gstv4l2object.c

/* GStreamer
 *
 * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
 *               2006 Edgard Lima <edgard.lima@indt.org.br>
 *
 * gstv4l2object.c: base class for V4L2 elements
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version. This library is distributed in the hope
 * that it will be useful, but WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.  See the GNU Library General Public License for more details.
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301,
 * USA.
 */

/* FIXME 0.11: suppress warnings for deprecated API such as GValueArray
 * with newer GLib versions (>= 2.31.0) */
#define GLIB_DISABLE_DEPRECATION_WARNINGS

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>

#ifdef HAVE_GUDEV
#include <gudev/gudev.h>
#endif

#include "v4l2_calls.h"
#include "gstv4l2tuner.h"
#ifdef HAVE_XVIDEO
#include "gstv4l2videooverlay.h"
#endif
#include "gstv4l2colorbalance.h"

#include "gst/gst-i18n-plugin.h"

#include <gst/video/video.h>

/* videodev2.h is not versioned and we can't easily check for the presence
 * of enum values at compile time, but the V4L2_CAP_VIDEO_OUTPUT_OVERLAY define
 * was added in the same commit as V4L2_FIELD_INTERLACED_{TB,BT} (b2787845) */
#ifndef V4L2_CAP_VIDEO_OUTPUT_OVERLAY
#define V4L2_FIELD_INTERLACED_TB 8
#define V4L2_FIELD_INTERLACED_BT 9
#endif

#ifndef V4L2_PIX_FMT_NV12M
#define V4L2_PIX_FMT_NV12M GST_MAKE_FOURCC ('N', 'M', '1', '2')
#endif
#ifndef V4L2_PIX_FMT_NV12MT
#define V4L2_PIX_FMT_NV12MT GST_MAKE_FOURCC ('T', 'M', '1', '2')
#endif
#ifndef V4L2_PIX_FMT_NV21M
#define V4L2_PIX_FMT_NV21M GST_MAKE_FOURCC ('N', 'M', '2', '1')
#endif
#ifndef V4L2_PIX_FMT_MPEG1
#define V4L2_PIX_FMT_MPEG1 GST_MAKE_FOURCC ('M', 'P', 'G', '1')
#endif
#ifndef V4L2_PIX_FMT_MPEG2
#define V4L2_PIX_FMT_MPEG2 GST_MAKE_FOURCC ('M', 'P', 'G', '2')
#endif
#ifndef V4L2_PIX_FMT_MPEG4
#define V4L2_PIX_FMT_MPEG4 GST_MAKE_FOURCC ('M', 'P', 'G', '4')
#endif

GST_DEBUG_CATEGORY_EXTERN (v4l2_debug);
GST_DEBUG_CATEGORY_EXTERN (GST_CAT_PERFORMANCE);
#define GST_CAT_DEFAULT v4l2_debug

#define DEFAULT_PROP_DEVICE_NAME        NULL
#define DEFAULT_PROP_DEVICE_FD          -1
#define DEFAULT_PROP_FLAGS              0
#define DEFAULT_PROP_TV_NORM            0
#define DEFAULT_PROP_CHANNEL            NULL
#define DEFAULT_PROP_FREQUENCY          0
#define DEFAULT_PROP_IO_MODE            GST_V4L2_IO_AUTO

#define ENCODED_BUFFER_SIZE             (1 * 1024 * 1024)

enum
{
  PROP_0,
  V4L2_STD_OBJECT_PROPS,
};

static GSList *gst_v4l2_object_get_format_list (GstV4l2Object * v4l2object);

#if 0
G_LOCK_DEFINE_STATIC (probe_lock);

const GList *
gst_v4l2_probe_get_properties (GstPropertyProbe * probe)
{
  GObjectClass *klass = G_OBJECT_GET_CLASS (probe);
  static GList *list = NULL;

  G_LOCK (probe_lock);

  if (!list) {
    list = g_list_append (NULL, g_object_class_find_property (klass, "device"));
  }

  G_UNLOCK (probe_lock);

  return list;
}

static gboolean init = FALSE;
static GList *devices = NULL;

#ifdef HAVE_GUDEV
static gboolean
gst_v4l2_class_probe_devices_with_udev (GstElementClass * klass, gboolean check,
    GList ** klass_devices)
{
  GUdevClient *client = NULL;
  GList *item;

  if (!check) {
    while (devices) {
      gchar *device = devices->data;
      devices = g_list_remove (devices, device);
      g_free (device);
    }

