gstreamer/sys/v4l2/gstv4l2.c

/* GStreamer
 *
 * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
 *               2006 Edgard Lima <edgard.lima@gmail.com>
 *
 * gstv4l2.c: plugin 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.
 */

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

#ifndef _GNU_SOURCE
# define _GNU_SOURCE            /* O_CLOEXEC */
#endif

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

#include <gst/gst.h>

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

#include "ext/videodev2.h"
#include "v4l2-utils.h"

#include "gstv4l2object.h"
#include "gstv4l2src.h"
#include "gstv4l2sink.h"
#include "gstv4l2radio.h"
#include "gstv4l2videodec.h"
#include "gstv4l2deviceprovider.h"
#include "gstv4l2transform.h"

/* used in v4l2_calls.c and v4l2src_calls.c */
GST_DEBUG_CATEGORY (v4l2_debug);
#define GST_CAT_DEFAULT v4l2_debug

#ifdef GST_V4L2_ENABLE_PROBE
/* This is a minimalist probe, for speed, we only enumerate formats */
static GstCaps *
gst_v4l2_probe_template_caps (const gchar * device, gint video_fd,
    enum v4l2_buf_type type)
{
  gint n;
  struct v4l2_fmtdesc format;
  GstCaps *caps;

  GST_DEBUG ("Getting %s format enumerations", device);
  caps = gst_caps_new_empty ();

  for (n = 0;; n++) {
    GstStructure *template;

    memset (&format, 0, sizeof (format));

    format.index = n;
    format.type = type;

    if (ioctl (video_fd, VIDIOC_ENUM_FMT, &format) < 0)
      break;                    /* end of enumeration */

    GST_LOG ("index:       %u", format.index);
    GST_LOG ("type:        %d", format.type);
    GST_LOG ("flags:       %08x", format.flags);
    GST_LOG ("description: '%s'", format.description);
    GST_LOG ("pixelformat: %" GST_FOURCC_FORMAT,
        GST_FOURCC_ARGS (format.pixelformat));

    template = gst_v4l2_object_v4l2fourcc_to_structure (format.pixelformat);

    if (template) {
      GstStructure *alt_t = NULL;

      switch (format.pixelformat) {
        case V4L2_PIX_FMT_RGB32:
          alt_t = gst_structure_copy (template);
          gst_structure_set (alt_t, "format", G_TYPE_STRING, "ARGB", NULL);
          break;
        case V4L2_PIX_FMT_BGR32:
          alt_t = gst_structure_copy (template);
          gst_structure_set (alt_t, "format", G_TYPE_STRING, "BGRA", NULL);
        default:
          break;
      }

      gst_caps_append_structure (caps, template);

      if (alt_t)
        gst_caps_append_structure (caps, alt_t);
    }
  }

  return gst_caps_simplify (caps);
}

static gboolean
gst_v4l2_probe_and_register (GstPlugin * plugin)
{
  GstV4l2Iterator *it;
  gint video_fd = -1;
  struct v4l2_capability vcap;
  gboolean ret = TRUE;
  guint32 device_caps;

  it = gst_v4l2_iterator_new ();

  while (gst_v4l2_iterator_next (it)) {
    GstCaps *src_caps, *sink_caps;
    gchar *basename;

    if (video_fd >= 0)
      close (video_fd);

    video_fd = open (it->device_path, O_RDWR | O_CLOEXEC);

    if (video_fd == -1) {
      GST_DEBUG ("Failed to open %s: %s", it->device_path, g_strerror (errno));
      continue;
    }

    memset (&vcap, 0, sizeof (vcap));

    if (ioctl (video_fd, VIDIOC_QUERYCAP, &vcap) < 0) {
      GST_DEBUG ("Failed to get device capabilities: %s", g_strerror (errno));
      continue;
    }

    if (vcap.capabilities & V4L2_CAP_DEVICE_CAPS)
      device_caps = vcap.device_caps;
    else
      device_caps = vcap.capabilities;

    if (!((device_caps & (V4L2_CAP_VIDEO_M2M | V4L2_CAP_VIDEO_M2M_MPLANE)) ||
            /* But legacy driver may expose both CAPTURE and OUTPUT */
            ((device_caps &
                    (V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_VIDEO_CAPTURE_MPLANE)) &&
                (device_caps &
                    (V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_VIDEO_OUTPUT_MPLANE)))))
      continue;

