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gstreamer/subprojects/gst-plugins-good/sys/v4l2/gstv4l2src.c
Xavier Claessens b80f4a1fa4 v4l2src: Consider framerate during caps selection 
This simplifies the way it picks the closest caps to preference and take into
consideration the framerate to avoid picking high resolution at 5fps or so.
Simply calculate a "distance" of caps A and B from the preference and put
closest first, sorting by framerate first.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5777>
2023-12-08 21:05:46 +00:00

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/* GStreamer
*
* Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
* 2006 Edgard Lima <edgard.lima@gmail.com>
*
* gstv4l2src.c: Video4Linux2 source element
*
* 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.
*/
/**
* SECTION:element-v4l2src
* @title: v4l2src
*
* v4l2src can be used to capture video from v4l2 devices, like webcams and tv
* cards.
*
* ## Example launch lines
* |[
* gst-launch-1.0 v4l2src ! xvimagesink
* ]| This pipeline shows the video captured from /dev/video0 tv card and for
* webcams.
* |[
* gst-launch-1.0 v4l2src ! jpegdec ! xvimagesink
* ]| This pipeline shows the video captured from a webcam that delivers jpeg
* images.
*
* Since 1.14, the use of libv4l2 has been disabled due to major bugs in the
* emulation layer. To enable usage of this library, set the environment
* variable GST_V4L2_USE_LIBV4L2=1.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <string.h>
#include <sys/time.h>
#include <unistd.h>
#include <gst/video/gstvideometa.h>
#include <gst/video/gstvideopool.h>
#include "gstv4l2elements.h"
#include "gstv4l2src.h"
#include "gstv4l2colorbalance.h"
#include "gstv4l2tuner.h"
#include "gstv4l2vidorient.h"
#include <glib/gi18n-lib.h>
GST_DEBUG_CATEGORY (v4l2src_debug);
#define GST_CAT_DEFAULT v4l2src_debug
#define DEFAULT_PROP_DEVICE "/dev/video0"
enum
{
PROP_0,
V4L2_STD_OBJECT_PROPS,
PROP_CROP_TOP,
PROP_CROP_LEFT,
PROP_CROP_BOTTOM,
PROP_CROP_RIGHT,
PROP_CROP_BOUNDS,
PROP_LAST
};
/* signals and args */
enum
{
SIGNAL_PRE_SET_FORMAT,
LAST_SIGNAL
};
static guint gst_v4l2_signals[LAST_SIGNAL] = { 0 };
GST_IMPLEMENT_V4L2_COLOR_BALANCE_METHODS (GstV4l2Src, gst_v4l2src);
GST_IMPLEMENT_V4L2_TUNER_METHODS (GstV4l2Src, gst_v4l2src);
GST_IMPLEMENT_V4L2_VIDORIENT_METHODS (GstV4l2Src, gst_v4l2src);
static void gst_v4l2src_uri_handler_init (gpointer g_iface,
gpointer iface_data);
#define gst_v4l2src_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstV4l2Src, gst_v4l2src, GST_TYPE_PUSH_SRC,
G_IMPLEMENT_INTERFACE (GST_TYPE_URI_HANDLER, gst_v4l2src_uri_handler_init);
G_IMPLEMENT_INTERFACE (GST_TYPE_TUNER, gst_v4l2src_tuner_interface_init);
G_IMPLEMENT_INTERFACE (GST_TYPE_COLOR_BALANCE,
gst_v4l2src_color_balance_interface_init);
G_IMPLEMENT_INTERFACE (GST_TYPE_VIDEO_ORIENTATION,
gst_v4l2src_video_orientation_interface_init));
GST_ELEMENT_REGISTER_DEFINE_WITH_CODE (v4l2src,
"v4l2src", GST_RANK_PRIMARY, GST_TYPE_V4L2SRC, v4l2_element_init (plugin));
struct PreferredCapsInfo
{
gint width;
gint height;
gint fps_n;
gint fps_d;
};
static void gst_v4l2src_finalize (GstV4l2Src * v4l2src);
/* element methods */
static GstStateChangeReturn gst_v4l2src_change_state (GstElement * element,
GstStateChange transition);
/* basesrc methods */
static gboolean gst_v4l2src_start (GstBaseSrc * src);
static gboolean gst_v4l2src_unlock (GstBaseSrc * src);
static gboolean gst_v4l2src_unlock_stop (GstBaseSrc * src);
static gboolean gst_v4l2src_stop (GstBaseSrc * src);
static GstCaps *gst_v4l2src_get_caps (GstBaseSrc * src, GstCaps * filter);
static gboolean gst_v4l2src_query (GstBaseSrc * bsrc, GstQuery * query);
static gboolean gst_v4l2src_decide_allocation (GstBaseSrc * src,
GstQuery * query);
static GstFlowReturn gst_v4l2src_create (GstPushSrc * src, GstBuffer ** out);
static GstCaps *gst_v4l2src_fixate (GstBaseSrc * basesrc, GstCaps * caps,
struct PreferredCapsInfo *pref);
static gboolean gst_v4l2src_negotiate (GstBaseSrc * basesrc);
static void gst_v4l2src_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_v4l2src_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static void
gst_v4l2src_class_init (GstV4l2SrcClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *element_class;
GstBaseSrcClass *basesrc_class;
GstPushSrcClass *pushsrc_class;
gobject_class = G_OBJECT_CLASS (klass);
element_class = GST_ELEMENT_CLASS (klass);
basesrc_class = GST_BASE_SRC_CLASS (klass);
pushsrc_class = GST_PUSH_SRC_CLASS (klass);
gobject_class->finalize = (GObjectFinalizeFunc) gst_v4l2src_finalize;
gobject_class->set_property = gst_v4l2src_set_property;
gobject_class->get_property = gst_v4l2src_get_property;
element_class->change_state = gst_v4l2src_change_state;
gst_v4l2_object_install_properties_helper (gobject_class,
DEFAULT_PROP_DEVICE);
/**
* GstV4l2Src:crop-top:
*
* Number of pixels to crop from the top edge of captured video
* stream
*
* Since: 1.22
*/
g_object_class_install_property (gobject_class, PROP_CROP_TOP,
g_param_spec_uint ("crop-top", "Crop top",
"Pixels to crop at top of video capture input",
0, G_MAXUINT, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
/**
* GstV4l2Src:crop-left:
*
* Number of pixels to crop from the left edge of captured video
* stream
*
* Since: 1.22
*/
g_object_class_install_property (gobject_class, PROP_CROP_LEFT,
g_param_spec_uint ("crop-left", "Crop left",
"Pixels to crop at left of video capture input",
0, G_MAXUINT, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
/**
* GstV4l2Src:crop-bottom:
*
* Number of pixels to crop from the bottom edge of captured video
* stream
*
* Since: 1.22
*/
g_object_class_install_property (gobject_class, PROP_CROP_BOTTOM,
g_param_spec_uint ("crop-bottom", "Crop bottom",
"Pixels to crop at bottom of video capture input",
0, G_MAXUINT, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
/**
* GstV4l2Src:crop-right:
*
* Number of pixels to crop from the right edge of captured video
* stream
*
* Since: 1.22
*/
g_object_class_install_property (gobject_class, PROP_CROP_RIGHT,
g_param_spec_uint ("crop-right", "Crop right",
"Pixels to crop at right of video capture input",
0, G_MAXUINT, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
/**
* GstV4l2Src:crop-bounds:
*
* Crop bounding region. All crop regions must lie within this region.
