Function enum_frame_intervals

rustcv-camera/src/backend/linux/sys.rs:146–166

(
    fd: RawFd,
    pixel_format: u32,
    width: u32,
    height: u32,
    index: u32,
)

/// 枚举指定格式和尺寸下支持的帧间隔（VIDIOC_ENUM_FRAMEINTERVALS）。
#[allow(dead_code)]
pub fn enum_frame_intervals(
    fd: RawFd,
    pixel_format: u32,
    width: u32,
    height: u32,
    index: u32,
) -> io::Result<v4l2_frmivalenum> {
    let mut interval: v4l2_frmivalenum = unsafe { std::mem::zeroed() };
    interval.index = index;
    interval.pixel_format = pixel_format;
    interval.width = width;
    interval.height = height;
    unsafe {
        v4l2_ioctl(
            fd,
            VIDIOC_ENUM_FRAMEINTERVALS,
            &mut interval as *mut _ as *mut libc::c_void,
        )?;
    }
    Ok(interval)
}

// ─── Format get/set ─────────────────────────────────────────────────────────