEMENTED,
              ("Format %d not supported", self->video_format), (NULL));
          break;
      }
      break;
    case PROP_TIMECODE_FORMAT:
      self->timecode_format =
          gst_decklink_timecode_format_from_enum ((GstDecklinkTimecodeFormat)
          g_value_get_enum (value));
      break;
    case PROP_OUTPUT_STREAM_TIME:
      self->output_stream_time = g_value_get_boolean (value);
      break;
    case PROP_SKIP_FIRST_TIME:
      self->skip_first_time = g_value_get_uint64 (value);
      break;
    case PROP_DROP_NO_SIGNAL_FRAMES:
      self->drop_no_signal_frames = g_value_get_boolean (value);
      break;
    case PROP_OUTPUT_CC:
      self->output_cc = g_value_get_boolean (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
      break;
  }
}

void
gst_decklink_video_src_get_property (GObject * object, guint property_id,
    GValue * value, GParamSpec * pspec)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (object);

  switch (property_id) {
    case PROP_MODE:
      g_value_set_enum (value, self->mode);
      break;
    case PROP_CONNECTION:
      g_value_set_enum (value, self->connection);
      break;
    case PROP_DEVICE_NUMBER:
      g_value_set_int (value, self->device_number);
      break;
    case PROP_BUFFER_SIZE:
      g_value_set_uint (value, self->buffer_size);
      break;
    case PROP_VIDEO_FORMAT:
      g_value_set_enum (value, self->video_format);
      break;
    case PROP_TIMECODE_FORMAT:
      g_value_set_enum (value,
          gst_decklink_timecode_format_to_enum (self->timecode_format));
      break;
    case PROP_OUTPUT_STREAM_TIME:
      g_value_set_boolean (value, self->output_stream_time);
      break;
    case PROP_SKIP_FIRST_TIME:
      g_value_set_uint64 (value, self->skip_first_time);
      break;
    case PROP_DROP_NO_SIGNAL_FRAMES:
      g_value_set_boolean (value, self->drop_no_signal_frames);
      break;
    case PROP_SIGNAL:
      g_value_set_boolean (value, !self->no_signal);
      break;
    case PROP_HW_SERIAL_NUMBER:
      if (self->input)
        g_value_set_string (value, self->input->hw_serial_number);
      else
        g_value_set_string (value, NULL);
      break;
    case PROP_OUTPUT_CC:
      g_value_set_boolean (value, self->output_cc);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
      break;
  }
}

void
gst_decklink_video_src_finalize (GObject * object)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (object);

  g_free (self->times);
  self->times = NULL;
  g_mutex_clear (&self->lock);
  g_cond_clear (&self->cond);

  if (self->current_frames) {
    while (gst_queue_array_get_length (self->current_frames) > 0) {
      CaptureFrame *tmp = (CaptureFrame *)
          gst_queue_array_pop_head_struct (self->current_frames);
      capture_frame_clear (tmp);
    }
    gst_queue_array_free (self->current_frames);
    self->current_frames = NULL;
  }

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

static gboolean
gst_decklink_video_src_set_caps (GstBaseSrc * bsrc, GstCaps * caps)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (bsrc);
  GstCaps *current_caps;
  const GstDecklinkMode *mode;
  BMDVideoInputFlags flags;
  HRESULT ret;
  BMDPixelFormat format;

  GST_DEBUG_OBJECT (self, "Setting caps %" GST_PTR_FORMAT, caps);

  if ((current_caps = gst_pad_get_current_caps (GST_BASE_SRC_PAD (bsrc)))) {
    GST_DEBUG_OBJECT (self, "Pad already has caps %" GST_PTR_FORMAT, caps);

    if (!gst_caps_is_equal (caps, current_caps)) {
      GST_DEBUG_OBJECT (self, "New caps, reconfiguring");
      gst_caps_unref (current_caps);
      if (self->mode == GST_DECKLINK_MODE_AUTO) {
        return TRUE;
      } else {
        return FALSE;
      }
    } else {
      gst_caps_unref (current_caps);
      return TRUE;
    }
  }

  if (!gst_video_info_from_caps (&self->info, caps))
    return FALSE;

  if (self->input->config && self->connection != GST_DECKLINK_CONNECTION_AUTO) {
    ret = self->input->config->SetInt (bmdDeckLinkConfigVideoInputConnection,
        gst_decklink_get_connection (self->connection));
    if (ret != S_OK) {
      GST_ERROR_OBJECT (self,
          "Failed to set configuration (input source): 0x%08lx",
          (unsigned long) ret);
      return FALSE;
    }