* The bounds are represented as a four element array, that descibes the
* [x, y, width, height] of the area.
*
* The size and position of the crop
* bounds will only be known, once the v4l2 device is opened and the
* input source selected. Applications can connect to the
* "notify::crop-bounds" signal to be notified when the bounding region is
* updated, and set an appropriate crop region.
*
* Since: 1.22
*/
g_object_class_install_property (gobject_class, PROP_CROP_BOUNDS,
gst_param_spec_array ("crop-bounds", "Crop bounds",
"The bounding region for crop rectangles ('<x, y, width, height>').",
g_param_spec_int ("rect-value", "Rectangle Value",
"One of x, y, width or height value.", G_MININT, G_MAXINT, -1,
G_PARAM_READABLE | G_PARAM_STATIC_STRINGS),
G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
/**
* GstV4l2Src::prepare-format:
* @v4l2src: the v4l2src instance
* @fd: the file descriptor of the current device
* @caps: the caps of the format being set
*
* This signal gets emitted before calling the v4l2 VIDIOC_S_FMT ioctl
* (set format). This allows for any custom configuration of the device to
* happen prior to the format being set.
* This is mostly useful for UVC H264 encoding cameras which need the H264
* Probe & Commit to happen prior to the normal Probe & Commit.
*/
gst_v4l2_signals[SIGNAL_PRE_SET_FORMAT] = g_signal_new ("prepare-format",
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
0, NULL, NULL, NULL, G_TYPE_NONE, 2, G_TYPE_INT, GST_TYPE_CAPS);
gst_element_class_set_static_metadata (element_class,
"Video (video4linux2) Source", "Source/Video",
"Reads frames from a Video4Linux2 device",
"Edgard Lima <edgard.lima@gmail.com>, "
"Stefan Kost <ensonic@users.sf.net>");
gst_element_class_add_pad_template
(element_class,
gst_pad_template_new ("src", GST_PAD_SRC, GST_PAD_ALWAYS,
gst_v4l2_object_get_all_caps ()));
basesrc_class->get_caps = GST_DEBUG_FUNCPTR (gst_v4l2src_get_caps);
basesrc_class->start = GST_DEBUG_FUNCPTR (gst_v4l2src_start);
basesrc_class->unlock = GST_DEBUG_FUNCPTR (gst_v4l2src_unlock);
basesrc_class->unlock_stop = GST_DEBUG_FUNCPTR (gst_v4l2src_unlock_stop);
basesrc_class->stop = GST_DEBUG_FUNCPTR (gst_v4l2src_stop);
basesrc_class->query = GST_DEBUG_FUNCPTR (gst_v4l2src_query);
basesrc_class->negotiate = GST_DEBUG_FUNCPTR (gst_v4l2src_negotiate);
basesrc_class->decide_allocation =
GST_DEBUG_FUNCPTR (gst_v4l2src_decide_allocation);
pushsrc_class->create = GST_DEBUG_FUNCPTR (gst_v4l2src_create);
klass->v4l2_class_devices = NULL;
GST_DEBUG_CATEGORY_INIT (v4l2src_debug, "v4l2src", 0, "V4L2 source element");
}
static void
gst_v4l2src_init (GstV4l2Src * v4l2src)
{
/* fixme: give an update_fps_function */
v4l2src->v4l2object = gst_v4l2_object_new (GST_ELEMENT (v4l2src),
GST_OBJECT (GST_BASE_SRC_PAD (v4l2src)), V4L2_BUF_TYPE_VIDEO_CAPTURE,
DEFAULT_PROP_DEVICE, gst_v4l2_get_input, gst_v4l2_set_input, NULL);
/* Avoid the slow probes */
v4l2src->v4l2object->skip_try_fmt_probes = TRUE;
gst_base_src_set_format (GST_BASE_SRC (v4l2src), GST_FORMAT_TIME);
gst_base_src_set_live (GST_BASE_SRC (v4l2src), TRUE);
}
static void
gst_v4l2src_finalize (GstV4l2Src * v4l2src)
{
gst_v4l2_object_destroy (v4l2src->v4l2object);
G_OBJECT_CLASS (parent_class)->finalize ((GObject *) (v4l2src));
}
static void
gst_v4l2src_set_property (GObject * object,
guint prop_id, const GValue * value, GParamSpec * pspec)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (object);
if (!gst_v4l2_object_set_property_helper (v4l2src->v4l2object,
prop_id, value, pspec)) {
switch (prop_id) {
case PROP_CROP_TOP:
v4l2src->crop_top = g_value_get_uint (value);
break;
case PROP_CROP_LEFT:
v4l2src->crop_left = g_value_get_uint (value);
break;
case PROP_CROP_BOTTOM:
v4l2src->crop_bottom = g_value_get_uint (value);
break;
case PROP_CROP_RIGHT:
v4l2src->crop_right = g_value_get_uint (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
}
static void
gst_v4l2src_set_rect_value (GValue * value, struct v4l2_rect *rect)
{
GValue val = { 0 };
g_value_init (&val, G_TYPE_INT);
g_value_reset (value);
g_value_set_int (&val, rect->left);
gst_value_array_append_value (value, &val);
g_value_set_int (&val, rect->top);
gst_value_array_append_value (value, &val);
g_value_set_int (&val, rect->width);
gst_value_array_append_value (value, &val);
g_value_set_int (&val, rect->height);
gst_value_array_append_value (value, &val);
g_value_unset (&val);
}
static void
gst_v4l2src_get_property (GObject * object,
guint prop_id, GValue * value, GParamSpec * pspec)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (object);
if (!gst_v4l2_object_get_property_helper (v4l2src->v4l2object,
