gstreamer/sys/decklink/gstdecklink.cpp

/* GStreamer
 * Copyright (C) 2011 David Schleef <ds@schleef.org>
 * 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 <gst/gst.h>
#include "gstdecklink.h"
#include "gstdecklinkaudiosink.h"
#include "gstdecklinkvideosink.h"
#include "gstdecklinkaudiosrc.h"
#include "gstdecklinkvideosrc.h"

GST_DEBUG_CATEGORY_STATIC (gst_decklink_debug);
#define GST_CAT_DEFAULT gst_decklink_debug

GType
gst_decklink_mode_get_type (void)
{
  static gsize id = 0;
  static const GEnumValue modes[] = {
    {GST_DECKLINK_MODE_AUTO, "auto", "Automatic detection"},

    {GST_DECKLINK_MODE_NTSC, "ntsc", "NTSC SD 60i"},
    {GST_DECKLINK_MODE_NTSC2398, "ntsc2398", "NTSC SD 60i (24 fps)"},
    {GST_DECKLINK_MODE_PAL, "pal", "PAL SD 50i"},
    {GST_DECKLINK_MODE_NTSC_P, "ntsc-p", "NTSC SD 60p"},
    {GST_DECKLINK_MODE_PAL_P, "pal-p", "PAL SD 50p"},

    {GST_DECKLINK_MODE_1080p2398, "1080p2398", "HD1080 23.98p"},
    {GST_DECKLINK_MODE_1080p24, "1080p24", "HD1080 24p"},
    {GST_DECKLINK_MODE_1080p25, "1080p25", "HD1080 25p"},
    {GST_DECKLINK_MODE_1080p2997, "1080p2997", "HD1080 29.97p"},
    {GST_DECKLINK_MODE_1080p30, "1080p30", "HD1080 30p"},

    {GST_DECKLINK_MODE_1080i50, "1080i50", "HD1080 50i"},
    {GST_DECKLINK_MODE_1080i5994, "1080i5994", "HD1080 59.94i"},
    {GST_DECKLINK_MODE_1080i60, "1080i60", "HD1080 60i"},

    {GST_DECKLINK_MODE_1080p50, "1080p50", "HD1080 50p"},
    {GST_DECKLINK_MODE_1080p5994, "1080p5994", "HD1080 59.94p"},
    {GST_DECKLINK_MODE_1080p60, "1080p60", "HD1080 60p"},

    {GST_DECKLINK_MODE_720p50, "720p50", "HD720 50p"},
    {GST_DECKLINK_MODE_720p5994, "720p5994", "HD720 59.94p"},
    {GST_DECKLINK_MODE_720p60, "720p60", "HD720 60p"},

    {GST_DECKLINK_MODE_2048p2398, "2048p2398", "2k 23.98p"},
    {GST_DECKLINK_MODE_2048p24, "2048p24", "2k 24p"},
    {GST_DECKLINK_MODE_2048p25, "2048p25", "2k 25p"},

    {GST_DECKLINK_MODE_3184p2398, "3184p2398", "4k 23.98p"},
    {GST_DECKLINK_MODE_3184p24, "3184p24", "4k 24p"},
    {GST_DECKLINK_MODE_3184p25, "3184p25", "4k 25p"},
    {GST_DECKLINK_MODE_3184p2997, "3184p2997", "4k 29.97p"},
    {GST_DECKLINK_MODE_3184p30, "3184p30", "4k 30p"},
    {GST_DECKLINK_MODE_3184p50, "3184p50", "4k 50p"},
    {GST_DECKLINK_MODE_3184p5994, "3184p5994", "4k 59.94p"},
    {GST_DECKLINK_MODE_3184p60, "3184p60", "4k 60p"},

