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gstreamer/sys/v4l2/gstv4l2src.c
Stefan Kost 00ffa9c2dd v4l2src: add a function pointer for get_frame function and optimize a bit 
Use a function-pointer for mmap/read, as this can't change during capture. Also
sprinkle a few G_LIKELY/UNLIKELY to improve the error-less code path.
2009-09-11 22:24:47 +03:00

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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"
static const GstElementDetails gst_v4l2src_details =
GST_ELEMENT_DETAILS ("Video (video4linux2) Source",
"Source/Video",
"Reads frames from a video4linux2 (BT8x8) device",
"Edgard Lima <edgard.lima@indt.org.br>,"
" Stefan Kost <ensonic@users.sf.net>");
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 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;
}
void
gst_v4l2src_init_interfaces (GType type)
{
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_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 (gstelement_class, &gst_v4l2src_details);
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 */
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;
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;
}
}
/* FIXME: use the timestamp from the buffer itself! */
GST_BUFFER_TIMESTAMP (*buf) = timestamp;
}
return ret;
}
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