prop_id, value, pspec)) {
switch (prop_id) {
case PROP_CROP_TOP:
g_value_set_uint (value, v4l2src->crop_top);
break;
case PROP_CROP_LEFT:
g_value_set_uint (value, v4l2src->crop_left);
break;
case PROP_CROP_BOTTOM:
g_value_set_uint (value, v4l2src->crop_bottom);
break;
case PROP_CROP_RIGHT:
g_value_set_uint (value, v4l2src->crop_right);
break;
case PROP_CROP_BOUNDS:
gst_v4l2src_set_rect_value (value, &v4l2src->crop_bounds);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
}
static gboolean
gst_vl42_src_fixate_fields (GQuark field_id, GValue * value, gpointer user_data)
{
GstStructure *s = user_data;
if (field_id == g_quark_from_string ("interlace-mode"))
return TRUE;
if (field_id == g_quark_from_string ("colorimetry"))
return TRUE;
gst_structure_fixate_field (s, g_quark_to_string (field_id));
return TRUE;
}
static void
gst_v4l2_src_fixate_struct_with_preference (GstStructure * s,
struct PreferredCapsInfo *pref)
{
if (gst_structure_has_field (s, "width"))
gst_structure_fixate_field_nearest_int (s, "width", pref->width);
if (gst_structure_has_field (s, "height"))
gst_structure_fixate_field_nearest_int (s, "height", pref->height);
if (gst_structure_has_field (s, "framerate"))
gst_structure_fixate_field_nearest_fraction (s, "framerate", pref->fps_n,
pref->fps_d);
/* Finally, fixate everything else except the interlace-mode and colorimetry
* which still need further negotiation as it wasn't probed */
gst_structure_map_in_place (s, gst_vl42_src_fixate_fields, s);
}
static void
gst_v4l2_src_parse_fixed_struct (GstStructure * s,
gint * width, gint * height, gint * fps_n, gint * fps_d)
{
if (gst_structure_has_field (s, "width") && width)
gst_structure_get_int (s, "width", width);
if (gst_structure_has_field (s, "height") && height)
gst_structure_get_int (s, "height", height);
if (gst_structure_has_field (s, "framerate") && fps_n && fps_d)
gst_structure_get_fraction (s, "framerate", fps_n, fps_d);
}
static gint
gst_v4l2src_fixed_caps_compare (GstCaps * caps_a, GstCaps * caps_b,
struct PreferredCapsInfo *pref)
{
GstStructure *a, *b;
gint aw = G_MAXINT, ah = G_MAXINT;
gint bw = G_MAXINT, bh = G_MAXINT;
gint a_fps_n = G_MAXINT, a_fps_d = 1;
gint b_fps_n = G_MAXINT, b_fps_d = 1;
gint a_distance, b_distance;
a = gst_caps_get_structure (caps_a, 0);
b = gst_caps_get_structure (caps_b, 0);
gst_v4l2_src_parse_fixed_struct (a, &aw, &ah, &a_fps_n, &a_fps_d);
gst_v4l2_src_parse_fixed_struct (b, &bw, &bh, &b_fps_n, &b_fps_d);
// Sort first the one with closest framerate to preference. Note that any
// framerate lower then 1 frame per second will be considered the same. In
// practice this should be fine considering that these framerate only exists
// for still picture, in which case the resolution is most likely the key.
a_distance = ABS ((a_fps_n / a_fps_d) - (pref->fps_n / pref->fps_d));
b_distance = ABS ((b_fps_n / b_fps_d) - (pref->fps_n / pref->fps_d));
if (a_distance != b_distance)
return a_distance - b_distance;
// If same framerate, sort first the one with closest resolution to preference
a_distance = ABS (aw * ah - pref->width * pref->height);
b_distance = ABS (bw * bh - pref->width * pref->height);
gint ret = a_distance - b_distance;
GST_TRACE ("Placing %" GST_PTR_FORMAT " %s %" GST_PTR_FORMAT,
caps_a, ret > 0 ? "after" : "before", caps_b);
return ret;
}
static gboolean
gst_v4l2src_do_source_crop (GstV4l2Src * v4l2src)
{
struct v4l2_rect def_crop;
if (v4l2src->apply_crop_settings)
return gst_v4l2_object_set_crop (v4l2src->v4l2object, &v4l2src->crop_rect);
/* If no crop setting is given, reset to the default. Resetting the default
* crop may fail if the device does not support cropping. This should not
* be considered an error. */
if (gst_v4l2_object_get_crop_default (v4l2src->v4l2object, &def_crop))
gst_v4l2_object_set_crop (v4l2src->v4l2object, &def_crop);
return TRUE;
}
static gboolean
gst_v4l2src_set_format (GstV4l2Src * v4l2src, GstCaps * caps,
GstV4l2Error * error)
{
GstV4l2Object *obj;
obj = v4l2src->v4l2object;
/* make sure we stop capturing and dealloc buffers */
if (!gst_v4l2_object_stop (obj))
return FALSE;
g_signal_emit (v4l2src, gst_v4l2_signals[SIGNAL_PRE_SET_FORMAT], 0,
v4l2src->v4l2object->video_fd, caps);
if (!gst_v4l2src_do_source_crop (v4l2src))
return FALSE;
return gst_v4l2_object_set_format (obj, caps, error);
}
static GstCaps *
gst_v4l2src_fixate (GstBaseSrc * basesrc, GstCaps * caps,
struct PreferredCapsInfo *pref)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (basesrc);
GstV4l2Object *obj = v4l2src->v4l2object;
GList *caps_list = NULL;
GstStructure *s;
gint i = G_MAXINT;
GstV4l2Error error = GST_V4L2_ERROR_INIT;
