Megapixels/camera.c

#include "camera.h"

#include <assert.h>
#include <errno.h>
#include <glib.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <sys/mman.h>

#define MAX_VIDEO_BUFFERS 20

static const char *pixel_format_names[MP_PIXEL_FMT_MAX] = {
	"unsupported", "BGGR8",	  "GBRG8",   "GRBG8", "RGGB8", "BGGR10P",
	"GBRG10P",     "GRBG10P", "RGGB10P", "UYVY",  "YUYV",
};

const char *
mp_pixel_format_to_str(uint32_t pixel_format)
{
	g_return_val_if_fail(pixel_format < MP_PIXEL_FMT_MAX, "INVALID");
	return pixel_format_names[pixel_format];
}

MPPixelFormat
mp_pixel_format_from_str(const char *name)
{
	for (MPPixelFormat i = 0; i < MP_PIXEL_FMT_MAX; ++i) {
		if (strcasecmp(pixel_format_names[i], name) == 0) {
			return i;
		}
	}
	g_return_val_if_reached(MP_PIXEL_FMT_UNSUPPORTED);
}

static const uint32_t pixel_format_v4l_pixel_formats[MP_PIXEL_FMT_MAX] = {
	0,
	V4L2_PIX_FMT_SBGGR8,
	V4L2_PIX_FMT_SGBRG8,
	V4L2_PIX_FMT_SGRBG8,
	V4L2_PIX_FMT_SRGGB8,
	V4L2_PIX_FMT_SBGGR10P,
	V4L2_PIX_FMT_SGBRG10P,
	V4L2_PIX_FMT_SGRBG10P,
	V4L2_PIX_FMT_SRGGB10P,
	V4L2_PIX_FMT_UYVY,
	V4L2_PIX_FMT_YUYV,
};

uint32_t
mp_pixel_format_to_v4l_pixel_format(MPPixelFormat pixel_format)
{
	g_return_val_if_fail(pixel_format < MP_PIXEL_FMT_MAX, 0);
	return pixel_format_v4l_pixel_formats[pixel_format];
}

MPPixelFormat
mp_pixel_format_from_v4l_pixel_format(uint32_t v4l_pixel_format)
{
	for (MPPixelFormat i = 0; i < MP_PIXEL_FMT_MAX; ++i) {
		if (pixel_format_v4l_pixel_formats[i] == v4l_pixel_format) {
			return i;
		}
	}
	return MP_PIXEL_FMT_UNSUPPORTED;
}

static const uint32_t pixel_format_v4l_bus_codes[MP_PIXEL_FMT_MAX] = {
	0,
	MEDIA_BUS_FMT_SBGGR8_1X8,
	MEDIA_BUS_FMT_SGBRG8_1X8,
	MEDIA_BUS_FMT_SGRBG8_1X8,
	MEDIA_BUS_FMT_SRGGB8_1X8,
	MEDIA_BUS_FMT_SBGGR10_1X10,
	MEDIA_BUS_FMT_SGBRG10_1X10,
	MEDIA_BUS_FMT_SGRBG10_1X10,
	MEDIA_BUS_FMT_SRGGB10_1X10,
	MEDIA_BUS_FMT_UYVY8_2X8,
	MEDIA_BUS_FMT_YUYV8_2X8,
};

uint32_t
mp_pixel_format_to_v4l_bus_code(MPPixelFormat pixel_format)
{
	g_return_val_if_fail(pixel_format < MP_PIXEL_FMT_MAX, 0);
	return pixel_format_v4l_bus_codes[pixel_format];
}

MPPixelFormat
mp_pixel_format_from_v4l_bus_code(uint32_t v4l_bus_code)
{
	for (MPPixelFormat i = 0; i < MP_PIXEL_FMT_MAX; ++i) {
		if (pixel_format_v4l_bus_codes[i] == v4l_bus_code) {
			return i;
		}
	}
	return MP_PIXEL_FMT_UNSUPPORTED;
}

uint32_t
mp_pixel_format_bits_per_pixel(MPPixelFormat pixel_format)
{
	g_return_val_if_fail(pixel_format < MP_PIXEL_FMT_MAX, 0);
	switch (pixel_format) {
	case MP_PIXEL_FMT_BGGR8:
	case MP_PIXEL_FMT_GBRG8:
	case MP_PIXEL_FMT_GRBG8:
	case MP_PIXEL_FMT_RGGB8:
		return 8;
	case MP_PIXEL_FMT_BGGR10P:
	case MP_PIXEL_FMT_GBRG10P:
	case MP_PIXEL_FMT_GRBG10P:
	case MP_PIXEL_FMT_RGGB10P:
		return 10;
	case MP_PIXEL_FMT_UYVY:
	case MP_PIXEL_FMT_YUYV:
		return 16;
	default:
		return 0;
	}
}

uint32_t
mp_pixel_format_width_to_bytes(MPPixelFormat pixel_format, uint32_t width)
{
	uint32_t bits_per_pixel = mp_pixel_format_bits_per_pixel(pixel_format);
	uint64_t bits_per_width = width * (uint64_t)bits_per_pixel;

	uint64_t remainder = bits_per_width % 8;
	if (remainder == 0)
		return bits_per_width / 8;

