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gstreamer/sys/v4l2/gstv4l2src.c
Havoc Pennington 9b9f9d0a2a v4l2src: in negotiate, check for error return from set_caps 
Fixes #621723  (partially)

set_caps can fail if the video device is running, in that case
setting its format leads to EBUSY.

If set_caps fails then we will not have set up the buffer pool
(it will be NULL) which leads to a crash when we try to pull
buffers. If we fail the negotiate on set_caps failure, then we
won't go to playing state and won't crash.

This is a small improvement. Of course, a nicer fix would
be to make set_caps work in the case where the format is
unchanged. If the format has changed, failing is
probably correct because we need to close the device
(go to NULL state) in order to set caps.
2010-06-16 17:48:47 +02:00

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/* GStreamer
*
* Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
* 2006 Edgard Lima <edgard.lima@indt.org.br>
*
* 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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:element-v4l2src
*
* v4l2src can be used to capture video from v4l2 devices, like webcams and tv
* cards.
*
* <refsect2>
* <title>Example launch lines</title>
* |[
* gst-launch v4l2src ! xvimagesink
* ]| This pipeline shows the video captured from /dev/video0 tv card and for
* webcams.
* |[
* gst-launch v4l2src ! jpegdec ! xvimagesink
* ]| This pipeline shows the video captured from a webcam that delivers jpeg
* images.
* </refsect2>
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <string.h>
#include <sys/time.h>
#include "v4l2src_calls.h"
#include <unistd.h>
#include "gstv4l2colorbalance.h"
#include "gstv4l2tuner.h"
#if 0 /* overlay is still not implemented #ifdef HAVE_XVIDEO */
#include "gstv4l2xoverlay.h"
#endif
#include "gstv4l2vidorient.h"
#include "gst/gst-i18n-plugin.h"
GST_DEBUG_CATEGORY (v4l2src_debug);
#define GST_CAT_DEFAULT v4l2src_debug
#define PROP_DEF_QUEUE_SIZE 2
#define PROP_DEF_ALWAYS_COPY TRUE
#define DEFAULT_PROP_DEVICE "/dev/video0"
enum
{
PROP_0,
V4L2_STD_OBJECT_PROPS,
PROP_QUEUE_SIZE,
PROP_ALWAYS_COPY
};
GST_IMPLEMENT_V4L2_PROBE_METHODS (GstV4l2SrcClass, gst_v4l2src);
GST_IMPLEMENT_V4L2_COLOR_BALANCE_METHODS (GstV4l2Src, gst_v4l2src);
GST_IMPLEMENT_V4L2_TUNER_METHODS (GstV4l2Src, gst_v4l2src);
#if 0 /* overlay is still not implemented #ifdef HAVE_XVIDEO */
GST_IMPLEMENT_V4L2_XOVERLAY_METHODS (GstV4l2Src, gst_v4l2src);
#endif
GST_IMPLEMENT_V4L2_VIDORIENT_METHODS (GstV4l2Src, gst_v4l2src);
static void gst_v4l2src_uri_handler_init (gpointer g_iface,
gpointer iface_data);
static gboolean
gst_v4l2src_iface_supported (GstImplementsInterface * iface, GType iface_type)
{
GstV4l2Object *v4l2object = GST_V4L2SRC (iface)->v4l2object;
#if 0 /* overlay is still not implemented #ifdef HAVE_XVIDEO */
g_assert (iface_type == GST_TYPE_TUNER ||
iface_type == GST_TYPE_X_OVERLAY ||
iface_type == GST_TYPE_COLOR_BALANCE ||
iface_type == GST_TYPE_VIDEO_ORIENTATION);
#else
g_assert (iface_type == GST_TYPE_TUNER ||
iface_type == GST_TYPE_COLOR_BALANCE ||
iface_type == GST_TYPE_VIDEO_ORIENTATION);
#endif
if (v4l2object->video_fd == -1)
return FALSE;