GstCaps *fcaps = NULL;
GST_DEBUG_OBJECT (basesrc, "Fixating caps %" GST_PTR_FORMAT, caps);
GST_DEBUG_OBJECT (basesrc, "Preferred size %ix%i", pref->width, pref->height);
/* Sort the structures to get the caps that is nearest to our preferences,
* first. Use single struct caps for sorting so we preserve the features. */
for (i = 0; i < gst_caps_get_size (caps); i++) {
GstCaps *tmp = gst_caps_copy_nth (caps, i);
s = gst_caps_get_structure (tmp, 0);
gst_v4l2_src_fixate_struct_with_preference (s, pref);
caps_list = g_list_insert_sorted_with_data (caps_list, tmp,
(GCompareDataFunc) gst_v4l2src_fixed_caps_compare, pref);
}
gst_caps_unref (caps);
caps = gst_caps_new_empty ();
while (caps_list) {
GstCaps *tmp = caps_list->data;
caps_list = g_list_delete_link (caps_list, caps_list);
gst_caps_append (caps, tmp);
}
GST_DEBUG_OBJECT (basesrc, "sorted and normalized caps %" GST_PTR_FORMAT,
caps);
/* Each structure in the caps has been fixated, except for the
* interlace-mode and colorimetry. Now normalize the caps so we can
* enumerate the possibilities */
caps = gst_caps_normalize (caps);
/* try hard to avoid TRY_FMT since some UVC camera just crash when this
* is called at run-time. */
if (gst_v4l2_object_caps_is_subset (obj, caps)) {
fcaps = gst_v4l2_object_get_current_caps (obj);
GST_DEBUG_OBJECT (basesrc, "reuse current caps %" GST_PTR_FORMAT, fcaps);
goto out;
}
for (i = 0; i < gst_caps_get_size (caps); ++i) {
gst_v4l2_clear_error (&error);
if (fcaps)
gst_caps_unref (fcaps);
fcaps = gst_caps_copy_nth (caps, i);
/* Just check if the format is acceptable, once we know
* no buffers should be outstanding we try S_FMT.
*
* Basesrc will do an allocation query that
* should indirectly reclaim buffers, after that we can
* set the format and then configure our pool */
if (gst_v4l2_object_try_format (obj, fcaps, &error)) {
/* make sure the caps changed before doing anything */
if (gst_v4l2_object_caps_equal (obj, fcaps))
break;
v4l2src->renegotiation_adjust = v4l2src->offset + 1;
v4l2src->pending_set_fmt = TRUE;
break;
}
/* Only EIVAL make sense, report any other errors, this way we don't keep
* probing if the device got disconnected, or if it's firmware stopped
* responding */
if (error.error->code != GST_RESOURCE_ERROR_SETTINGS) {
i = G_MAXINT;
break;
}
}
if (i >= gst_caps_get_size (caps)) {
gst_v4l2_error (v4l2src, &error);
if (fcaps)
gst_caps_unref (fcaps);
gst_caps_unref (caps);
return NULL;
}
out:
gst_caps_unref (caps);
GST_DEBUG_OBJECT (basesrc, "fixated caps %" GST_PTR_FORMAT, fcaps);
return fcaps;
}
static gboolean
gst_v4l2src_query_preferred_dv_timings (GstV4l2Src * v4l2src,
struct PreferredCapsInfo *pref)
{
GstV4l2Object *obj = v4l2src->v4l2object;
struct v4l2_dv_timings dv_timings = { 0, };
const struct v4l2_bt_timings *bt = &dv_timings.bt;
gboolean not_streaming;
gint tot_width, tot_height;
gint gcd;
if (!gst_v4l2_query_dv_timings (obj, &dv_timings))
return FALSE;
pref->width = bt->width;
pref->height = bt->height;
tot_height = bt->height +
bt->vfrontporch + bt->vsync + bt->vbackporch +
bt->il_vfrontporch + bt->il_vsync + bt->il_vbackporch;
tot_width = bt->width + bt->hfrontporch + bt->hsync + bt->hbackporch;
pref->fps_n = bt->pixelclock;
pref->fps_d = tot_width * tot_height;
if (bt->interlaced)
pref->fps_d /= 2;
gcd = gst_util_greatest_common_divisor (pref->fps_n, pref->fps_d);
pref->fps_n /= gcd;
pref->fps_d /= gcd;
/* If are are not streaming (e.g. we received source-change event), lock the
* new timing immediatly so that TRY_FMT can properly work */
{
GstBufferPool *obj_pool = gst_v4l2_object_get_buffer_pool (obj);
not_streaming = !obj_pool || !GST_V4L2_BUFFER_POOL_IS_STREAMING (obj_pool);
if (obj_pool)
gst_object_unref (obj_pool);
}
if (not_streaming) {
gst_v4l2_set_dv_timings (obj, &dv_timings);
/* Setting a new DV timings invalidates the probed caps. */
gst_caps_replace (&obj->probed_caps, NULL);
}
GST_INFO_OBJECT (v4l2src, "Using DV Timings: %i x %i (%i/%i fps)",
pref->width, pref->height, pref->fps_n, pref->fps_d);
return TRUE;
}
static gboolean
gst_v4l2src_query_preferred_size (GstV4l2Src * v4l2src,
struct PreferredCapsInfo *pref)
{
struct v4l2_input in = { 0, };
if (!gst_v4l2_get_input (v4l2src->v4l2object, &in.index))
return FALSE;
if (!gst_v4l2_query_input (v4l2src->v4l2object, &in))
return FALSE;
GST_INFO_OBJECT (v4l2src, "Detect input %u as `%s`", in.index, in.name);
/* Notify signal status using WARNING/INFO messages */
if (in.status & (V4L2_IN_ST_NO_POWER | V4L2_IN_ST_NO_SIGNAL)) {
if (!v4l2src->no_signal)
/* note: taken from decklinksrc element */
GST_ELEMENT_WARNING (v4l2src, RESOURCE, READ, ("Signal lost"),
