[libcamera-devel] [PATCH v2 02/27] gst: Add utility to convert StreamFormats to GstCaps

[Laurent Pinchart]

Hi Nicolas,

Thank you for the patch.

On Thu, Feb 27, 2020 at 03:03:42PM -0500, Nicolas Dufresne wrote:
> This transforms the basic information found in StreamFormats to GstCaps.
> This can be handy to reply to early caps query or inside a device
> provider. Note that we ignored generated range as they are harmful to
> caps negotiation. We also don't simplify the caps for readability
> reasons, so some of the discrete value may be included in a range.
> 
> Signed-off-by: Nicolas Dufresne <nicolas.dufresne at collabora.com>
> ---
>  src/gstreamer/gstlibcamera-utils.cpp | 98 ++++++++++++++++++++++++++++
>  src/gstreamer/gstlibcamera-utils.h   | 18 +++++
>  src/gstreamer/meson.build            |  1 +
>  3 files changed, 117 insertions(+)
>  create mode 100644 src/gstreamer/gstlibcamera-utils.cpp
>  create mode 100644 src/gstreamer/gstlibcamera-utils.h
> 
> diff --git a/src/gstreamer/gstlibcamera-utils.cpp b/src/gstreamer/gstlibcamera-utils.cpp
> new file mode 100644
> index 0000000..dc129c3
> --- /dev/null
> +++ b/src/gstreamer/gstlibcamera-utils.cpp
> @@ -0,0 +1,98 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2020, Collabora Ltd.
> + *     Author: Nicolas Dufresne <nicolas.dufresne at collabora.com>
> + *
> + * gstlibcamera-utils.c - GStreamer libcamera Utility Function
> + */
> +
> +#include "gstlibcamera-utils.h"

Missing blank line here.

> +#include <linux/drm_fourcc.h>
> +
> +using namespace libcamera;
> +
> +static struct {
> +	GstVideoFormat gst_format;
> +	guint drm_fourcc;
> +} format_map[] = {
> +	{ GST_VIDEO_FORMAT_ENCODED, DRM_FORMAT_MJPEG },
> +	{ GST_VIDEO_FORMAT_RGB, DRM_FORMAT_BGR888 },
> +	{ GST_VIDEO_FORMAT_BGR, DRM_FORMAT_RGB888 },
> +	{ GST_VIDEO_FORMAT_ARGB, DRM_FORMAT_BGRA8888 },
> +	{ GST_VIDEO_FORMAT_NV12, DRM_FORMAT_NV12 },
> +	{ GST_VIDEO_FORMAT_NV21, DRM_FORMAT_NV21 },
> +	{ GST_VIDEO_FORMAT_NV16, DRM_FORMAT_NV16 },
> +	{ GST_VIDEO_FORMAT_NV61, DRM_FORMAT_NV61 },
> +	{ GST_VIDEO_FORMAT_NV24, DRM_FORMAT_NV24 },
> +	{ GST_VIDEO_FORMAT_UYVY, DRM_FORMAT_UYVY },
> +	{ GST_VIDEO_FORMAT_VYUY, DRM_FORMAT_VYUY },
> +	{ GST_VIDEO_FORMAT_YUY2, DRM_FORMAT_YUYV },
> +	{ GST_VIDEO_FORMAT_YVYU, DRM_FORMAT_YVYU },
> +	/* \todo NV42 is used in libcamera but is not mapped in GStreamer yet. */
> +};
> +
> +static inline GstVideoFormat
> +drm_to_gst_format(guint drm_fourcc)
> +{
> +	for (const auto &item : format_map)

	for (const auto &item : format_map) {
> +		if (item.drm_fourcc == drm_fourcc)
> +			return item.gst_format;
	}

Sweet, I didn't know C++ allowed range loops on plain C arrays :-)