    GST_INFO ("Enumerating video4linux devices from udev");
    client = g_udev_client_new (NULL);
    if (!client) {
      GST_WARNING ("Failed to initialize gudev client");
      goto finish;
    }

    item = g_udev_client_query_by_subsystem (client, "video4linux");
    while (item) {
      GUdevDevice *device = item->data;
      gchar *devnode = g_strdup (g_udev_device_get_device_file (device));
      gint api = g_udev_device_get_property_as_int (device, "ID_V4L_VERSION");
      GST_INFO ("Found new device: %s, API: %d", devnode, api);
      /* Append v4l2 devices only. If api is 0 probably v4l_id has
         been stripped out of the current udev installation, append
         anyway */
      if (api == 0) {
        GST_WARNING
            ("Couldn't retrieve ID_V4L_VERSION, silly udev installation?");
      }
      if ((api == 2 || api == 0)) {
        devices = g_list_append (devices, devnode);
      } else {
        g_free (devnode);
      }
      g_object_unref (device);
      item = item->next;
    }
    g_list_free (item);
    init = TRUE;
  }

finish:
  if (client) {
    g_object_unref (client);
  }

  *klass_devices = devices;

  return init;
}
#endif /* HAVE_GUDEV */

static gboolean
gst_v4l2_class_probe_devices (GstElementClass * klass, gboolean check,
    GList ** klass_devices)
{
  if (!check) {
    const gchar *dev_base[] = { "/dev/video", "/dev/v4l2/video", NULL };
    gint base, n, fd;

    while (devices) {
      gchar *device = devices->data;
      devices = g_list_remove (devices, device);
      g_free (device);
    }

    /*
     * detect /dev entries
     */
    for (n = 0; n < 64; n++) {
      for (base = 0; dev_base[base] != NULL; base++) {
        struct stat s;
        gchar *device = g_strdup_printf ("%s%d",
            dev_base[base],
            n);

        /*
         * does the /dev/ entry exist at all?
         */
        if (stat (device, &s) == 0) {
          /*
           * yes: is a device attached?
           */
          if (S_ISCHR (s.st_mode)) {

            if ((fd = open (device, O_RDWR | O_NONBLOCK)) > 0 || errno == EBUSY) {
              if (fd > 0)
                close (fd);

              devices = g_list_append (devices, device);
              break;
            }
          }
        }
        g_free (device);
      }
    }
    init = TRUE;
  }

  *klass_devices = devices;

  return init;
}

void
gst_v4l2_probe_probe_property (GstPropertyProbe * probe,
    guint prop_id, const GParamSpec * pspec, GList ** klass_devices)
{
  GstElementClass *klass = GST_ELEMENT_GET_CLASS (probe);

  switch (prop_id) {
    case PROP_DEVICE:
#ifdef HAVE_GUDEV
      if (!gst_v4l2_class_probe_devices_with_udev (klass, FALSE, klass_devices))
        gst_v4l2_class_probe_devices (klass, FALSE, klass_devices);
#else /* !HAVE_GUDEV */
      gst_v4l2_class_probe_devices (klass, FALSE, klass_devices);
#endif /* HAVE_GUDEV */
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (probe, prop_id, pspec);
      break;
  }
}

gboolean
gst_v4l2_probe_needs_probe (GstPropertyProbe * probe,
    guint prop_id, const GParamSpec * pspec, GList ** klass_devices)
{
  GstElementClass *klass = GST_ELEMENT_GET_CLASS (probe);
  gboolean ret = FALSE;

  switch (prop_id) {
    case PROP_DEVICE:
#ifdef HAVE_GUDEV
      ret =
          !gst_v4l2_class_probe_devices_with_udev (klass, FALSE, klass_devices);
#else /* !HAVE_GUDEV */
      ret = !gst_v4l2_class_probe_devices (klass, TRUE, klass_devices);
#endif /* HAVE_GUDEV */
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (probe, prop_id, pspec);
      break;
  }
  return ret;
}

static GValueArray *
gst_v4l2_class_list_devices (GstElementClass * klass, GList ** klass_devices)
{
  GValueArray *array;
  GValue value = { 0 };
  GList *item;

  if (!*klass_devices)
    return NULL;