    {0, NULL, NULL}
  };

  if (g_once_init_enter (&id)) {
    GType tmp = g_enum_register_static ("GstDecklinkModes", modes);
    g_once_init_leave (&id, tmp);
  }

  return (GType) id;
}

GType
gst_decklink_connection_get_type (void)
{
  static gsize id = 0;
  static const GEnumValue connections[] = {
    {GST_DECKLINK_CONNECTION_AUTO, "auto", "Auto"},
    {GST_DECKLINK_CONNECTION_SDI, "sdi", "SDI"},
    {GST_DECKLINK_CONNECTION_HDMI, "hdmi", "HDMI"},
    {GST_DECKLINK_CONNECTION_OPTICAL_SDI, "optical-sdi", "Optical SDI"},
    {GST_DECKLINK_CONNECTION_COMPONENT, "component", "Component"},
    {GST_DECKLINK_CONNECTION_COMPOSITE, "composite", "Composite"},
    {GST_DECKLINK_CONNECTION_SVIDEO, "svideo", "S-Video"},
    {0, NULL, NULL}
  };

  if (g_once_init_enter (&id)) {
    GType tmp = g_enum_register_static ("GstDecklinkConnection", connections);
    g_once_init_leave (&id, tmp);
  }

  return (GType) id;
}

GType
gst_decklink_audio_connection_get_type (void)
{
  static gsize id = 0;
  static const GEnumValue connections[] = {
    {GST_DECKLINK_AUDIO_CONNECTION_AUTO, "auto", "Automatic"},
    {GST_DECKLINK_AUDIO_CONNECTION_EMBEDDED, "embedded",
        "SDI/HDMI embedded audio"},
    {GST_DECKLINK_AUDIO_CONNECTION_AES_EBU, "aes", "AES/EBU input"},
    {GST_DECKLINK_AUDIO_CONNECTION_ANALOG, "analog", "Analog input"},
    {GST_DECKLINK_AUDIO_CONNECTION_ANALOG_XLR, "analog-xlr",
        "Analog input (XLR)"},
    {GST_DECKLINK_AUDIO_CONNECTION_ANALOG_RCA, "analog-rca",
        "Analog input (RCA)"},
    {0, NULL, NULL}
  };

  if (g_once_init_enter (&id)) {
    GType tmp =
        g_enum_register_static ("GstDecklinkAudioConnection", connections);
    g_once_init_leave (&id, tmp);
  }

  return (GType) id;
}

#define NTSC 10, 11, false, false
#define PAL 12, 11, true, false
#define HD 1, 1, false, true

static const GstDecklinkMode modes[] = {
  {bmdModeNTSC, 720, 486, 30000, 1001, true, NTSC},     // default is ntsc

  {bmdModeNTSC, 720, 486, 30000, 1001, true, NTSC},
  {bmdModeNTSC2398, 720, 486, 24000, 1001, true, NTSC},
  {bmdModePAL, 720, 576, 25, 1, true, PAL},
  {bmdModeNTSCp, 720, 486, 30000, 1001, false, NTSC},
  {bmdModePALp, 720, 576, 25, 1, false, PAL},

  {bmdModeHD1080p2398, 1920, 1080, 24000, 1001, false, HD},
  {bmdModeHD1080p24, 1920, 1080, 24, 1, false, HD},
  {bmdModeHD1080p25, 1920, 1080, 25, 1, false, HD},
  {bmdModeHD1080p2997, 1920, 1080, 30000, 1001, false, HD},
  {bmdModeHD1080p30, 1920, 1080, 30, 1, false, HD},

  {bmdModeHD1080i50, 1920, 1080, 50, 1, true, HD},
  {bmdModeHD1080i5994, 1920, 1080, 60000, 1001, true, HD},
  {bmdModeHD1080i6000, 1920, 1080, 60, 1, true, HD},

  {bmdModeHD1080p50, 1920, 1080, 50, 1, false, HD},
  {bmdModeHD1080p5994, 1920, 1080, 60000, 1001, false, HD},
  {bmdModeHD1080p6000, 1920, 1080, 60, 1, false, HD},

