C++ GST_V4L2_IS_OPEN函数代码示例

static gboolean
gst_v4l2_video_dec_open (GstVideoDecoder * decoder)
{
  GstV4l2VideoDec *self = GST_V4L2_VIDEO_DEC (decoder);

  GST_DEBUG_OBJECT (self, "Opening");

  if (!gst_v4l2_object_open (self->v4l2output))
    goto failure;

  if (!gst_v4l2_object_open_shared (self->v4l2capture, self->v4l2output))
    goto failure;

  self->probed_sinkcaps = gst_v4l2_object_get_caps (self->v4l2output,
      gst_v4l2_object_get_codec_caps ());

  if (gst_caps_is_empty (self->probed_sinkcaps))
    goto no_encoded_format;

  self->probed_srccaps = gst_v4l2_object_get_caps (self->v4l2capture,
      gst_v4l2_object_get_raw_caps ());

  if (gst_caps_is_empty (self->probed_srccaps))
    goto no_raw_format;

  return TRUE;

no_encoded_format:
  GST_ELEMENT_ERROR (self, RESOURCE, SETTINGS,
      (_("Encoder on device %s has no supported input format"),
          self->v4l2output->videodev), (NULL));
  goto failure;


no_raw_format:
  GST_ELEMENT_ERROR (self, RESOURCE, SETTINGS,
      (_("Encoder on device %s has no supported output format"),
          self->v4l2output->videodev), (NULL));
  goto failure;

failure:
  if (GST_V4L2_IS_OPEN (self->v4l2output))
    gst_v4l2_object_close (self->v4l2output);

  if (GST_V4L2_IS_OPEN (self->v4l2capture))
    gst_v4l2_object_close (self->v4l2capture);

  gst_caps_replace (&self->probed_srccaps, NULL);
  gst_caps_replace (&self->probed_sinkcaps, NULL);

  return FALSE;
}

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;

/******************************************************
 * gst_v4l2src_capture_stop():
 *   stop streaming capture
 * return value: TRUE on success, FALSE on error
 ******************************************************/
gboolean
gst_v4l2src_capture_stop (GstV4l2Src * v4l2src)
{
  GST_DEBUG_OBJECT (v4l2src, "stopping capturing");

  if (!GST_V4L2_IS_OPEN (v4l2src->v4l2object)) {
    goto done;
  }
  if (!GST_V4L2_IS_ACTIVE (v4l2src->v4l2object)) {
    goto done;
  }

  if (v4l2src->use_mmap) {
    /* we actually need to sync on all queued buffers but not
     * on the non-queued ones */
    if (!gst_v4l2_object_stop_streaming (v4l2src->v4l2object)) {
      return FALSE;
    }
  }

done:

  /* make an optional pending wait stop */
  v4l2src->quit = TRUE;
  v4l2src->is_capturing = FALSE;

  return TRUE;
}

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 void
gst_v4l2sink_sync_overlay_fields (GstV4l2Sink * v4l2sink)
{
  if (GST_V4L2_IS_OPEN (v4l2sink->v4l2object)) {

    gint fd = v4l2sink->v4l2object->video_fd;
    struct v4l2_format format;

    memset (&format, 0x00, sizeof (struct v4l2_format));
    format.type = V4L2_BUF_TYPE_VIDEO_OVERLAY;

    g_return_if_fail (v4l2_ioctl (fd, VIDIOC_G_FMT, &format) >= 0);

    if (v4l2sink->overlay_fields_set) {
      if (v4l2sink->overlay_fields_set & OVERLAY_TOP_SET)
        format.fmt.win.w.top = v4l2sink->overlay.top;
      if (v4l2sink->overlay_fields_set & OVERLAY_LEFT_SET)
        format.fmt.win.w.left = v4l2sink->overlay.left;
      if (v4l2sink->overlay_fields_set & OVERLAY_WIDTH_SET)
        format.fmt.win.w.width = v4l2sink->overlay.width;
      if (v4l2sink->overlay_fields_set & OVERLAY_HEIGHT_SET)
        format.fmt.win.w.height = v4l2sink->overlay.height;