  array = g_value_array_new (g_list_length (*klass_devices));
  item = *klass_devices;
  g_value_init (&value, G_TYPE_STRING);
  while (item) {
    gchar *device = item->data;

    g_value_set_string (&value, device);
    g_value_array_append (array, &value);

    item = item->next;
  }
  g_value_unset (&value);

  return array;
}

GValueArray *
gst_v4l2_probe_get_values (GstPropertyProbe * probe,
    guint prop_id, const GParamSpec * pspec, GList ** klass_devices)
{
  GstElementClass *klass = GST_ELEMENT_GET_CLASS (probe);
  GValueArray *array = NULL;

  switch (prop_id) {
    case PROP_DEVICE:
      array = gst_v4l2_class_list_devices (klass, klass_devices);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (probe, prop_id, pspec);
      break;
  }

  return array;
}
#endif

#define GST_TYPE_V4L2_DEVICE_FLAGS (gst_v4l2_device_get_type ())
static GType
gst_v4l2_device_get_type (void)
{
  static GType v4l2_device_type = 0;

  if (v4l2_device_type == 0) {
    static const GFlagsValue values[] = {
      {V4L2_CAP_VIDEO_CAPTURE, "Device supports video capture", "capture"},
      {V4L2_CAP_VIDEO_OUTPUT, "Device supports video playback", "output"},
      {V4L2_CAP_VIDEO_OVERLAY, "Device supports video overlay", "overlay"},

      {V4L2_CAP_VBI_CAPTURE, "Device supports the VBI capture", "vbi-capture"},
      {V4L2_CAP_VBI_OUTPUT, "Device supports the VBI output", "vbi-output"},

      {V4L2_CAP_TUNER, "Device has a tuner or modulator", "tuner"},
      {V4L2_CAP_AUDIO, "Device has audio inputs or outputs", "audio"},

      {0, NULL, NULL}
    };

    v4l2_device_type =
        g_flags_register_static ("GstV4l2DeviceTypeFlags", values);
  }

  return v4l2_device_type;
}

#define GST_TYPE_V4L2_TV_NORM (gst_v4l2_tv_norm_get_type ())
static GType
gst_v4l2_tv_norm_get_type (void)
{
  static GType v4l2_tv_norm = 0;

  if (!v4l2_tv_norm) {
    static const GEnumValue tv_norms[] = {
      {0, "none", "none"},

      {V4L2_STD_NTSC, "NTSC", "NTSC"},
      {V4L2_STD_NTSC_M, "NTSC-M", "NTSC-M"},
      {V4L2_STD_NTSC_M_JP, "NTSC-M-JP", "NTSC-M-JP"},
      {V4L2_STD_NTSC_M_KR, "NTSC-M-KR", "NTSC-M-KR"},
      {V4L2_STD_NTSC_443, "NTSC-443", "NTSC-443"},

      {V4L2_STD_PAL, "PAL", "PAL"},
      {V4L2_STD_PAL_BG, "PAL-BG", "PAL-BG"},
      {V4L2_STD_PAL_B, "PAL-B", "PAL-B"},
      {V4L2_STD_PAL_B1, "PAL-B1", "PAL-B1"},
      {V4L2_STD_PAL_G, "PAL-G", "PAL-G"},
      {V4L2_STD_PAL_H, "PAL-H", "PAL-H"},
      {V4L2_STD_PAL_I, "PAL-I", "PAL-I"},
      {V4L2_STD_PAL_DK, "PAL-DK", "PAL-DK"},
      {V4L2_STD_PAL_D, "PAL-D", "PAL-D"},
      {V4L2_STD_PAL_D1, "PAL-D1", "PAL-D1"},
      {V4L2_STD_PAL_K, "PAL-K", "PAL-K"},
      {V4L2_STD_PAL_M, "PAL-M", "PAL-M"},
      {V4L2_STD_PAL_N, "PAL-N", "PAL-N"},
      {V4L2_STD_PAL_Nc, "PAL-Nc", "PAL-Nc"},
      {V4L2_STD_PAL_60, "PAL-60", "PAL-60"},

