From effb4083f50f11be92c925b0ca449efd16f14811 Mon Sep 17 00:00:00 2001
From: Johannes Randerath <j.randerath@posteo.de>
Date: Sun, 12 Oct 2025 22:10:47 +0200
Subject: [PATCH] Initial commit; added webcam stream to gstreamer pipeline

---
 .gitignore      |  1 +
 meson.build     |  3 ++
 stream_source.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 96 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 meson.build
 create mode 100644 stream_source.c

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a007fea
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+build/*
diff --git a/meson.build b/meson.build
new file mode 100644
index 0000000..1e5db2e
--- /dev/null
+++ b/meson.build
@@ -0,0 +1,3 @@
+project('fancybirds', 'c')
+gstdep = dependency('gstreamer-1.0')
+executable('stream_source', 'stream_source.c', dependencies : gstdep)
diff --git a/stream_source.c b/stream_source.c
new file mode 100644
index 0000000..2065052
--- /dev/null
+++ b/stream_source.c
@@ -0,0 +1,92 @@
+#include "gst/gstbin.h"
+#include "gst/gstbus.h"
+#include "gst/gstclock.h"
+#include "gst/gstelement.h"
+#include "gst/gstelementfactory.h"
+#include "gst/gstmessage.h"
+#include "gst/gstobject.h"
+#include "gst/gstpipeline.h"
+#include "gst/gstutils.h"
+#include <gst/gst.h>
+
+typedef struct _CustomData {
+  GstElement *pipeline;
+  GstElement *source;
+} CustomData;
+
+int main(int argc, char *argv[]) {
+  GstBus *bus;
+  GstMessage *msg;
+  GstElement *video_queue;
+  GstElement *video_convert;
+  GstElement *video_sink;
+  CustomData data;
+  GstStateChangeReturn ret;
+  gboolean terminate = FALSE;
+  
+  gst_init(&argc, &argv);
+  data.source = gst_element_factory_make("v4l2src", "source");
+  video_queue = gst_element_factory_make("queue", "video_queue");
+  video_convert = gst_element_factory_make("videoconvert", "video_convert");
+  video_sink = gst_element_factory_make("autovideosink", "video_sink");
+  data.pipeline = gst_pipeline_new("media-pipeline");
+
+  if (!data.source || !video_queue || !video_convert || !video_sink || !data.pipeline) {
+    g_printerr("Couldn't create all elements.\n");
+    return -1;
+  }
+  g_object_set(data.source, "device", "/dev/video2", NULL);
+  
+  gst_bin_add_many(GST_BIN(data.pipeline), data.source, video_queue, video_convert, video_sink, NULL);
+  if (!gst_element_link_many(data.source, video_queue, video_convert, video_sink, NULL)) {
+    g_printerr("Couldn't link stream elements.\n");
+    gst_object_unref(data.pipeline);
+    return -1;
+  }
+
+  ret = gst_element_set_state(data.pipeline, GST_STATE_PLAYING);
+  if (ret == GST_STATE_CHANGE_FAILURE) {
+    g_printerr("Failed to start playing.\n");
+    return -1;
+  }
+  
+  bus = gst_element_get_bus(data.pipeline);
+  do {
+    msg = gst_bus_timed_pop_filtered(bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_STATE_CHANGED | GST_MESSAGE_ERROR | GST_MESSAGE_EOS);
+
+    switch (GST_MESSAGE_TYPE(msg)) {
+    case GST_MESSAGE_ERROR: {
+      GError *err;
+      gchar *debug_info;
+      gst_message_parse_error(msg, &err, &debug_info);
+      g_printerr("Error received from element %s: %s\n", GST_ELEMENT_NAME(msg->src), err->message);
+      g_printerr("Debug info: %s\n", debug_info ? debug_info : "none");
+
+      g_error_free(err);
+      g_free(debug_info);
+      terminate = TRUE;
+      break;
+    }
+    case GST_MESSAGE_EOS:
+      g_print("End-of-stream reached.\n");
+      terminate = TRUE;
+      break;
+    case GST_MESSAGE_STATE_CHANGED:
+      if (GST_MESSAGE_SRC(msg) == GST_OBJECT(data.pipeline)) {
+	GstState old_state, new_state, pending_state;
+	gst_message_parse_state_changed(msg, &old_state, &new_state, &pending_state);
+	g_print("Changed from state %d to state %d\n", old_state, new_state);
+      }
+      break;
+    default:
+      break;
+    }
+    
+  }while (!terminate);
+
+  gst_object_unref(bus);
+  gst_element_set_state(data.pipeline, GST_STATE_NULL);
+  gst_object_unref(data.pipeline);
+  
+  return 0;
+}