("No input source was detected - video frames invalid"));
v4l2src->no_signal = TRUE;
} else if (v4l2src->no_signal) {
if (v4l2src->no_signal)
GST_ELEMENT_INFO (v4l2src, RESOURCE, READ,
("Signal recovered"), ("Input source detected"));
v4l2src->no_signal = FALSE;
}
if (in.capabilities & V4L2_IN_CAP_NATIVE_SIZE) {
GST_FIXME_OBJECT (v4l2src, "missing support for native video size");
return FALSE;
} else if (in.capabilities & V4L2_IN_CAP_DV_TIMINGS) {
return gst_v4l2src_query_preferred_dv_timings (v4l2src, pref);
} else if (in.capabilities & V4L2_IN_CAP_STD) {
GST_FIXME_OBJECT (v4l2src, "missing support for video standards");
return FALSE;
}
return FALSE;
}
static gboolean
gst_v4l2src_setup_source_crop (GstV4l2Src * v4l2src,
struct PreferredCapsInfo *pref)
{
gint cropped_width, cropped_height;
struct v4l2_rect *crop_bounds = &v4l2src->crop_bounds;
v4l2src->apply_crop_settings = FALSE;
if (!gst_v4l2_object_get_crop_bounds (v4l2src->v4l2object, crop_bounds))
return FALSE;
g_object_notify (G_OBJECT (v4l2src), "crop-bounds");
cropped_width = crop_bounds->width - v4l2src->crop_left - v4l2src->crop_right;
cropped_height =
crop_bounds->height - v4l2src->crop_top - v4l2src->crop_bottom;
if (v4l2src->crop_left < crop_bounds->left
|| v4l2src->crop_top < crop_bounds->top
|| cropped_width <= 0 || cropped_height <= 0) {
GST_WARNING_OBJECT (v4l2src, "Ignoring out of bounds crop region");
return FALSE;
}
if (cropped_width == crop_bounds->width
&& cropped_height == crop_bounds->height) {
GST_DEBUG_OBJECT (v4l2src,
"No cropping requested, keep current preferred size");
return FALSE;
}
v4l2src->crop_rect.left = v4l2src->crop_left;
v4l2src->crop_rect.top = v4l2src->crop_top;
v4l2src->crop_rect.width = cropped_width;
v4l2src->crop_rect.height = cropped_height;
v4l2src->apply_crop_settings = TRUE;
pref->width = cropped_width;
pref->height = cropped_height;
GST_INFO_OBJECT (v4l2src, "Updated preferred capture size to %i x %i",
pref->width, pref->height);
return TRUE;
}
static gboolean
gst_v4l2src_negotiate (GstBaseSrc * basesrc)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (basesrc);
GstCaps *thiscaps;
GstCaps *caps = NULL;
GstCaps *peercaps = NULL;
gboolean result = FALSE;
/* Let's prefer a good resolution as of today's standard. */
struct PreferredCapsInfo pref = {
3840, 2160, 120, 1
};
gboolean have_pref;
/* For drivers that has DV timings or other default size query
* capabilities, we will prefer that resolution. This must happen before we
* probe the caps, as locking DV Timings or standards will change result of
* the caps enumeration. */
have_pref = gst_v4l2src_query_preferred_size (v4l2src, &pref);
have_pref |= gst_v4l2src_setup_source_crop (v4l2src, &pref);
/* first see what is possible on our source pad */
thiscaps = gst_pad_query_caps (GST_BASE_SRC_PAD (basesrc), NULL);
GST_DEBUG_OBJECT (basesrc, "caps of src: %" GST_PTR_FORMAT, thiscaps);
/* nothing or anything is allowed, we're done */
if (thiscaps == NULL || gst_caps_is_any (thiscaps))
goto no_nego_needed;
/* get the peer caps without a filter as we'll filter ourselves later on */
peercaps = gst_pad_peer_query_caps (GST_BASE_SRC_PAD (basesrc), NULL);
GST_DEBUG_OBJECT (basesrc, "caps of peer: %" GST_PTR_FORMAT, peercaps);
if (peercaps && !gst_caps_is_any (peercaps)) {
/* Prefer the first caps we are compatible with that the peer proposed */
caps = gst_caps_intersect_full (peercaps, thiscaps,
GST_CAPS_INTERSECT_FIRST);
GST_DEBUG_OBJECT (basesrc, "intersect: %" GST_PTR_FORMAT, caps);
gst_caps_unref (thiscaps);
} else {
/* no peer or peer have ANY caps, work with our own caps then */
caps = thiscaps;
}
if (caps) {
/* now fixate */
if (!gst_caps_is_empty (caps)) {
/* otherwise consider the first structure from peercaps to be a
* preference. This is useful for matching a reported native display,
* or simply to avoid transformation to happen downstream. */
if (!have_pref && peercaps && !gst_caps_is_any (peercaps)) {
GstStructure *pref_s = gst_caps_get_structure (peercaps, 0);
pref_s = gst_structure_copy (pref_s);
gst_v4l2_src_fixate_struct_with_preference (pref_s, &pref);
gst_v4l2_src_parse_fixed_struct (pref_s, &pref.width, &pref.height,
&pref.fps_n, &pref.fps_d);
gst_structure_free (pref_s);
}
caps = gst_v4l2src_fixate (basesrc, caps, &pref);
/* Fixating may fail as we now set the selected format */
if (!caps) {
result = FALSE;
goto done;
}
GST_INFO_OBJECT (basesrc, "fixated to: %" GST_PTR_FORMAT, caps);
if (gst_caps_is_any (caps)) {
/* hmm, still anything, so element can do anything and
* nego is not needed */
result = TRUE;
} else if (gst_caps_is_fixed (caps)) {
/* yay, fixed caps, use those then */