#if 0 /* overlay is still not implemented #ifdef HAVE_XVIDEO */
if (iface_type == GST_TYPE_X_OVERLAY && !GST_V4L2_IS_OVERLAY (v4l2object))
return FALSE;
#endif
return TRUE;
}
static void
gst_v4l2src_interface_init (GstImplementsInterfaceClass * klass)
{
/*
* default virtual functions
*/
klass->supported = gst_v4l2src_iface_supported;
}
static void
gst_v4l2src_init_interfaces (GType type)
{
static const GInterfaceInfo urihandler_info = {
gst_v4l2src_uri_handler_init,
NULL,
NULL
};
static const GInterfaceInfo v4l2iface_info = {
(GInterfaceInitFunc) gst_v4l2src_interface_init,
NULL,
NULL,
};
static const GInterfaceInfo v4l2_tuner_info = {
(GInterfaceInitFunc) gst_v4l2src_tuner_interface_init,
NULL,
NULL,
};
#if 0 /* overlay is still not implemented #ifdef HAVE_XVIDEO */
static const GInterfaceInfo v4l2_xoverlay_info = {
(GInterfaceInitFunc) gst_v4l2src_xoverlay_interface_init,
NULL,
NULL,
};
#endif
static const GInterfaceInfo v4l2_colorbalance_info = {
(GInterfaceInitFunc) gst_v4l2src_color_balance_interface_init,
NULL,
NULL,
};
static const GInterfaceInfo v4l2_videoorientation_info = {
(GInterfaceInitFunc) gst_v4l2src_video_orientation_interface_init,
NULL,
NULL,
};
static const GInterfaceInfo v4l2_propertyprobe_info = {
(GInterfaceInitFunc) gst_v4l2src_property_probe_interface_init,
NULL,
NULL,
};
g_type_add_interface_static (type, GST_TYPE_URI_HANDLER, &urihandler_info);
g_type_add_interface_static (type,
GST_TYPE_IMPLEMENTS_INTERFACE, &v4l2iface_info);
g_type_add_interface_static (type, GST_TYPE_TUNER, &v4l2_tuner_info);
#if 0 /* overlay is still not implemented #ifdef HAVE_XVIDEO */
g_type_add_interface_static (type, GST_TYPE_X_OVERLAY, &v4l2_xoverlay_info);
#endif
g_type_add_interface_static (type,
GST_TYPE_COLOR_BALANCE, &v4l2_colorbalance_info);
g_type_add_interface_static (type,
GST_TYPE_VIDEO_ORIENTATION, &v4l2_videoorientation_info);
g_type_add_interface_static (type, GST_TYPE_PROPERTY_PROBE,
&v4l2_propertyprobe_info);
}
GST_BOILERPLATE_FULL (GstV4l2Src, gst_v4l2src, GstPushSrc, GST_TYPE_PUSH_SRC,
gst_v4l2src_init_interfaces);
static void gst_v4l2src_dispose (GObject * object);
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 gboolean gst_v4l2src_set_caps (GstBaseSrc * src, GstCaps * caps);
static GstCaps *gst_v4l2src_get_caps (GstBaseSrc * src);
static gboolean gst_v4l2src_query (GstBaseSrc * bsrc, GstQuery * query);
static GstFlowReturn gst_v4l2src_create (GstPushSrc * src, GstBuffer ** out);
static void gst_v4l2src_fixate (GstBaseSrc * basesrc, GstCaps * caps);
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);
/* get_frame io methods */
static GstFlowReturn
gst_v4l2src_get_read (GstV4l2Src * v4l2src, GstBuffer ** buf);
static GstFlowReturn
gst_v4l2src_get_mmap (GstV4l2Src * v4l2src, GstBuffer ** buf);
static void
gst_v4l2src_base_init (gpointer g_class)
{
GstElementClass *gstelement_class = GST_ELEMENT_CLASS (g_class);
GstV4l2SrcClass *gstv4l2src_class = GST_V4L2SRC_CLASS (g_class);
gstv4l2src_class->v4l2_class_devices = NULL;
GST_DEBUG_CATEGORY_INIT (v4l2src_debug, "v4l2src", 0, "V4L2 source element");
gst_element_class_set_details_simple (gstelement_class,
"Video (video4linux2) Source", "Source/Video",
