static gboolean
gst_dtmf_src_negotiate (GstBaseSrc * basesrc)
{
  GstDTMFSrc *dtmfsrc = GST_DTMF_SRC (basesrc);
  GstCaps *caps;
  GstStructure *s;
  gboolean ret;

  caps = gst_pad_get_allowed_caps (GST_BASE_SRC_PAD (basesrc));

  if (!caps)
    caps =
        gst_caps_copy (gst_pad_get_pad_template_caps (GST_BASE_SRC_PAD
            (basesrc)));

  if (gst_caps_is_empty (caps))
    return FALSE;

  gst_caps_truncate (caps);
  s = gst_caps_get_structure (caps, 0);

  gst_structure_fixate_field_nearest_int (s, "rate", DEFAULT_SAMPLE_RATE);

  if (!gst_structure_get_int (s, "rate", &dtmfsrc->sample_rate)) {
    GST_ERROR_OBJECT (dtmfsrc, "Could not get rate");
    gst_caps_unref (caps);
    return FALSE;
  }

  ret = gst_pad_set_caps (GST_BASE_SRC_PAD (basesrc), caps);

  gst_caps_unref (caps);

  return ret;
}

static GstCaps *
gst_decklink_audio_src_get_caps (GstBaseSrc * bsrc, GstCaps * filter)
{
  GstDecklinkAudioSrc *self = GST_DECKLINK_AUDIO_SRC_CAST (bsrc);
  GstCaps *caps;

  // We don't support renegotiation
  caps = gst_pad_get_current_caps (GST_BASE_SRC_PAD (bsrc));

  if (!caps) {
    GstCaps *channel_filter, *templ;
    templ = gst_pad_get_pad_template_caps (GST_BASE_SRC_PAD (bsrc));
    channel_filter =
        gst_caps_new_simple ("audio/x-raw", "channels", G_TYPE_INT,
        self->channels, NULL);
    caps = gst_caps_intersect (channel_filter, templ);
    gst_caps_unref (channel_filter);
    gst_caps_unref (templ);
  }

  if (filter) {
    GstCaps *tmp =
        gst_caps_intersect_full (filter, caps, GST_CAPS_INTERSECT_FIRST);
    gst_caps_unref (caps);
    caps = tmp;
  }

  return caps;
}

static GstFlowReturn
gst_win_inet_src_create (GstPushSrc * pushsrc, GstBuffer ** buffer)
{
  GstWinInetSrc *self = GST_WIN_INET_SRC (pushsrc);
  GstBaseSrc *basesrc = GST_BASE_SRC (pushsrc);
  GstBuffer *buf = NULL;
  GstFlowReturn ret = GST_FLOW_OK;
  DWORD bytes_read = 0;

  do {
    GstCaps *caps = GST_PAD_CAPS (GST_BASE_SRC_PAD (self));

    if (self->icy_caps != NULL)
      caps = self->icy_caps;

    ret = gst_pad_alloc_buffer (GST_BASE_SRC_PAD (basesrc),
        self->cur_offset, basesrc->blocksize, caps, &buf);

    if (G_LIKELY (ret == GST_FLOW_OK)) {
      if (InternetReadFile (self->url, GST_BUFFER_DATA (buf),
              basesrc->blocksize, &bytes_read)) {
        if (bytes_read == 0) {
          if (self->poll_mode) {
            if (gst_win_inet_src_open (self)) {
              gst_buffer_unref (buf);
              buf = NULL;
            } else {
              ret = GST_FLOW_ERROR;
            }
          } else {
            GST_ERROR_OBJECT (self, "short read (eof?)");
            ret = GST_FLOW_UNEXPECTED;
          }
        }
      } else {
        GST_ERROR_OBJECT (self, "InternetReadFile failed: 0x%08lx",
            GetLastError ());

        ret = GST_FLOW_ERROR;
      }
    }
  }
  while (bytes_read == 0 && ret == GST_FLOW_OK);

  if (ret == GST_FLOW_OK) {
    GST_BUFFER_SIZE (buf) = bytes_read;
    self->cur_offset += bytes_read;