      g_return_if_fail (v4l2_ioctl (fd, VIDIOC_S_FMT, &format) >= 0);
      v4l2sink->overlay_fields_set = 0;
    }

    v4l2sink->overlay = format.fmt.win.w;
  }
}

gboolean
gst_v4l2_tuner_set_frequency (GstV4l2Object * v4l2object,
    GstTunerChannel * channel, gulong frequency)
{
  GstV4l2TunerChannel *v4l2channel = GST_V4L2_TUNER_CHANNEL (channel);
  gint chan;

  /* assert that we're opened and that we're using a known item */
  g_return_val_if_fail (GST_V4L2_IS_OPEN (v4l2object), FALSE);
  g_return_val_if_fail (GST_TUNER_CHANNEL_HAS_FLAG (channel,
          GST_TUNER_CHANNEL_FREQUENCY), FALSE);
  g_return_val_if_fail (gst_v4l2_tuner_contains_channel (v4l2object,
          v4l2channel), FALSE);

  if (v4l2object->get_in_out_func (v4l2object, &chan)) {
    if (chan == GST_V4L2_TUNER_CHANNEL (channel)->index &&
        GST_TUNER_CHANNEL_HAS_FLAG (channel, GST_TUNER_CHANNEL_FREQUENCY)) {
      if (gst_v4l2_set_frequency (v4l2object, v4l2channel->tuner, frequency)) {
        gst_tuner_frequency_changed (GST_TUNER (v4l2object->element), channel,
            frequency);
        return TRUE;
      }
    }
  }

  return FALSE;
}

gboolean
gst_v4l2_get_input (GstV4l2Object * v4l2object, gint * input)
{
  gint n;

  GST_DEBUG_OBJECT (v4l2object->element, "trying to get input");

  if (!GST_V4L2_IS_OPEN (v4l2object))
    return FALSE;

  if (v4l2_ioctl (v4l2object->video_fd, VIDIOC_G_INPUT, &n) < 0)
    goto input_failed;

  *input = n;

  GST_DEBUG_OBJECT (v4l2object->element, "input: %d", n);

  return TRUE;

  /* ERRORS */
input_failed:
  {
    GST_ELEMENT_WARNING (v4l2object->element, RESOURCE, SETTINGS,
        (_("Failed to get current input on device '%s'. May be it is a radio device"), v4l2object->videodev), GST_ERROR_SYSTEM);
    return FALSE;
  }
}

static GstCaps *
gst_v4l2sink_get_caps (GstBaseSink * bsink)
{
  GstV4l2Sink *v4l2sink = GST_V4L2SINK (bsink);
  GstCaps *ret;
  GSList *walk;
  GSList *formats;

  if (!GST_V4L2_IS_OPEN (v4l2sink->v4l2object)) {
    /* FIXME: copy? */
    GST_DEBUG_OBJECT (v4l2sink, "device is not open");
    return
        gst_caps_copy (gst_pad_get_pad_template_caps (GST_BASE_SINK_PAD
            (v4l2sink)));
  }

  if (v4l2sink->probed_caps) {
    LOG_CAPS (v4l2sink, v4l2sink->probed_caps);
    return gst_caps_ref (v4l2sink->probed_caps);
  }

  formats = gst_v4l2_object_get_format_list (v4l2sink->v4l2object);

  ret = gst_caps_new_empty ();

  for (walk = v4l2sink->v4l2object->formats; walk; walk = walk->next) {
    struct v4l2_fmtdesc *format;

    GstStructure *template;

/******************************************************
 * gst_v4l2_signal_strength():
 *   get the strength of the signal on the current input
 * return value: TRUE on success, FALSE on error
 ******************************************************/
gboolean
gst_v4l2_signal_strength (GstV4l2Object * v4l2object,
    gint tunernum, gulong * signal_strength)
{
  struct v4l2_tuner tuner = { 0, };

