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https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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1fc8347c1e
Add a simple utility to illustrate how to set input cropping on v4l2src. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1089>
213 lines
5.7 KiB
C
213 lines
5.7 KiB
C
/* GStreamer
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* Copyright (C) 2021 Damian Hobson-Garcia <dhobsong@igel.co.jp>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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/* demo application showing v4l2src cropping */
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <gst/gst.h>
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#define PLAY_TIME_SEC 5
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struct rect
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{
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guint left;
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guint top;
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guint width;
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guint height;
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};
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static gboolean
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bus_call (GstBus * bus, GstMessage * msg, gpointer data)
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{
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GMainLoop *loop = (GMainLoop *) data;
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switch (GST_MESSAGE_TYPE (msg)) {
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case GST_MESSAGE_EOS:
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g_print ("End of stream\n");
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g_main_loop_quit (loop);
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break;
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case GST_MESSAGE_ERROR:{
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gchar *debug;
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GError *error;
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gst_message_parse_error (msg, &error, &debug);
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g_free (debug);
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g_printerr ("Error: %s\n", error->message);
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g_error_free (error);
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g_main_loop_quit (loop);
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break;
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}
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default:
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break;
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}
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return TRUE;
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}
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static void
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on_crop_bounds (GstElement * element, GParamSpec * pspec, void *data)
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{
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GValue bounds = { 0 };
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int i;
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union
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{
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struct rect rect;
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guint vals[4];
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} crop_bounds;
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struct rect crop;
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g_value_init (&bounds, G_PARAM_SPEC_VALUE_TYPE (pspec));
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g_object_get_property (G_OBJECT (element), "crop-bounds", &bounds);
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if (gst_value_array_get_size (&bounds) != 4) {
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g_error ("Invalid crop bounds received");
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return;
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}
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for (i = 0; i < 4; i++) {
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const GValue *val = gst_value_array_get_value (&bounds, i);
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if (!G_VALUE_HOLDS_INT (val)) {
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g_error ("Invalid crop bounds value received");
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return;
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}
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crop_bounds.vals[i] = g_value_get_int (val);
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}
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g_print ("Crop bounds: @(%d, %d), %dx%d\n", crop_bounds.rect.left,
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crop_bounds.rect.top, crop_bounds.rect.width, crop_bounds.rect.height);
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/* Crop out a region from the bottom right quandrant of the
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* crop bounding region */
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crop.left = (crop_bounds.rect.width - crop_bounds.rect.left) / 2;
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crop.top = (crop_bounds.rect.height - crop_bounds.rect.top) / 2;
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crop.width = crop.left / 2;
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crop.height = crop.left / 2;
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g_print ("Setting crop region to @(%d, %d), %dx%d\n", crop.left, crop.top,
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crop.width, crop.height);
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g_object_set (G_OBJECT (element),
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"crop-left", crop.left,
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"crop-top", crop.top,
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"crop-right", crop_bounds.rect.width - crop.left - crop.width,
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"crop-bottom", crop_bounds.rect.height - crop.top - crop.height, NULL);
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}
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static const gchar *device = "/dev/video0";
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static const gchar *videosink = "autovideosink";
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static GOptionEntry entries[] = {
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{"device", 'd', 0, G_OPTION_ARG_STRING, &device, "V4L2 Camera Device",
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NULL},
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{"videosink", 's', 0, G_OPTION_ARG_STRING, &videosink, "Video Sink to use",
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NULL},
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{NULL}
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};
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static gboolean
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send_eos (gpointer user_data)
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{
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GstElement *pipeline = user_data;
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gst_element_send_event (pipeline, gst_event_new_eos ());
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return FALSE;
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}
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int
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main (int argc, char *argv[])
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{
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GMainLoop *loop;
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GstElement *pipeline, *source, *conv, *sink;
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GstBus *bus;
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guint bus_watch_id;
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GError *error = NULL;
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GOptionContext *context;
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gboolean ret;
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context = g_option_context_new ("- test v4l2src crop");
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g_option_context_add_main_entries (context, entries, GETTEXT_PACKAGE);
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g_option_context_add_group (context, gst_init_get_option_group ());
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ret = g_option_context_parse (context, &argc, &argv, &error);
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g_option_context_free (context);
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if (!ret) {
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g_print ("option parsing failed: %s\n", error->message);
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g_error_free (error);
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return 1;
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}
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gst_init (&argc, &argv);
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loop = g_main_loop_new (NULL, FALSE);
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/* Create gstreamer elements */
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pipeline = gst_pipeline_new ("v4l2src crop sample");
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source = gst_element_factory_make ("v4l2src", "source");
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conv = gst_element_factory_make ("videoconvert", "converter");
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sink = gst_element_factory_make (videosink, "video-output");
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if (!pipeline || !source || !conv || !sink) {
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g_printerr ("One or more elements could not be created. Exiting.\n");
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return -1;
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}
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/* Set up the v4l2src element */
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g_object_set (G_OBJECT (source), "device", device, NULL);
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/* Add a message handler */
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bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
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bus_watch_id = gst_bus_add_watch (bus, bus_call, loop);
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gst_object_unref (bus);
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gst_bin_add_many (GST_BIN (pipeline), source, conv, sink, NULL);
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gst_element_link_many (source, conv, sink, NULL);
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/* Connect a callback to be notified when the crop bounding region is
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* retreived from the V4L2 device */
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g_signal_connect (source, "notify::crop-bounds", (GCallback) on_crop_bounds,
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NULL);
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/* Set the pipeline to "playing" state */
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gst_element_set_state (pipeline, GST_STATE_PLAYING);
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/* Stop the playback after specified time */
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g_timeout_add_seconds (PLAY_TIME_SEC, send_eos, pipeline);
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g_main_loop_run (loop);
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/* Out of the main loop, clean up nicely */
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g_print ("Stopping playback\n");
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gst_element_set_state (pipeline, GST_STATE_NULL);
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g_print ("Deleting pipeline\n");
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gst_object_unref (GST_OBJECT (pipeline));
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g_source_remove (bus_watch_id);
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g_main_loop_unref (loop);
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return 0;
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}
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