    if (self->connection == GST_DECKLINK_CONNECTION_COMPOSITE) {
      ret = self->input->config->SetInt (bmdDeckLinkConfigAnalogVideoInputFlags,
          bmdAnalogVideoFlagCompositeSetup75);
      if (ret != S_OK) {
        GST_ERROR_OBJECT (self,
            "Failed to set configuration (composite setup): 0x%08lx",
            (unsigned long) ret);
        return FALSE;
      }
    }
  }

  flags = bmdVideoInputFlagDefault;
  if (self->mode == GST_DECKLINK_MODE_AUTO) {
    bool autoDetection = false;

    if (self->input->attributes) {
      ret =
          self->input->
          attributes->GetFlag (BMDDeckLinkSupportsInputFormatDetection,
          &autoDetection);
      if (ret != S_OK) {
        GST_ERROR_OBJECT (self,
            "Failed to get attribute (autodetection): 0x%08lx",
            (unsigned long) ret);
        return FALSE;
      }
      if (autoDetection)
        flags |= bmdVideoInputEnableFormatDetection;
    }
    if (!autoDetection) {
      GST_ERROR_OBJECT (self, "Failed to activate auto-detection");
      return FALSE;
    }
  }

  mode = gst_decklink_get_mode (self->mode);
  g_assert (mode != NULL);

  format = self->caps_format;
  ret = self->input->input->EnableVideoInput (mode->mode, format, flags);
  if (ret != S_OK) {
    GST_WARNING_OBJECT (self, "Failed to enable video input: 0x%08lx",
        (unsigned long) ret);
    return FALSE;
  }

  g_mutex_lock (&self->input->lock);
  self->input->mode = mode;
  self->input->video_enabled = TRUE;
  if (self->input->start_streams)
    self->input->start_streams (self->input->videosrc);
  g_mutex_unlock (&self->input->lock);

  return TRUE;
}

static GstCaps *
gst_decklink_video_src_get_caps (GstBaseSrc * bsrc, GstCaps * filter)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (bsrc);
  GstCaps *mode_caps, *caps;
  BMDPixelFormat format;
  GstDecklinkModeEnum mode;

  g_mutex_lock (&self->lock);
  mode = self->caps_mode;
  format = self->caps_format;
  g_mutex_unlock (&self->lock);

  mode_caps = gst_decklink_mode_get_caps (mode, format, TRUE);

  if (filter) {
    caps =
        gst_caps_intersect_full (filter, mode_caps, GST_CAPS_INTERSECT_FIRST);
    gst_caps_unref (mode_caps);
  } else {
    caps = mode_caps;
  }

  return caps;
}

static void
gst_decklink_video_src_update_time_mapping (GstDecklinkVideoSrc * self,
    GstClockTime capture_time, GstClockTime stream_time)
{
  if (self->window_skip_count == 0) {
    GstClockTime num, den, b, xbase;
    gdouble r_squared;

    self->times[2 * self->window_fill] = stream_time;
    self->times[2 * self->window_fill + 1] = capture_time;

    self->window_fill++;
    self->window_skip_count++;
    if (self->window_skip_count >= self->window_skip)
      self->window_skip_count = 0;

    if (self->window_fill >= self->window_size) {
      guint fps =
          ((gdouble) self->info.fps_n + self->info.fps_d -
          1) / ((gdouble) self->info.fps_d);

      /* Start by updating first every frame, once full every second frame,
       * etc. until we update once every 4 seconds */
      if (self->window_skip < 4 * fps)
        self->window_skip *= 2;
      if (self->window_skip >= 4 * fps)
        self->window_skip = 4 * fps;

      self->window_fill = 0;
      self->window_filled = TRUE;
    }

    /* First sample ever, create some basic mapping to start */
    if (!self->window_filled && self->window_fill == 1) {
      self->current_time_mapping.xbase = stream_time;
      self->current_time_mapping.b = capture_time;
      self->current_time_mapping.num = 1;
      self->current_time_mapping.den = 1;
      self->next_time_mapping_pending = FALSE;
    }

    /* Only bother calculating anything here once we had enough measurements,
     * i.e. let's take the window size as a start */
    if (self->window_filled &&
        gst_calculate_linear_regression (self->times, self->times_temp,
            self->window_size, &num, &den, &b, &xbase, &r_squared)) {