result = gst_base_src_set_caps (basesrc, caps);
}
}
gst_caps_unref (caps);
}
done:
if (peercaps)
gst_caps_unref (peercaps);
return result;
no_nego_needed:
{
GST_INFO_OBJECT (basesrc, "no negotiation needed");
if (thiscaps)
gst_caps_unref (thiscaps);
return TRUE;
}
}
static GstCaps *
gst_v4l2src_get_caps (GstBaseSrc * src, GstCaps * filter)
{
GstV4l2Src *v4l2src;
GstV4l2Object *obj;
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));
}
return gst_v4l2_object_get_caps (obj, filter);
}
static gboolean
gst_v4l2src_decide_allocation (GstBaseSrc * bsrc, GstQuery * query)
{
GstV4l2Src *src = GST_V4L2SRC (bsrc);
GstBufferPool *bpool = gst_v4l2_object_get_buffer_pool (src->v4l2object);
gboolean ret = TRUE;
if (src->pending_set_fmt) {
GstCaps *caps = gst_pad_get_current_caps (GST_BASE_SRC_PAD (bsrc));
GstV4l2Error error = GST_V4L2_ERROR_INIT;
/* Setting the format replaces the current pool */
gst_clear_object (&bpool);
caps = gst_caps_make_writable (caps);
ret = gst_v4l2src_set_format (src, caps, &error);
if (ret) {
GstV4l2BufferPool *pool;
bpool = gst_v4l2_object_get_buffer_pool (src->v4l2object);
pool = GST_V4L2_BUFFER_POOL (bpool);
gst_v4l2_buffer_pool_enable_resolution_change (pool);
} else {
gst_v4l2_error (src, &error);
}
gst_caps_unref (caps);
src->pending_set_fmt = FALSE;
} else if (gst_buffer_pool_is_active (bpool)) {
/* Trick basesrc into not deactivating the active pool. Renegotiating here
* would otherwise turn off and on the camera. */
GstAllocator *allocator;
GstAllocationParams params;
GstBufferPool *pool;
gst_base_src_get_allocator (bsrc, &allocator, &params);
pool = gst_base_src_get_buffer_pool (bsrc);
if (gst_query_get_n_allocation_params (query))
gst_query_set_nth_allocation_param (query, 0, allocator, &params);
else
gst_query_add_allocation_param (query, allocator, &params);
if (gst_query_get_n_allocation_pools (query))
gst_query_set_nth_allocation_pool (query, 0, pool,
src->v4l2object->info.size, 1, 0);
else
gst_query_add_allocation_pool (query, pool, src->v4l2object->info.size, 1,
0);
if (pool)
gst_object_unref (pool);
if (allocator)
gst_object_unref (allocator);
if (bpool)
gst_object_unref (bpool);
return GST_BASE_SRC_CLASS (parent_class)->decide_allocation (bsrc, query);
}
if (ret) {
ret = gst_v4l2_object_decide_allocation (src->v4l2object, query);
if (ret)
ret = GST_BASE_SRC_CLASS (parent_class)->decide_allocation (bsrc, query);
}
if (ret) {
if (!gst_buffer_pool_set_active (bpool, TRUE))
goto activate_failed;
}
if (bpool)
gst_object_unref (bpool);
return ret;
activate_failed:
{
GST_ELEMENT_ERROR (src, RESOURCE, SETTINGS,
(_("Failed to allocate required memory.")),
("Buffer pool activation failed"));
if (bpool)
gst_object_unref (bpool);
return FALSE;
}
}
static gboolean
gst_v4l2src_query (GstBaseSrc * bsrc, GstQuery * query)
{
GstV4l2Src *src;
GstV4l2Object *obj;
gboolean res = FALSE;
src = GST_V4L2SRC (bsrc);
obj = src->v4l2object;
switch (GST_QUERY_TYPE (query)) {
case GST_QUERY_LATENCY:{
GstClockTime min_latency, max_latency;
guint32 fps_n, fps_d;
guint num_buffers = 0;
/* device must be open */
if (!GST_V4L2_IS_OPEN (obj)) {
GST_WARNING_OBJECT (src,
"Can't give latency since device isn't open !");
goto done;
}
fps_n = GST_V4L2_FPS_N (obj);
fps_d = GST_V4L2_FPS_D (obj);
/* we must have a framerate */
if (fps_n <= 0 || fps_d <= 0) {
GST_WARNING_OBJECT (src,
"Can't give latency since framerate isn't fixated !");
goto done;
}
/* min latency is the time to capture one frame/field */
min_latency = gst_util_uint64_scale_int (GST_SECOND, fps_d, fps_n);
if (GST_VIDEO_INFO_INTERLACE_MODE (&obj->info) ==
GST_VIDEO_INTERLACE_MODE_ALTERNATE)
min_latency /= 2;
/* max latency is total duration of the frame buffer */
{
GstBufferPool *obj_pool = gst_v4l2_object_get_buffer_pool (obj);
if (obj_pool != NULL) {
num_buffers = GST_V4L2_BUFFER_POOL_CAST (obj_pool)->max_latency;
gst_object_unref (obj_pool);
}
}
if (num_buffers == 0)
max_latency = -1;
else
max_latency = num_buffers * min_latency;
GST_DEBUG_OBJECT (bsrc,
"report latency min %" GST_TIME_FORMAT " max %" GST_TIME_FORMAT,
GST_TIME_ARGS (min_latency), GST_TIME_ARGS (max_latency));
/* we are always live, the min latency is 1 frame and the max latency is
* the complete buffer of frames. */
gst_query_set_latency (query, TRUE, min_latency, max_latency);
res = TRUE;
break;
}
default:
res = GST_BASE_SRC_CLASS (parent_class)->query (bsrc, query);
break;
}
done:
return res;
}
/* start and stop are not symmetric -- start will open the device, but not start
* capture. it's setcaps that will start capture, which is called via basesrc's
* negotiate method. stop will both stop capture and close the device.