    *buffer = buf;
  } else {
    if (buf != NULL)
      gst_buffer_unref (buf);
  }

  return ret;
}

static int
gst_dv1394src_iec61883_receive (unsigned char *data, int len,
    int complete, void *cbdata)
{
  GstDV1394Src *dv1394src = GST_DV1394SRC (cbdata);

  if (G_UNLIKELY (!GST_PAD_CAPS (GST_BASE_SRC_PAD (dv1394src)))) {
    GstCaps *caps;
    unsigned char *p = data;

    // figure format (NTSC/PAL)
    if (p[3] & 0x80) {
      // PAL
      dv1394src->frame_size = PAL_FRAMESIZE;
      dv1394src->frame_rate = PAL_FRAMERATE;
      GST_DEBUG ("PAL data");
      caps = gst_caps_new_simple ("video/x-dv",
          "format", G_TYPE_STRING, "PAL",
          "systemstream", G_TYPE_BOOLEAN, TRUE, NULL);
    } else {
      // NTSC (untested)
      dv1394src->frame_size = NTSC_FRAMESIZE;
      dv1394src->frame_rate = NTSC_FRAMERATE;
      GST_DEBUG
          ("NTSC data [untested] - please report success/failure to <[email protected]>");
      caps = gst_caps_new_simple ("video/x-dv",
          "format", G_TYPE_STRING, "NTSC",
          "systemstream", G_TYPE_BOOLEAN, TRUE, NULL);
    }
    gst_pad_set_caps (GST_BASE_SRC_PAD (dv1394src), caps);
    gst_caps_unref (caps);
  }

  dv1394src->frame = NULL;
  if (G_LIKELY ((dv1394src->frame_sequence + 1) % (dv1394src->skip +
              dv1394src->consecutive) < dv1394src->consecutive)) {
    if (complete && len == dv1394src->frame_size) {
      guint8 *bufdata;
      GstBuffer *buf;

      buf = gst_buffer_new_and_alloc (dv1394src->frame_size);

      GST_BUFFER_OFFSET (buf) = dv1394src->frame_sequence;
      bufdata = GST_BUFFER_DATA (buf);
      memcpy (bufdata, data, len);
      dv1394src->buf = buf;
    }
  }
  dv1394src->frame_sequence++;
  return 0;
}

static GstFlowReturn
gst_neonhttp_src_create (GstPushSrc * psrc, GstBuffer ** outbuf)
{
  GstNeonhttpSrc *src;
  GstBaseSrc *basesrc;
  GstFlowReturn ret;
  gint read;

  src = GST_NEONHTTP_SRC (psrc);
  basesrc = GST_BASE_SRC_CAST (psrc);

  /* The caller should know the number of bytes and not read beyond EOS. */
  if (G_UNLIKELY (src->eos))
    goto eos;

  /* Create the buffer. */
  ret = gst_pad_alloc_buffer (GST_BASE_SRC_PAD (basesrc),
      basesrc->segment.last_stop, basesrc->blocksize,
      src->icy_caps ? src->icy_caps :
      GST_PAD_CAPS (GST_BASE_SRC_PAD (basesrc)), outbuf);

  if (G_UNLIKELY (ret != GST_FLOW_OK))
    goto done;

  read = gst_neonhttp_src_request_dispatch (src, *outbuf);
  if (G_UNLIKELY (read < 0))
    goto read_error;

  GST_LOG_OBJECT (src, "returning %u bytes", GST_BUFFER_SIZE (*outbuf));

done:
  return ret;