"Reads frames from a Video4Linux2 device",
"Edgard Lima <edgard.lima@indt.org.br>,"
" Stefan Kost <ensonic@users.sf.net>");
gst_element_class_add_pad_template
(gstelement_class,
gst_pad_template_new ("src", GST_PAD_SRC, GST_PAD_ALWAYS,
gst_v4l2_object_get_all_caps ()));
}
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->dispose = gst_v4l2src_dispose;
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);
g_object_class_install_property (gobject_class, PROP_QUEUE_SIZE,
g_param_spec_uint ("queue-size", "Queue size",
"Number of buffers to be enqueud in the driver in streaming mode",
GST_V4L2_MIN_BUFFERS, GST_V4L2_MAX_BUFFERS, PROP_DEF_QUEUE_SIZE,
G_PARAM_READWRITE));
g_object_class_install_property (gobject_class, PROP_ALWAYS_COPY,
g_param_spec_boolean ("always-copy", "Always Copy",
"If the buffer will or not be used directly from mmap",
PROP_DEF_ALWAYS_COPY, G_PARAM_READWRITE));
basesrc_class->get_caps = GST_DEBUG_FUNCPTR (gst_v4l2src_get_caps);
basesrc_class->set_caps = GST_DEBUG_FUNCPTR (gst_v4l2src_set_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->fixate = GST_DEBUG_FUNCPTR (gst_v4l2src_fixate);
basesrc_class->negotiate = GST_DEBUG_FUNCPTR (gst_v4l2src_negotiate);
pushsrc_class->create = GST_DEBUG_FUNCPTR (gst_v4l2src_create);
}
static void
gst_v4l2src_init (GstV4l2Src * v4l2src, GstV4l2SrcClass * klass)
{
/* fixme: give an update_fps_function */
v4l2src->v4l2object = gst_v4l2_object_new (GST_ELEMENT (v4l2src),
V4L2_BUF_TYPE_VIDEO_CAPTURE, DEFAULT_PROP_DEVICE,
gst_v4l2_get_input, gst_v4l2_set_input, NULL);
/* number of buffers requested */
v4l2src->num_buffers = PROP_DEF_QUEUE_SIZE;
v4l2src->always_copy = PROP_DEF_ALWAYS_COPY;
v4l2src->is_capturing = FALSE;
gst_base_src_set_format (GST_BASE_SRC (v4l2src), GST_FORMAT_TIME);
gst_base_src_set_live (GST_BASE_SRC (v4l2src), TRUE);
v4l2src->fps_d = 0;
v4l2src->fps_n = 0;
}
static void
gst_v4l2src_dispose (GObject * object)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (object);
if (v4l2src->probed_caps) {
gst_caps_unref (v4l2src->probed_caps);
}
G_OBJECT_CLASS (parent_class)->dispose (object);
}
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_QUEUE_SIZE:
v4l2src->num_buffers = g_value_get_uint (value);
break;
case PROP_ALWAYS_COPY:
v4l2src->always_copy = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
}
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_QUEUE_SIZE:
g_value_set_uint (value, v4l2src->num_buffers);
break;
case PROP_ALWAYS_COPY:
g_value_set_boolean (value, v4l2src->always_copy);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
}
/* this function is a bit of a last resort */
static void
gst_v4l2src_fixate (GstBaseSrc * basesrc, GstCaps * caps)
{
GstStructure *structure;
gint i;
GST_DEBUG_OBJECT (basesrc, "fixating caps %" GST_PTR_FORMAT, caps);
for (i = 0; i < gst_caps_get_size (caps); ++i) {
const GValue *v;
structure = gst_caps_get_structure (caps, i);
/* FIXME such sizes? we usually fixate to something in the 320x200
* range... */
/* We are fixating to greater possble size (limited to GST_V4L2_MAX_SIZE)
and the maximum framerate resolution for that size */
gst_structure_fixate_field_nearest_int (structure, "width",
GST_V4L2_MAX_SIZE);
gst_structure_fixate_field_nearest_int (structure, "height",
GST_V4L2_MAX_SIZE);
gst_structure_fixate_field_nearest_fraction (structure, "framerate",
G_MAXINT, 1);
v = gst_structure_get_value (structure, "format");
if (v && G_VALUE_TYPE (v) != GST_TYPE_FOURCC) {
guint32 fourcc;
g_return_if_fail (G_VALUE_TYPE (v) == GST_TYPE_LIST);
fourcc = gst_value_get_fourcc (gst_value_list_get_value (v, 0));
gst_structure_set (structure, "format", GST_TYPE_FOURCC, fourcc, NULL);
}
}
GST_DEBUG_OBJECT (basesrc, "fixated caps %" GST_PTR_FORMAT, caps);
}
static gboolean
gst_v4l2src_negotiate (GstBaseSrc * basesrc)
{
GstCaps *thiscaps;
GstCaps *caps = NULL;
GstCaps *peercaps = NULL;
gboolean result = FALSE;
/* first see what is possible on our source pad */
thiscaps = gst_pad_get_caps (GST_BASE_SRC_PAD (basesrc));
GST_DEBUG_OBJECT (basesrc, "caps of src: %" GST_PTR_FORMAT, thiscaps);
LOG_CAPS (basesrc, 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 */
peercaps = gst_pad_peer_get_caps (GST_BASE_SRC_PAD (basesrc));
GST_DEBUG_OBJECT (basesrc, "caps of peer: %" GST_PTR_FORMAT, peercaps);
LOG_CAPS (basesrc, peercaps);
if (peercaps && !gst_caps_is_any (peercaps)) {
GstCaps *icaps = NULL;
int i;
/* Prefer the first caps we are compatible with that the peer proposed */
for (i = 0; i < gst_caps_get_size (peercaps); i++) {
/* get intersection */
GstCaps *ipcaps = gst_caps_copy_nth (peercaps, i);
GST_DEBUG_OBJECT (basesrc, "peer: %" GST_PTR_FORMAT, ipcaps);
LOG_CAPS (basesrc, ipcaps);
icaps = gst_caps_intersect (thiscaps, ipcaps);
gst_caps_unref (ipcaps);
if (!gst_caps_is_empty (icaps))
break;
gst_caps_unref (icaps);
icaps = NULL;
}
GST_DEBUG_OBJECT (basesrc, "intersect: %" GST_PTR_FORMAT, icaps);
LOG_CAPS (basesrc, icaps);
if (icaps) {
/* If there are multiple intersections pick the one with the smallest
* resolution strictly bigger then the first peer caps */
if (gst_caps_get_size (icaps) > 1) {
GstStructure *s = gst_caps_get_structure (peercaps, 0);
int best = 0;
int twidth, theight;
int width = G_MAXINT, height = G_MAXINT;
if (gst_structure_get_int (s, "width", &twidth)
&& gst_structure_get_int (s, "height", &theight)) {
/* Walk the structure backwards to get the first entry of the
* smallest resolution bigger (or equal to) the preferred resolution)
*/
for (i = gst_caps_get_size (icaps) - 1; i >= 0; i--) {
GstStructure *is = gst_caps_get_structure (icaps, i);
int w, h;
if (gst_structure_get_int (is, "width", &w)
&& gst_structure_get_int (is, "height", &h)) {
if (w >= twidth && w <= width && h >= theight && h <= height) {
width = w;
height = h;
best = i;
}
}
}
}
caps = gst_caps_copy_nth (icaps, best);
gst_caps_unref (icaps);
} else {
caps = icaps;
}
}
gst_caps_unref (thiscaps);
gst_caps_unref (peercaps);
} else {
/* no peer or peer have ANY caps, work with our own caps then */
caps = thiscaps;
}
if (caps) {
caps = gst_caps_make_writable (caps);
gst_caps_truncate (caps);
/* now fixate */
if (!gst_caps_is_empty (caps)) {
gst_pad_fixate_caps (GST_BASE_SRC_PAD (basesrc), caps);
GST_DEBUG_OBJECT (basesrc, "fixated to: %" GST_PTR_FORMAT, caps);
LOG_CAPS (basesrc, 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 */
if (gst_pad_set_caps (GST_BASE_SRC_PAD (basesrc), caps))
result = TRUE;
}
}
gst_caps_unref (caps);
}
return result;
no_nego_needed:
{
GST_DEBUG_OBJECT (basesrc, "no negotiation needed");
if (thiscaps)
gst_caps_unref (thiscaps);
return TRUE;
}
}
static GstCaps *
gst_v4l2src_get_caps (GstBaseSrc * src)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (src);
GstCaps *ret;
GSList *walk;
GSList *formats;
if (!GST_V4L2_IS_OPEN (v4l2src->v4l2object)) {
/* FIXME: copy? */
return
gst_caps_copy (gst_pad_get_pad_template_caps (GST_BASE_SRC_PAD
(v4l2src)));
}
if (v4l2src->probed_caps)
return gst_caps_ref (v4l2src->probed_caps);
formats = gst_v4l2_object_get_format_list (v4l2src->v4l2object);
ret = gst_caps_new_empty ();
for (walk = v4l2src->v4l2object->formats; walk; walk = walk->next) {
struct v4l2_fmtdesc *format;
GstStructure *template;
format = (struct v4l2_fmtdesc *) walk->data;
template = gst_v4l2_object_v4l2fourcc_to_structure (format->pixelformat);
if (template) {
GstCaps *tmp;
tmp =
gst_v4l2_object_probe_caps_for_format (v4l2src->v4l2object,
format->pixelformat, template);
if (tmp)
gst_caps_append (ret, tmp);
gst_structure_free (template);
} else {
GST_DEBUG_OBJECT (v4l2src, "unknown format %u", format->pixelformat);
}
}
v4l2src->probed_caps = gst_caps_ref (ret);
GST_INFO_OBJECT (v4l2src, "probed caps: %" GST_PTR_FORMAT, ret);
return ret;
}
static gboolean
gst_v4l2src_set_caps (GstBaseSrc * src, GstCaps * caps)
{
GstV4l2Src *v4l2src;
gint w = 0, h = 0;
struct v4l2_fmtdesc *format;
guint fps_n, fps_d;
guint size;
v4l2src = GST_V4L2SRC (src);
/* if we're not open, punt -- we'll get setcaps'd later via negotiate */
if (!GST_V4L2_IS_OPEN (v4l2src->v4l2object))
return FALSE;
/* make sure we stop capturing and dealloc buffers */
if (GST_V4L2_IS_ACTIVE (v4l2src->v4l2object)) {
/* both will throw an element-error on failure */
if (!gst_v4l2src_capture_stop (v4l2src))
return FALSE;
if (!gst_v4l2src_capture_deinit (v4l2src))
return FALSE;
}
/* we want our own v4l2 type of fourcc codes */
if (!gst_v4l2_object_get_caps_info (v4l2src->v4l2object, caps, &format, &w,
&h, &fps_n, &fps_d, &size)) {
GST_DEBUG_OBJECT (v4l2src,
"can't get capture format from caps %" GST_PTR_FORMAT, caps);
return FALSE;
}
GST_DEBUG_OBJECT (v4l2src, "trying to set_capture %dx%d at %d/%d fps, "
"format %s", w, h, fps_n, fps_d, format->description);
if (!gst_v4l2src_set_capture (v4l2src, format->pixelformat, w, h, fps_n,
fps_d))
/* error already posted */
return FALSE;
if (!gst_v4l2src_capture_init (v4l2src, caps))
return FALSE;
if (v4l2src->use_mmap) {
v4l2src->get_frame = gst_v4l2src_get_mmap;
} else {
v4l2src->get_frame = gst_v4l2src_get_read;
}
if (!gst_v4l2src_capture_start (v4l2src))
return FALSE;
/* now store the expected output size */
v4l2src->frame_byte_size = size;
return TRUE;
}
static gboolean
gst_v4l2src_query (GstBaseSrc * bsrc, GstQuery * query)
{
GstV4l2Src *src;
gboolean res = FALSE;
src = GST_V4L2SRC (bsrc);
switch (GST_QUERY_TYPE (query)) {
case GST_QUERY_LATENCY:{
GstClockTime min_latency, max_latency;
/* device must be open */
if (!GST_V4L2_IS_OPEN (src->v4l2object)) {
GST_WARNING_OBJECT (src,
"Can't give latency since device isn't open !");
goto done;