*/
static gboolean
gst_v4l2src_start (GstBaseSrc * src)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (src);
v4l2src->offset = 0;
v4l2src->next_offset_same = FALSE;
v4l2src->renegotiation_adjust = 0;
/* activate settings for first frame */
v4l2src->ctrl_time = 0;
gst_object_sync_values (GST_OBJECT (src), v4l2src->ctrl_time);
v4l2src->has_bad_timestamp = FALSE;
v4l2src->last_timestamp = 0;
return TRUE;
}
static gboolean
gst_v4l2src_unlock (GstBaseSrc * src)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (src);
return gst_v4l2_object_unlock (v4l2src->v4l2object);
}
static gboolean
gst_v4l2src_unlock_stop (GstBaseSrc * src)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (src);
v4l2src->last_timestamp = 0;
return gst_v4l2_object_unlock_stop (v4l2src->v4l2object);
}
static gboolean
gst_v4l2src_stop (GstBaseSrc * src)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (src);
GstV4l2Object *obj = v4l2src->v4l2object;
if (GST_V4L2_IS_ACTIVE (obj)) {
if (!gst_v4l2_object_stop (obj))
return FALSE;
}
v4l2src->pending_set_fmt = FALSE;
return TRUE;
}
static GstStateChangeReturn
gst_v4l2src_change_state (GstElement * element, GstStateChange transition)
{
GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
GstV4l2Src *v4l2src = GST_V4L2SRC (element);
GstV4l2Object *obj = v4l2src->v4l2object;
GstV4l2Error error = GST_V4L2_ERROR_INIT;
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
/* open the device */
if (!gst_v4l2_object_open (obj, &error)) {
gst_v4l2_error (v4l2src, &error);
return GST_STATE_CHANGE_FAILURE;
}
break;
default:
break;
}
ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
switch (transition) {
case GST_STATE_CHANGE_READY_TO_NULL:
/* close the device */
if (!gst_v4l2_object_close (obj))
return GST_STATE_CHANGE_FAILURE;
break;
default:
break;
}
return ret;
}
static gboolean
gst_v4l2src_handle_resolution_change (GstV4l2Src * v4l2src)
{
GST_INFO_OBJECT (v4l2src, "Resolution change detected.");
/* It is required to always cycle through streamoff, we also need to
* streamoff in order to allow locking a new DV_TIMING which will
* influence the output of TRY_FMT */
gst_v4l2src_stop (GST_BASE_SRC (v4l2src));
/* Force renegotiation */
v4l2src->renegotiation_adjust = v4l2src->offset + 1;
v4l2src->pending_set_fmt = TRUE;
return gst_base_src_negotiate (GST_BASE_SRC (v4l2src));
}
static GstFlowReturn
gst_v4l2src_create (GstPushSrc * src, GstBuffer ** buf)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (src);
GstV4l2Object *obj = v4l2src->v4l2object;
GstFlowReturn ret;
GstClock *clock;
GstClockTime abs_time, base_time, timestamp, duration;
GstClockTime delay;
GstMessage *qos_msg;
gboolean half_frame;
do {
ret = GST_BASE_SRC_CLASS (parent_class)->alloc (GST_BASE_SRC (src), 0,
obj->info.size, buf);
if (G_UNLIKELY (ret != GST_FLOW_OK)) {
if (ret == GST_V4L2_FLOW_RESOLUTION_CHANGE) {
if (!gst_v4l2src_handle_resolution_change (v4l2src)) {
ret = GST_FLOW_NOT_NEGOTIATED;
goto error;
}
continue;
}
goto alloc_failed;
}
{
GstV4l2BufferPool *obj_pool =
GST_V4L2_BUFFER_POOL_CAST (gst_v4l2_object_get_buffer_pool (obj));
ret = gst_v4l2_buffer_pool_process (obj_pool, buf, NULL);
if (obj_pool)
gst_object_unref (obj_pool);
if (G_UNLIKELY (ret == GST_V4L2_FLOW_RESOLUTION_CHANGE)) {
if (!gst_v4l2src_handle_resolution_change (v4l2src)) {
ret = GST_FLOW_NOT_NEGOTIATED;
goto error;
}
}
}
} while (ret == GST_V4L2_FLOW_CORRUPTED_BUFFER ||
ret == GST_V4L2_FLOW_RESOLUTION_CHANGE);
if (G_UNLIKELY (ret != GST_FLOW_OK))
goto error;
timestamp = GST_BUFFER_TIMESTAMP (*buf);
duration = obj->duration;
/* timestamps, LOCK to get clock and base time. */
/* FIXME: element clock and base_time is rarely changing */
GST_OBJECT_LOCK (v4l2src);
if ((clock = GST_ELEMENT_CLOCK (v4l2src))) {
/* we have a clock, get base time and ref clock */
base_time = GST_ELEMENT (v4l2src)->base_time;
gst_object_ref (clock);
} else {
/* no clock, can't set timestamps */
base_time = GST_CLOCK_TIME_NONE;
}
GST_OBJECT_UNLOCK (v4l2src);
/* sample pipeline clock */
if (clock) {
abs_time = gst_clock_get_time (clock);
gst_object_unref (clock);
} else {
abs_time = GST_CLOCK_TIME_NONE;
}
retry:
if (!v4l2src->has_bad_timestamp && timestamp != GST_CLOCK_TIME_NONE) {
struct timespec now;
GstClockTime gstnow;
/* v4l2 specs say to use the system time although many drivers switched to
* the more desirable monotonic time. We first try to use the monotonic time
* and see how that goes */
clock_gettime (CLOCK_MONOTONIC, &now);
gstnow = GST_TIMESPEC_TO_TIME (now);
if (timestamp > gstnow || (gstnow - timestamp) > (10 * GST_SECOND)) {
/* very large diff, fall back to system time */
gstnow = g_get_real_time () * GST_USECOND;
}
/* Detect buggy drivers here, and stop using their timestamp. Failing any
* of these condition would imply a very buggy driver:
* - Timestamp in the future
* - Timestamp is going backward compare to last seen timestamp
* - Timestamp is jumping forward for less then a frame duration
* - Delay is bigger then the actual timestamp
* */
if (timestamp > gstnow) {
GST_WARNING_OBJECT (v4l2src,
"Timestamp in the future detected, ignoring driver timestamps");
v4l2src->has_bad_timestamp = TRUE;
goto retry;
}
if (v4l2src->last_timestamp > timestamp) {
GST_WARNING_OBJECT (v4l2src,