  {bmdModeHD720p50, 1280, 720, 50, 1, false, HD},
  {bmdModeHD720p5994, 1280, 720, 60000, 1001, false, HD},
  {bmdModeHD720p60, 1280, 720, 60, 1, false, HD},

  {bmdMode2k2398, 2048, 1556, 24000, 1001, false, HD},
  {bmdMode2k24, 2048, 1556, 24, 1, false, HD},
  {bmdMode2k25, 2048, 1556, 25, 1, false, HD},

  {bmdMode4K2160p2398, 3840, 2160, 24000, 1001, false, HD},
  {bmdMode4K2160p24, 3840, 2160, 24, 1, false, HD},
  {bmdMode4K2160p25, 3840, 2160, 25, 1, false, HD},
  {bmdMode4K2160p2997, 3840, 2160, 30000, 1001, false, HD},
  {bmdMode4K2160p30, 3840, 2160, 30, 1, false, HD},
  {bmdMode4K2160p50, 3840, 2160, 55, 1, false, HD},
  {bmdMode4K2160p5994, 3840, 2160, 60000, 1001, false, HD},
  {bmdMode4K2160p60, 3840, 2160, 60, 1, false, HD}
};

const GstDecklinkMode *
gst_decklink_get_mode (GstDecklinkModeEnum e)
{
  if (e < GST_DECKLINK_MODE_AUTO || e > GST_DECKLINK_MODE_3184p60)
    return NULL;
  return &modes[e];
}

const GstDecklinkModeEnum
gst_decklink_get_mode_enum_from_bmd (BMDDisplayMode mode)
{
  GstDecklinkModeEnum displayMode = GST_DECKLINK_MODE_NTSC;
  switch (mode) {
    case bmdModeNTSC:
      displayMode = GST_DECKLINK_MODE_NTSC;
      break;
    case bmdModeNTSC2398:
      displayMode = GST_DECKLINK_MODE_NTSC2398;
      break;
    case bmdModePAL:
      displayMode = GST_DECKLINK_MODE_PAL;
      break;
    case bmdModeNTSCp:
      displayMode = GST_DECKLINK_MODE_NTSC_P;
      break;
    case bmdModePALp:
      displayMode = GST_DECKLINK_MODE_PAL_P;
      break;
    case bmdModeHD1080p2398:
      displayMode = GST_DECKLINK_MODE_1080p2398;
      break;
    case bmdModeHD1080p24:
      displayMode = GST_DECKLINK_MODE_1080p24;
      break;
    case bmdModeHD1080p25:
      displayMode = GST_DECKLINK_MODE_1080p25;
      break;
    case bmdModeHD1080p2997:
      displayMode = GST_DECKLINK_MODE_1080p2997;
      break;
    case bmdModeHD1080p30:
      displayMode = GST_DECKLINK_MODE_1080p30;
      break;
    case bmdModeHD1080i50:
      displayMode = GST_DECKLINK_MODE_1080i50;
      break;
    case bmdModeHD1080i5994:
      displayMode = GST_DECKLINK_MODE_1080i5994;
      break;
    case bmdModeHD1080i6000:
      displayMode = GST_DECKLINK_MODE_1080i60;
      break;
    case bmdModeHD1080p50:
      displayMode = GST_DECKLINK_MODE_1080p50;
      break;
    case bmdModeHD1080p5994:
      displayMode = GST_DECKLINK_MODE_1080p5994;
      break;
    case bmdModeHD1080p6000:
      displayMode = GST_DECKLINK_MODE_1080p60;
      break;
    case bmdModeHD720p50:
      displayMode = GST_DECKLINK_MODE_720p50;
      break;
    case bmdModeHD720p5994:
      displayMode = GST_DECKLINK_MODE_720p5994;
      break;
    case bmdModeHD720p60:
      displayMode = GST_DECKLINK_MODE_720p60;
      break;
    case bmdMode2k2398:
      displayMode = GST_DECKLINK_MODE_2048p2398;
      break;
    case bmdMode2k24:
      displayMode = GST_DECKLINK_MODE_2048p24;
      break;
    case bmdMode2k25:
      displayMode = GST_DECKLINK_MODE_2048p25;
      break;
    case bmdMode4K2160p2398:
      displayMode = GST_DECKLINK_MODE_3184p2398;
      break;
    case bmdMode4K2160p24:
      displayMode = GST_DECKLINK_MODE_3184p24;
      break;
    case bmdMode4K2160p25:
      displayMode = GST_DECKLINK_MODE_3184p25;
      break;
    case bmdMode4K2160p2997:
      displayMode = GST_DECKLINK_MODE_3184p2997;
      break;
    case bmdMode4K2160p30:
      displayMode = GST_DECKLINK_MODE_3184p30;
      break;
    case bmdMode4K2160p50:
      displayMode = GST_DECKLINK_MODE_3184p50;
      break;
    case bmdMode4K2160p5994:
      displayMode = GST_DECKLINK_MODE_3184p5994;
      break;
    case bmdMode4K2160p60:
      displayMode = GST_DECKLINK_MODE_3184p60;
      break;
    default:
      g_assert_not_reached ();
      break;
  }
  return displayMode;
}

