[libcamera-devel] [PATCH v2] test: gstreamer: Add a test for gstreamer multi stream

Laurent Pinchart laurent.pinchart at ideasonboard.com
Sun Aug 29 03:09:11 CEST 2021


Hi Vedant,

Thank you for the patch.

On Sat, Aug 28, 2021 at 11:07:53PM +0530, Vedant Paranjape wrote:
> This patch adds a test to test if multi stream using libcamera's
> gstreamer element works.
> 
> We need to work around one issue with ASan when enabled in the
> build:
> 
> - glib has a known leak at initialization time. This is covered by the
>   suppression file shipped with glib, but it's not clear how to use it
>   automatically. For now, disable leak detection to avoid test failures.
> 
> Signed-off-by: Vedant Paranjape <vedantparanjape160201 at gmail.com>
> ---
>  .../gstreamer/gstreamer_multi_stream_test.cpp | 225 ++++++++++++++++++
>  test/gstreamer/meson.build                    |   1 +
>  2 files changed, 226 insertions(+)
>  create mode 100644 test/gstreamer/gstreamer_multi_stream_test.cpp
> 
> diff --git a/test/gstreamer/gstreamer_multi_stream_test.cpp b/test/gstreamer/gstreamer_multi_stream_test.cpp
> new file mode 100644
> index 00000000..e32b07a4
> --- /dev/null
> +++ b/test/gstreamer/gstreamer_multi_stream_test.cpp
> @@ -0,0 +1,225 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2021, Vedant Paranjape
> + *
> + * gstreamer_single_stream_test.cpp - GStreamer single stream capture test
> + */
> +
> +#include <iostream>
> +#include <unistd.h>
> +
> +#include <libcamera/base/utils.h>
> +
> +#include <libcamera/libcamera.h>
> +
> +#include "libcamera/internal/source_paths.h"
> +
> +#include <gst/gst.h>
> +
> +#include "test.h"
> +
> +using namespace std;
> +
> +extern "C" {
> +const char *__asan_default_options()
> +{
> +	/*
> +	 * Disable leak detection due to a known global variable initialization
> +	 * leak in glib's g_quark_init(). This should ideally be handled by
> +	 * using a suppression file instead of disabling leak detection.
> +	 */
> +	return "detect_leaks=false";
> +}
> +}
> +
> +class GstreamerSingleStreamTest : public Test
> +{
> +protected:
> +	int init() override
> +	{
> +		/*
> +		 * GStreamer by default spawns a process to run the
> +		 * gst-plugin-scanner helper. If libcamera is compiled with ASan
> +		 * enabled, and as GStreamer is most likely not, this causes the
> +		 * ASan link order check to fail when gst-plugin-scanner
> +		 * dlopen()s the plugin as many libraries will have already been
> +		 * loaded by then. Fix this issue by disabling spawning of a
> +		 * child helper process when scanning the build directory for
> +		 * plugins.
> +		 */
> +		gst_registry_fork_set_enabled(false);
> +
> +		/* Initialize GStreamer */
> +		g_autoptr(GError) errInit = NULL;
> +		if (!gst_init_check(nullptr, nullptr, &errInit)) {
> +			g_printerr("Could not initialize GStreamer: %s\n",
> +				   errInit ? errInit->message : "unknown error");
> +
> +			return TestFail;
> +		}
> +
> +		/*
> +		 * Remove the system libcamera plugin, if any, and add the
> +		 * plugin from the build directory.
> +		 */
> +		GstRegistry *registry = gst_registry_get();
> +		GstPlugin *plugin = gst_registry_lookup(registry, "libgstlibcamera.so");
> +		if (plugin) {
> +			gst_registry_remove_plugin(registry, plugin);
> +			gst_object_unref(plugin);
> +		}
> +
> +		std::string path = libcamera::utils::libcameraBuildPath()
> +				 + "src/gstreamer";
> +		if (!gst_registry_scan_path(registry, path.c_str())) {
> +			g_printerr("Failed to add plugin to registry\n");
> +			gst_deinit();
> +			return TestFail;
> +		}

There's quite a bit of duplicated code between this and the single
stream test. Could you refactor the single stream test to create a base
class that can be shared with this one ?

> +
> +		/* Check if platform support multistream output */
> +		libcamera::CameraManager cm;
> +		cm.start();
> +		if (cm.cameras()[0]->streams().size() <= 1) {
> +			cm.stop();
> +			return TestSkip;
> +		}
> +		cm.stop();

Is there a guarantee that libcamerasrc will pick the same camera ? It
seems quite fragile to me. Isn't there a way to instead query the
libcamerasrc element for the number of pads it supports ? More than
that, as not all cameras support multiple streams, it would be nice if
the test could iterate over all cameras to find one that does.

> +
> +		/* Create the elements */
> +		libcameraSrc_ = gst_element_factory_make("libcamerasrc", "libcamera");
> +		convert0_ = gst_element_factory_make("videoconvert", "convert0");
> +		convert1_ = gst_element_factory_make("videoconvert", "convert1");
> +		sink0_ = gst_element_factory_make("fakesink", "sink0");
> +		sink1_ = gst_element_factory_make("fakesink", "sink1");
> +		queue0_ = gst_element_factory_make("queue", "camera_queue0");
> +		queue1_ = gst_element_factory_make("queue", "camera_queue1");

Looks like there's room to make the code more generic, posibly storing
the elements in containers.

> +
> +		/* Create the empty pipeline_ */
> +		pipeline_ = gst_pipeline_new("test-pipeline");
> +
> +		if (!pipeline_ || !convert0_ || !convert1_ || !sink0_ ||
> +			!sink1_ || !queue0_ || !queue1_ || !libcameraSrc_) {
> +			g_printerr("Not all elements could be created. %p.%p.%p.%p.%p.%p.%p.%p\n",
> +						pipeline_, convert0_, convert1_, sink0_,
> +						sink1_, queue0_, queue1_, libcameraSrc_);
> +			if (pipeline_)
> +				gst_object_unref(pipeline_);
> +			if (convert0_)
> +				gst_object_unref(convert0_);
> +			if (convert1_)
> +				gst_object_unref(convert1_);
> +			if (sink0_)
> +				gst_object_unref(sink0_);
> +			if (sink1_)
> +				gst_object_unref(sink1_);
> +			if (queue0_)
> +				gst_object_unref(queue0_);
> +			if (queue1_)
> +				gst_object_unref(queue1_);
> +			if (libcameraSrc_)
> +				gst_object_unref(libcameraSrc_);
> +			gst_deinit();
> +
> +			return TestFail;
> +		}
> +
> +		return TestPass;
> +	}
> +
> +	void cleanup() override
> +	{
> +		gst_object_unref(pipeline_);
> +		gst_deinit();
> +	}
> +
> +	int run() override
> +	{
> +		GstStateChangeReturn ret;
> +
> +		/* Build the pipeline */
> +		gst_bin_add_many(GST_BIN(pipeline_), libcameraSrc_, queue0_, queue1_,
> +							convert0_, convert1_, sink0_, sink1_, NULL);
> +		if (gst_element_link_many(queue0_, convert0_, sink0_, NULL) != TRUE
> +				|| gst_element_link_many(queue1_, convert1_, sink1_, NULL) != TRUE) {
> +			g_printerr("Elements could not be linked.\n");
> +			return TestFail;
> +		}
> +
> +		g_autoptr(GstPad) src_pad = gst_element_get_static_pad(libcameraSrc_, "src");
> +		g_autoptr(GstPad) request_pad = gst_element_get_request_pad(libcameraSrc_, "src_%u");
> +		GstPad *queue0_sink_pad = gst_element_get_static_pad(queue0_, "sink");
> +		GstPad *queue1_sink_pad = gst_element_get_static_pad(queue1_, "sink");
> +
> +		if (gst_pad_link(src_pad, queue0_sink_pad) != GST_PAD_LINK_OK
> +				|| gst_pad_link(request_pad, queue1_sink_pad) != GST_PAD_LINK_OK) {
> +			if (queue0_sink_pad)
> +				gst_object_unref(queue0_sink_pad);
> +			if (queue1_sink_pad)
> +				gst_object_unref(queue1_sink_pad);
> +			g_printerr("Pads could not be linked.\n");
> +			return TestFail;
> +		}
> +		gst_object_unref(queue0_sink_pad);
> +		gst_object_unref(queue1_sink_pad);
> +
> +		/* Start playing */
> +		ret = gst_element_set_state(pipeline_, GST_STATE_PLAYING);
> +		if (ret == GST_STATE_CHANGE_FAILURE) {
> +			g_printerr("Unable to set the pipeline to the playing state.\n");
> +			return TestFail;
> +		}
> +
> +		/* Wait until error or EOS or timeout after 2 seconds */
> +		constexpr GstMessageType msgType =
> +			static_cast<GstMessageType>(GST_MESSAGE_ERROR | GST_MESSAGE_EOS);
> +		constexpr GstClockTime timeout = 2 * GST_SECOND;
> +
> +		g_autoptr(GstBus) bus = gst_element_get_bus(pipeline_);
> +		g_autoptr(GstMessage) msg = gst_bus_timed_pop_filtered(bus, timeout, msgType);
> +
> +		gst_element_set_state(pipeline_, GST_STATE_NULL);
> +
> +		/* Parse error message */
> +		if (msg == NULL)
> +			return TestPass;
> +
> +		switch (GST_MESSAGE_TYPE(msg)) {
> +		case GST_MESSAGE_ERROR:
> +			gstreamer_print_error(msg);
> +			break;
> +		case GST_MESSAGE_EOS:
> +			g_print("End-Of-Stream reached.\n");
> +			break;
> +		default:
> +			g_printerr("Unexpected message received.\n");
> +			break;
> +		}
> +
> +		return TestFail;
> +	}
> +
> +private:
> +	void gstreamer_print_error(GstMessage *msg)
> +	{
> +		g_autoptr(GError) err = NULL;
> +		g_autofree gchar *debug_info = NULL;
> +
> +		gst_message_parse_error(msg, &err, &debug_info);
> +		g_printerr("Error received from element %s: %s\n",
> +				GST_OBJECT_NAME(msg->src), err->message);
> +		g_printerr("Debugging information: %s\n",
> +				debug_info ? debug_info : "none");
> +	}
> +
> +	GstElement *pipeline_;
> +	GstElement *libcameraSrc_;
> +	GstElement *queue0_;
> +	GstElement *queue1_;
> +	GstElement *convert0_;
> +	GstElement *convert1_;
> +	GstElement *sink0_;
> +	GstElement *sink1_;
> +};
> +
> +TEST_REGISTER(GstreamerSingleStreamTest)
> diff --git a/test/gstreamer/meson.build b/test/gstreamer/meson.build
> index b99aa0da..e28225b2 100644
> --- a/test/gstreamer/meson.build
> +++ b/test/gstreamer/meson.build
> @@ -6,6 +6,7 @@ endif
>  
>  gstreamer_tests = [
>      ['single_stream_test',   'gstreamer_single_stream_test.cpp'],
> +    ['multi_stream_test',   'gstreamer_multi_stream_test.cpp'],
>  ]
>  gstreamer_dep = dependency('gstreamer-1.0', required: true)
>  

-- 
Regards,

Laurent Pinchart


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