      GST_DEBUG_OBJECT (self,
          "Calculated new time mapping: pipeline time = %lf * (stream time - %"
          G_GUINT64_FORMAT ") + %" G_GUINT64_FORMAT " (%lf)",
          ((gdouble) num) / ((gdouble) den), xbase, b, r_squared);

      self->next_time_mapping.xbase = xbase;
      self->next_time_mapping.b = b;
      self->next_time_mapping.num = num;
      self->next_time_mapping.den = den;
      self->next_time_mapping_pending = TRUE;
    }
  } else {
    self->window_skip_count++;
    if (self->window_skip_count >= self->window_skip)
      self->window_skip_count = 0;
  }

  if (self->next_time_mapping_pending) {
    GstClockTime expected, new_calculated, diff, max_diff;

    expected =
        gst_clock_adjust_with_calibration (NULL, stream_time,
        self->current_time_mapping.xbase, self->current_time_mapping.b,
        self->current_time_mapping.num, self->current_time_mapping.den);
    new_calculated =
        gst_clock_adjust_with_calibration (NULL, stream_time,
        self->next_time_mapping.xbase, self->next_time_mapping.b,
        self->next_time_mapping.num, self->next_time_mapping.den);

    if (new_calculated > expected)
      diff = new_calculated - expected;
    else
      diff = expected - new_calculated;

    /* At most 5% frame duration change per update */
    max_diff =
        gst_util_uint64_scale (GST_SECOND / 20, self->info.fps_d,
        self->info.fps_n);

    GST_DEBUG_OBJECT (self,
        "New time mapping causes difference of %" GST_TIME_FORMAT,
        GST_TIME_ARGS (diff));
    GST_DEBUG_OBJECT (self, "Maximum allowed per frame %" GST_TIME_FORMAT,
        GST_TIME_ARGS (max_diff));

    if (diff > max_diff) {
      /* adjust so that we move that much closer */
      if (new_calculated > expected) {
        self->current_time_mapping.b = expected + max_diff;
        self->current_time_mapping.xbase = stream_time;
      } else {
        self->current_time_mapping.b = expected - max_diff;
        self->current_time_mapping.xbase = stream_time;
      }
    } else {
      self->current_time_mapping.xbase = self->next_time_mapping.xbase;
      self->current_time_mapping.b = self->next_time_mapping.b;
      self->current_time_mapping.num = self->next_time_mapping.num;
      self->current_time_mapping.den = self->next_time_mapping.den;
      self->next_time_mapping_pending = FALSE;
    }
  }
}

static void
gst_decklink_video_src_got_frame (GstElement * element,
    IDeckLinkVideoInputFrame * frame, GstDecklinkModeEnum mode,
    GstClockTime capture_time, GstClockTime stream_time,
    GstClockTime stream_duration, GstClockTime hardware_time,
    GstClockTime hardware_duration, IDeckLinkTimecode * dtc, gboolean no_signal)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (element);
  GstClockTime timestamp, duration;

  GST_LOG_OBJECT (self,
      "Got video frame at %" GST_TIME_FORMAT " / %" GST_TIME_FORMAT " (%"
      GST_TIME_FORMAT "), no signal: %d", GST_TIME_ARGS (capture_time),
      GST_TIME_ARGS (stream_time), GST_TIME_ARGS (stream_duration), no_signal);

  if (self->drop_no_signal_frames && no_signal)
    return;

  g_mutex_lock (&self->lock);
  if (self->first_time == GST_CLOCK_TIME_NONE)
    self->first_time = stream_time;

  if (self->skip_first_time > 0
      && stream_time - self->first_time < self->skip_first_time) {
    g_mutex_unlock (&self->lock);
    GST_DEBUG_OBJECT (self,
        "Skipping frame as requested: %" GST_TIME_FORMAT " < %" GST_TIME_FORMAT,
        GST_TIME_ARGS (stream_time),
        GST_TIME_ARGS (self->skip_first_time + self->first_time));
    return;
  }

  gst_decklink_video_src_update_time_mapping (self, capture_time, stream_time);
  if (self->output_stream_time) {
    timestamp = stream_time;
    duration = stream_duration;
  } else {
    timestamp =
        gst_clock_adjust_with_calibration (NULL, stream_time,
        self->current_time_mapping.xbase, self->current_time_mapping.b,
        self->current_time_mapping.num, self->current_time_mapping.den);
    duration =
        gst_util_uint64_scale (stream_duration, self->current_time_mapping.num,
        self->current_time_mapping.den);
  }

