gstreamer/sys/v4l/gstv4lsrc.c
Andy Wingo 1049c792c8 removal of //-style comments don't link plugins to core libs -- the versioning is done internally to the plugins with...
Original commit message from CVS:
* removal of //-style comments
* don't link plugins to core libs -- the versioning is done internally to the plugins with the plugin_info struct,
and symbol resolution is lazy, so we can always know if a plugin can be loaded by the plugin_info data. in theory.
2002-03-19 04:10:06 +00:00

682 lines
22 KiB
C

/* G-Streamer BT8x8/V4L frame grabber plugin
* Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
*
* 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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <string.h>
#include <sys/time.h>
#include "v4lsrc_calls.h"
static GstElementDetails gst_v4lsrc_details = {
"Video (video4linux/raw) Source",
"Source/Video",
"Reads raw frames from a video4linux (BT8x8) device",
VERSION,
"Ronald Bultje <rbultje@ronald.bitfreak.net>",
"(C) 2001",
};
/* V4lSrc signals and args */
enum {
/* FILL ME */
LAST_SIGNAL
};
/* arguments */
enum {
ARG_0,
ARG_WIDTH,
ARG_HEIGHT,
ARG_PALETTE,
ARG_PALETTE_NAME,
ARG_NUMBUFS,
ARG_BUFSIZE
};
/* init functions */
static void gst_v4lsrc_class_init (GstV4lSrcClass *klass);
static void gst_v4lsrc_init (GstV4lSrc *v4lsrc);
/* pad/buffer functions */
static GstPadConnectReturn gst_v4lsrc_srcconnect (GstPad *pad,
GstCaps *caps);
static GstBuffer* gst_v4lsrc_get (GstPad *pad);
/* get/set params */
static void gst_v4lsrc_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec);
static void gst_v4lsrc_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec);
/* state handling */
static GstElementStateReturn gst_v4lsrc_change_state (GstElement *element);
/* bufferpool functions */
static GstBuffer* gst_v4lsrc_buffer_new (GstBufferPool *pool,
gint64 location,
gint size,
gpointer user_data);
static GstBuffer* gst_v4lsrc_buffer_copy (GstBuffer *srcbuf);
static void gst_v4lsrc_buffer_free (GstBuffer *buf);
static GstCaps *capslist = NULL;
static GstPadTemplate *src_template;
static GstElementClass *parent_class = NULL;\
/*static guint gst_v4lsrc_signals[LAST_SIGNAL] = { 0 }; */
GType
gst_v4lsrc_get_type (void)
{
static GType v4lsrc_type = 0;
if (!v4lsrc_type) {
static const GTypeInfo v4lsrc_info = {
sizeof(GstV4lSrcClass),
NULL,
NULL,
(GClassInitFunc)gst_v4lsrc_class_init,
NULL,
NULL,
sizeof(GstV4lSrc),
0,
(GInstanceInitFunc)gst_v4lsrc_init,
NULL
};
v4lsrc_type = g_type_register_static(GST_TYPE_V4LELEMENT, "GstV4lSrc", &v4lsrc_info, 0);
}
return v4lsrc_type;
}
static void
gst_v4lsrc_class_init (GstV4lSrcClass *klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
gobject_class = (GObjectClass*)klass;
gstelement_class = (GstElementClass*)klass;
parent_class = g_type_class_ref(GST_TYPE_V4LELEMENT);
g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_WIDTH,
g_param_spec_int("width","width","width",
G_MININT,G_MAXINT,0,G_PARAM_READWRITE));
g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_HEIGHT,
g_param_spec_int("height","height","height",
G_MININT,G_MAXINT,0,G_PARAM_READWRITE));
g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_PALETTE,
g_param_spec_int("palette","palette","palette",
G_MININT,G_MAXINT,0,G_PARAM_READWRITE));
g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_PALETTE_NAME,
g_param_spec_string("palette_name","palette_name","palette_name",
NULL, G_PARAM_READABLE));
