gstreamer/subprojects/gst-plugins-good/tests/examples/v4l2/v4l2src-crop.c

214 lines
5.7 KiB
C
Raw Normal View History

/* GStreamer
* Copyright (C) 2021 Damian Hobson-Garcia <dhobsong@igel.co.jp>
*
* 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.
*/
/* demo application showing v4l2src cropping */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/gst.h>
#define PLAY_TIME_SEC 5
struct rect
{
guint left;
guint top;
guint width;
guint height;
};
static gboolean
bus_call (GstBus * bus, GstMessage * msg, gpointer data)
{
GMainLoop *loop = (GMainLoop *) data;
switch (GST_MESSAGE_TYPE (msg)) {
case GST_MESSAGE_EOS:
g_print ("End of stream\n");
g_main_loop_quit (loop);
break;
case GST_MESSAGE_ERROR:{
gchar *debug;
GError *error;
gst_message_parse_error (msg, &error, &debug);
g_free (debug);
g_printerr ("Error: %s\n", error->message);
g_error_free (error);
g_main_loop_quit (loop);
break;
}
default:
break;
}
return TRUE;
}
static void
on_crop_bounds (GstElement * element, GParamSpec * pspec, void *data)
{
GValue bounds = { 0 };
int i;
union
{
struct rect rect;
guint vals[4];
} crop_bounds;
struct rect crop;
g_value_init (&bounds, G_PARAM_SPEC_VALUE_TYPE (pspec));
g_object_get_property (G_OBJECT (element), "crop-bounds", &bounds);
if (gst_value_array_get_size (&bounds) != 4) {
g_error ("Invalid crop bounds received");
return;
}
for (i = 0; i < 4; i++) {
const GValue *val = gst_value_array_get_value (&bounds, i);
if (!G_VALUE_HOLDS_INT (val)) {
g_error ("Invalid crop bounds value received");
return;
}
crop_bounds.vals[i] = g_value_get_int (val);
}
g_print ("Crop bounds: @(%d, %d), %dx%d\n", crop_bounds.rect.left,
crop_bounds.rect.top, crop_bounds.rect.width, crop_bounds.rect.height);
/* Crop out a region from the bottom right quandrant of the
* crop bounding region */
crop.left = (crop_bounds.rect.width - crop_bounds.rect.left) / 2;
crop.top = (crop_bounds.rect.height - crop_bounds.rect.top) / 2;
crop.width = crop.left / 2;
crop.height = crop.left / 2;
g_print ("Setting crop region to @(%d, %d), %dx%d\n", crop.left, crop.top,
crop.width, crop.height);
g_object_set (G_OBJECT (element),
"crop-left", crop.left,
"crop-top", crop.top,
"crop-right", crop_bounds.rect.width - crop.left - crop.width,
"crop-bottom", crop_bounds.rect.height - crop.top - crop.height, NULL);
}
static const gchar *device = "/dev/video0";
static const gchar *videosink = "autovideosink";
static GOptionEntry entries[] = {
{"device", 'd', 0, G_OPTION_ARG_STRING, &device, "V4L2 Camera Device",
NULL},
{"videosink", 's', 0, G_OPTION_ARG_STRING, &videosink, "Video Sink to use",
NULL},
{NULL}
};
static gboolean
send_eos (gpointer user_data)
{
GstElement *pipeline = user_data;
gst_element_send_event (pipeline, gst_event_new_eos ());
return FALSE;
}
int
main (int argc, char *argv[])
{
GMainLoop *loop;
GstElement *pipeline, *source, *conv, *sink;
GstBus *bus;
guint bus_watch_id;
GError *error = NULL;
GOptionContext *context;
gboolean ret;
context = g_option_context_new ("- test v4l2src crop");
g_option_context_add_main_entries (context, entries, GETTEXT_PACKAGE);
g_option_context_add_group (context, gst_init_get_option_group ());
ret = g_option_context_parse (context, &argc, &argv, &error);
g_option_context_free (context);
if (!ret) {
g_print ("option parsing failed: %s\n", error->message);
g_error_free (error);
return 1;
}
gst_init (&argc, &argv);
loop = g_main_loop_new (NULL, FALSE);
/* Create gstreamer elements */
pipeline = gst_pipeline_new ("v4l2src crop sample");
source = gst_element_factory_make ("v4l2src", "source");
conv = gst_element_factory_make ("videoconvert", "converter");
sink = gst_element_factory_make (videosink, "video-output");
if (!pipeline || !source || !conv || !sink) {
g_printerr ("One or more elements could not be created. Exiting.\n");
return -1;
}
/* Set up the v4l2src element */
g_object_set (G_OBJECT (source), "device", device, NULL);
/* Add a message handler */
bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
bus_watch_id = gst_bus_add_watch (bus, bus_call, loop);
gst_object_unref (bus);
gst_bin_add_many (GST_BIN (pipeline), source, conv, sink, NULL);
gst_element_link_many (source, conv, sink, NULL);
/* Connect a callback to be notified when the crop bounding region is
* retreived from the V4L2 device */
g_signal_connect (source, "notify::crop-bounds", (GCallback) on_crop_bounds,
NULL);
/* Set the pipeline to "playing" state */
gst_element_set_state (pipeline, GST_STATE_PLAYING);
/* Stop the playback after specified time */
g_timeout_add_seconds (PLAY_TIME_SEC, send_eos, pipeline);
g_main_loop_run (loop);
/* Out of the main loop, clean up nicely */
g_print ("Stopping playback\n");
gst_element_set_state (pipeline, GST_STATE_NULL);
g_print ("Deleting pipeline\n");
gst_object_unref (GST_OBJECT (pipeline));
g_source_remove (bus_watch_id);
g_main_loop_unref (loop);
return 0;
}