  GST_LOG_OBJECT (self,
      "Converted times to %" GST_TIME_FORMAT " (%"
      GST_TIME_FORMAT ")", GST_TIME_ARGS (timestamp), GST_TIME_ARGS (duration));

  if (!self->flushing) {
    CaptureFrame f;
    const GstDecklinkMode *bmode;
    GstVideoTimeCodeFlags flags = GST_VIDEO_TIME_CODE_FLAGS_NONE;
    guint field_count = 0;
    guint skipped_frames = 0;
    GstClockTime from_timestamp = GST_CLOCK_TIME_NONE;
    GstClockTime to_timestamp = GST_CLOCK_TIME_NONE;

    while (gst_queue_array_get_length (self->current_frames) >=
        self->buffer_size) {
      CaptureFrame *tmp = (CaptureFrame *)
          gst_queue_array_pop_head_struct (self->current_frames);
      if (skipped_frames == 0)
        from_timestamp = tmp->timestamp;
      skipped_frames++;
      to_timestamp = tmp->timestamp;
      capture_frame_clear (tmp);
    }

    if (skipped_frames > 0)
      GST_WARNING_OBJECT (self,
          "Dropped %u old frames from %" GST_TIME_FORMAT " to %"
          GST_TIME_FORMAT, skipped_frames, GST_TIME_ARGS (from_timestamp),
          GST_TIME_ARGS (to_timestamp));

    memset (&f, 0, sizeof (f));
    f.frame = frame;
    f.timestamp = timestamp;
    f.duration = duration;
    f.stream_timestamp = stream_time;
    f.stream_duration = stream_duration;
    f.hardware_timestamp = hardware_time;
    f.hardware_duration = hardware_duration;
    f.mode = mode;
    f.format = frame->GetPixelFormat ();
    f.no_signal = no_signal;
    if (dtc != NULL) {
      uint8_t hours, minutes, seconds, frames;
      HRESULT res;

      res = dtc->GetComponents (&hours, &minutes, &seconds, &frames);
      if (res != S_OK) {
        GST_ERROR ("Could not get components for timecode %p: 0x%08lx", dtc,
            (unsigned long) res);
        f.tc = NULL;
      } else {
        GST_DEBUG_OBJECT (self, "Got timecode %02d:%02d:%02d:%02d",
            hours, minutes, seconds, frames);
        bmode = gst_decklink_get_mode (mode);
        if (bmode->interlaced)
          flags =
              (GstVideoTimeCodeFlags) (flags |
              GST_VIDEO_TIME_CODE_FLAGS_INTERLACED);
        if (bmode->fps_d == 1001) {
          if (bmode->fps_n == 30000 || bmode->fps_n == 60000) {
            /* Some occurrences have been spotted where the driver mistakenly
             * fails to set the drop-frame flag for drop-frame timecodes.
             * Assume always drop-frame for 29.97 and 59.94 FPS */
            flags =
                (GstVideoTimeCodeFlags) (flags |
                GST_VIDEO_TIME_CODE_FLAGS_DROP_FRAME);
          } else {
            /* Drop-frame isn't defined for any other framerates (e.g. 23.976)
             * */
            flags =
                (GstVideoTimeCodeFlags) (flags &
                ~GST_VIDEO_TIME_CODE_FLAGS_DROP_FRAME);
          }
        }
        f.tc =
            gst_video_time_code_new (bmode->fps_n, bmode->fps_d, NULL, flags,
            hours, minutes, seconds, frames, field_count);
      }
      dtc->Release ();
    } else {
      f.tc = NULL;
    }

    frame->AddRef ();
    gst_queue_array_push_tail_struct (self->current_frames, &f);
    g_cond_signal (&self->cond);
  }
  g_mutex_unlock (&self->lock);
}

static void
extract_cc_from_vbi (GstDecklinkVideoSrc * self, GstBuffer ** buffer,
    VideoFrame * vf, const GstDecklinkMode * mode)
{
  IDeckLinkVideoFrameAncillary *vanc_frame = NULL;
  gint fi;
  guint8 *vancdata;
  GstVideoFormat videoformat;
  gboolean found = FALSE;

  if (vf->frame->GetAncillaryData (&vanc_frame) != S_OK)
    return;

  videoformat =
      gst_decklink_video_format_from_type (vanc_frame->GetPixelFormat ());

  if (videoformat == GST_VIDEO_FORMAT_UNKNOWN) {
    GST_DEBUG_OBJECT (self, "Unknown video format for Ancillary data");
    vanc_frame->Release ();
    return;
  }

  if (videoformat != self->anc_vformat && self->vbiparser) {
    gst_video_vbi_parser_free (self->vbiparser);
    self->vbiparser = NULL;
  }