      {V4L2_STD_SECAM, "SECAM", "SECAM"},
      {V4L2_STD_SECAM_B, "SECAM-B", "SECAM-B"},
      {V4L2_STD_SECAM_G, "SECAM-G", "SECAM-G"},
      {V4L2_STD_SECAM_H, "SECAM-H", "SECAM-H"},
      {V4L2_STD_SECAM_DK, "SECAM-DK", "SECAM-DK"},
      {V4L2_STD_SECAM_D, "SECAM-D", "SECAM-D"},
      {V4L2_STD_SECAM_K, "SECAM-K", "SECAM-K"},
      {V4L2_STD_SECAM_K1, "SECAM-K1", "SECAM-K1"},
      {V4L2_STD_SECAM_L, "SECAM-L", "SECAM-L"},
      {V4L2_STD_SECAM_LC, "SECAM-Lc", "SECAM-Lc"},

      {0, NULL, NULL}
    };

    v4l2_tv_norm = g_enum_register_static ("V4L2_TV_norms", tv_norms);
  }

  return v4l2_tv_norm;
}

GType
gst_v4l2_io_mode_get_type (void)
{
  static GType v4l2_io_mode = 0;

  if (!v4l2_io_mode) {
    static const GEnumValue io_modes[] = {
      {GST_V4L2_IO_AUTO, "GST_V4L2_IO_AUTO", "auto"},
      {GST_V4L2_IO_RW, "GST_V4L2_IO_RW", "rw"},
      {GST_V4L2_IO_MMAP, "GST_V4L2_IO_MMAP", "mmap"},
      {GST_V4L2_IO_USERPTR, "GST_V4L2_IO_USERPTR", "userptr"},
      {GST_V4L2_IO_DMABUF, "GST_V4L2_IO_DMABUF", "dmabuf"},

      {0, NULL, NULL}
    };
    v4l2_io_mode = g_enum_register_static ("GstV4l2IOMode", io_modes);
  }
  return v4l2_io_mode;
}

void
gst_v4l2_object_install_properties_helper (GObjectClass * gobject_class,
    const char *default_device)
{
  g_object_class_install_property (gobject_class, PROP_DEVICE,
      g_param_spec_string ("device", "Device", "Device location",
          default_device, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_DEVICE_NAME,
      g_param_spec_string ("device-name", "Device name",
          "Name of the device", DEFAULT_PROP_DEVICE_NAME,
          G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_DEVICE_FD,
      g_param_spec_int ("device-fd", "File descriptor",
          "File descriptor of the device", -1, G_MAXINT, DEFAULT_PROP_DEVICE_FD,
          G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_FLAGS,
      g_param_spec_flags ("flags", "Flags", "Device type flags",
          GST_TYPE_V4L2_DEVICE_FLAGS, DEFAULT_PROP_FLAGS,
          G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));

  /**
   * GstV4l2Src:brightness:
   *
   * Picture brightness, or more precisely, the black level
   */
  g_object_class_install_property (gobject_class, PROP_BRIGHTNESS,
      g_param_spec_int ("brightness", "Brightness",
          "Picture brightness, or more precisely, the black level", G_MININT,
          G_MAXINT, 0,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | GST_PARAM_CONTROLLABLE));
  /**
   * GstV4l2Src:contrast:
   *
   * Picture contrast or luma gain
   */
  g_object_class_install_property (gobject_class, PROP_CONTRAST,
      g_param_spec_int ("contrast", "Contrast",
          "Picture contrast or luma gain", G_MININT,
          G_MAXINT, 0,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | GST_PARAM_CONTROLLABLE));
  /**
   * GstV4l2Src:saturation:
   *
   * Picture color saturation or chroma gain
   */
  g_object_class_install_property (gobject_class, PROP_SATURATION,
      g_param_spec_int ("saturation", "Saturation",
          "Picture color saturation or chroma gain", G_MININT,
          G_MAXINT, 0,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | GST_PARAM_CONTROLLABLE));
  /**
   * GstV4l2Src:hue:
   *
   * Hue or color balance
   */
  g_object_class_install_property (gobject_class, PROP_HUE,
      g_param_spec_int ("hue", "Hue",
          "Hue or color balance", G_MININT,
          G_MAXINT, 0,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | GST_PARAM_CONTROLLABLE));