    GST_DEBUG ("Probing '%s' located at '%s'",
        it->device_name ? it->device_name : (const gchar *) vcap.driver,
        it->device_path);

    /* get sink supported format (no MPLANE for codec) */
    sink_caps = gst_caps_merge (gst_v4l2_probe_template_caps (it->device_path,
            video_fd, V4L2_BUF_TYPE_VIDEO_OUTPUT),
        gst_v4l2_probe_template_caps (it->device_path, video_fd,
            V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE));

    /* get src supported format */
    src_caps = gst_caps_merge (gst_v4l2_probe_template_caps (it->device_path,
            video_fd, V4L2_BUF_TYPE_VIDEO_CAPTURE),
        gst_v4l2_probe_template_caps (it->device_path, video_fd,
            V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE));

    /* Skip devices without any supported formats */
    if (gst_caps_is_empty (sink_caps) || gst_caps_is_empty (src_caps)) {
      gst_caps_unref (sink_caps);
      gst_caps_unref (src_caps);
      continue;
    }

    basename = g_path_get_basename (it->device_path);

    if (gst_v4l2_is_video_dec (sink_caps, src_caps))
      ret = gst_v4l2_video_dec_register (plugin, basename, it->device_path,
          sink_caps, src_caps);
    else if (gst_v4l2_is_transform (sink_caps, src_caps))
      ret = gst_v4l2_transform_register (plugin, basename, it->device_path,
          sink_caps, src_caps);
    /* else if ( ... etc. */

    gst_caps_unref (sink_caps);
    gst_caps_unref (src_caps);
    g_free (basename);

    if (!ret)
      break;
  }

  if (video_fd >= 0)
    close (video_fd);

  gst_v4l2_iterator_free (it);

  return ret;
}
#endif

static gboolean
plugin_init (GstPlugin * plugin)
{
  const gchar *paths[] = { "/dev", "/dev/v4l2", NULL };
  const gchar *names[] = { "video", NULL };

  GST_DEBUG_CATEGORY_INIT (v4l2_debug, "v4l2", 0, "V4L2 API calls");

  /* Add some depedency, so the dynamic features get updated upon changes in
   * /dev/video* */
  gst_plugin_add_dependency (plugin,
      NULL, paths, names, GST_PLUGIN_DEPENDENCY_FLAG_FILE_NAME_IS_PREFIX);

  if (!gst_element_register (plugin, "v4l2src", GST_RANK_PRIMARY,
          GST_TYPE_V4L2SRC) ||
      !gst_element_register (plugin, "v4l2sink", GST_RANK_NONE,
          GST_TYPE_V4L2SINK) ||
      !gst_element_register (plugin, "v4l2radio", GST_RANK_NONE,
          GST_TYPE_V4L2RADIO) ||
      !gst_device_provider_register (plugin, "v4l2deviceprovider",
          GST_RANK_PRIMARY, GST_TYPE_V4L2_DEVICE_PROVIDER)
      /* etc. */
#ifdef GST_V4L2_ENABLE_PROBE
      || !gst_v4l2_probe_and_register (plugin)
#endif
      )
    return FALSE;

#ifdef ENABLE_NLS
  bindtextdomain (GETTEXT_PACKAGE, LOCALEDIR);
  bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
#endif /* ENABLE_NLS */

  return TRUE;
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    video4linux2,
    "elements for Video 4 Linux",
    plugin_init, VERSION, GST_LICENSE, GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN)