[libcamera-devel] [PATCH v1 05/23] gst: Add pads to the source

[Laurent Pinchart]

Hi Nicolas,

Thank you for the patch.

On Tue, Jan 28, 2020 at 10:31:52PM -0500, Nicolas Dufresne wrote:
> From: Nicolas Dufresne <nicolas.dufresne at collabora.com>
> 
> This simply add the boiler plate for pads on the source element. The

s/add/adds/

> design is that we have one pad, called "src", that will always be
> present, and then more pads can be requested prior in READY or less
> state. Initially pads have one property "stream-role" that let you
> decide which role this pad will have.
> 
> Signed-off-by: Nicolas Dufresne <nicolas.dufresne at collabora.com>
> ---
>  src/gstreamer/gstlibcamerapad.cpp | 101 ++++++++++++++++++++++++++++++
>  src/gstreamer/gstlibcamerapad.h   |  19 ++++++
>  src/gstreamer/gstlibcamerasrc.cpp |  19 ++++++
>  src/gstreamer/meson.build         |   1 +
>  4 files changed, 140 insertions(+)
>  create mode 100644 src/gstreamer/gstlibcamerapad.cpp
>  create mode 100644 src/gstreamer/gstlibcamerapad.h
> 
> diff --git a/src/gstreamer/gstlibcamerapad.cpp b/src/gstreamer/gstlibcamerapad.cpp
> new file mode 100644
> index 0000000..c6c22e4
> --- /dev/null
> +++ b/src/gstreamer/gstlibcamerapad.cpp
> @@ -0,0 +1,101 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2019, Collabora Ltd.
> + *     Author: Nicolas Dufresne <nicolas.dufresne at collabora.com>
> + *
> + * gstlibcamerapad.cpp - GStreamer Capture Pad
> + */
> +
> +#include "gstlibcamerapad.h"
> +#include "gstlibcamera-utils.h"
> +
> +#include <libcamera/stream.h>
> +
> +using namespace libcamera;
> +
> +struct _GstLibcameraPad {
> +	GstPad parent;
> +	StreamRole role;
> +};
> +
> +enum {
> +	PROP_0,
> +	PROP_STREAM_ROLE
> +};
> +
> +G_DEFINE_TYPE(GstLibcameraPad, gst_libcamera_pad, GST_TYPE_PAD);
> +
> +static void
> +gst_libcamera_pad_set_property(GObject *object, guint prop_id,
> +			       const GValue *value, GParamSpec *pspec)
> +{
> +	auto *self = GST_LIBCAMERA_PAD(object);
> +	GST_OBJECT_LOCKER(self);
> +
> +	switch (prop_id) {
> +	case PROP_STREAM_ROLE:
> +		self->role = (StreamRole)g_value_get_enum(value);
> +		break;
> +	default:
> +		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
> +		break;
> +	}
> +}
> +
> +static void
> +gst_libcamera_pad_get_property(GObject *object, guint prop_id, GValue *value,
> +			       GParamSpec *pspec)
> +{
> +	auto *self = GST_LIBCAMERA_PAD(object);
> +	GST_OBJECT_LOCKER(self);
> +
> +	switch (prop_id) {
> +	case PROP_STREAM_ROLE:
> +		g_value_set_enum(value, self->role);
> +		break;
> +	default:
> +		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
> +		break;
> +	}
> +}
> +
> +static void
> +gst_libcamera_pad_init(GstLibcameraPad *self)
> +{
> +}
> +
> +static GType
> +gst_libcamera_stream_role_get_type(void)
> +{
> +	static GType type = 0;
> +	static const GEnumValue values[] = {
> +		{ StillCapture, "libcamera::StillCapture", "still-capture" },
> +		{ VideoRecording, "libcamera::VideoRecording", "video-recording" },
> +		{ Viewfinder, "libcamera::Viewfinder", "view-finder" },
> +		{ 0, NULL, NULL }
> +	};
> +
> +	if (!type)
> +		type = g_enum_register_static("GstLibcameraStreamRole", values);
> +
> +	return type;
> +}
> +
> +static void
> +gst_libcamera_pad_class_init(GstLibcameraPadClass *klass)
> +{
> +	auto *object_class = G_OBJECT_CLASS(klass);
> +
> +	object_class->set_property = gst_libcamera_pad_set_property;
> +	object_class->get_property = gst_libcamera_pad_get_property;
> +
> +	auto *spec = g_param_spec_enum("stream-role", "Stream Role",
> +				       "The selected stream role",
> +				       gst_libcamera_stream_role_get_type(),
> +				       VideoRecording,
> +				       (GParamFlags)(GST_PARAM_MUTABLE_READY
> +					             | G_PARAM_CONSTRUCT
> +						     | G_PARAM_READWRITE
> +						     | G_PARAM_STATIC_STRINGS));
> +	g_object_class_install_property(object_class, PROP_STREAM_ROLE, spec);
> +}
> diff --git a/src/gstreamer/gstlibcamerapad.h b/src/gstreamer/gstlibcamerapad.h
> new file mode 100644
> index 0000000..2e745f1
> --- /dev/null
> +++ b/src/gstreamer/gstlibcamerapad.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2019, Collabora Ltd.
> + *     Author: Nicolas Dufresne <nicolas.dufresne at collabora.com>
> + *
> + * gstlibcamerapad.h - GStreamer Capture Element
> + */
> +
> +#include <gst/gst.h>
> +
> +#ifndef __GST_LIBCAMERA_PAD_H__
> +#define __GST_LIBCAMERA_PAD_H__
> +
> +#define GST_TYPE_LIBCAMERA_PAD gst_libcamera_pad_get_type()
> +G_DECLARE_FINAL_TYPE(GstLibcameraPad, gst_libcamera_pad,
> +		     GST_LIBCAMERA, PAD, GstPad)
> +
> +
> +#endif /* __GST_LIBCAMERA_PAD_H__ */
> diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> index 39a06a4..a8bcede 100644
> --- a/src/gstreamer/gstlibcamerasrc.cpp
> +++ b/src/gstreamer/gstlibcamerasrc.cpp
> @@ -7,6 +7,7 @@
>   */
>  
>  #include "gstlibcamerasrc.h"
> +#include "gstlibcamerapad.h"