g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_NUMBUFS,
g_param_spec_int("num_buffers","num_buffers","num_buffers",
G_MININT,G_MAXINT,0,G_PARAM_READABLE));
g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_BUFSIZE,
g_param_spec_int("buffer_size","buffer_size","buffer_size",
G_MININT,G_MAXINT,0,G_PARAM_READABLE));
gobject_class->set_property = gst_v4lsrc_set_property;
gobject_class->get_property = gst_v4lsrc_get_property;
gstelement_class->change_state = gst_v4lsrc_change_state;
}
static void
gst_v4lsrc_init (GstV4lSrc *v4lsrc)
{
v4lsrc->srcpad = gst_pad_new_from_template (src_template, "src");
gst_element_add_pad(GST_ELEMENT(v4lsrc), v4lsrc->srcpad);
gst_pad_set_get_function (v4lsrc->srcpad, gst_v4lsrc_get);
gst_pad_set_connect_function (v4lsrc->srcpad, gst_v4lsrc_srcconnect);
v4lsrc->bufferpool = gst_buffer_pool_new();
gst_buffer_pool_set_buffer_new_function(v4lsrc->bufferpool, gst_v4lsrc_buffer_new);
gst_buffer_pool_set_buffer_copy_function(v4lsrc->bufferpool, gst_v4lsrc_buffer_copy);
gst_buffer_pool_set_buffer_free_function(v4lsrc->bufferpool, gst_v4lsrc_buffer_free);
gst_buffer_pool_set_user_data(v4lsrc->bufferpool, v4lsrc);
v4lsrc->palette = 0; /* means 'any' - user can specify a specific palette */
v4lsrc->width = 160;
v4lsrc->height = 120;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 1.5;
v4lsrc->capslist = capslist;
}
static GstPadConnectReturn
gst_v4lsrc_srcconnect (GstPad *pad,
GstCaps *vscapslist)
{
GstV4lSrc *v4lsrc;
GstCaps *caps, *newcaps;
gint palette;
v4lsrc = GST_V4LSRC (gst_pad_get_parent (pad));
palette = v4lsrc->palette;
/* TODO: caps = gst_caps_normalize(capslist); */
for (caps = vscapslist ; caps != NULL ; caps = vscapslist = vscapslist->next)
{
if (v4lsrc->palette > 0)
{
switch (v4lsrc->palette)
{
case VIDEO_PALETTE_YUV420P:
if (gst_caps_get_fourcc_int (caps, "format") != GST_MAKE_FOURCC('I','4','2','0') &&
gst_caps_get_fourcc_int (caps, "format") != GST_MAKE_FOURCC('I','Y','U','V'))
goto try_next;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 1.5;
goto try_caps;
case VIDEO_PALETTE_YUV422:
case VIDEO_PALETTE_YUYV:
if (gst_caps_get_fourcc_int (caps, "format") != GST_MAKE_FOURCC('Y','U','Y','2'))
goto try_next;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 2;
goto try_caps;
case VIDEO_PALETTE_UYVY:
if (gst_caps_get_fourcc_int (caps, "format") != GST_MAKE_FOURCC('U','Y','V','Y'))
goto try_next;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 2;
goto try_caps;
case VIDEO_PALETTE_YUV411:
if (gst_caps_get_fourcc_int (caps, "format") != GST_MAKE_FOURCC('Y','4','1','P'))
goto try_next;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 1.5;
goto try_caps;
case VIDEO_PALETTE_RGB555:
if (gst_caps_get_fourcc_int (caps, "format") != GST_MAKE_FOURCC('R','G','B',' ') ||
gst_caps_get_int(caps, "depth") != 15)
goto try_next;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 2;
goto try_caps;
case VIDEO_PALETTE_RGB565:
if (gst_caps_get_fourcc_int (caps, "format") != GST_MAKE_FOURCC('R','G','B',' ') ||
gst_caps_get_int(caps, "depth") != 16)
goto try_next;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 2;
goto try_caps;
case VIDEO_PALETTE_RGB24:
if (gst_caps_get_fourcc_int (caps, "format") != GST_MAKE_FOURCC('R','G','B',' ') ||
gst_caps_get_int(caps, "depth") != 24)
goto try_next;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 3;
goto try_caps;
case VIDEO_PALETTE_RGB32:
if (gst_caps_get_fourcc_int (caps, "format") != GST_MAKE_FOURCC('R','G','B',' ') ||