static const BMDVideoConnection connections[] = {
  0,                            /* auto */
  bmdVideoConnectionSDI,
  bmdVideoConnectionHDMI,
  bmdVideoConnectionOpticalSDI,
  bmdVideoConnectionComponent,
  bmdVideoConnectionComposite,
  bmdVideoConnectionSVideo
};

const BMDVideoConnection
gst_decklink_get_connection (GstDecklinkConnectionEnum e)
{
  g_return_val_if_fail (e != GST_DECKLINK_CONNECTION_AUTO,
      bmdVideoConnectionSDI);

  if (e <= GST_DECKLINK_CONNECTION_AUTO || e > GST_DECKLINK_CONNECTION_SVIDEO)
    e = GST_DECKLINK_CONNECTION_SDI;

  return connections[e];
}

static GstStructure *
gst_decklink_mode_get_structure (GstDecklinkModeEnum e)
{
  const GstDecklinkMode *mode = &modes[e];

  return gst_structure_new ("video/x-raw",
      "format", G_TYPE_STRING, "UYVY",
      "width", G_TYPE_INT, mode->width,
      "height", G_TYPE_INT, mode->height,
      "framerate", GST_TYPE_FRACTION, mode->fps_n, mode->fps_d,
      "interlace-mode", G_TYPE_STRING,
      mode->interlaced ? "interleaved" : "progressive", "pixel-aspect-ratio",
      GST_TYPE_FRACTION, mode->par_n, mode->par_d, "colorimetry", G_TYPE_STRING,
      mode->is_hdtv ? "bt709" : "bt601", "chroma-site", G_TYPE_STRING, "mpeg2",
      NULL);
}

GstCaps *
gst_decklink_mode_get_caps (GstDecklinkModeEnum e)
{
  GstCaps *caps;

  caps = gst_caps_new_empty ();
  gst_caps_append_structure (caps, gst_decklink_mode_get_structure (e));

  return caps;
}

GstCaps *
gst_decklink_mode_get_template_caps (void)
{
  int i;
  GstCaps *caps;
  GstStructure *s;

  caps = gst_caps_new_empty ();
  for (i = 0; i < (int) G_N_ELEMENTS (modes); i++) {
    s = gst_decklink_mode_get_structure ((GstDecklinkModeEnum) i);
    gst_caps_append_structure (caps, s);
  }