	return (bits_per_width + 8 - remainder) / 8;
}

uint32_t
mp_pixel_format_width_to_colors(MPPixelFormat pixel_format, uint32_t width)
{
	g_return_val_if_fail(pixel_format < MP_PIXEL_FMT_MAX, 0);
	switch (pixel_format) {
	case MP_PIXEL_FMT_BGGR8:
	case MP_PIXEL_FMT_GBRG8:
	case MP_PIXEL_FMT_GRBG8:
	case MP_PIXEL_FMT_RGGB8:
		return width / 2;
	case MP_PIXEL_FMT_BGGR10P:
	case MP_PIXEL_FMT_GBRG10P:
	case MP_PIXEL_FMT_GRBG10P:
	case MP_PIXEL_FMT_RGGB10P:
		return width / 2 * 5;
	case MP_PIXEL_FMT_UYVY:
	case MP_PIXEL_FMT_YUYV:
		return width;
	default:
		return 0;
	}
}

uint32_t
mp_pixel_format_height_to_colors(MPPixelFormat pixel_format, uint32_t height)
{
	g_return_val_if_fail(pixel_format < MP_PIXEL_FMT_MAX, 0);
	switch (pixel_format) {
	case MP_PIXEL_FMT_BGGR8:
	case MP_PIXEL_FMT_GBRG8:
	case MP_PIXEL_FMT_GRBG8:
	case MP_PIXEL_FMT_RGGB8:
	case MP_PIXEL_FMT_BGGR10P:
	case MP_PIXEL_FMT_GBRG10P:
	case MP_PIXEL_FMT_GRBG10P:
	case MP_PIXEL_FMT_RGGB10P:
		return height / 2;
	case MP_PIXEL_FMT_UYVY:
	case MP_PIXEL_FMT_YUYV:
		return height;
	default:
		return 0;
	}
}

bool
mp_camera_mode_is_equivalent(const MPCameraMode *m1, const MPCameraMode *m2)
{
	return m1->pixel_format == m2->pixel_format &&
	       m1->frame_interval.numerator == m2->frame_interval.numerator &&
	       m1->frame_interval.denominator == m2->frame_interval.denominator &&
	       m1->width == m2->width && m1->height == m2->height;
}

static void
errno_printerr(const char *s)
{
	g_printerr("MPCamera: %s error %d, %s\n", s, errno, strerror(errno));
}

static int
xioctl(int fd, int request, void *arg)
{
	int r;
	do {
		r = ioctl(fd, request, arg);
	} while (r == -1 && errno == EINTR);
	return r;
}

struct video_buffer {
	uint32_t length;
	uint8_t *data;
};

struct _MPCamera {
	int video_fd;
	int subdev_fd;

	bool has_set_mode;
	MPCameraMode current_mode;

	struct video_buffer buffers[MAX_VIDEO_BUFFERS];
	uint32_t num_buffers;

	bool use_mplane;
};

MPCamera *
mp_camera_new(int video_fd, int subdev_fd)
{
	g_return_val_if_fail(video_fd != -1, NULL);

	// Query capabilities
	struct v4l2_capability cap;
	if (xioctl(video_fd, VIDIOC_QUERYCAP, &cap) == -1) {
		return NULL;
	}

	// Check whether this is a video capture device
	bool use_mplane;
	if (cap.capabilities & V4L2_CAP_VIDEO_CAPTURE_MPLANE) {
		use_mplane = true;
		printf("!!\n");
	} else if (cap.capabilities & V4L2_CAP_VIDEO_CAPTURE) {
		use_mplane = false;
	} else {
		return NULL;
	}

	MPCamera *camera = malloc(sizeof(MPCamera));
	camera->video_fd = video_fd;
	camera->subdev_fd = subdev_fd;
	camera->has_set_mode = false;
	camera->num_buffers = 0;
	camera->use_mplane = use_mplane;
	return camera;
}

void
mp_camera_free(MPCamera *camera)
{
	g_warn_if_fail(camera->num_buffers == 0);
	if (camera->num_buffers != 0) {
		mp_camera_stop_capture(camera);
	}

	free(camera);
}

bool
mp_camera_is_subdev(MPCamera *camera)
{
	return camera->subdev_fd != -1;
}

int
mp_camera_get_video_fd(MPCamera *camera)
{
	return camera->video_fd;
}

int
mp_camera_get_subdev_fd(MPCamera *camera)
{
	return camera->subdev_fd;
}

static bool
camera_mode_impl(MPCamera *camera, int request, MPCameraMode *mode)
{
	uint32_t pixfmt = mp_pixel_format_from_v4l_pixel_format(mode->pixel_format);
	struct v4l2_format fmt = {};
	if (camera->use_mplane) {
		fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
		fmt.fmt.pix_mp.width = mode->width;
		fmt.fmt.pix_mp.height = mode->height;
		fmt.fmt.pix_mp.pixelformat = pixfmt;
		fmt.fmt.pix_mp.field = V4L2_FIELD_ANY;
	} else {
		fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		fmt.fmt.pix.width = mode->width;
		fmt.fmt.pix.height = mode->height;
		fmt.fmt.pix.pixelformat = pixfmt;
		fmt.fmt.pix.field = V4L2_FIELD_ANY;
	}

	if (xioctl(camera->video_fd, request, &fmt) == -1) {
		return false;
	}

	if (camera->use_mplane) {
		mode->width = fmt.fmt.pix_mp.width;
		mode->height = fmt.fmt.pix_mp.height;
		mode->pixel_format = mp_pixel_format_from_v4l_pixel_format(
			fmt.fmt.pix_mp.pixelformat);
	} else {
		mode->width = fmt.fmt.pix.width;
		mode->height = fmt.fmt.pix.height;
		mode->pixel_format = mp_pixel_format_from_v4l_pixel_format(
			fmt.fmt.pix.pixelformat);
	}

	return true;
}

bool
mp_camera_try_mode(MPCamera *camera, MPCameraMode *mode)
{
	if (!camera_mode_impl(camera, VIDIOC_TRY_FMT, mode)) {
		errno_printerr("VIDIOC_S_FMT");
		return false;
	}
	return true;
}