  GST_DEBUG_OBJECT (v4l2object->element, "trying to get signal strength");

  if (!GST_V4L2_IS_OPEN (v4l2object))
    return FALSE;

  tuner.index = tunernum;
  if (v4l2_ioctl (v4l2object->video_fd, VIDIOC_G_TUNER, &tuner) < 0)
    goto tuner_failed;

  *signal_strength = tuner.signal;

  return TRUE;

  /* ERRORS */
tuner_failed:
  {
    GST_ELEMENT_WARNING (v4l2object->element, RESOURCE, SETTINGS,
        (_("Failed to get signal strength for device '%s'."),
            v4l2object->videodev), GST_ERROR_SYSTEM);
    return FALSE;
  }
}

/******************************************************
 * gst_v4l2_set_attribute():
 *   try to set the value of one specific attribute
 * return value: TRUE on success, FALSE on error
 ******************************************************/
gboolean
gst_v4l2_set_attribute (GstV4l2Object * v4l2object,
    int attribute_num, const int value)
{
  struct v4l2_control control = { 0, };

  GST_DEBUG_OBJECT (v4l2object->element, "setting value of attribute %d to %d",
      attribute_num, value);

  if (!GST_V4L2_IS_OPEN (v4l2object))
    return FALSE;

  control.id = attribute_num;
  control.value = value;
  if (v4l2_ioctl (v4l2object->video_fd, VIDIOC_S_CTRL, &control) < 0)
    goto ctrl_failed;

  return TRUE;

  /* ERRORS */
ctrl_failed:
  {
    GST_ELEMENT_WARNING (v4l2object->element, RESOURCE, SETTINGS,
        (_("Failed to set value %d for control %d on device '%s'."),
            value, attribute_num, v4l2object->videodev), GST_ERROR_SYSTEM);
    return FALSE;
  }
}

/******************************************************
 * gst_v4l2_get_capabilities():
 *   get the device's capturing capabilities
 * return value: TRUE on success, FALSE on error
 ******************************************************/
gboolean
gst_v4l2_get_capabilities (GstV4l2Object * v4l2object)
{
  GstElement *e;

  e = v4l2object->element;

  GST_DEBUG_OBJECT (e, "getting capabilities");

  if (!GST_V4L2_IS_OPEN (v4l2object))
    return FALSE;

  if (v4l2_ioctl (v4l2object->video_fd, VIDIOC_QUERYCAP, &v4l2object->vcap) < 0)
    goto cap_failed;

  GST_LOG_OBJECT (e, "driver:      '%s'", v4l2object->vcap.driver);
  GST_LOG_OBJECT (e, "card:        '%s'", v4l2object->vcap.card);
  GST_LOG_OBJECT (e, "bus_info:    '%s'", v4l2object->vcap.bus_info);
  GST_LOG_OBJECT (e, "version:     %08x", v4l2object->vcap.version);
  GST_LOG_OBJECT (e, "capabilites: %08x", v4l2object->vcap.capabilities);

  return TRUE;

  /* ERRORS */
cap_failed:
  {
    GST_ELEMENT_ERROR (v4l2object->element, RESOURCE, SETTINGS,
        (_("Error getting capabilities for device '%s': "
                "It isn't a v4l2 driver. Check if it is a v4l1 driver."),
            v4l2object->videodev), GST_ERROR_SYSTEM);
    return FALSE;
  }
}

/******************************************************
 * gst_v4l2_set_frequency():
 *   set frequency
 * return value: TRUE on success, FALSE on error
 ******************************************************/
gboolean
gst_v4l2_set_frequency (GstV4l2Object * v4l2object,
    gint tunernum, gulong frequency)
{
  struct v4l2_frequency freq = { 0, };

  GstTunerChannel *channel;