  return caps;
}

#define GST_TYPE_DECKLINK_CLOCK \
  (gst_decklink_clock_get_type())
#define GST_DECKLINK_CLOCK(obj) \
  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_DECKLINK_CLOCK,GstDecklinkClock))
#define GST_DECKLINK_CLOCK_CLASS(klass) \
  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_DECKLINK_CLOCK,GstDecklinkClockClass))
#define GST_IS_Decklink_CLOCK(obj) \
  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_DECKLINK_CLOCK))
#define GST_IS_Decklink_CLOCK_CLASS(klass) \
  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_DECKLINK_CLOCK))
#define GST_DECKLINK_CLOCK_CAST(obj) \
  ((GstDecklinkClock*)(obj))

typedef struct _GstDecklinkClock GstDecklinkClock;
typedef struct _GstDecklinkClockClass GstDecklinkClockClass;

struct _GstDecklinkClock
{
  GstSystemClock clock;

  IDeckLinkInput *input;
  IDeckLinkOutput *output;
};

struct _GstDecklinkClockClass
{
  GstSystemClockClass parent_class;
};

GType gst_decklink_clock_get_type (void);
static GstClock *gst_decklink_clock_new (const gchar * name);

typedef struct _Device Device;
struct _Device
{
  GstDecklinkOutput output;
  GstDecklinkInput input;
};

class GStreamerDecklinkInputCallback:public IDeckLinkInputCallback
{
private:
  GstDecklinkInput * m_input;
  GMutex m_mutex;
  gint m_refcount;
public:
    GStreamerDecklinkInputCallback (GstDecklinkInput * input)
  : IDeckLinkInputCallback ()
  {
    m_input = input;
    g_mutex_init (&m_mutex);
  }

  virtual ~ GStreamerDecklinkInputCallback ()
  {
    g_mutex_clear (&m_mutex);
  }

  virtual HRESULT STDMETHODCALLTYPE QueryInterface (REFIID, LPVOID *)
  {
    return E_NOINTERFACE;
  }

  virtual ULONG STDMETHODCALLTYPE AddRef (void)
  {
    ULONG ret;

    g_mutex_lock (&m_mutex);
    m_refcount++;
    ret = m_refcount;
    g_mutex_unlock (&m_mutex);

    return ret;
  }

  virtual ULONG STDMETHODCALLTYPE Release (void)
  {
    ULONG ret;

    g_mutex_lock (&m_mutex);
    m_refcount--;
    ret = m_refcount;
    g_mutex_unlock (&m_mutex);


    if (ret == 0) {
      delete this;
    }

    return ret;
  }

  virtual HRESULT STDMETHODCALLTYPE
      VideoInputFormatChanged (BMDVideoInputFormatChangedEvents,
      IDeckLinkDisplayMode * mode, BMDDetectedVideoInputFormatFlags)
  {
    GST_INFO ("Video input format changed");

    g_mutex_lock (&m_input->lock);
    m_input->input->PauseStreams ();
    m_input->input->EnableVideoInput (mode->GetDisplayMode (),
        bmdFormat8BitYUV, bmdVideoInputEnableFormatDetection);
    m_input->input->FlushStreams ();
    m_input->input->StartStreams ();
    m_input->mode =
        gst_decklink_get_mode (gst_decklink_get_mode_enum_from_bmd
        (mode->GetDisplayMode ()));
    g_mutex_unlock (&m_input->lock);

    return S_OK;
  }

  virtual HRESULT STDMETHODCALLTYPE
      VideoInputFrameArrived (IDeckLinkVideoInputFrame * video_frame,
      IDeckLinkAudioInputPacket * audio_packet)
  {
    GstClockTime clock_time = gst_clock_get_time (m_input->clock);

    g_mutex_lock (&m_input->lock);
    if (m_input->got_video_frame) {
      GstClockTime capture_time = clock_time -
          gst_element_get_base_time (m_input->videosrc);
      m_input->got_video_frame (m_input->videosrc, video_frame,
          gst_decklink_get_mode_enum_from_bmd (m_input->mode->mode),
          capture_time);
    }

    if (m_input->got_audio_packet) {
      GstClockTime capture_time = clock_time -
          gst_element_get_base_time (m_input->audiosrc);
      m_input->got_audio_packet (m_input->audiosrc, audio_packet, capture_time);
    }

    g_mutex_unlock (&m_input->lock);
    return S_OK;
  }
};