  GST_DEBUG_OBJECT (self, "Checking for ancillary data in VBI");

  fi = self->last_cc_vbi_line;
  if (fi == -1)
    fi = 1;

  while (fi < 22 && !found) {
    if (vanc_frame->GetBufferForVerticalBlankingLine (fi,
            (void **) &vancdata) == S_OK) {
      GstVideoAncillary gstanc;
      if (self->vbiparser == NULL) {
        self->vbiparser = gst_video_vbi_parser_new (videoformat, mode->width);
        self->anc_vformat = videoformat;
      }
      GST_DEBUG_OBJECT (self, "Might have data on line %d", fi);
      gst_video_vbi_parser_add_line (self->vbiparser, vancdata);

      while (gst_video_vbi_parser_get_ancillary (self->vbiparser,
              &gstanc) == GST_VIDEO_VBI_PARSER_RESULT_OK) {
        switch (GST_VIDEO_ANCILLARY_DID16 (&gstanc)) {
          case GST_VIDEO_ANCILLARY_DID16_S334_EIA_708:
            GST_DEBUG_OBJECT (self,
                "Adding CEA-708 CDP meta to buffer for line %d", fi);
            GST_MEMDUMP_OBJECT (self, "CDP", gstanc.data, gstanc.data_count);
            gst_buffer_add_video_caption_meta (*buffer,
                GST_VIDEO_CAPTION_TYPE_CEA708_CDP, gstanc.data,
                gstanc.data_count);

            break;
          case GST_VIDEO_ANCILLARY_DID16_S334_EIA_608:
            GST_DEBUG_OBJECT (self,
                "Adding CEA-608 meta to buffer for line %d", fi);
            GST_MEMDUMP_OBJECT (self, "CEA608", gstanc.data, gstanc.data_count);
            /* The first byte actually contains the field and line offset but
             * for CEA608-in-CEA708 we can't store the line offset, and it's
             * generally not needed
             */
            gstanc.data[0] = (gstanc.data[0] & 0x80) ? 0xFD : 0xFC;
            gst_buffer_add_video_caption_meta (*buffer,
                GST_VIDEO_CAPTION_TYPE_CEA608_IN_CEA708_RAW, gstanc.data,
                gstanc.data_count);
            break;
          default:
            /* otherwise continue looking */
            continue;
        }

        found = TRUE;
        self->last_cc_vbi_line = fi;
        break;
      }
    }

    /* If we didn't find it at the previous line, start again searching from
     * line 1 onwards */
    if (!found && (gint) self->last_cc_vbi_line != -1) {
      self->last_cc_vbi_line = -1;
      fi = 1;
    } else {
      fi++;
    }
  }

  if (!found)
    self->last_cc_vbi_line = -1;

  vanc_frame->Release ();
}

static GstFlowReturn
gst_decklink_video_src_create (GstPushSrc * bsrc, GstBuffer ** buffer)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (bsrc);
  GstFlowReturn flow_ret = GST_FLOW_OK;
  const guint8 *data;
  gsize data_size;
  VideoFrame *vf;
  CaptureFrame f;
  GstCaps *caps;
  gboolean caps_changed = FALSE;
  const GstDecklinkMode *mode;
  static GstStaticCaps stream_reference =
      GST_STATIC_CAPS ("timestamp/x-decklink-stream");
  static GstStaticCaps hardware_reference =
      GST_STATIC_CAPS ("timestamp/x-decklink-hardware");

  g_mutex_lock (&self->lock);
  while (gst_queue_array_is_empty (self->current_frames) && !self->flushing) {
    g_cond_wait (&self->cond, &self->lock);
  }

  if (self->flushing) {
    GST_DEBUG_OBJECT (self, "Flushing");
    g_mutex_unlock (&self->lock);
    return GST_FLOW_FLUSHING;
  }

  f = *(CaptureFrame *) gst_queue_array_pop_head_struct (self->current_frames);
  g_mutex_unlock (&self->lock);
  // If we're not flushing, we should have a valid frame from the queue
  g_assert (f.frame != NULL);