"Timestamp going backward, ignoring driver timestamps");
v4l2src->has_bad_timestamp = TRUE;
goto retry;
}
delay = gstnow - timestamp;
if (delay > timestamp) {
GST_WARNING_OBJECT (v4l2src,
"Timestamp does not correlate with any clock, ignoring driver timestamps");
v4l2src->has_bad_timestamp = TRUE;
goto retry;
}
/* Save last timestamp for sanity checks */
v4l2src->last_timestamp = timestamp;
GST_DEBUG_OBJECT (v4l2src, "ts: %" GST_TIME_FORMAT " now %" GST_TIME_FORMAT
" delay %" GST_TIME_FORMAT, GST_TIME_ARGS (timestamp),
GST_TIME_ARGS (gstnow), GST_TIME_ARGS (delay));
} else {
/* we assume 1 frame/field latency otherwise */
if (GST_CLOCK_TIME_IS_VALID (duration))
delay = duration;
else
delay = 0;
}
/* set buffer metadata */
if (G_LIKELY (abs_time != GST_CLOCK_TIME_NONE)) {
/* the time now is the time of the clock minus the base time */
timestamp = abs_time - base_time;
/* adjust for delay in the device */
if (timestamp > delay)
timestamp -= delay;
else
timestamp = 0;
} else {
timestamp = GST_CLOCK_TIME_NONE;
}
/* activate settings for next frame */
if (GST_CLOCK_TIME_IS_VALID (duration)) {
v4l2src->ctrl_time += duration;
} else {
/* this is not very good (as it should be the next timestamp),
* still good enough for linear fades (as long as it is not -1)
*/
v4l2src->ctrl_time = timestamp;
}
gst_object_sync_values (GST_OBJECT (src), v4l2src->ctrl_time);
GST_LOG_OBJECT (src, "sync to %" GST_TIME_FORMAT " out ts %" GST_TIME_FORMAT,
GST_TIME_ARGS (v4l2src->ctrl_time), GST_TIME_ARGS (timestamp));
if (v4l2src->next_offset_same &&
GST_BUFFER_OFFSET_IS_VALID (*buf) &&
GST_BUFFER_OFFSET (*buf) != v4l2src->offset) {
/* Probably had a lost field then, best to forget about last field. */
GST_WARNING_OBJECT (v4l2src,
"lost field detected - ts: %" GST_TIME_FORMAT,
GST_TIME_ARGS (timestamp));
v4l2src->next_offset_same = FALSE;
}
half_frame = (GST_BUFFER_FLAG_IS_SET (*buf, GST_VIDEO_BUFFER_FLAG_ONEFIELD));
if (half_frame)
v4l2src->next_offset_same = !v4l2src->next_offset_same;
/* use generated offset values only if there are not already valid ones
* set by the v4l2 device */
if (!GST_BUFFER_OFFSET_IS_VALID (*buf)
|| !GST_BUFFER_OFFSET_END_IS_VALID (*buf)
|| GST_BUFFER_OFFSET (*buf) <=
(v4l2src->offset - v4l2src->renegotiation_adjust)) {
GST_BUFFER_OFFSET (*buf) = v4l2src->offset;
GST_BUFFER_OFFSET_END (*buf) = v4l2src->offset + 1;
if (!half_frame || !v4l2src->next_offset_same)
v4l2src->offset++;
} else {
/* adjust raw v4l2 device sequence, will restart at null in case of renegotiation
* (streamoff/streamon) */
GST_BUFFER_OFFSET (*buf) += v4l2src->renegotiation_adjust;
GST_BUFFER_OFFSET_END (*buf) += v4l2src->renegotiation_adjust;
/* check for frame loss with given (from v4l2 device) buffer offset */
if ((v4l2src->offset != 0)
&& (!half_frame || v4l2src->next_offset_same)
&& (GST_BUFFER_OFFSET (*buf) != (v4l2src->offset + 1))) {
guint64 lost_frame_count = GST_BUFFER_OFFSET (*buf) - v4l2src->offset - 1;
GST_WARNING_OBJECT (v4l2src,
"lost frames detected: count = %" G_GUINT64_FORMAT " - ts: %"
GST_TIME_FORMAT, lost_frame_count, GST_TIME_ARGS (timestamp));
qos_msg = gst_message_new_qos (GST_OBJECT_CAST (v4l2src), TRUE,
GST_CLOCK_TIME_NONE, GST_CLOCK_TIME_NONE, timestamp,
GST_CLOCK_TIME_IS_VALID (duration) ? lost_frame_count *
duration : GST_CLOCK_TIME_NONE);
gst_element_post_message (GST_ELEMENT_CAST (v4l2src), qos_msg);
}
v4l2src->offset = GST_BUFFER_OFFSET (*buf);
}
GST_BUFFER_TIMESTAMP (*buf) = timestamp;
GST_BUFFER_DURATION (*buf) = duration;
return ret;
/* ERROR */
alloc_failed:
{
if (ret != GST_FLOW_FLUSHING)
GST_ELEMENT_ERROR (src, RESOURCE, NO_SPACE_LEFT,
("Failed to allocate a buffer"), (NULL));
return ret;
}
error:
{
gst_buffer_replace (buf, NULL);
if (ret == GST_V4L2_FLOW_LAST_BUFFER) {
GST_ELEMENT_ERROR (src, RESOURCE, FAILED,
("Driver returned a buffer with no payload, this most likely "
"indicate a bug in the driver."), (NULL));
ret = GST_FLOW_ERROR;
} else {
GST_DEBUG_OBJECT (src, "error processing buffer %d (%s)", ret,
gst_flow_get_name (ret));
}
return ret;
}
}
/* GstURIHandler interface */
static GstURIType
gst_v4l2src_uri_get_type (GType type)
{
return GST_URI_SRC;
}
static const gchar *const *
gst_v4l2src_uri_get_protocols (GType type)
{
static const gchar *protocols[] = { "v4l2", NULL };
return protocols;
}
static gchar *
gst_v4l2src_uri_get_uri (GstURIHandler * handler)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (handler);
if (v4l2src->v4l2object->videodev != NULL) {
return g_strdup_printf ("v4l2://%s", v4l2src->v4l2object->videodev);
}
return g_strdup ("v4l2://");
}
static gboolean
gst_v4l2src_uri_set_uri (GstURIHandler * handler, const gchar * uri,
GError ** error)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (handler);
const gchar *device = DEFAULT_PROP_DEVICE;
if (strcmp (uri, "v4l2://") != 0) {
device = uri + 7;
}
g_object_set (v4l2src, "device", device, NULL);
return TRUE;
}
static void
gst_v4l2src_uri_handler_init (gpointer g_iface, gpointer iface_data)
{
GstURIHandlerInterface *iface = (GstURIHandlerInterface *) g_iface;
iface->get_type = gst_v4l2src_uri_get_type;
iface->get_protocols = gst_v4l2src_uri_get_protocols;
iface->get_uri = gst_v4l2src_uri_get_uri;
iface->set_uri = gst_v4l2src_uri_set_uri;
}
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