#ifdef _MSC_VER
/* FIXME: We currently never deinit this */

static GMutex com_init_lock;
static GMutex com_deinit_lock;
static GCond com_init_cond;
static GCond com_deinit_cond;
static GCond com_deinited_cond;
static gboolean com_initialized = FALSE;

/* COM initialization/uninitialization thread */
static gpointer
gst_decklink_com_thread (gpointer data)
{
  HRESULT res;

  g_mutex_lock (&com_init_lock);

  /* Initialize COM with a MTA for this process. This thread will
   * be the first one to enter the apartement and the last one to leave
   * it, unitializing COM properly */

  res = CoInitializeEx (0, COINIT_MULTITHREADED);
  if (res == S_FALSE)
    GST_WARNING ("COM has been already initialized in the same process");
  else if (res == RPC_E_CHANGED_MODE)
    GST_WARNING ("The concurrency model of COM has changed.");
  else
    GST_INFO ("COM intialized succesfully");

  com_initialized = TRUE;

  /* Signal other threads waiting on this condition that COM was initialized */
  g_cond_signal (&com_init_cond);

  g_mutex_unlock (&com_init_lock);

  /* Wait until the unitialize condition is met to leave the COM apartement */
  g_mutex_lock (&com_deinit_lock);
  g_cond_wait (&com_deinit_cond, &com_deinit_lock);

  CoUninitialize ();
  GST_INFO ("COM unintialized succesfully");
  com_initialized = FALSE;
  g_cond_signal (&com_deinited_cond);
  g_mutex_unlock (&com_deinit_lock);

  return NULL;
}
#endif /* _MSC_VER */

static GOnce devices_once = G_ONCE_INIT;
static int n_devices;
static Device devices[10];

static gpointer
init_devices (gpointer data)
{
  IDeckLinkIterator *iterator;
  IDeckLink *decklink = NULL;
  HRESULT ret;
  int i;

#ifdef _MSC_VER
  // Start COM thread for Windows

  g_mutex_lock (&com_init_lock);

  /* create the COM initialization thread */
  g_thread_create ((GThreadFunc) gst_decklink_com_thread, NULL, FALSE, NULL);

  /* wait until the COM thread signals that COM has been initialized */
  g_cond_wait (&com_init_cond, &com_init_lock);
  g_mutex_unlock (&com_init_lock);
#endif /* _MSC_VER */

  iterator = CreateDeckLinkIteratorInstance ();
  if (iterator == NULL) {
    GST_ERROR ("no driver");
    return NULL;
  }

  i = 0;
  ret = iterator->Next (&decklink);
  while (ret == S_OK) {
    ret = decklink->QueryInterface (IID_IDeckLinkInput,
        (void **) &devices[i].input.input);
    if (ret != S_OK) {
      GST_WARNING ("selected device does not have input interface");
    } else {
      devices[i].input.device = decklink;
      devices[i].input.clock = gst_decklink_clock_new ("GstDecklinkInputClock");
      GST_DECKLINK_CLOCK_CAST (devices[i].input.clock)->input =
          devices[i].input.input;
      devices[i].input.
          input->SetCallback (new GStreamerDecklinkInputCallback (&devices[i].
              input));
    }

    ret = decklink->QueryInterface (IID_IDeckLinkOutput,
        (void **) &devices[i].output.output);
    if (ret != S_OK) {
      GST_WARNING ("selected device does not have output interface");
    } else {
      devices[i].output.device = decklink;
      devices[i].output.clock =
          gst_decklink_clock_new ("GstDecklinkOutputClock");
      GST_DECKLINK_CLOCK_CAST (devices[i].output.clock)->output =
          devices[i].output.output;
    }