  g_mutex_lock (&self->lock);
  if (self->caps_mode != f.mode) {
    if (self->mode == GST_DECKLINK_MODE_AUTO) {
      GST_DEBUG_OBJECT (self, "Mode changed from %d to %d", self->caps_mode,
          f.mode);
      caps_changed = TRUE;
      self->caps_mode = f.mode;
    } else {
      g_mutex_unlock (&self->lock);
      GST_ELEMENT_ERROR (self, CORE, NEGOTIATION,
          ("Invalid mode in captured frame"),
          ("Mode set to %d but captured %d", self->caps_mode, f.mode));
      capture_frame_clear (&f);
      return GST_FLOW_NOT_NEGOTIATED;
    }
  }
  if (self->caps_format != f.format) {
    if (self->video_format == GST_DECKLINK_VIDEO_FORMAT_AUTO) {
      GST_DEBUG_OBJECT (self, "Format changed from %d to %d", self->caps_format,
          f.format);
      caps_changed = TRUE;
      self->caps_format = f.format;
    } else {
      g_mutex_unlock (&self->lock);
      GST_ELEMENT_ERROR (self, CORE, NEGOTIATION,
          ("Invalid pixel format in captured frame"),
          ("Format set to %d but captured %d", self->caps_format, f.format));
      capture_frame_clear (&f);
      return GST_FLOW_NOT_NEGOTIATED;
    }
  }

  /* 1 ns error can be just a rounding error, so that's OK. The Decklink
   * drivers give us a really steady stream time, so anything above 1 ns can't
   * be a rounding error and is therefore something to worry about */
  if (self->expected_stream_time != GST_CLOCK_TIME_NONE &&
      ABSDIFF (self->expected_stream_time, f.stream_timestamp) > 1) {
    GstMessage *msg;
    GstClockTime running_time;

    self->dropped += f.stream_timestamp - self->expected_stream_time;
    running_time = gst_segment_to_running_time (&GST_BASE_SRC (self)->segment,
        GST_FORMAT_TIME, f.timestamp);

    msg = gst_message_new_qos (GST_OBJECT (self), TRUE, running_time, f.stream_timestamp,
        f.timestamp, f.duration);
    gst_message_set_qos_stats (msg, GST_FORMAT_TIME, self->processed,
        self->dropped);
    gst_element_post_message (GST_ELEMENT (self), msg);
  }
  if (self->first_stream_time == GST_CLOCK_TIME_NONE)
    self->first_stream_time = f.stream_timestamp;
  self->processed = f.stream_timestamp - self->dropped - self->first_stream_time;
  self->expected_stream_time = f.stream_timestamp + f.stream_duration;

  g_mutex_unlock (&self->lock);
  if (caps_changed) {
    self->last_cc_vbi_line = -1;
    caps = gst_decklink_mode_get_caps (f.mode, f.format, TRUE);
    gst_video_info_from_caps (&self->info, caps);
    gst_base_src_set_caps (GST_BASE_SRC_CAST (bsrc), caps);
    gst_element_post_message (GST_ELEMENT_CAST (self),
        gst_message_new_latency (GST_OBJECT_CAST (self)));
    gst_caps_unref (caps);
    if (self->vbiparser) {
      gst_video_vbi_parser_free (self->vbiparser);
      self->vbiparser = NULL;
      self->anc_vformat = GST_VIDEO_FORMAT_UNKNOWN;
    }
  }

  f.frame->GetBytes ((gpointer *) & data);
  data_size = self->info.size;

  vf = (VideoFrame *) g_malloc0 (sizeof (VideoFrame));

  *buffer =
      gst_buffer_new_wrapped_full ((GstMemoryFlags) GST_MEMORY_FLAG_READONLY,
      (gpointer) data, data_size, 0, data_size, vf,
      (GDestroyNotify) video_frame_free);

  vf->frame = f.frame;
  f.frame->AddRef ();
  vf->input = self->input->input;
  vf->input->AddRef ();

  if (f.no_signal) {
    if (!self->no_signal) {
      self->no_signal = TRUE;
      g_object_notify (G_OBJECT (self), "signal");
      GST_ELEMENT_WARNING (GST_ELEMENT (self), RESOURCE, READ, ("No signal"),
          ("No input source was detected - video frames invalid"));
    }
  } else {
    if (self->no_signal) {
      self->no_signal = FALSE;
      g_object_notify (G_OBJECT (self), "signal");
      GST_ELEMENT_INFO (GST_ELEMENT (self), RESOURCE, READ, ("Signal found"),
          ("Input source detected"));
    }
  }

  mode = gst_decklink_get_mode (self->mode);