gst_caps_get_int(caps, "depth") != 32)
goto try_next;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 4;
goto try_caps;
default:
goto try_next;
}
}
else
{
switch (gst_caps_get_fourcc_int(caps, "format"))
{
case GST_MAKE_FOURCC('I','4','2','0'):
case GST_MAKE_FOURCC('I','Y','U','V'):
palette = VIDEO_PALETTE_YUV420P;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 1.5;
goto try_caps;
case GST_MAKE_FOURCC('Y','U','Y','2'):
palette = VIDEO_PALETTE_YUV422;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 2;
goto try_caps;
case GST_MAKE_FOURCC('U','Y','V','Y'):
palette = VIDEO_PALETTE_UYVY;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 2;
goto try_caps;
case GST_MAKE_FOURCC('Y','4','1','P'):
palette = VIDEO_PALETTE_YUV411;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 1.5;
goto try_caps;
case GST_MAKE_FOURCC('R','G','B',' '):
switch (gst_caps_get_int(caps, "depth"))
{
case 15:
palette = VIDEO_PALETTE_RGB555;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 2;
goto try_caps;
case 16:
palette = VIDEO_PALETTE_RGB565;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 2;
goto try_caps;
case 24:
palette = VIDEO_PALETTE_RGB24;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 3;
goto try_caps;
case 32:
palette = VIDEO_PALETTE_RGB32;
v4lsrc->buffer_size = v4lsrc->width * v4lsrc->height * 4;
goto try_caps;
default:
goto try_next;
}
default:
goto try_next;
}
}
/* if this caps wasn't useful, try the next one */
try_next:
continue;
/* if this caps was useful, try it out */
try_caps:
/* TODO: try the current 'palette' out on the video device */
if (!gst_v4lsrc_set_capture(v4lsrc, v4lsrc->width, v4lsrc->height, palette))
continue;
/* try to connect the pad/caps with the actual width/height */
if (palette >= VIDEO_PALETTE_RGB565 && palette <= VIDEO_PALETTE_RGB555)
newcaps = gst_caps_new("v4lsrc_caps",
"video/raw",
gst_props_new(
"format", GST_PROPS_FOURCC(gst_caps_get_fourcc_int(caps, "format")),
"width", GST_PROPS_INT(v4lsrc->width),
"height", GST_PROPS_INT(v4lsrc->height),
"bpp", GST_PROPS_INT(gst_caps_get_int(caps, "bpp")),
"depth", GST_PROPS_INT(gst_caps_get_int(caps, "depth")),
NULL ) );
else
newcaps = gst_caps_new("v4lsrc_caps",
"video/raw",
gst_props_new(
"format", GST_PROPS_FOURCC(gst_caps_get_fourcc_int(caps, "format")),
"width", GST_PROPS_INT(v4lsrc->width),
"height", GST_PROPS_INT(v4lsrc->height),
NULL ) );
gst_caps_debug (newcaps, "new caps to set on v4lsrc's src pad");
if (!gst_pad_try_set_caps(v4lsrc->srcpad, newcaps))
continue;
else
return GST_PAD_CONNECT_OK;
}
/* still nothing - no good caps */
return GST_PAD_CONNECT_REFUSED;
}
static GstBuffer*
gst_v4lsrc_get (GstPad *pad)
{
GstV4lSrc *v4lsrc;
GstBuffer *buf;
gint num;
g_return_val_if_fail (pad != NULL, NULL);
v4lsrc = GST_V4LSRC (gst_pad_get_parent (pad));
buf = gst_buffer_new_from_pool(v4lsrc->bufferpool, 0, 0);
if (!buf)
{
gst_element_error(GST_ELEMENT(v4lsrc),
"Failed to create a new GstBuffer");
return NULL;
}
/* grab a frame from the device */
if (!gst_v4lsrc_grab_frame(v4lsrc, &num))
return NULL;
GST_BUFFER_DATA(buf) = gst_v4lsrc_get_buffer(v4lsrc, num);
GST_BUFFER_SIZE(buf) = v4lsrc->buffer_size;
buf->timestamp = v4lsrc->timestamp_soft_sync[num].tv_sec * 1000000000 +
v4lsrc->timestamp_soft_sync[num].tv_usec * 1000;
return buf;
}
static void
gst_v4lsrc_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GstV4lSrc *v4lsrc;
g_return_if_fail(GST_IS_V4LSRC(object));
v4lsrc = GST_V4LSRC(object);