  /**
   * GstV4l2Src:norm:
   *
   * TV norm
   */
  g_object_class_install_property (gobject_class, PROP_TV_NORM,
      g_param_spec_enum ("norm", "TV norm",
          "video standard",
          GST_TYPE_V4L2_TV_NORM, DEFAULT_PROP_TV_NORM,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  /**
   * GstV4l2Src:io-mode:
   *
   * IO Mode
   */
  g_object_class_install_property (gobject_class, PROP_IO_MODE,
      g_param_spec_enum ("io-mode", "IO mode",
          "I/O mode",
          GST_TYPE_V4L2_IO_MODE, DEFAULT_PROP_IO_MODE,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  /**
   * GstV4l2Src:extra-controls:
   *
   * Additional v4l2 controls for the device. The controls are identified
   * by the control name (lowercase with '_' for any non-alphanumeric
   * characters).
   *
   * Since: 1.2
   */
  g_object_class_install_property (gobject_class, PROP_EXTRA_CONTROLS,
      g_param_spec_boxed ("extra-controls", "Extra Controls",
          "Extra v4l2 controls (CIDs) for the device",
          GST_TYPE_STRUCTURE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  /**
   * GstV4l2Src:pixel-aspect-ratio:
   *
   * The pixel aspect ratio of the device. This overwrites the pixel aspect
   * ratio queried from the device.
   *
   * Since: 1.2
   */
  g_object_class_install_property (gobject_class, PROP_PIXEL_ASPECT_RATIO,
      g_param_spec_string ("pixel-aspect-ratio", "Pixel Aspect Ratio",
          "Overwrite the pixel aspect ratio of the device", "1/1",
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  /**
   * GstV4l2Src:force-aspect-ratio:
   *
   * When enabled, the pixel aspect ratio queried from the device or set
   * with the pixel-aspect-ratio property will be enforced.
   *
   * Since: 1.2
   */
  g_object_class_install_property (gobject_class, PROP_FORCE_ASPECT_RATIO,
      g_param_spec_boolean ("force-aspect-ratio", "Force aspect ratio",
          "When enabled, the pixel aspect ratio will be enforced", TRUE,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

}

GstV4l2Object *
gst_v4l2_object_new (GstElement * element,
    enum v4l2_buf_type type,
    const char *default_device,
    GstV4l2GetInOutFunction get_in_out_func,
    GstV4l2SetInOutFunction set_in_out_func,
    GstV4l2UpdateFpsFunction update_fps_func)
{
  GstV4l2Object *v4l2object;

  /*
   * some default values
   */
  v4l2object = g_new0 (GstV4l2Object, 1);

  v4l2object->type = type;
  v4l2object->formats = NULL;

  v4l2object->element = element;
  v4l2object->get_in_out_func = get_in_out_func;
  v4l2object->set_in_out_func = set_in_out_func;
  v4l2object->update_fps_func = update_fps_func;

  v4l2object->video_fd = -1;
  v4l2object->poll = gst_poll_new (TRUE);
  v4l2object->active = FALSE;
  v4l2object->videodev = g_strdup (default_device);

  v4l2object->norms = NULL;
  v4l2object->channels = NULL;
  v4l2object->colors = NULL;

  v4l2object->xwindow_id = 0;

  v4l2object->keep_aspect = TRUE;

  v4l2object->n_v4l2_planes = 0;

  /*
   * this boolean only applies in v4l2-MPLANE mode.
   * TRUE: means it prefers to use several v4l2 (non contiguous)
   * planes. For example if the device supports NV12 and NV12M
   * both in MPLANE mode, then it will prefer NV12M
   * FALSE: means it prefers to use one v4l2 plane (which contains
   * all gst planes as if it was working in non-v4l2-MPLANE mode.
   * For example if the device supports NV12 and NV12M
   * both in MPLANE mode, then it will prefer NV12
   *
   * this boolean is also used to manage the case where the
   * device only supports the mode MPLANE and at the same time it
   * does not support both NV12 and NV12M. So in this case we first
   * try to use the prefered config, and at least try the other case
   * if it fails. For example in MPLANE mode if it has NV12 and not
   * NV21M then even if you set prefered_non_contiguous to TRUE it will
   * try NV21 as well.
   */
  v4l2object->prefered_non_contiguous = TRUE;

  v4l2object->no_initial_format = FALSE;

  return v4l2object;
}

static gboolean gst_v4l2_object_clear_format_list (GstV4l2Object * v4l2object);


void
gst_v4l2_object_destroy (GstV4l2Object * v4l2object)
{
  g_return_if_fail (v4l2object != NULL);

  if (v4l2object->videodev)
    g_free (v4l2object->videodev);