> +	return GST_VIDEO_FORMAT_UNKNOWN;
> +}
> +
> +static GstStructure *
> +bare_structure_from_fourcc(guint fourcc)
> +{
> +	GstVideoFormat gst_format = drm_to_gst_format(fourcc);
> +
> +	if (gst_format == GST_VIDEO_FORMAT_UNKNOWN)
> +		return nullptr;
> +
> +	if (gst_format != GST_VIDEO_FORMAT_ENCODED)
> +		return gst_structure_new("video/x-raw", "format", G_TYPE_STRING,
> +					 gst_video_format_to_string(gst_format), nullptr);
> +
> +	switch (fourcc) {
> +	case DRM_FORMAT_MJPEG:
> +		return gst_structure_new_empty("image/jpeg");
> +	default:
> +		return nullptr;
> +	}
> +}
> +
> +GstCaps *
> +gst_libcamera_stream_formats_to_caps(const StreamFormats &formats)
> +{
> +	GstCaps *caps = gst_caps_new_empty();
> +
> +	for (unsigned int fourcc : formats.pixelformats()) {
> +		g_autoptr(GstStructure) bare_s = bare_structure_from_fourcc(fourcc);
> +
> +		if (!bare_s) {
> +			GST_WARNING("Unsupported DRM format %" GST_FOURCC_FORMAT,
> +				    GST_FOURCC_ARGS(fourcc));
> +			continue;
> +		}
> +
> +		for (const Size &size : formats.sizes(fourcc)) {
> +			GstStructure *s = gst_structure_copy(bare_s);
> +			gst_structure_set(s,
> +					  "width", G_TYPE_INT, size.width,
> +					  "height", G_TYPE_INT, size.height,
> +					  nullptr);
> +			gst_caps_append_structure(caps, s);
> +		}
> +
> +		const SizeRange &range = formats.range(fourcc);
> +		if (range.hStep && range.vStep) {
> +			GstStructure *s = gst_structure_copy(bare_s);
> +			gst_structure_set(s,
> +					  "width", GST_TYPE_INT_RANGE, range.min.width, range.max.width, range.hStep,
> +					  "height", GST_TYPE_INT_RANGE, range.min.height, range.max.height, range.vStep,
> +					  nullptr);
> +			gst_caps_append_structure(caps, s);
> +		}
> +	}
> +
> +	return caps;
> +}
> diff --git a/src/gstreamer/gstlibcamera-utils.h b/src/gstreamer/gstlibcamera-utils.h
> new file mode 100644
> index 0000000..33160b8
> --- /dev/null
> +++ b/src/gstreamer/gstlibcamera-utils.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2020, Collabora Ltd.
> + *     Author: Nicolas Dufresne <nicolas.dufresne at collabora.com>
> + *
> + * gstlibcamera-utils.h - GStreamer libcamera Utility Functions
> + */
> +
> +#ifndef __GST_LIBCAMERA_UTILS_H_

s/__GST_LIBCAMERA_UTILS_H_/__GST_LIBCAMERA_UTILS_H__/

Missing

#define __GST_LIBCAMERA_UTILS_H__

> +
> +#include <gst/gst.h>
> +#include <gst/video/video.h>
> +
> +#include <libcamera/stream.h>
> +
> +GstCaps *gst_libcamera_stream_formats_to_caps(const libcamera::StreamFormats &formats);
> +
> +#endif /* __GST_LIBCAMERA_UTILS_H_ */

__GST_LIBCAMERA_UTILS_H__ here too.

> diff --git a/src/gstreamer/meson.build b/src/gstreamer/meson.build
> index 832b8a5..f409107 100644
> --- a/src/gstreamer/meson.build
> +++ b/src/gstreamer/meson.build
> @@ -1,4 +1,5 @@
>  libcamera_gst_sources = [
> +    'gstlibcamera-utils.cpp',
>      'gstlibcamera.c',
>      'gstlibcamerasrc.cpp',
>  ]

-- 
Regards,

Laurent Pinchart