switch (prop_id) {
case ARG_WIDTH:
v4lsrc->width = g_value_get_int(value);
break;
case ARG_HEIGHT:
v4lsrc->height = g_value_get_int(value);
break;
case ARG_PALETTE:
v4lsrc->palette = g_value_get_int(value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_v4lsrc_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GstV4lSrc *v4lsrc;
g_return_if_fail(GST_IS_V4LSRC(object));
v4lsrc = GST_V4LSRC(object);
switch (prop_id) {
case ARG_WIDTH:
g_value_set_int(value, v4lsrc->mmap.width);
break;
case ARG_HEIGHT:
g_value_set_int(value, v4lsrc->mmap.height);
break;
case ARG_PALETTE:
g_value_set_int(value, v4lsrc->mmap.format);
break;
case ARG_PALETTE_NAME:
g_value_set_string(value, g_strdup(palette_name[v4lsrc->mmap.format]));
break;
case ARG_NUMBUFS:
g_value_set_int(value, v4lsrc->mbuf.frames);
break;
case ARG_BUFSIZE:
g_value_set_int(value, v4lsrc->mbuf.size/(v4lsrc->mbuf.frames*1024));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static GstElementStateReturn
gst_v4lsrc_change_state (GstElement *element)
{
GstV4lSrc *v4lsrc;
GstElementStateReturn parent_value;
gint transition = GST_STATE_TRANSITION (element);
guint32 fourcc;
gint depth=0, bpp=0;
GstCaps *caps;
g_return_val_if_fail(GST_IS_V4LSRC(element), GST_STATE_FAILURE);
v4lsrc = GST_V4LSRC(element);
switch (transition) {
case GST_STATE_NULL_TO_READY:
break;
case GST_STATE_READY_TO_PAUSED:
/* extremely ugly hack for a weird behaviour in the capsnego system - try capsnego again */
switch (v4lsrc->mmap.format)
{
case VIDEO_PALETTE_RGB555:
fourcc = GST_MAKE_FOURCC('R','G','B',' ');
bpp = 16;
depth = 15;
break;
case VIDEO_PALETTE_RGB565:
fourcc = GST_MAKE_FOURCC('R','G','B',' ');
bpp = 16;
depth = 16;
break;
case VIDEO_PALETTE_RGB24:
fourcc = GST_MAKE_FOURCC('R','G','B',' ');
bpp = 24;
depth = 24;
break;
case VIDEO_PALETTE_RGB32:
fourcc = GST_MAKE_FOURCC('R','G','B',' ');
bpp = 32;
depth = 32;
break;
case VIDEO_PALETTE_YUV411:
fourcc = GST_MAKE_FOURCC('Y','4','1','P');
break;
case VIDEO_PALETTE_YUV422:
fourcc = GST_MAKE_FOURCC('Y','U','Y','2');
break;
case VIDEO_PALETTE_YUV420P:
fourcc = GST_MAKE_FOURCC('I','4','2','0');
break;
case VIDEO_PALETTE_UYVY:
fourcc = GST_MAKE_FOURCC('U','Y','V','Y');
break;
}
if (bpp && depth)
caps = gst_caps_new("v4lsrc_caps",
"video/raw",
gst_props_new(
"format", GST_PROPS_FOURCC(fourcc),
"width", GST_PROPS_INT(v4lsrc->width),
"height", GST_PROPS_INT(v4lsrc->height),
"bpp", GST_PROPS_INT(bpp),
"depth", GST_PROPS_INT(depth),
NULL ) );
else
caps = gst_caps_new("v4lsrc_caps",
"video/raw",
gst_props_new(
"format", GST_PROPS_FOURCC(fourcc),
"width", GST_PROPS_INT(v4lsrc->width),
"height", GST_PROPS_INT(v4lsrc->height),
NULL ) );
if (!gst_pad_try_set_caps(v4lsrc->srcpad, caps))
return GST_STATE_FAILURE;
if (!gst_v4lsrc_capture_init(v4lsrc))
return GST_STATE_FAILURE;
break;
case GST_STATE_PAUSED_TO_PLAYING:
/* queue all buffer, start streaming capture */
if (!gst_v4lsrc_capture_start(v4lsrc))
return GST_STATE_FAILURE;
break;
case GST_STATE_PLAYING_TO_PAUSED:
/* de-queue all queued buffers */
if (!gst_v4lsrc_capture_stop(v4lsrc))
return GST_STATE_FAILURE;
break;
case GST_STATE_PAUSED_TO_READY:
/* stop capturing, unmap all buffers */
if (!gst_v4lsrc_capture_deinit(v4lsrc))
return GST_STATE_FAILURE;
break;
case GST_STATE_READY_TO_NULL:
break;
}
if (GST_ELEMENT_CLASS (parent_class)->change_state)
GST_ELEMENT_CLASS (parent_class)->change_state (element);
/* FIXME, this gives a not supported error on my machine?