  if (v4l2object->poll)
    gst_poll_free (v4l2object->poll);

  if (v4l2object->channel)
    g_free (v4l2object->channel);

  if (v4l2object->formats) {
    gst_v4l2_object_clear_format_list (v4l2object);
  }

  if (v4l2object->probed_caps) {
    gst_caps_unref (v4l2object->probed_caps);
  }

  g_free (v4l2object);
}


static gboolean
gst_v4l2_object_clear_format_list (GstV4l2Object * v4l2object)
{
  g_slist_foreach (v4l2object->formats, (GFunc) g_free, NULL);
  g_slist_free (v4l2object->formats);
  v4l2object->formats = NULL;

  return TRUE;
}

static gint
gst_v4l2_object_prop_to_cid (guint prop_id)
{
  gint cid = -1;

  switch (prop_id) {
    case PROP_BRIGHTNESS:
      cid = V4L2_CID_BRIGHTNESS;
      break;
    case PROP_CONTRAST:
      cid = V4L2_CID_CONTRAST;
      break;
    case PROP_SATURATION:
      cid = V4L2_CID_SATURATION;
      break;
    case PROP_HUE:
      cid = V4L2_CID_HUE;
      break;
    default:
      GST_WARNING ("unmapped property id: %d", prop_id);
  }
  return cid;
}


gboolean
gst_v4l2_object_set_property_helper (GstV4l2Object * v4l2object,
    guint prop_id, const GValue * value, GParamSpec * pspec)
{
  switch (prop_id) {
    case PROP_DEVICE:
      g_free (v4l2object->videodev);
      v4l2object->videodev = g_value_dup_string (value);
      break;
    case PROP_BRIGHTNESS:
    case PROP_CONTRAST:
    case PROP_SATURATION:
    case PROP_HUE:
    {
      gint cid = gst_v4l2_object_prop_to_cid (prop_id);

      if (cid != -1) {
        if (GST_V4L2_IS_OPEN (v4l2object)) {
          gst_v4l2_set_attribute (v4l2object, cid, g_value_get_int (value));
        }
      }
      return TRUE;
    }
      break;
    case PROP_TV_NORM:
      v4l2object->tv_norm = g_value_get_enum (value);
      break;
#if 0
    case PROP_CHANNEL:
      if (GST_V4L2_IS_OPEN (v4l2object)) {
        GstTuner *tuner = GST_TUNER (v4l2object->element);
        GstTunerChannel *channel = gst_tuner_find_channel_by_name (tuner,
            (gchar *) g_value_get_string (value));

        if (channel) {
          /* like gst_tuner_set_channel (tuner, channel)
             without g_object_notify */
          gst_v4l2_tuner_set_channel (v4l2object, channel);
        }
      } else {
        g_free (v4l2object->channel);
        v4l2object->channel = g_value_dup_string (value);
      }
      break;
    case PROP_FREQUENCY:
      if (GST_V4L2_IS_OPEN (v4l2object)) {
        GstTuner *tuner = GST_TUNER (v4l2object->element);
        GstTunerChannel *channel = gst_tuner_get_channel (tuner);

        if (channel &&
            GST_TUNER_CHANNEL_HAS_FLAG (channel, GST_TUNER_CHANNEL_FREQUENCY)) {
          /* like
             gst_tuner_set_frequency (tuner, channel, g_value_get_ulong (value))
             without g_object_notify */
          gst_v4l2_tuner_set_frequency (v4l2object, channel,
              g_value_get_ulong (value));
        }
      } else {
        v4l2object->frequency = g_value_get_ulong (value);
      }
      break;
#endif
    case PROP_IO_MODE:
      v4l2object->req_mode = g_value_get_enum (value);
      break;
    case PROP_EXTRA_CONTROLS:{
      const GstStructure *s = gst_value_get_structure (value);

      if (v4l2object->extra_controls)
        gst_structure_free (v4l2object->extra_controls);