const MPCameraMode *
mp_camera_get_mode(const MPCamera *camera)
{
	return &camera->current_mode;
}

bool
mp_camera_set_mode(MPCamera *camera, MPCameraMode *mode)
{
	// Set the mode in the subdev the camera is one
	if (mp_camera_is_subdev(camera)) {
		struct v4l2_subdev_frame_interval interval = {};
		interval.pad = 0;
		interval.interval = mode->frame_interval;
		if (xioctl(camera->subdev_fd, VIDIOC_SUBDEV_S_FRAME_INTERVAL,
			   &interval) == -1) {
			errno_printerr("VIDIOC_SUBDEV_S_FRAME_INTERVAL");
			return false;
		}

		bool did_set_frame_rate = interval.interval.numerator ==
						  mode->frame_interval.numerator &&
					  interval.interval.denominator ==
						  mode->frame_interval.denominator;

		struct v4l2_subdev_format fmt = {};
		fmt.pad = 0;
		fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
		fmt.format.width = mode->width;
		fmt.format.height = mode->height;
		fmt.format.code =
			mp_pixel_format_to_v4l_bus_code(mode->pixel_format);
		fmt.format.field = V4L2_FIELD_ANY;
		if (xioctl(camera->subdev_fd, VIDIOC_SUBDEV_S_FMT, &fmt) == -1) {
			errno_printerr("VIDIOC_SUBDEV_S_FMT");
			return false;
		}

		// Some drivers like ov5640 don't allow you to set the frame format with
		// too high a frame-rate, but that means the frame-rate won't be set
		// after the format change. So we need to try again here if we didn't
		// succeed before. Ideally we'd be able to set both at once.
		if (!did_set_frame_rate) {
			interval.interval = mode->frame_interval;
			if (xioctl(camera->subdev_fd, VIDIOC_SUBDEV_S_FRAME_INTERVAL,
				   &interval) == -1) {
				errno_printerr("VIDIOC_SUBDEV_S_FRAME_INTERVAL");
			}
		}

		// Update the mode
		mode->pixel_format =
			mp_pixel_format_from_v4l_bus_code(fmt.format.code);
		mode->frame_interval = interval.interval;
		mode->width = fmt.format.width;
		mode->height = fmt.format.height;
	}

	// Set the mode for the video device
	{
		if (!camera_mode_impl(camera, VIDIOC_S_FMT, mode)) {
			errno_printerr("VIDIOC_S_FMT");
			return false;
		}
	}

	camera->has_set_mode = true;
	camera->current_mode = *mode;

	return true;
}

bool
mp_camera_start_capture(MPCamera *camera)
{
	g_return_val_if_fail(camera->has_set_mode, false);
	g_return_val_if_fail(camera->num_buffers == 0, false);

	enum v4l2_buf_type buftype = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	if (camera->use_mplane) {
		buftype = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
	}

	// Start by requesting buffers
	struct v4l2_requestbuffers req = {};
	req.count = MAX_VIDEO_BUFFERS;
	req.type = buftype;
	req.memory = V4L2_MEMORY_MMAP;

	if (xioctl(camera->video_fd, VIDIOC_REQBUFS, &req) == -1) {
		errno_printerr("VIDIOC_REQBUFS");
		return false;
	}

	if (req.count < 2) {
		g_printerr(
			"Insufficient buffer memory. Only %d buffers available.\n",
			req.count);
		goto error;
	}

	for (uint32_t i = 0; i < req.count; ++i) {
		// Query each buffer and mmap it
		struct v4l2_buffer buf = {
			.type = buftype,
			.memory = V4L2_MEMORY_MMAP,
			.index = i,
		};

		struct v4l2_plane planes[1];
		if (camera->use_mplane) {
			buf.m.planes = planes;
			buf.length = 1;
		}

		if (xioctl(camera->video_fd, VIDIOC_QUERYBUF, &buf) == -1) {
			errno_printerr("VIDIOC_QUERYBUF");
			break;
		}

		if (camera->use_mplane) {
			camera->buffers[i].length = planes[0].length;
			camera->buffers[i].data =
				mmap(NULL, planes[0].length, PROT_READ, MAP_SHARED,
				     camera->video_fd, planes[0].m.mem_offset);
		} else {
			camera->buffers[i].length = buf.length;
			camera->buffers[i].data =
				mmap(NULL, buf.length, PROT_READ, MAP_SHARED,
				     camera->video_fd, buf.m.offset);
		}

		if (camera->buffers[i].data == MAP_FAILED) {
			errno_printerr("mmap");
			break;
		}

		++camera->num_buffers;
	}

	if (camera->num_buffers != req.count) {
		g_printerr("Unable to map all buffers\n");
		goto error;
	}

	for (uint32_t i = 0; i < camera->num_buffers; ++i) {
		struct v4l2_buffer buf = {
			.type = buftype,
			.memory = V4L2_MEMORY_MMAP,
			.index = i,
		};

		struct v4l2_plane planes[1];
		if (camera->use_mplane) {
			buf.m.planes = planes;
			buf.length = 1;
		}

		// Queue the buffer for capture
		if (xioctl(camera->video_fd, VIDIOC_QBUF, &buf) == -1) {
			errno_printerr("VIDIOC_QBUF");
			goto error;
		}
	}

	// Start capture
	enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	if (xioctl(camera->video_fd, VIDIOC_STREAMON, &type) == -1) {
		errno_printerr("VIDIOC_STREAMON");
		goto error;
	}

	return true;

error:
	// Unmap any mapped buffers
	assert(camera->num_buffers <= MAX_VIDEO_BUFFERS);
	for (uint32_t i = 0; i < camera->num_buffers; ++i) {
		if (munmap(camera->buffers[i].data, camera->buffers[i].length) ==
		    -1) {
			errno_printerr("munmap");
		}
	}

	// Reset allocated buffers
	{
		struct v4l2_requestbuffers req = {};
		req.count = 0;
		req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		req.memory = V4L2_MEMORY_MMAP;

		if (xioctl(camera->video_fd, VIDIOC_REQBUFS, &req) == -1) {
			errno_printerr("VIDIOC_REQBUFS");
		}
	}

	return false;
}

bool
mp_camera_stop_capture(MPCamera *camera)
{
	g_return_val_if_fail(camera->num_buffers > 0, false);

	enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	if (xioctl(camera->video_fd, VIDIOC_STREAMOFF, &type) == -1) {
		errno_printerr("VIDIOC_STREAMOFF");
	}

	assert(camera->num_buffers <= MAX_VIDEO_BUFFERS);
	for (int i = 0; i < camera->num_buffers; ++i) {
		if (munmap(camera->buffers[i].data, camera->buffers[i].length) ==
		    -1) {
			errno_printerr("munmap");
		}
	}

	camera->num_buffers = 0;

	struct v4l2_requestbuffers req = {};
	req.count = 0;
	req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	req.memory = V4L2_MEMORY_MMAP;
	if (xioctl(camera->video_fd, VIDIOC_REQBUFS, &req) == -1) {
		errno_printerr("VIDIOC_REQBUFS");
	}

	return true;
}

bool
mp_camera_is_capturing(MPCamera *camera)
{
	return camera->num_buffers > 0;
}

bool
mp_camera_capture_image(MPCamera *camera, void (*callback)(MPImage, void *),
			void *user_data)
{
	struct v4l2_buffer buf = {};
	buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	buf.memory = V4L2_MEMORY_MMAP;

	struct v4l2_plane planes[1];
	if (camera->use_mplane) {
		buf.m.planes = planes;
		buf.length = 1;
	}

	if (xioctl(camera->video_fd, VIDIOC_DQBUF, &buf) == -1) {
		switch (errno) {
		case EAGAIN:
			return true;
		case EIO:
			/* Could ignore EIO, see spec. */
			/* fallthrough */
		default:
			errno_printerr("VIDIOC_DQBUF");
			return false;
		}
	}

	uint32_t pixel_format = camera->current_mode.pixel_format;
	uint32_t width = camera->current_mode.width;
	uint32_t height = camera->current_mode.height;

	uint32_t bytesused;
	if (camera->use_mplane) {
		bytesused = planes[0].bytesused;
	} else {
		bytesused = buf.bytesused;
	}

	assert(bytesused ==
	       mp_pixel_format_width_to_bytes(pixel_format, width) * height);
	assert(bytesused == camera->buffers[buf.index].length);

	MPImage image = {
		.pixel_format = pixel_format,
		.width = width,
		.height = height,
		.data = camera->buffers[buf.index].data,
	};

	callback(image, user_data);

	// The callback may have stopped the capture, only queue the buffer if we're
	// still capturing.
	if (mp_camera_is_capturing(camera)) {
		if (xioctl(camera->video_fd, VIDIOC_QBUF, &buf) == -1) {
			errno_printerr("VIDIOC_QBUF");
			return false;
		}
	}

	return true;
}

struct _MPCameraModeList {
	MPCameraMode mode;
	MPCameraModeList *next;
};

static MPCameraModeList *
get_subdev_modes(MPCamera *camera, bool (*check)(MPCamera *, MPCameraMode *))
{
	MPCameraModeList *item = NULL;

	for (uint32_t fmt_index = 0;; ++fmt_index) {
		struct v4l2_subdev_mbus_code_enum fmt = {};
		fmt.index = fmt_index;
		fmt.pad = 0;
		fmt.which = V4L2_SUBDEV_FORMAT_TRY;
		if (xioctl(camera->subdev_fd, VIDIOC_SUBDEV_ENUM_MBUS_CODE, &fmt) ==
		    -1) {
			if (errno != EINVAL) {
				errno_printerr("VIDIOC_SUBDEV_ENUM_MBUS_CODE");
			}
			break;
		}

		// Skip unsupported formats
		uint32_t format = mp_pixel_format_from_v4l_bus_code(fmt.code);
		if (format == MP_PIXEL_FMT_UNSUPPORTED) {
			continue;
		}

		for (uint32_t frame_index = 0;; ++frame_index) {
			struct v4l2_subdev_frame_size_enum frame = {};
			frame.index = frame_index;
			frame.pad = 0;
			frame.code = fmt.code;
			frame.which = V4L2_SUBDEV_FORMAT_TRY;
			if (xioctl(camera->subdev_fd, VIDIOC_SUBDEV_ENUM_FRAME_SIZE,
				   &frame) == -1) {
				if (errno != EINVAL) {
					errno_printerr(
						"VIDIOC_SUBDEV_ENUM_FRAME_SIZE");
				}
				break;
			}

			// TODO: Handle other types
			if (frame.min_width != frame.max_width ||
			    frame.min_height != frame.max_height) {
				break;
			}

			for (uint32_t interval_index = 0;; ++interval_index) {
				struct v4l2_subdev_frame_interval_enum interval = {};
				interval.index = interval_index;
				interval.pad = 0;
				interval.code = fmt.code;
				interval.width = frame.max_width;
				interval.height = frame.max_height;
				interval.which = V4L2_SUBDEV_FORMAT_TRY;
				if (xioctl(camera->subdev_fd,
					   VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL,
					   &interval) == -1) {
					if (errno != EINVAL) {
						errno_printerr(
							"VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL");
					}
					break;
				}

				MPCameraMode mode = {
					.pixel_format = format,
					.frame_interval = interval.interval,
					.width = frame.max_width,
					.height = frame.max_height,
				};

				if (!check(camera, &mode)) {
					continue;
				}

				MPCameraModeList *new_item =
					malloc(sizeof(MPCameraModeList));
				new_item->mode = mode;
				new_item->next = item;
				item = new_item;
			}
		}
	}

	return item;
}

static MPCameraModeList *
get_video_modes(MPCamera *camera, bool (*check)(MPCamera *, MPCameraMode *))
{
	MPCameraModeList *item = NULL;

	for (uint32_t fmt_index = 0;; ++fmt_index) {
		struct v4l2_fmtdesc fmt = {};
		fmt.index = fmt_index;
		fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		if (xioctl(camera->video_fd, VIDIOC_ENUM_FMT, &fmt) == -1) {
			if (errno != EINVAL) {
				errno_printerr("VIDIOC_ENUM_FMT");
			}
			break;
		}

		// Skip unsupported formats
		uint32_t format =
			mp_pixel_format_from_v4l_pixel_format(fmt.pixelformat);
		if (format == MP_PIXEL_FMT_UNSUPPORTED) {
			continue;
		}

		for (uint32_t frame_index = 0;; ++frame_index) {
			struct v4l2_frmsizeenum frame = {};
			frame.index = frame_index;
			frame.pixel_format = fmt.pixelformat;
			if (xioctl(camera->video_fd, VIDIOC_ENUM_FRAMESIZES,
				   &frame) == -1) {
				if (errno != EINVAL) {
					errno_printerr("VIDIOC_ENUM_FRAMESIZES");
				}
				break;
			}

			// TODO: Handle other types
			if (frame.type != V4L2_FRMSIZE_TYPE_DISCRETE) {
				break;
			}

			for (uint32_t interval_index = 0;; ++interval_index) {
				struct v4l2_frmivalenum interval = {};
				interval.index = interval_index;
				interval.pixel_format = fmt.pixelformat;
				interval.width = frame.discrete.width;
				interval.height = frame.discrete.height;
				if (xioctl(camera->video_fd,
					   VIDIOC_ENUM_FRAMEINTERVALS,
					   &interval) == -1) {
					if (errno != EINVAL) {
						errno_printerr(
							"VIDIOC_ENUM_FRAMESIZES");
					}
					break;
				}

				// TODO: Handle other types
				if (interval.type != V4L2_FRMIVAL_TYPE_DISCRETE) {
					break;
				}

				MPCameraMode mode = {
					.pixel_format = format,
					.frame_interval = interval.discrete,
					.width = frame.discrete.width,
					.height = frame.discrete.height,
				};

				if (!check(camera, &mode)) {
					continue;
				}

				MPCameraModeList *new_item =
					malloc(sizeof(MPCameraModeList));
				new_item->mode = mode;
				new_item->next = item;
				item = new_item;
			}
		}
	}

	return item;
}

static bool
all_modes(MPCamera *camera, MPCameraMode *mode)
{
	return true;
}

static bool
available_modes(MPCamera *camera, MPCameraMode *mode)
{
	MPCameraMode attempt = *mode;
	return mp_camera_try_mode(camera, &attempt) &&
	       mp_camera_mode_is_equivalent(mode, &attempt);
}

MPCameraModeList *
mp_camera_list_supported_modes(MPCamera *camera)
{
	if (mp_camera_is_subdev(camera)) {
		return get_subdev_modes(camera, all_modes);
	} else {
		return get_video_modes(camera, all_modes);
	}
}

MPCameraModeList *
mp_camera_list_available_modes(MPCamera *camera)
{
	if (mp_camera_is_subdev(camera)) {
		return get_subdev_modes(camera, available_modes);
	} else {
		return get_video_modes(camera, available_modes);
	}
}

MPCameraMode *
mp_camera_mode_list_get(MPCameraModeList *list)
{
	g_return_val_if_fail(list, NULL);
	return &list->mode;
}

MPCameraModeList *
mp_camera_mode_list_next(MPCameraModeList *list)
{
	g_return_val_if_fail(list, NULL);
	return list->next;
}

void
mp_camera_mode_list_free(MPCameraModeList *list)
{
	while (list) {
		MPCameraModeList *tmp = list;
		list = tmp->next;
		free(tmp);
	}
}

struct int_str_pair {
	uint32_t value;
	const char *str;
};

struct int_str_pair control_id_names[] = {
	{ V4L2_CID_BRIGHTNESS, "BRIGHTNESS" },
	{ V4L2_CID_CONTRAST, "CONTRAST" },
	{ V4L2_CID_SATURATION, "SATURATION" },
	{ V4L2_CID_HUE, "HUE" },
	{ V4L2_CID_AUDIO_VOLUME, "AUDIO_VOLUME" },
	{ V4L2_CID_AUDIO_BALANCE, "AUDIO_BALANCE" },
	{ V4L2_CID_AUDIO_BASS, "AUDIO_BASS" },
	{ V4L2_CID_AUDIO_TREBLE, "AUDIO_TREBLE" },
	{ V4L2_CID_AUDIO_MUTE, "AUDIO_MUTE" },
	{ V4L2_CID_AUDIO_LOUDNESS, "AUDIO_LOUDNESS" },
	{ V4L2_CID_BLACK_LEVEL, "BLACK_LEVEL" },
	{ V4L2_CID_AUTO_WHITE_BALANCE, "AUTO_WHITE_BALANCE" },
	{ V4L2_CID_DO_WHITE_BALANCE, "DO_WHITE_BALANCE" },
	{ V4L2_CID_RED_BALANCE, "RED_BALANCE" },
	{ V4L2_CID_BLUE_BALANCE, "BLUE_BALANCE" },
	{ V4L2_CID_GAMMA, "GAMMA" },
	{ V4L2_CID_WHITENESS, "WHITENESS" },
	{ V4L2_CID_EXPOSURE, "EXPOSURE" },
	{ V4L2_CID_AUTOGAIN, "AUTOGAIN" },
	{ V4L2_CID_GAIN, "GAIN" },
	{ V4L2_CID_HFLIP, "HFLIP" },
	{ V4L2_CID_VFLIP, "VFLIP" },
	{ V4L2_CID_POWER_LINE_FREQUENCY, "POWER_LINE_FREQUENCY" },
	{ V4L2_CID_HUE_AUTO, "HUE_AUTO" },
	{ V4L2_CID_WHITE_BALANCE_TEMPERATURE, "WHITE_BALANCE_TEMPERATURE" },
	{ V4L2_CID_SHARPNESS, "SHARPNESS" },
	{ V4L2_CID_BACKLIGHT_COMPENSATION, "BACKLIGHT_COMPENSATION" },
	{ V4L2_CID_CHROMA_AGC, "CHROMA_AGC" },
	{ V4L2_CID_COLOR_KILLER, "COLOR_KILLER" },
	{ V4L2_CID_COLORFX, "COLORFX" },
	{ V4L2_CID_AUTOBRIGHTNESS, "AUTOBRIGHTNESS" },
	{ V4L2_CID_BAND_STOP_FILTER, "BAND_STOP_FILTER" },
	{ V4L2_CID_ROTATE, "ROTATE" },
	{ V4L2_CID_BG_COLOR, "BG_COLOR" },
	{ V4L2_CID_CHROMA_GAIN, "CHROMA_GAIN" },
	{ V4L2_CID_ILLUMINATORS_1, "ILLUMINATORS_1" },
	{ V4L2_CID_ILLUMINATORS_2, "ILLUMINATORS_2" },
	{ V4L2_CID_MIN_BUFFERS_FOR_CAPTURE, "MIN_BUFFERS_FOR_CAPTURE" },
	{ V4L2_CID_MIN_BUFFERS_FOR_OUTPUT, "MIN_BUFFERS_FOR_OUTPUT" },
	{ V4L2_CID_ALPHA_COMPONENT, "ALPHA_COMPONENT" },
	{ V4L2_CID_COLORFX_CBCR, "COLORFX_CBCR" },
	{ V4L2_CID_LASTP1, "LASTP1" },
	{ V4L2_CID_USER_MEYE_BASE, "USER_MEYE_BASE" },
	{ V4L2_CID_USER_BTTV_BASE, "USER_BTTV_BASE" },
	{ V4L2_CID_USER_S2255_BASE, "USER_S2255_BASE" },
	{ V4L2_CID_USER_SI476X_BASE, "USER_SI476X_BASE" },
	{ V4L2_CID_USER_TI_VPE_BASE, "USER_TI_VPE_BASE" },
	{ V4L2_CID_USER_SAA7134_BASE, "USER_SAA7134_BASE" },
	{ V4L2_CID_USER_ADV7180_BASE, "USER_ADV7180_BASE" },
	{ V4L2_CID_USER_TC358743_BASE, "USER_TC358743_BASE" },
	{ V4L2_CID_USER_MAX217X_BASE, "USER_MAX217X_BASE" },
	{ V4L2_CID_USER_IMX_BASE, "USER_IMX_BASE" },
	// { V4L2_CID_USER_ATMEL_ISC_BASE, "USER_ATMEL_ISC_BASE" },
	{ V4L2_CID_CAMERA_CLASS_BASE, "CAMERA_CLASS_BASE" },
	{ V4L2_CID_CAMERA_CLASS, "CAMERA_CLASS" },
	{ V4L2_CID_EXPOSURE_AUTO, "EXPOSURE_AUTO" },
	{ V4L2_CID_EXPOSURE_ABSOLUTE, "EXPOSURE_ABSOLUTE" },
	{ V4L2_CID_EXPOSURE_AUTO_PRIORITY, "EXPOSURE_AUTO_PRIORITY" },
	{ V4L2_CID_PAN_RELATIVE, "PAN_RELATIVE" },
	{ V4L2_CID_TILT_RELATIVE, "TILT_RELATIVE" },
	{ V4L2_CID_PAN_RESET, "PAN_RESET" },
	{ V4L2_CID_TILT_RESET, "TILT_RESET" },
	{ V4L2_CID_PAN_ABSOLUTE, "PAN_ABSOLUTE" },
	{ V4L2_CID_TILT_ABSOLUTE, "TILT_ABSOLUTE" },
	{ V4L2_CID_FOCUS_ABSOLUTE, "FOCUS_ABSOLUTE" },
	{ V4L2_CID_FOCUS_RELATIVE, "FOCUS_RELATIVE" },
	{ V4L2_CID_FOCUS_AUTO, "FOCUS_AUTO" },
	{ V4L2_CID_ZOOM_ABSOLUTE, "ZOOM_ABSOLUTE" },
	{ V4L2_CID_ZOOM_RELATIVE, "ZOOM_RELATIVE" },
	{ V4L2_CID_ZOOM_CONTINUOUS, "ZOOM_CONTINUOUS" },
	{ V4L2_CID_PRIVACY, "PRIVACY" },
	{ V4L2_CID_IRIS_ABSOLUTE, "IRIS_ABSOLUTE" },
	{ V4L2_CID_IRIS_RELATIVE, "IRIS_RELATIVE" },
	{ V4L2_CID_AUTO_EXPOSURE_BIAS, "AUTO_EXPOSURE_BIAS" },
	{ V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE, "AUTO_N_PRESET_WHITE_BALANCE" },
	{ V4L2_CID_WIDE_DYNAMIC_RANGE, "WIDE_DYNAMIC_RANGE" },
	{ V4L2_CID_IMAGE_STABILIZATION, "IMAGE_STABILIZATION" },
	{ V4L2_CID_ISO_SENSITIVITY, "ISO_SENSITIVITY" },
	{ V4L2_CID_ISO_SENSITIVITY_AUTO, "ISO_SENSITIVITY_AUTO" },
	{ V4L2_CID_EXPOSURE_METERING, "EXPOSURE_METERING" },
	{ V4L2_CID_SCENE_MODE, "SCENE_MODE" },
	{ V4L2_CID_3A_LOCK, "3A_LOCK" },
	{ V4L2_CID_AUTO_FOCUS_START, "AUTO_FOCUS_START" },
	{ V4L2_CID_AUTO_FOCUS_STOP, "AUTO_FOCUS_STOP" },
	{ V4L2_CID_AUTO_FOCUS_STATUS, "AUTO_FOCUS_STATUS" },
	{ V4L2_CID_AUTO_FOCUS_RANGE, "AUTO_FOCUS_RANGE" },
	{ V4L2_CID_PAN_SPEED, "PAN_SPEED" },
	{ V4L2_CID_TILT_SPEED, "TILT_SPEED" },
	// { V4L2_CID_CAMERA_ORIENTATION, "CAMERA_ORIENTATION" },
	// { V4L2_CID_CAMERA_SENSOR_ROTATION, "CAMERA_SENSOR_ROTATION" },
	{ V4L2_CID_FLASH_LED_MODE, "FLASH_LED_MODE" },
	{ V4L2_CID_FLASH_STROBE_SOURCE, "FLASH_STROBE_SOURCE" },
	{ V4L2_CID_FLASH_STROBE, "FLASH_STROBE" },
	{ V4L2_CID_FLASH_STROBE_STOP, "FLASH_STROBE_STOP" },
	{ V4L2_CID_FLASH_STROBE_STATUS, "FLASH_STROBE_STATUS" },
	{ V4L2_CID_FLASH_TIMEOUT, "FLASH_TIMEOUT" },
	{ V4L2_CID_FLASH_INTENSITY, "FLASH_INTENSITY" },
	{ V4L2_CID_FLASH_TORCH_INTENSITY, "FLASH_TORCH_INTENSITY" },
	{ V4L2_CID_FLASH_INDICATOR_INTENSITY, "FLASH_INDICATOR_INTENSITY" },
	{ V4L2_CID_FLASH_FAULT, "FLASH_FAULT" },
	{ V4L2_CID_FLASH_CHARGE, "FLASH_CHARGE" },
	{ V4L2_CID_FLASH_READY, "FLASH_READY" },
};