  /* ERRORS */
eos:
  {
    GST_DEBUG_OBJECT (src, "EOS reached");
    return GST_FLOW_UNEXPECTED;
  }
read_error:
  {
    GST_ELEMENT_ERROR (src, RESOURCE, READ,
        (NULL), ("Could not read any bytes (%i, %s)", read,
            ne_get_error (src->session)));
    gst_buffer_unref (*outbuf);
    *outbuf = NULL;
    return GST_FLOW_ERROR;
  }
}

static GstCaps *
gst_data_uri_src_get_caps (GstBaseSrc * basesrc, GstCaps * filter)
{
  GstDataURISrc *src = GST_DATA_URI_SRC (basesrc);
  GstCaps *caps;

  GST_OBJECT_LOCK (src);
  if (gst_pad_has_current_caps (GST_BASE_SRC_PAD (basesrc)))
    caps = gst_pad_get_current_caps (GST_BASE_SRC_PAD (basesrc));
  else
    caps = gst_caps_new_any ();
  GST_OBJECT_UNLOCK (src);

  return caps;
}

static void
gst_aravis_init (GstAravis *gst_aravis, GstAravisClass *g_class)
{
	GstPad *pad = GST_BASE_SRC_PAD (gst_aravis);

	gst_pad_set_fixatecaps_function (pad, gst_aravis_fixate_caps);

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

	gst_aravis->camera_name = NULL;

	gst_aravis->gain = -1;
	gst_aravis->gain_auto = FALSE;
	gst_aravis->exposure_time_us = -1;
	gst_aravis->exposure_auto = FALSE;
	gst_aravis->offset_x = 0;
	gst_aravis->offset_y = 0;
	gst_aravis->h_binning = -1;
	gst_aravis->v_binning = -1;
	gst_aravis->packet_resend = TRUE;
	gst_aravis->payload = 0;

	gst_aravis->buffer_timeout_us = GST_ARAVIS_BUFFER_TIMEOUT_DEFAULT;

	gst_aravis->camera = NULL;
	gst_aravis->stream = NULL;

	gst_aravis->all_caps = NULL;
	gst_aravis->fixed_caps = NULL;
}

static void
gst_multi_file_src_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstMultiFileSrc *src = GST_MULTI_FILE_SRC (object);

  switch (prop_id) {
    case ARG_LOCATION:
      gst_multi_file_src_set_location (src, g_value_get_string (value));
      break;
    case ARG_INDEX:
      src->index = g_value_get_int (value);
      break;
    case ARG_CAPS:
    {
      const GstCaps *caps = gst_value_get_caps (value);
      GstCaps *new_caps;

      if (caps == NULL) {
        new_caps = gst_caps_new_any ();
      } else {
        new_caps = gst_caps_copy (caps);
      }
      gst_caps_replace (&src->caps, new_caps);
      gst_pad_set_caps (GST_BASE_SRC_PAD (src), new_caps);
    }
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_audio_test_src_init (GstAudioTestSrc * src, GstAudioTestSrcClass * g_class)
{
  GstPad *pad = GST_BASE_SRC_PAD (src);

  gst_pad_set_fixatecaps_function (pad, gst_audio_test_src_src_fixate);

  src->samplerate = 44100;
  src->format = GST_AUDIO_TEST_SRC_FORMAT_NONE;

  src->volume = DEFAULT_VOLUME;
  src->freq = DEFAULT_FREQ;

  /* we operate in time */
  gst_base_src_set_format (GST_BASE_SRC (src), GST_FORMAT_TIME);
  gst_base_src_set_live (GST_BASE_SRC (src), DEFAULT_IS_LIVE);

  src->samples_per_buffer = DEFAULT_SAMPLES_PER_BUFFER;
  src->generate_samples_per_buffer = src->samples_per_buffer;
  src->timestamp_offset = DEFAULT_TIMESTAMP_OFFSET;
  src->can_activate_pull = DEFAULT_CAN_ACTIVATE_PULL;

  src->gen = NULL;

  src->wave = DEFAULT_WAVE;
  gst_base_src_set_blocksize (GST_BASE_SRC (src), -1);
}