    ret = decklink->QueryInterface (IID_IDeckLinkConfiguration,
        (void **) &devices[i].input.config);
    if (ret != S_OK) {
      GST_WARNING ("selected device does not have config interface");
    }

    ret = decklink->QueryInterface (IID_IDeckLinkAttributes,
        (void **) &devices[i].input.attributes);
    if (ret != S_OK) {
      GST_WARNING ("selected device does not have attributes interface");
    }

    ret = iterator->Next (&decklink);
    i++;

    if (i == 10) {
      GST_WARNING ("this hardware has more then 10 devices");
      break;
    }
  }

  n_devices = i;

  iterator->Release ();

  return NULL;
}

GstDecklinkOutput *
gst_decklink_acquire_nth_output (gint n, GstElement * sink, gboolean is_audio)
{
  GstDecklinkOutput *output;

  g_once (&devices_once, init_devices, NULL);

  if (n >= n_devices)
    return NULL;

  output = &devices[n].output;
  if (!output->output) {
    GST_ERROR ("Device %d has no output", n);
    return NULL;
  }

  g_mutex_lock (&output->lock);
  if (is_audio && !output->audiosink) {
    output->audiosink = GST_ELEMENT_CAST (gst_object_ref (sink));
    g_mutex_unlock (&output->lock);
    return output;
  } else if (!output->videosink) {
    output->videosink = GST_ELEMENT_CAST (gst_object_ref (sink));
    g_mutex_unlock (&output->lock);
    return output;
  }
  g_mutex_unlock (&output->lock);

  GST_ERROR ("Output device %d (audio: %d) in use already", n, is_audio);
  return NULL;
}

void
gst_decklink_release_nth_output (gint n, GstElement * sink, gboolean is_audio)
{
  GstDecklinkOutput *output;

  if (n >= n_devices)
    return;

  output = &devices[n].output;
  g_assert (output->output);

  g_mutex_lock (&output->lock);
  if (is_audio) {
    g_assert (output->audiosink == sink);
    gst_object_unref (sink);
    output->audiosink = NULL;
  } else {
    g_assert (output->videosink == sink);
    gst_object_unref (sink);
    output->videosink = NULL;
  }
  g_mutex_unlock (&output->lock);
}

void
gst_decklink_output_set_audio_clock (GstDecklinkOutput * output,
    GstClock * clock)
{
  g_mutex_lock (&output->lock);
  if (output->audio_clock)
    gst_object_unref (output->audio_clock);
  output->audio_clock = clock;
  if (clock)
    gst_object_ref (clock);
  g_mutex_unlock (&output->lock);
}


GstClock *
gst_decklink_output_get_audio_clock (GstDecklinkOutput * output)
{
  GstClock *ret = NULL;

  g_mutex_lock (&output->lock);
  if (output->audio_clock)
    ret = GST_CLOCK_CAST (gst_object_ref (output->audio_clock));
  g_mutex_unlock (&output->lock);

  return ret;
}

GstDecklinkInput *
gst_decklink_acquire_nth_input (gint n, GstElement * src, gboolean is_audio)
{
  GstDecklinkInput *input;

  g_once (&devices_once, init_devices, NULL);

  if (n >= n_devices)
    return NULL;

  input = &devices[n].input;
  if (!input->input) {
    GST_ERROR ("Device %d has no input", n);
    return NULL;
  }

  g_mutex_lock (&input->lock);
  if (is_audio && !input->audiosrc) {
    input->audiosrc = GST_ELEMENT_CAST (gst_object_ref (src));
    g_mutex_unlock (&input->lock);
    return input;
  } else if (!input->videosrc) {
    input->videosrc = GST_ELEMENT_CAST (gst_object_ref (src));
    g_mutex_unlock (&input->lock);
    return input;
  }
  g_mutex_unlock (&input->lock);