Alphabetical order here too (I'll stop saying it now :-)).

>  
>  struct _GstLibcameraSrc {
>  	GstElement parent;
> @@ -14,6 +15,18 @@ struct _GstLibcameraSrc {
>  
>  G_DEFINE_TYPE(GstLibcameraSrc, gst_libcamera_src, GST_TYPE_ELEMENT);
>  
> +#define TEMPLATE_CAPS GST_STATIC_CAPS("video/x-raw;image/jpeg")

JPEG is only supported by UVC in libcamera. Should we default to a YUV
format ?

> +
> +/* For the simple case, we have a src pad that is always present. */
> +GstStaticPadTemplate src_template = {
> +	"src", GST_PAD_SRC, GST_PAD_ALWAYS, TEMPLATE_CAPS
> +};
> +
> +/* More pads can be requested in state < PAUSED */
> +GstStaticPadTemplate request_src_template = {
> +	"src_%s", GST_PAD_SRC, GST_PAD_REQUEST, TEMPLATE_CAPS
> +};
> +
>  static void
>  gst_libcamera_src_init(GstLibcameraSrc *self)
>  {
> @@ -28,4 +41,10 @@ gst_libcamera_src_class_init(GstLibcameraSrcClass *klass)
>  				       "LibCamera Source", "Source/Video",
>  				       "Linux Camera source using libcamera",
>  				       "Nicolas Dufresne <nicolas.dufresne at collabora.com");
> +	gst_element_class_add_static_pad_template_with_gtype(element_class,
> +							     &src_template,
> +							     GST_TYPE_LIBCAMERA_PAD);
> +	gst_element_class_add_static_pad_template_with_gtype(element_class,
> +							     &request_src_template,
> +							     GST_TYPE_LIBCAMERA_PAD);
>  }
> diff --git a/src/gstreamer/meson.build b/src/gstreamer/meson.build
> index 7769b78..e497bf4 100644
> --- a/src/gstreamer/meson.build
> +++ b/src/gstreamer/meson.build
> @@ -3,6 +3,7 @@ libcamera_gst_sources = [
>      'gstlibcamera-utils.cpp',
>      'gstlibcamerasrc.cpp',
>      'gstlibcameraprovider.cpp',
> +    'gstlibcamerapad.cpp',
>  ]
>  
>  libcamera_gst_c_args = [

-- 
Regards,

Laurent Pinchart