static GstCaps *
gst_v4l2src_get_caps (GstBaseSrc * src)
{
  GstV4l2Src *v4l2src = GST_V4L2SRC (src);
  GstCaps *ret;
  GSList *walk;
  GSList *formats;

  if (!GST_V4L2_IS_OPEN (v4l2src->v4l2object)) {
    /* FIXME: copy? */
    return
        gst_caps_copy (gst_pad_get_pad_template_caps (GST_BASE_SRC_PAD
            (v4l2src)));
  }

  if (v4l2src->probed_caps)
    return gst_caps_ref (v4l2src->probed_caps);

  formats = gst_v4l2_object_get_format_list (v4l2src->v4l2object);

  ret = gst_caps_new_empty ();

  for (walk = formats; walk; walk = walk->next) {
    struct v4l2_fmtdesc *format;

    GstStructure *template;

static void
gst_dv1394src_init (GstDV1394Src * dv1394src, GstDV1394SrcClass * klass)
{
  GstPad *srcpad = GST_BASE_SRC_PAD (dv1394src);

  gst_base_src_set_live (GST_BASE_SRC (dv1394src), TRUE);
  gst_base_src_set_format (GST_BASE_SRC (dv1394src), GST_FORMAT_TIME);
  gst_base_src_set_do_timestamp (GST_BASE_SRC (dv1394src), TRUE);
  gst_pad_use_fixed_caps (srcpad);

  dv1394src->port = DEFAULT_PORT;
  dv1394src->channel = DEFAULT_CHANNEL;

  dv1394src->consecutive = DEFAULT_CONSECUTIVE;
  dv1394src->skip = DEFAULT_SKIP;
  dv1394src->drop_incomplete = DEFAULT_DROP_INCOMPLETE;
  dv1394src->use_avc = DEFAULT_USE_AVC;
  dv1394src->guid = DEFAULT_GUID;
  dv1394src->uri = g_strdup_printf ("dv://%d", dv1394src->port);
  dv1394src->device_name = g_strdup_printf ("Default");

  READ_SOCKET (dv1394src) = -1;
  WRITE_SOCKET (dv1394src) = -1;

  /* initialized when first header received */
  dv1394src->frame_size = 0;

  dv1394src->buf = NULL;
  dv1394src->frame = NULL;
  dv1394src->frame_sequence = 0;

  dv1394src->provided_clock = gst_1394_clock_new ("dv1394clock");
}

static GstCaps *
gst_v4l2src_get_caps (GstBaseSrc * src, GstCaps * filter)
{
  GstV4l2Src *v4l2src;
  GstV4l2Object *obj;
  GstCaps *ret;
  GSList *walk;
  GSList *formats;

  v4l2src = GST_V4L2SRC (src);
  obj = v4l2src->v4l2object;

  if (!GST_V4L2_IS_OPEN (obj)) {
    return gst_pad_get_pad_template_caps (GST_BASE_SRC_PAD (v4l2src));
  }

  if (v4l2src->probed_caps)
    return gst_caps_ref (v4l2src->probed_caps);

  formats = gst_v4l2_object_get_format_list (obj);

  ret = gst_caps_new_empty ();

  for (walk = formats; walk; walk = walk->next) {
    struct v4l2_fmtdesc *format;
    GstStructure *template;

static GstCaps *
gst_dshowvideosrc_get_caps (GstBaseSrc * basesrc, GstCaps * filter)
{
  GstDshowVideoSrc *src = GST_DSHOWVIDEOSRC (basesrc);
  GstCaps *caps;

  if (src->caps) {
    caps = gst_caps_ref (src->caps);
  } else {
    caps = gst_pad_get_pad_template_caps (GST_BASE_SRC_PAD (src));
  }

  if (caps) {
    GstCaps *filtcaps;