  GST_ERROR ("Input device %d (audio: %d) in use already", n, is_audio);
  return NULL;
}

void
gst_decklink_release_nth_input (gint n, GstElement * src, gboolean is_audio)
{
  GstDecklinkInput *input;

  if (n >= n_devices)
    return;

  input = &devices[n].input;
  g_assert (input->input);

  g_mutex_lock (&input->lock);
  if (is_audio) {
    g_assert (input->audiosrc == src);
    gst_object_unref (src);
    input->audiosrc = NULL;
  } else {
    g_assert (input->videosrc == src);
    gst_object_unref (src);
    input->videosrc = NULL;
  }
  g_mutex_unlock (&input->lock);
}

G_DEFINE_TYPE (GstDecklinkClock, gst_decklink_clock, GST_TYPE_SYSTEM_CLOCK);

static GstClockTime gst_decklink_clock_get_internal_time (GstClock * clock);

static void
gst_decklink_clock_class_init (GstDecklinkClockClass * klass)
{
  GstClockClass *clock_class = (GstClockClass *) klass;

  clock_class->get_internal_time = gst_decklink_clock_get_internal_time;
}

static void
gst_decklink_clock_init (GstDecklinkClock * clock)
{
  GST_OBJECT_FLAG_SET (clock, GST_CLOCK_FLAG_CAN_SET_MASTER);
}

static GstClock *
gst_decklink_clock_new (const gchar * name)
{
  GstDecklinkClock *self =
      GST_DECKLINK_CLOCK (g_object_new (GST_TYPE_DECKLINK_CLOCK, "name", name,
          "clock-type", GST_CLOCK_TYPE_OTHER, NULL));

  return GST_CLOCK_CAST (self);
}

static GstClockTime
gst_decklink_clock_get_internal_time (GstClock * clock)
{
  GstDecklinkClock *self = GST_DECKLINK_CLOCK (clock);
  GstClockTime result;
  BMDTimeValue time;
  HRESULT ret;

  GST_OBJECT_LOCK (clock);
  if (self->input != NULL) {
    ret =
        self->input->GetHardwareReferenceClock (GST_SECOND, &time, NULL, NULL);
    if (ret == S_OK && time >= 0)
      result = time;
    else
      result = GST_CLOCK_TIME_NONE;
  } else if (self->output != NULL) {
    ret =
        self->output->GetHardwareReferenceClock (GST_SECOND, &time, NULL, NULL);
    if (ret == S_OK && time >= 0)
      result = time;
    else
      result = GST_CLOCK_TIME_NONE;
  } else {
    result = GST_CLOCK_TIME_NONE;
  }
  GST_OBJECT_UNLOCK (clock);
  GST_LOG_OBJECT (clock, "result %" GST_TIME_FORMAT, GST_TIME_ARGS (result));

  return result;
}

static gboolean
plugin_init (GstPlugin * plugin)
{
  GST_DEBUG_CATEGORY_INIT (gst_decklink_debug, "decklink", 0,
      "debug category for decklink plugin");

  gst_element_register (plugin, "decklinkaudiosink", GST_RANK_NONE,
      GST_TYPE_DECKLINK_AUDIO_SINK);
  gst_element_register (plugin, "decklinkvideosink", GST_RANK_NONE,
      GST_TYPE_DECKLINK_VIDEO_SINK);
  gst_element_register (plugin, "decklinkaudiosrc", GST_RANK_NONE,
      GST_TYPE_DECKLINK_AUDIO_SRC);
  gst_element_register (plugin, "decklinkvideosrc", GST_RANK_NONE,
      GST_TYPE_DECKLINK_VIDEO_SRC);
  return TRUE;
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    decklink,
    "Blackmagic Decklink plugin",
    plugin_init, VERSION, "LGPL", PACKAGE_NAME, GST_PACKAGE_ORIGIN)