      v4l2object->extra_controls = s ? gst_structure_copy (s) : NULL;
      if (GST_V4L2_IS_OPEN (v4l2object))
        gst_v4l2_set_controls (v4l2object, v4l2object->extra_controls);
      break;
    }
    case PROP_PIXEL_ASPECT_RATIO:
      g_free (v4l2object->par);
      v4l2object->par = g_new0 (GValue, 1);
      g_value_init (v4l2object->par, GST_TYPE_FRACTION);
      if (!g_value_transform (value, v4l2object->par)) {
        g_warning ("Could not transform string to aspect ratio");
        gst_value_set_fraction (v4l2object->par, 1, 1);
      }
      GST_DEBUG_OBJECT (v4l2object->element, "set PAR to %d/%d",
          gst_value_get_fraction_numerator (v4l2object->par),
          gst_value_get_fraction_denominator (v4l2object->par));
      break;
    case PROP_FORCE_ASPECT_RATIO:
      v4l2object->keep_aspect = g_value_get_boolean (value);
      break;
    default:
      return FALSE;
      break;
  }
  return TRUE;
}


gboolean
gst_v4l2_object_get_property_helper (GstV4l2Object * v4l2object,
    guint prop_id, GValue * value, GParamSpec * pspec)
{
  switch (prop_id) {
    case PROP_DEVICE:
      g_value_set_string (value, v4l2object->videodev);
      break;
    case PROP_DEVICE_NAME:
    {
      const guchar *new = NULL;

      if (GST_V4L2_IS_OPEN (v4l2object)) {
        new = v4l2object->vcap.card;
      } else if (gst_v4l2_open (v4l2object)) {
        new = v4l2object->vcap.card;
        gst_v4l2_close (v4l2object);
      }
      g_value_set_string (value, (gchar *) new);
      break;
    }
    case PROP_DEVICE_FD:
    {
      if (GST_V4L2_IS_OPEN (v4l2object))
        g_value_set_int (value, v4l2object->video_fd);
      else
        g_value_set_int (value, DEFAULT_PROP_DEVICE_FD);
      break;
    }
    case PROP_FLAGS:
    {
      guint flags = 0;

      if (GST_V4L2_IS_OPEN (v4l2object)) {
        flags |= v4l2object->vcap.capabilities &
            (V4L2_CAP_VIDEO_CAPTURE |
            V4L2_CAP_VIDEO_OUTPUT |
            V4L2_CAP_VIDEO_OVERLAY |
            V4L2_CAP_VBI_CAPTURE |
            V4L2_CAP_VBI_OUTPUT | V4L2_CAP_TUNER | V4L2_CAP_AUDIO);

        if (v4l2object->vcap.capabilities & V4L2_CAP_VIDEO_CAPTURE_MPLANE)
          flags |= V4L2_CAP_VIDEO_CAPTURE;

        if (v4l2object->vcap.capabilities & V4L2_CAP_VIDEO_OUTPUT_MPLANE)
          flags |= V4L2_CAP_VIDEO_OUTPUT;
      }
      g_value_set_flags (value, flags);
      break;
    }
    case PROP_BRIGHTNESS:
    case PROP_CONTRAST:
    case PROP_SATURATION:
    case PROP_HUE:
    {
      gint cid = gst_v4l2_object_prop_to_cid (prop_id);

      if (cid != -1) {
        if (GST_V4L2_IS_OPEN (v4l2object)) {
          gint v;
          if (gst_v4l2_get_attribute (v4l2object, cid, &v)) {
            g_value_set_int (value, v);
          }
        }
      }
      return TRUE;
    }
      break;
    case PROP_TV_NORM:
      g_value_set_enum (value, v4l2object->tv_norm);
      break;
    case PROP_IO_MODE:
      g_value_set_enum (value, v4l2object->req_mode);
      break;
    case PROP_EXTRA_CONTROLS:
      gst_value_set_structure (value, v4l2object->extra_controls);
      break;
    case PROP_PIXEL_ASPECT_RATIO:
      if (v4l2object->par)
        g_value_transform (v4l2object->par, value);
      break;
    case PROP_FORCE_ASPECT_RATIO:
      g_value_set_boolean (value, v4l2object->keep_aspect);
      break;
    default:
      return FALSE;
      break;
  }
  return TRUE;
}

static void
gst_v4l2_set_defaults (GstV4l2Object * v4l2object)
{
  GstTunerNorm *norm = NULL;
  GstTunerChannel *channel = NULL;
  GstTuner *tuner;

  if (!GST_IS_TUNER (v4l2object->element))
    return;

  tuner = GST_TUNER (v4l2object->element);