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

    return filtcaps;
  }

  return NULL;
}

static void
gst_multi_file_src_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstMultiFileSrc *src = GST_MULTI_FILE_SRC (object);

  switch (prop_id) {
    case PROP_LOCATION:
      gst_multi_file_src_set_location (src, g_value_get_string (value));
      break;
    case PROP_INDEX:
      GST_OBJECT_LOCK (src);
      /* index was really meant to be read-only, but for backwards-compatibility
       * we set start_index to make it work as it used to */
      if (!GST_OBJECT_FLAG_IS_SET (src, GST_BASE_SRC_FLAG_STARTED))
        src->start_index = g_value_get_int (value);
      else
        src->index = g_value_get_int (value);
      GST_OBJECT_UNLOCK (src);
      break;
    case PROP_START_INDEX:
      src->start_index = g_value_get_int (value);
      break;
    case PROP_STOP_INDEX:
      src->stop_index = g_value_get_int (value);
      break;
    case PROP_CAPS:
    {
      GstStructure *st = NULL;
      const GstCaps *caps = gst_value_get_caps (value);
      GstCaps *new_caps;

      if (caps == NULL) {
        new_caps = gst_caps_new_any ();
      } else {
        new_caps = gst_caps_copy (caps);
      }
      gst_caps_replace (&src->caps, new_caps);
      gst_pad_set_caps (GST_BASE_SRC_PAD (src), new_caps);

      if (new_caps && gst_caps_get_size (new_caps) == 1 &&
          (st = gst_caps_get_structure (new_caps, 0))
          && gst_structure_get_fraction (st, "framerate", &src->fps_n,
              &src->fps_d)) {
        GST_INFO_OBJECT (src, "Seting framerate to %d/%d", src->fps_n,
            src->fps_d);
      } else {
        src->fps_n = -1;
        src->fps_d = -1;
      }
    }
      break;
    case PROP_LOOP:
      src->loop = g_value_get_boolean (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static GstCaps *
gst_genicamsrc_get_caps (GstBaseSrc * bsrc, GstCaps * filter)
{
  GstGenicamSrc *src = GST_GENICAM_SRC (bsrc);
  GstCaps *caps;

  if (src->hDS == NULL) {
    caps = gst_pad_get_pad_template_caps (GST_BASE_SRC_PAD (src));
  } else {
    caps = gst_caps_copy (src->caps);
  }

  GST_DEBUG_OBJECT (src, "The caps before filtering are %" GST_PTR_FORMAT,
      caps);

  if (filter && caps) {
    GstCaps *tmp = gst_caps_intersect (caps, filter);
    gst_caps_unref (caps);
    caps = tmp;
  }

  GST_DEBUG_OBJECT (src, "The caps after filtering are %" GST_PTR_FORMAT, caps);

  return caps;
}

static GstFlowReturn
gst_dc1394_create (GstPushSrc * psrc, GstBuffer ** buffer)
{
    GstDc1394 *src;
    GstBuffer *outbuf;
    GstCaps *caps;
    dc1394video_frame_t *frame[1];
    GstFlowReturn res = GST_FLOW_OK;
    dc1394error_t err;

    src = GST_DC1394 (psrc);

    err = dc1394_capture_dequeue (src->camera, DC1394_CAPTURE_POLICY_WAIT, frame);

    if (err != DC1394_SUCCESS) {
        GST_ELEMENT_ERROR (src, RESOURCE, FAILED,
                           ("failed to dequeue frame"), ("failed to dequeue frame"));
        goto error;
    }

    outbuf = gst_buffer_new_and_alloc (frame[0]->image_bytes);

    memcpy (GST_BUFFER_MALLOCDATA (outbuf), (guchar *) frame[0]->image,
            frame[0]->image_bytes * sizeof (guchar));

    GST_BUFFER_DATA (outbuf) = GST_BUFFER_MALLOCDATA (outbuf);

    caps = gst_pad_get_caps (GST_BASE_SRC_PAD (psrc));
    gst_buffer_set_caps (outbuf, caps);
    gst_caps_unref (caps);