}
/* we must have a framerate */
if (src->fps_n <= 0 || src->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 */
min_latency =
gst_util_uint64_scale_int (GST_SECOND, src->fps_d, src->fps_n);
/* max latency is total duration of the frame buffer */
max_latency = src->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;
return TRUE;
}
static gboolean
gst_v4l2src_unlock (GstBaseSrc * src)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (src);
GST_LOG_OBJECT (src, "Flushing");
gst_poll_set_flushing (v4l2src->v4l2object->poll, TRUE);
return TRUE;
}
static gboolean
gst_v4l2src_unlock_stop (GstBaseSrc * src)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (src);
GST_LOG_OBJECT (src, "No longer flushing");
gst_poll_set_flushing (v4l2src->v4l2object->poll, FALSE);
return TRUE;
}
static gboolean
gst_v4l2src_stop (GstBaseSrc * src)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (src);
if (GST_V4L2_IS_ACTIVE (v4l2src->v4l2object)
&& !gst_v4l2src_capture_stop (v4l2src))
return FALSE;
if (v4l2src->v4l2object->buffer != NULL) {
if (!gst_v4l2src_capture_deinit (v4l2src))
return FALSE;
}
v4l2src->fps_d = 0;
v4l2src->fps_n = 0;
return TRUE;
}
static GstStateChangeReturn
gst_v4l2src_change_state (GstElement * element, GstStateChange transition)
{
GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
GstV4l2Src *v4l2src = GST_V4L2SRC (element);
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
/* open the device */
if (!gst_v4l2_object_start (v4l2src->v4l2object))
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_stop (v4l2src->v4l2object))
return GST_STATE_CHANGE_FAILURE;
if (v4l2src->probed_caps) {
gst_caps_unref (v4l2src->probed_caps);
v4l2src->probed_caps = NULL;
}
break;
default:
break;
}
return ret;
}
static GstFlowReturn
gst_v4l2src_get_read (GstV4l2Src * v4l2src, GstBuffer ** buf)
{
gint amount;
gint ret;
gint buffersize;
buffersize = v4l2src->frame_byte_size;
*buf = gst_buffer_new_and_alloc (buffersize);
do {
ret = gst_poll_wait (v4l2src->v4l2object->poll, GST_CLOCK_TIME_NONE);
if (G_UNLIKELY (ret < 0)) {
if (errno == EBUSY)
goto stopped;
if (errno == ENXIO) {
GST_DEBUG_OBJECT (v4l2src,
"v4l2 device doesn't support polling. Disabling");
v4l2src->v4l2object->can_poll_device = FALSE;
} else {
if (errno != EAGAIN && errno != EINTR)
goto select_error;
}
}
amount =
v4l2_read (v4l2src->v4l2object->video_fd, GST_BUFFER_DATA (*buf),
buffersize);
if (amount == buffersize) {
break;
} else if (amount == -1) {
if (errno == EAGAIN || errno == EINTR) {
continue;
} else
goto read_error;
} else {
/* short reads can happen if a signal interrupts the read */
continue;
}
} while (TRUE);
/* we set the buffer metadata in gst_v4l2src_create() */
return GST_FLOW_OK;
/* ERRORS */
select_error:
{
GST_ELEMENT_ERROR (v4l2src, RESOURCE, READ, (NULL),
("select error %d: %s (%d)", ret, g_strerror (errno), errno));
return GST_FLOW_ERROR;
}
stopped:
{
GST_DEBUG ("stop called");
return GST_FLOW_WRONG_STATE;
}
read_error:
{
GST_ELEMENT_ERROR (v4l2src, RESOURCE, READ,
(_("Error reading %d bytes from device '%s'."),
buffersize, v4l2src->v4l2object->videodev), GST_ERROR_SYSTEM);
gst_buffer_unref (*buf);
return GST_FLOW_ERROR;
}
}