  if (v4l2object->tv_norm)
    norm = gst_v4l2_tuner_get_norm_by_std_id (v4l2object, v4l2object->tv_norm);
  GST_DEBUG_OBJECT (v4l2object->element, "tv_norm=0x%" G_GINT64_MODIFIER "x, "
      "norm=%p", (guint64) v4l2object->tv_norm, norm);
  if (norm) {
    gst_tuner_set_norm (tuner, norm);
  } else {
    norm =
        GST_TUNER_NORM (gst_tuner_get_norm (GST_TUNER (v4l2object->element)));
    if (norm) {
      v4l2object->tv_norm =
          gst_v4l2_tuner_get_std_id_by_norm (v4l2object, norm);
      gst_tuner_norm_changed (tuner, norm);
    }
  }

  if (v4l2object->channel)
    channel = gst_tuner_find_channel_by_name (tuner, v4l2object->channel);
  if (channel) {
    gst_tuner_set_channel (tuner, channel);
  } else {
    channel =
        GST_TUNER_CHANNEL (gst_tuner_get_channel (GST_TUNER
            (v4l2object->element)));
    if (channel) {
      g_free (v4l2object->channel);
      v4l2object->channel = g_strdup (channel->label);
      gst_tuner_channel_changed (tuner, channel);
    }
  }

  if (channel
      && GST_TUNER_CHANNEL_HAS_FLAG (channel, GST_TUNER_CHANNEL_FREQUENCY)) {
    if (v4l2object->frequency != 0) {
      gst_tuner_set_frequency (tuner, channel, v4l2object->frequency);
    } else {
      v4l2object->frequency = gst_tuner_get_frequency (tuner, channel);
      if (v4l2object->frequency == 0) {
        /* guess */
        gst_tuner_set_frequency (tuner, channel, 1000);
      } else {
      }
    }
  }
}

gboolean
gst_v4l2_object_open (GstV4l2Object * v4l2object)
{
  if (gst_v4l2_open (v4l2object))
    gst_v4l2_set_defaults (v4l2object);
  else
    return FALSE;

#ifdef HAVE_XVIDEO
  gst_v4l2_video_overlay_start (v4l2object);
#endif

  return TRUE;
}

gboolean
gst_v4l2_object_open_shared (GstV4l2Object * v4l2object, GstV4l2Object * other)
{
  gboolean ret;

  ret = gst_v4l2_dup (v4l2object, other);

#ifdef HAVE_XVIDEO
  gst_v4l2_video_overlay_start (v4l2object);
#endif

  return ret;
}

gboolean
gst_v4l2_object_close (GstV4l2Object * v4l2object)
{
#ifdef HAVE_XVIDEO
  gst_v4l2_video_overlay_stop (v4l2object);
#endif

  if (!gst_v4l2_close (v4l2object))
    return FALSE;

  gst_caps_replace (&v4l2object->probed_caps, NULL);

  if (v4l2object->formats) {
    gst_v4l2_object_clear_format_list (v4l2object);
  }

  return TRUE;
}


/*
 * common format / caps utilities:
 */
typedef enum
{
  GST_V4L2_RAW = 1 << 0,
  GST_V4L2_CODEC = 1 << 1,
  GST_V4L2_TRANSPORT = 1 << 2,
  GST_V4L2_ALL = 0xffff
} GstV4L2FormatFlags;

typedef struct
{
  guint32 format;
  gboolean dimensions;
  GstV4L2FormatFlags flags;
} GstV4L2FormatDesc;

static const GstV4L2FormatDesc gst_v4l2_formats[] = {
  /* from Linux 2.6.15 videodev2.h */
  {V4L2_PIX_FMT_RGB332, TRUE, GST_V4L2_RAW},
  {V4L2_PIX_FMT_RGB555, TRUE, GST_V4L2_RAW},
  {V4L2_PIX_FMT_RGB565, TRUE, GST_V4L2_RAW},
  {V4L2_PIX_FMT_RGB555X, TRUE, GST_V4L2_RAW},
  {V4L2_PIX_FMT_RGB565X, TRUE, GST_V4L2_RAW},
  {V4L2_PIX_FMT_BGR24, TRUE, GST_V4L2_RAW},
  {V4L2_PIX_FMT_RGB24, TRUE, GST_V4L2_RAW},
  {V4L2_PIX_FMT_BGR32, TRUE, GST_V4L2_RAW},
  {V4L2_PIX_FMT_RGB32, TRUE, GST_V4L2_RAW},