  GST_DEBUG_OBJECT (v4l2object->element,
      "setting current tuner frequency to %lu", frequency);

  if (!GST_V4L2_IS_OPEN (v4l2object))
    return FALSE;

  channel = gst_tuner_get_channel (GST_TUNER (v4l2object->element));

  freq.tuner = tunernum;
  /* fill in type - ignore error */
  v4l2_ioctl (v4l2object->video_fd, VIDIOC_G_FREQUENCY, &freq);
  freq.frequency = frequency / channel->freq_multiplicator;

  if (v4l2_ioctl (v4l2object->video_fd, VIDIOC_S_FREQUENCY, &freq) < 0)
    goto freq_failed;

  return TRUE;

  /* ERRORS */
freq_failed:
  {
    GST_ELEMENT_WARNING (v4l2object->element, RESOURCE, SETTINGS,
        (_("Failed to set current tuner frequency for device '%s' to %lu Hz."),
            v4l2object->videodev, frequency), GST_ERROR_SYSTEM);
    return FALSE;
  }
}

gboolean
gst_v4l2_set_output (GstV4l2Object * v4l2object, gint output)
{
  GST_DEBUG_OBJECT (v4l2object->element, "trying to set output to %d", output);

  if (!GST_V4L2_IS_OPEN (v4l2object))
    return FALSE;

  if (v4l2_ioctl (v4l2object->video_fd, VIDIOC_S_OUTPUT, &output) < 0)
    goto output_failed;

  return TRUE;

  /* ERRORS */
output_failed:
  if (v4l2object->vcap.capabilities & V4L2_CAP_TUNER) {
    /* only give a warning message if driver actually claims to have tuner
     * support
     */
    GST_ELEMENT_WARNING (v4l2object->element, RESOURCE, SETTINGS,
        (_("Failed to set output %d on device %s."),
            output, v4l2object->videodev), GST_ERROR_SYSTEM);
  }
  return FALSE;
}

gboolean
gst_v4l2_get_output (GstV4l2Object * v4l2object, gint * output)
{
  gint n;

  GST_DEBUG_OBJECT (v4l2object->element, "trying to get output");

  if (!GST_V4L2_IS_OPEN (v4l2object))
    return FALSE;

  if (v4l2_ioctl (v4l2object->video_fd, VIDIOC_G_OUTPUT, &n) < 0)
    goto output_failed;

  *output = n;

  GST_DEBUG_OBJECT (v4l2object->element, "output: %d", n);

  return TRUE;

  /* ERRORS */
output_failed:
  if (v4l2object->vcap.capabilities & V4L2_CAP_TUNER) {
    /* only give a warning message if driver actually claims to have tuner
     * support
     */
    GST_ELEMENT_WARNING (v4l2object->element, RESOURCE, SETTINGS,
        (_("Failed to get current output on device '%s'. May be it is a radio device"), v4l2object->videodev), GST_ERROR_SYSTEM);
  }
  return FALSE;
}

static gboolean
gst_v4l2_decoder_cmd (GstV4l2Object * v4l2object, guint cmd, guint flags)
{
  struct v4l2_decoder_cmd dcmd = { 0, };

  GST_DEBUG_OBJECT (v4l2object->element,
      "sending v4l2 decoder command %u with flags %u", cmd, flags);

  if (!GST_V4L2_IS_OPEN (v4l2object))
    return FALSE;

  dcmd.cmd = cmd;
  dcmd.flags = flags;
  if (v4l2_ioctl (v4l2object->video_fd, VIDIOC_DECODER_CMD, &dcmd) < 0)
    goto dcmd_failed;

  return TRUE;

dcmd_failed:
  if (errno == ENOTTY) {
    GST_INFO_OBJECT (v4l2object->element,
        "Failed to send decoder command %u with flags %u for '%s'. (%s)",
        cmd, flags, v4l2object->videodev, g_strerror (errno));
  } else {
    GST_ERROR_OBJECT (v4l2object->element,
        "Failed to send decoder command %u with flags %u for '%s'. (%s)",
        cmd, flags, v4l2object->videodev, g_strerror (errno));
  }
  return FALSE;
}