switch (transition) {
case GST_STATE_NULL_TO_READY:
if ((GST_V4LELEMENT(v4lsrc)->norm >= VIDEO_MODE_PAL ||
GST_V4LELEMENT(v4lsrc)->norm < VIDEO_MODE_AUTO) ||
GST_V4LELEMENT(v4lsrc)->channel < 0)
if (!gst_v4l_set_chan_norm(GST_V4LELEMENT(v4lsrc),
0, GST_V4LELEMENT(v4lsrc)->norm))
return GST_STATE_FAILURE;
break;
}
*/
return GST_STATE_SUCCESS;
}
static GstBuffer*
gst_v4lsrc_buffer_new (GstBufferPool *pool,
gint64 location,
gint size,
gpointer user_data)
{
GstBuffer *buffer;
buffer = gst_buffer_new();
if (!buffer) return NULL;
buffer->pool_private = user_data;
/* TODO: add interlacing info to buffer as metadata (height>288 or 240 = topfieldfirst, else noninterlaced) */
return buffer;
}
static GstBuffer*
gst_v4lsrc_buffer_copy (GstBuffer *srcbuf)
{
GstBuffer *buffer;
buffer = gst_buffer_new();
if (!buffer) return NULL;
GST_BUFFER_DATA(buffer) = g_malloc(GST_BUFFER_SIZE(srcbuf));
if (!GST_BUFFER_DATA(buffer)) return NULL;
GST_BUFFER_SIZE(buffer) = GST_BUFFER_SIZE(srcbuf);
memcpy(GST_BUFFER_DATA(buffer), GST_BUFFER_DATA(srcbuf), GST_BUFFER_SIZE(srcbuf));
GST_BUFFER_TIMESTAMP(buffer) = GST_BUFFER_TIMESTAMP(srcbuf);
return buffer;
}
static void
gst_v4lsrc_buffer_free (GstBuffer *buf)
{
GstV4lSrc *v4lsrc = buf->pool_private;
int n;
for (n=0;n<v4lsrc->mbuf.frames;n++)
if (GST_BUFFER_DATA(buf) == gst_v4lsrc_get_buffer(v4lsrc, n))
{
gst_v4lsrc_requeue_frame(v4lsrc, n);
return;
}
gst_element_error(GST_ELEMENT(v4lsrc),
"Couldn\'t find the buffer");
}
static gboolean
plugin_init (GModule *module,
GstPlugin *plugin)
{
GstElementFactory *factory;
GstCaps *caps;
gint i;
gulong format[5] = { GST_MAKE_FOURCC('Y','U','Y','2'), /* VIDEO_PALETTE_YUV422/_YUYV */
GST_MAKE_FOURCC('I','4','2','0'), /* VIDEO_PALETTE_YUV420P */
GST_MAKE_FOURCC('I','Y','U','V'), /* VIDEO_PALETTE_YUV420P */
GST_MAKE_FOURCC('U','Y','V','Y'), /* VIDEO_PALETTE_UYVY */
GST_MAKE_FOURCC('Y','4','1','P') /* VIDEO_PALETTE_YUV411 */
};
gint rgb_bpp[4] = { 16, 16, 24, 32 };
gint rgb_depth[4] = { 15, 16, 24, 32 };
/* create an elementfactory for the v4lsrc */
factory = gst_elementfactory_new("v4lsrc",GST_TYPE_V4LSRC,
&gst_v4lsrc_details);
g_return_val_if_fail(factory != NULL, FALSE);
/* make a list of all available caps - first the YUV formats */
for (i=0;i<5;i++)
{
caps = gst_caps_new ("v4lsrc_caps",
"video/raw",
gst_props_new (
"format", GST_PROPS_FOURCC(format[i]),
"width", GST_PROPS_INT_RANGE (0, G_MAXINT),
"height", GST_PROPS_INT_RANGE (0, G_MAXINT),
NULL )
);
capslist = gst_caps_append(capslist, caps);
}
/* now all the RGB formats */
for (i=0;i<4;i++)
{
caps = gst_caps_new ("v4lsrc_caps",
"video/raw",
gst_props_new (
"format", GST_PROPS_FOURCC(GST_MAKE_FOURCC('R','G','B',' ')),
"width", GST_PROPS_INT_RANGE (0, G_MAXINT),
"height", GST_PROPS_INT_RANGE (0, G_MAXINT),
"bpp", GST_PROPS_INT(rgb_bpp[i]),
"depth", GST_PROPS_INT(rgb_depth[i]),
NULL )
);
capslist = gst_caps_append(capslist, caps);
}
src_template = gst_padtemplate_new (
"src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
capslist, NULL);
gst_elementfactory_add_padtemplate (factory, src_template);
gst_plugin_add_feature (plugin, GST_PLUGIN_FEATURE (factory));
return TRUE;
}
GstPluginDesc plugin_desc = {
GST_VERSION_MAJOR,
GST_VERSION_MINOR,
"v4lsrc",
plugin_init
};