static GstFlowReturn
gst_v4l2src_get_mmap (GstV4l2Src * v4l2src, GstBuffer ** buf)
{
GstBuffer *temp;
GstFlowReturn ret;
guint size;
guint count = 0;
again:
ret = gst_v4l2src_grab_frame (v4l2src, &temp);
if (G_UNLIKELY (ret != GST_FLOW_OK))
goto done;
if (v4l2src->frame_byte_size > 0) {
size = GST_BUFFER_SIZE (temp);
/* if size does not match what we expected, try again */
if (size != v4l2src->frame_byte_size) {
GST_ELEMENT_WARNING (v4l2src, RESOURCE, READ,
(_("Got unexpected frame size of %u instead of %u."),
size, v4l2src->frame_byte_size), (NULL));
gst_buffer_unref (temp);
if (count++ > 50)
goto size_error;
goto again;
}
}
*buf = temp;
done:
return ret;
/* ERRORS */
size_error:
{
GST_ELEMENT_ERROR (v4l2src, RESOURCE, READ,
(_("Error reading %d bytes on device '%s'."),
v4l2src->frame_byte_size, v4l2src->v4l2object->videodev), (NULL));
return GST_FLOW_ERROR;
}
}
static GstFlowReturn
gst_v4l2src_create (GstPushSrc * src, GstBuffer ** buf)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (src);
GstFlowReturn ret;
ret = v4l2src->get_frame (v4l2src, buf);
/* set buffer metadata */
if (G_LIKELY (ret == GST_FLOW_OK && *buf)) {
GstClock *clock;
GstClockTime timestamp;
GstClockTime duration = GST_CLOCK_TIME_NONE;
GST_BUFFER_OFFSET (*buf) = v4l2src->offset++;
GST_BUFFER_OFFSET_END (*buf) = v4l2src->offset;
/* timestamps, LOCK to get clock and base time. */
GST_OBJECT_LOCK (v4l2src);
if ((clock = GST_ELEMENT_CLOCK (v4l2src))) {
/* we have a clock, get base time and ref clock */
timestamp = GST_ELEMENT (v4l2src)->base_time;
gst_object_ref (clock);
} else {
/* no clock, can't set timestamps */
timestamp = GST_CLOCK_TIME_NONE;
}
GST_OBJECT_UNLOCK (v4l2src);
if (clock) {
/* the time now is the time of the clock minus the base time */
timestamp = gst_clock_get_time (clock) - timestamp;
gst_object_unref (clock);
/* if we have a framerate adjust timestamp for frame latency */
if (v4l2src->fps_n > 0 && v4l2src->fps_d > 0) {
GstClockTime latency;
latency = gst_util_uint64_scale_int (GST_SECOND, v4l2src->fps_d,
v4l2src->fps_n);
if (timestamp > latency)
timestamp -= latency;
else
timestamp = 0;
duration = latency;
}
}
/* FIXME: use the timestamp from the buffer itself! */
GST_BUFFER_TIMESTAMP (*buf) = timestamp;
GST_BUFFER_DURATION (*buf) = duration;
}
return ret;
}
/* GstURIHandler interface */
static GstURIType
gst_v4l2src_uri_get_type (void)
{
return GST_URI_SRC;
}
static gchar **
gst_v4l2src_uri_get_protocols (void)
{
static gchar *protocols[] = { (char *) "v4l2", NULL };
return protocols;
}
static const gchar *
gst_v4l2src_uri_get_uri (GstURIHandler * handler)
{
GstV4l2Src *v4l2src = GST_V4L2SRC (handler);
if (v4l2src->v4l2object->videodev != NULL) {
gchar uri[256];
/* need to return a const string, but also don't want to leak the generated
* string, so just intern it - there's a limited number of video devices
* after all */
g_snprintf (uri, sizeof (uri), "v4l2://%s", v4l2src->v4l2object->videodev);
return g_intern_string (uri);
}
return "v4l2://";
}
static gboolean
gst_v4l2src_uri_set_uri (GstURIHandler * handler, const gchar * uri)
{
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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