    GST_BUFFER_TIMESTAMP (outbuf) = src->timestamp_offset + src->running_time;
    if (src->rate_numerator != 0) {
        GST_BUFFER_DURATION (outbuf) = gst_util_uint64_scale_int (GST_SECOND,
                                       src->rate_denominator, src->rate_numerator);
    }

    src->n_frames++;
    if (src->rate_numerator != 0) {
        src->running_time = gst_util_uint64_scale_int (src->n_frames * GST_SECOND,
                            src->rate_denominator, src->rate_numerator);
    }

    if (dc1394_capture_enqueue (src->camera, frame[0]) != DC1394_SUCCESS) {
        GST_ELEMENT_ERROR (src, RESOURCE, FAILED, ("failed to enqueue frame"),
                           ("failed to enqueue frame"));
        goto error;
    }

    *buffer = outbuf;

    return res;

error:
    {
        return GST_FLOW_ERROR;
    }
}

static gboolean
gst_dshowvideosrc_push_buffer (guint8 * buffer, guint size, gpointer src_object,
    GstClockTime duration)
{
  GstDshowVideoSrc *src = GST_DSHOWVIDEOSRC (src_object);
  GstBuffer *buf = NULL;
  IPin *pPin = NULL;
  HRESULT hres = S_FALSE;
  AM_MEDIA_TYPE *pMediaType = NULL;

  if (!buffer || size == 0 || !src) {
    return FALSE;
  }

  /* create a new buffer assign to it the clock time as timestamp */
  buf = gst_buffer_new_and_alloc (size);

  GST_BUFFER_SIZE (buf) = size;

  GstClock *clock = gst_element_get_clock (GST_ELEMENT (src));
  GST_BUFFER_TIMESTAMP (buf) =
    GST_CLOCK_DIFF (gst_element_get_base_time (GST_ELEMENT (src)), gst_clock_get_time (clock));
  gst_object_unref (clock);

  GST_BUFFER_DURATION (buf) = duration;

  if (src->is_rgb) {
    /* FOR RGB directshow decoder will return bottom-up BITMAP
     * There is probably a way to get top-bottom video frames from
     * the decoder...
     */
    gint line = 0;
    gint stride = size / src->height;

    for (; line < src->height; line++) {
      memcpy (GST_BUFFER_DATA (buf) + (line * stride),
          buffer + (size - ((line + 1) * (stride))), stride);
    }
  } else {
    memcpy (GST_BUFFER_DATA (buf), buffer, size);
  }

  GST_DEBUG ("push_buffer => pts %" GST_TIME_FORMAT "duration %"
      GST_TIME_FORMAT, GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)),
      GST_TIME_ARGS (duration));

  /* the negotiate() method already set caps on the source pad */
  gst_buffer_set_caps (buf, GST_PAD_CAPS (GST_BASE_SRC_PAD (src)));

  g_mutex_lock (src->buffer_mutex);
  if (src->buffer != NULL)
    gst_buffer_unref (src->buffer);
  src->buffer = buf;
  g_cond_signal (src->buffer_cond);
  g_mutex_unlock (src->buffer_mutex);

  return TRUE;
}

static GstFlowReturn
gst_mms_create (GstPushSrc * psrc, GstBuffer ** buf)
{
  GstMMS *mmssrc;
  guint8 *data;
  guint blocksize;
  gint result;
  mms_off_t offset;

  *buf = NULL;

  mmssrc = GST_MMS (psrc);

  offset = mmsx_get_current_pos (mmssrc->connection);

  /* Check if a seek perhaps has wrecked our connection */
  if (offset == -1) {
    GST_DEBUG_OBJECT (mmssrc,
        "connection broken (probably an error during mmsx_seek_time during a convert query) returning FLOW_ERROR");
    return GST_FLOW_ERROR;
  }

