[libcamera-devel] [PATCH v1 05/23] gst: Add pads to the source
Nicolas Dufresne
nicolas.dufresne at collabora.com
Tue Feb 11 22:54:36 CET 2020
On mar, 2020-02-11 at 21:21 +0200, Laurent Pinchart wrote:
> 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 ?
It uses video/x-raw first followed by jpeg, which include all video formats that
are not compressed. This could benefit from a space after ";" in the caps
string. It's a bit hard to read this way.
>
> > +
> > +/* 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_templa
> > te,
> > + 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 = [
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