Enable liveview on Raspberry Pi

Author: yufengwangca

examples/camera-app/linux/README.md

@@ -117,3 +117,10 @@ git config --global --add safe.directory /var/connectedhomeip/third_party/pigwee
 # SCP command to transfer the file
 scp ./out/linux-arm64-camera-clang/chip-camera-app ubuntu@<RASPBERRY_PI_IP_ADDRESS>:/home/ubuntu
 ```
+
+5. Add your user to the video group
+
+```
+sudo usermod -aG video $USER
+newgrp video
+```

examples/camera-app/linux/src/camera-device.cpp

@@ -849,6 +849,44 @@ CameraError CameraDevice::StartVideoStream(const VideoStreamStruct & allocatedSt
     GstStateChangeReturn result = gst_element_set_state(videoPipeline, GST_STATE_PLAYING);
     if (result == GST_STATE_CHANGE_FAILURE)
     {
+        // Get error message from GStreamer bus
+        GstBus * bus = gst_element_get_bus(videoPipeline);
+        if (bus)
+        {
+            GstMessage * msg = gst_bus_pop_filtered(bus, (GstMessageType) (GST_MESSAGE_ERROR | GST_MESSAGE_WARNING));
+            if (msg)
+            {
+                GError * err       = nullptr;
+                gchar * debug_info = nullptr;
+
+                if (GST_MESSAGE_TYPE(msg) == GST_MESSAGE_ERROR)
+                {
+                    gst_message_parse_error(msg, &err, &debug_info);
+                    ChipLogError(Camera, "GStreamer Error: %s", err ? err->message : "unknown");
+                    if (debug_info)
+                    {
+                        ChipLogError(Camera, "Debug info: %s", debug_info);
+                    }
+                }
+                else if (GST_MESSAGE_TYPE(msg) == GST_MESSAGE_WARNING)
+                {
+                    gst_message_parse_warning(msg, &err, &debug_info);
+                    ChipLogError(Camera, "GStreamer Warning: %s", err ? err->message : "unknown");
+                    if (debug_info)
+                    {
+                        ChipLogError(Camera, "Debug info: %s", debug_info);
+                    }
+                }
+
+                if (err)
+                    g_error_free(err);
+                if (debug_info)
+                    g_free(debug_info);
+                gst_message_unref(msg);
+            }
+            gst_object_unref(bus);
+        }
+
         ChipLogError(Camera, "Failed to start video pipeline.");
         gst_object_unref(videoPipeline);
         it->videoContext = nullptr;

examples/camera-controller/README.md

@@ -43,6 +43,7 @@ sudo apt install \
   gstreamer1.0-plugins-bad \
   gstreamer1.0-libav \
   libgstreamer1.0-dev \
+  libavformat60 \
   libgstreamer-plugins-base1.0-dev
 ```