const char *
mp_control_id_to_str(uint32_t id)
{
	size_t size = sizeof(control_id_names) / sizeof(*control_id_names);

	for (size_t i = 0; i < size; ++i) {
		if (control_id_names[i].value == id) {
			return control_id_names[i].str;
		}
	}

	return "UNKNOWN";
}

struct int_str_pair control_type_names[] = {
	{ V4L2_CTRL_TYPE_INTEGER, "INTEGER" },
	{ V4L2_CTRL_TYPE_BOOLEAN, "BOOLEAN" },
	{ V4L2_CTRL_TYPE_MENU, "MENU" },
	{ V4L2_CTRL_TYPE_INTEGER_MENU, "INTEGER_MENU" },
	{ V4L2_CTRL_TYPE_BITMASK, "BITMASK" },
	{ V4L2_CTRL_TYPE_BUTTON, "BUTTON" },
	{ V4L2_CTRL_TYPE_INTEGER64, "INTEGER64" },
	{ V4L2_CTRL_TYPE_STRING, "STRING" },
	{ V4L2_CTRL_TYPE_CTRL_CLASS, "CTRL_CLASS" },
	{ V4L2_CTRL_TYPE_U8, "U8" },
	{ V4L2_CTRL_TYPE_U16, "U16" },
	{ V4L2_CTRL_TYPE_U32, "U32" },
	// { V4L2_CTRL_TYPE_MPEG2_SLICE_PARAMS, "MPEG2_SLICE_PARAMS" },
	// { V4L2_CTRL_TYPE_MPEG2_QUANTIZATION, "MPEG2_QUANTIZATION" },
	// { V4L2_CTRL_TYPE_AREA, "AREA" },
	// { V4L2_CTRL_TYPE_H264_SPS, "H264_SPS" },
	// { V4L2_CTRL_TYPE_H264_PPS, "H264_PPS" },
	// { V4L2_CTRL_TYPE_H264_SCALING_MATRIX, "H264_SCALING_MATRIX" },
	// { V4L2_CTRL_TYPE_H264_SLICE_PARAMS, "H264_SLICE_PARAMS" },
	// { V4L2_CTRL_TYPE_H264_DECODE_PARAMS, "H264_DECODE_PARAMS" },
	// { V4L2_CTRL_TYPE_HEVC_SPS, "HEVC_SPS" },
	// { V4L2_CTRL_TYPE_HEVC_PPS, "HEVC_PPS" },
	// { V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS, "HEVC_SLICE_PARAMS" },
};

const char *
mp_control_type_to_str(uint32_t type)
{
	size_t size = sizeof(control_type_names) / sizeof(*control_type_names);

	for (size_t i = 0; i < size; ++i) {
		if (control_type_names[i].value == type) {
			return control_type_names[i].str;
		}
	}

	return "UNKNOWN";
}

struct _MPControlList {
	MPControl control;
	MPControlList *next;
};

static int
control_fd(MPCamera *camera)
{
	if (camera->subdev_fd != -1) {
		return camera->subdev_fd;
	}
	return camera->video_fd;
}