  // If we have a format that supports VANC and we are asked to extract CC,
  // then do it here.
  if (self->output_cc && mode->vanc && !self->no_signal)
    extract_cc_from_vbi (self, buffer, vf, mode);

  if (f.no_signal)
    GST_BUFFER_FLAG_SET (*buffer, GST_BUFFER_FLAG_GAP);
  GST_BUFFER_TIMESTAMP (*buffer) = f.timestamp;
  GST_BUFFER_DURATION (*buffer) = f.duration;
  if (f.tc != NULL)
    gst_buffer_add_video_time_code_meta (*buffer, f.tc);
  gst_buffer_add_reference_timestamp_meta (*buffer,
      gst_static_caps_get (&stream_reference), f.stream_timestamp,
      f.stream_duration);
  gst_buffer_add_reference_timestamp_meta (*buffer,
      gst_static_caps_get (&hardware_reference), f.hardware_timestamp,
      f.hardware_duration);

  if (mode->interlaced && mode->tff)
    GST_BUFFER_FLAG_SET (*buffer,
        GST_VIDEO_BUFFER_FLAG_TFF | GST_VIDEO_BUFFER_FLAG_INTERLACED);

  GST_DEBUG_OBJECT (self,
      "Outputting buffer %p with timestamp %" GST_TIME_FORMAT " and duration %"
      GST_TIME_FORMAT, *buffer, GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (*buffer)),
      GST_TIME_ARGS (GST_BUFFER_DURATION (*buffer)));

  capture_frame_clear (&f);

  return flow_ret;
}

static gboolean
gst_decklink_video_src_query (GstBaseSrc * bsrc, GstQuery * query)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (bsrc);
  gboolean ret = TRUE;

  switch (GST_QUERY_TYPE (query)) {
    case GST_QUERY_LATENCY:{
      if (self->input) {
        GstClockTime min, max;
        const GstDecklinkMode *mode;

        g_mutex_lock (&self->lock);
        mode = gst_decklink_get_mode (self->caps_mode);
        g_mutex_unlock (&self->lock);

        min = gst_util_uint64_scale_ceil (GST_SECOND, mode->fps_d, mode->fps_n);
        max = self->buffer_size * min;

        gst_query_set_latency (query, TRUE, min, max);
        ret = TRUE;
      } else {
        ret = FALSE;
      }

      break;
    }
    default:
      ret = GST_BASE_SRC_CLASS (parent_class)->query (bsrc, query);
      break;
  }

  return ret;
}

static gboolean
gst_decklink_video_src_unlock (GstBaseSrc * bsrc)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (bsrc);

  g_mutex_lock (&self->lock);
  self->flushing = TRUE;
  g_cond_signal (&self->cond);
  g_mutex_unlock (&self->lock);

  return TRUE;
}

static gboolean
gst_decklink_video_src_unlock_stop (GstBaseSrc * bsrc)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (bsrc);

  g_mutex_lock (&self->lock);
  self->flushing = FALSE;
  while (gst_queue_array_get_length (self->current_frames) > 0) {
    CaptureFrame *tmp =
        (CaptureFrame *) gst_queue_array_pop_head_struct (self->current_frames);
    capture_frame_clear (tmp);
  }
  g_mutex_unlock (&self->lock);

  return TRUE;
}

static gboolean
gst_decklink_video_src_open (GstDecklinkVideoSrc * self)
{
  const GstDecklinkMode *mode;

  GST_DEBUG_OBJECT (self, "Opening");

  self->input =
      gst_decklink_acquire_nth_input (self->device_number,
      GST_ELEMENT_CAST (self), FALSE);
  if (!self->input) {
    GST_ERROR_OBJECT (self, "Failed to acquire input");
    return FALSE;
  }

  g_object_notify (G_OBJECT (self), "hw-serial-number");

  mode = gst_decklink_get_mode (self->mode);
  g_assert (mode != NULL);
  g_mutex_lock (&self->input->lock);
  self->input->mode = mode;
  self->input->format = self->caps_format;
  self->input->got_video_frame = gst_decklink_video_src_got_frame;
  self->input->start_streams = gst_decklink_video_src_start_streams;
  g_mutex_unlock (&self->input->lock);

  return TRUE;
}

static gboolean
gst_decklink_video_src_close (GstDecklinkVideoSrc * self)
{

  GST_DEBUG_OBJECT (self, "Closing");

  if (self->input) {
    g_mutex_lock (&self->input->lock);
    self->input->got_video_frame = NULL;
    self->input->mode = NULL;
    self->input->video_enabled = FALSE;
    self->input->start_streams = NULL;
    g_mutex_unlock (&self->input->lock);

