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");
                return false;
            }
        }

        // 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);

    // Start by requesting buffers
    struct v4l2_requestbuffers req = {};
    req.count = MAX_VIDEO_BUFFERS;
    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;
    }

    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 = V4L2_BUF_TYPE_VIDEO_CAPTURE,
            .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 = V4L2_BUF_TYPE_VIDEO_CAPTURE,
            .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;
}