  /* Choose blocksize best for optimum performance */
  if (offset == 0)
    blocksize = mmsx_get_asf_header_len (mmssrc->connection);
  else
    blocksize = mmsx_get_asf_packet_len (mmssrc->connection);

  *buf = gst_buffer_new_and_alloc (blocksize);

  data = GST_BUFFER_DATA (*buf);
  GST_BUFFER_SIZE (*buf) = 0;
  GST_LOG_OBJECT (mmssrc, "reading %d bytes", blocksize);
  result = mmsx_read (NULL, mmssrc->connection, (char *) data, blocksize);

  /* EOS? */
  if (result == 0)
    goto eos;

  GST_BUFFER_OFFSET (*buf) = offset;
  GST_BUFFER_SIZE (*buf) = result;

  GST_LOG_OBJECT (mmssrc, "Returning buffer with offset %" G_GINT64_FORMAT
      " and size %u", GST_BUFFER_OFFSET (*buf), GST_BUFFER_SIZE (*buf));

  gst_buffer_set_caps (*buf, GST_PAD_CAPS (GST_BASE_SRC_PAD (mmssrc)));

  return GST_FLOW_OK;

eos:
  {
    GST_DEBUG_OBJECT (mmssrc, "EOS");
    gst_buffer_unref (*buf);
    *buf = NULL;
    return GST_FLOW_UNEXPECTED;
  }
}

static GstCaps *
gst_directsound_src_getcaps (GstBaseSrc * bsrc, GstCaps * filter)
{
  GstCaps *caps = NULL;
  GST_DEBUG_OBJECT (bsrc, "get caps");

  caps = gst_pad_get_pad_template_caps (GST_BASE_SRC_PAD (bsrc));
  return caps;
}

static GstFlowReturn
gst_osx_video_src_create (GstPushSrc * src, GstBuffer ** buf)
{
  GstOSXVideoSrc *self = GST_OSX_VIDEO_SRC (src);
  ComponentResult err;
  GstCaps *caps;
  //GstClock * clock;

  // ###: we need to sleep between calls to SGIdle.  originally, the sleeping
  //   was done using gst_clock_id_wait(), but it turns out that approach
  //   doesn't work well.  it has two issues:
  //   1) every so often, gst_clock_id_wait() will block for a much longer
  //      period of time than requested (upwards of a minute) causing video
  //      to freeze until it finally returns.  this seems to happen once
  //      every few minutes, which probably means something like 1 in every
  //      several hundred calls gst_clock_id_wait() does the wrong thing.
  //   2) even when the gst_clock approach is working properly, it uses
  //      quite a bit of cpu in comparison to a simple usleep().  on one
  //      test machine, using gst_clock_id_wait() caused osxvideosrc to use
  //      nearly 100% cpu, while using usleep() brough the usage to less
  //      than 10%.
  //
  // so, for now, we comment out the gst_clock stuff and use usleep.

  //clock = gst_system_clock_obtain ();
  do {
    err = SGIdle (self->seq_grab);
    if (err != noErr) {
      GST_ERROR_OBJECT (self, "SGIdle returned %d", (int) err);
      gst_object_unref (clock);
      return GST_FLOW_UNEXPECTED;
    }

    if (self->buffer == NULL) {
      /*GstClockID clock_id;

         clock_id = gst_clock_new_single_shot_id (clock,
         (GstClockTime) (gst_clock_get_time(clock) +
         (GST_SECOND / ((float)FRAMERATE * 2))));
         gst_clock_id_wait (clock_id, NULL);
         gst_clock_id_unref (clock_id); */

      usleep (1000000 / (FRAMERATE * 2));
    }
  } while (self->buffer == NULL);
  //gst_object_unref (clock);

  *buf = self->buffer;
  self->buffer = NULL;

  caps = gst_pad_get_caps (GST_BASE_SRC_PAD (src));
  gst_buffer_set_caps (*buf, caps);
  gst_caps_unref (caps);

  return GST_FLOW_OK;
}