    gst_decklink_release_nth_input (self->device_number,
        GST_ELEMENT_CAST (self), FALSE);
    self->input = NULL;
  }

  return TRUE;
}

static gboolean
gst_decklink_video_src_stop (GstDecklinkVideoSrc * self)
{
  GST_DEBUG_OBJECT (self, "Stopping");

  while (gst_queue_array_get_length (self->current_frames) > 0) {
    CaptureFrame *tmp =
        (CaptureFrame *) gst_queue_array_pop_head_struct (self->current_frames);
    capture_frame_clear (tmp);
  }
  self->caps_mode = GST_DECKLINK_MODE_AUTO;

  if (self->input && self->input->video_enabled) {
    g_mutex_lock (&self->input->lock);
    self->input->video_enabled = FALSE;
    g_mutex_unlock (&self->input->lock);

    self->input->input->DisableVideoInput ();
  }

  if (self->vbiparser) {
    gst_video_vbi_parser_free (self->vbiparser);
    self->vbiparser = NULL;
    self->anc_vformat = GST_VIDEO_FORMAT_UNKNOWN;
  }

  return TRUE;
}

static void
gst_decklink_video_src_start_streams (GstElement * element)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (element);
  HRESULT res;

  if (self->input->video_enabled && (!self->input->audiosrc
          || self->input->audio_enabled)
      && (GST_STATE (self) == GST_STATE_PLAYING
          || GST_STATE_PENDING (self) == GST_STATE_PLAYING)) {
    GST_DEBUG_OBJECT (self, "Starting streams");

    g_mutex_lock (&self->lock);
    self->first_time = GST_CLOCK_TIME_NONE;
    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;
    g_mutex_unlock (&self->lock);
    res = self->input->input->StartStreams ();
    if (res != S_OK) {
      GST_ELEMENT_ERROR (self, STREAM, FAILED,
          (NULL), ("Failed to start streams: 0x%08lx", (unsigned long) res));
      return;
    }
  } else {
    GST_DEBUG_OBJECT (self, "Not starting streams yet");
  }
}

static GstStateChangeReturn
gst_decklink_video_src_change_state (GstElement * element,
    GstStateChange transition)
{
  GstDecklinkVideoSrc *self = GST_DECKLINK_VIDEO_SRC_CAST (element);
  GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;

  switch (transition) {
    case GST_STATE_CHANGE_NULL_TO_READY:
      self->processed = 0;
      self->dropped = 0;
      self->expected_stream_time = GST_CLOCK_TIME_NONE;
      self->first_stream_time = GST_CLOCK_TIME_NONE;
      if (!gst_decklink_video_src_open (self)) {
        ret = GST_STATE_CHANGE_FAILURE;
        goto out;
      }
      if (self->mode == GST_DECKLINK_MODE_AUTO &&
          self->video_format != GST_DECKLINK_VIDEO_FORMAT_AUTO) {
        GST_WARNING_OBJECT (self, "Warning: mode=auto and format!=auto may \
                            not work");
      }
      self->vbiparser = NULL;
      self->anc_vformat = GST_VIDEO_FORMAT_UNKNOWN;
      break;
    case GST_STATE_CHANGE_READY_TO_PAUSED:
      self->flushing = FALSE;
      break;
    default:
      break;
  }

  if (ret == GST_STATE_CHANGE_FAILURE)
    return ret;
  ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
  if (ret == GST_STATE_CHANGE_FAILURE)
    return ret;

  switch (transition) {
    case GST_STATE_CHANGE_PAUSED_TO_READY:
      self->no_signal = FALSE;

      gst_decklink_video_src_stop (self);
      break;
    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:{
      HRESULT res;

      GST_DEBUG_OBJECT (self, "Stopping streams");

      res = self->input->input->StopStreams ();
      if (res != S_OK) {
        GST_ELEMENT_ERROR (self, STREAM, FAILED,
            (NULL), ("Failed to stop streams: 0x%08lx", (unsigned long) res));
        ret = GST_STATE_CHANGE_FAILURE;
      }
      break;
    }
    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:{
      g_mutex_lock (&self->input->lock);
      if (self->input->start_streams)
        self->input->start_streams (self->input->videosrc);
      g_mutex_unlock (&self->input->lock);

      break;
    }
    case GST_STATE_CHANGE_READY_TO_NULL:
      gst_decklink_video_src_close (self);
      break;
    default:
      break;
  }
out:

  return ret;
}