MPControlList *
mp_camera_list_controls(MPCamera *camera)
{
	MPControlList *item = NULL;

	struct v4l2_query_ext_ctrl ctrl = {};
	ctrl.id = V4L2_CTRL_FLAG_NEXT_CTRL | V4L2_CTRL_FLAG_NEXT_COMPOUND;
	while (true) {
		if (xioctl(control_fd(camera), VIDIOC_QUERY_EXT_CTRL, &ctrl) == -1) {
			if (errno != EINVAL) {
				errno_printerr("VIDIOC_QUERY_EXT_CTRL");
			}
			break;
		}

		MPControl control = {
			.id = ctrl.id,
			.type = ctrl.type,
			.name = {},
			.min = ctrl.minimum,
			.max = ctrl.maximum,
			.step = ctrl.step,
			.default_value = ctrl.default_value,
			.flags = ctrl.flags,
			.element_size = ctrl.elem_size,
			.element_count = ctrl.elems,
			.dimensions_count = ctrl.nr_of_dims,
			.dimensions = {},
		};

		strcpy(control.name, ctrl.name);
		memcpy(control.dimensions, ctrl.dims,
		       sizeof(uint32_t) * V4L2_CTRL_MAX_DIMS);

		MPControlList *new_item = malloc(sizeof(MPControlList));
		new_item->control = control;
		new_item->next = item;
		item = new_item;

		ctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL | V4L2_CTRL_FLAG_NEXT_COMPOUND;
	}

	return item;
}

MPControl *
mp_control_list_get(MPControlList *list)
{
	g_return_val_if_fail(list, NULL);
	return &list->control;
}

MPControlList *
mp_control_list_next(MPControlList *list)
{
	g_return_val_if_fail(list, NULL);
	return list->next;
}

void
mp_control_list_free(MPControlList *list)
{
	while (list) {
		MPControlList *tmp = list;
		list = tmp->next;
		free(tmp);
	}
}

bool
mp_camera_query_control(MPCamera *camera, uint32_t id, MPControl *control)
{
	struct v4l2_query_ext_ctrl ctrl = {};
	ctrl.id = id;
	if (xioctl(control_fd(camera), VIDIOC_QUERY_EXT_CTRL, &ctrl) == -1) {
		if (errno != EINVAL) {
			errno_printerr("VIDIOC_QUERY_EXT_CTRL");
		}
		return false;
	}

	if (control) {
		control->id = ctrl.id;
		control->type = ctrl.type;
		strcpy(control->name, ctrl.name);
		control->min = ctrl.minimum;
		control->max = ctrl.maximum;
		control->step = ctrl.step;
		control->default_value = ctrl.default_value;
		control->flags = ctrl.flags;
		control->element_size = ctrl.elem_size;
		control->element_count = ctrl.elems;
		control->dimensions_count = ctrl.nr_of_dims;
		memcpy(control->dimensions, ctrl.dims,
		       sizeof(uint32_t) * V4L2_CTRL_MAX_DIMS);
	}
	return true;
}

static bool
control_impl_int32(MPCamera *camera, uint32_t id, int request, int32_t *value)
{
	struct v4l2_ext_control ctrl = {};
	ctrl.id = id;
	ctrl.value = *value;

	struct v4l2_ext_controls ctrls = {
		.ctrl_class = 0,
		.which = V4L2_CTRL_WHICH_CUR_VAL,
		.count = 1,
		.controls = &ctrl,
	};
	if (xioctl(control_fd(camera), request, &ctrls) == -1) {
		return false;
	}

	*value = ctrl.value;
	return true;
}

bool
mp_camera_control_try_int32(MPCamera *camera, uint32_t id, int32_t *v)
{
	return control_impl_int32(camera, id, VIDIOC_TRY_EXT_CTRLS, v);
}

bool
mp_camera_control_set_int32(MPCamera *camera, uint32_t id, int32_t v)
{
	return control_impl_int32(camera, id, VIDIOC_S_EXT_CTRLS, &v);
}

int32_t
mp_camera_control_get_int32(MPCamera *camera, uint32_t id)
{
	int32_t v = 0;
	control_impl_int32(camera, id, VIDIOC_G_EXT_CTRLS, &v);
	return v;
}

bool
mp_camera_control_try_boolean(MPCamera *camera, uint32_t id, bool *v)
{
	int32_t value = *v;
	bool s = control_impl_int32(camera, id, VIDIOC_TRY_EXT_CTRLS, &value);
	*v = value;
	return s;
}

bool
mp_camera_control_set_bool(MPCamera *camera, uint32_t id, bool v)
{
	int32_t value = v;
	return control_impl_int32(camera, id, VIDIOC_S_EXT_CTRLS, &value);
}

bool
mp_camera_control_get_bool(MPCamera *camera, uint32_t id)
{
	int32_t v = false;
	control_impl_int32(camera, id, VIDIOC_G_EXT_CTRLS, &v);
	return v;
}