Struct V4LCaptureDevice 

pub struct V4LCaptureDevice<'a> { /* private fields */ }

The backend struct that interfaces with V4L2. To see what this does, please see CaptureBackendTrait.

Quirks

• Calling set_resolution(), set_frame_rate(), or set_frame_format() each internally calls set_camera_format().

Implementations

impl<'a> V4LCaptureDevice<'a>

pub fn new( index: &CameraIndex, cam_fmt: RequestedFormat<'_>, ) -> Result<Self, NokhwaError>

Creates a new capture device using the V4L2 backend. Indexes are gives to devices by the OS, and usually numbered by order of discovery.

Errors

This function will error if the camera is currently busy or if V4L2 can’t read device information.

pub fn new_with( index: CameraIndex, width: u32, height: u32, fps: u32, fourcc: FrameFormat, ) -> Result<Self, NokhwaError>

👎Deprecated since 0.10.0:

please use new instead.

Create a new V4L2 Camera with desired settings. This may or may not work.

Errors

This function will error if the camera is currently busy or if V4L2 can’t read device information.

pub fn force_refresh_camera_format(&mut self) -> Result<(), NokhwaError>

Force refreshes the inner CameraFormat state.

Errors

If the internal representation in the driver is invalid, this will error.

Trait Implementations

impl<'a> CaptureBackendTrait for V4LCaptureDevice<'a>

fn backend(&self) -> ApiBackend

Returns the current backend used.

fn camera_info(&self) -> &CameraInfo

Gets the camera information such as Name and Index as a CameraInfo.

fn refresh_camera_format(&mut self) -> Result<(), NokhwaError>

Forcefully refreshes the stored camera format, bringing it into sync with “reality” (current camera state)

fn camera_format(&self) -> CameraFormat

Gets the current CameraFormat. This will force refresh to the current latest if it has changed.

fn set_camera_format( &mut self, new_fmt: CameraFormat, ) -> Result<(), NokhwaError>

Will set the current CameraFormat This will reset the current stream if used while stream is opened.

fn compatible_list_by_resolution( &mut self, fourcc: FrameFormat, ) -> Result<HashMap<Resolution, Vec<u32>>, NokhwaError>

A hashmap of Resolutions mapped to framerates. Not sorted!

fn compatible_fourcc(&mut self) -> Result<Vec<FrameFormat>, NokhwaError>

A Vector of compatible FrameFormats. Will only return 2 elements at most.

fn resolution(&self) -> Resolution

Gets the current camera resolution (See: Resolution, CameraFormat). This will force refresh to the current latest if it has changed.

fn set_resolution(&mut self, new_res: Resolution) -> Result<(), NokhwaError>

Will set the current Resolution This will reset the current stream if used while stream is opened.

fn frame_rate(&self) -> u32

Gets the current camera framerate (See: CameraFormat). This will force refresh to the current latest if it has changed.

fn set_frame_rate(&mut self, new_fps: u32) -> Result<(), NokhwaError>

Will set the current framerate This will reset the current stream if used while stream is opened.

fn frame_format(&self) -> FrameFormat

Gets the current camera’s frame format (See: FrameFormat, CameraFormat). This will force refresh to the current latest if it has changed.

fn set_frame_format(&mut self, fourcc: FrameFormat) -> Result<(), NokhwaError>

Will set the current FrameFormat This will reset the current stream if used while stream is opened.

fn camera_control( &self, control: KnownCameraControl, ) -> Result<CameraControl, NokhwaError>

Gets the value of KnownCameraControl.

fn camera_controls(&self) -> Result<Vec<CameraControl>, NokhwaError>

Gets the current supported list of KnownCameraControl

fn set_camera_control( &mut self, id: KnownCameraControl, value: ControlValueSetter, ) -> Result<(), NokhwaError>

Sets the control to control in the camera. Usually, the pipeline is calling camera_control(), getting a camera control that way then calling value() to get a ControlValueSetter and setting the value that way.

fn open_stream(&mut self) -> Result<(), NokhwaError>

Will open the camera stream with set parameters. This will be called internally if you try and call frame() before you call open_stream().

fn is_stream_open(&self) -> bool

Checks if stream if open. If it is, it will return true.

fn frame(&mut self) -> Result<Buffer, NokhwaError>

Will get a frame from the camera as a Buffer. Depending on the backend, if you have not called open_stream() before you called this, it will either return an error.

fn frame_raw(&mut self) -> Result<Cow<'_, [u8]>, NokhwaError>

Will get a frame from the camera without any processing applied, meaning you will usually get a frame you need to decode yourself.

fn stop_stream(&mut self) -> Result<(), NokhwaError>

Will drop the stream.

fn compatible_camera_formats( &mut self, ) -> Result<Vec<CameraFormat>, NokhwaError>

Gets the compatible CameraFormat of the camera

fn decoded_buffer_size(&self, alpha: bool) -> usize

The minimum buffer size needed to write the current frame. If alpha is true, it will instead return the minimum size of the buffer with an alpha channel as well. This assumes that you are decoding to RGB/RGBA for FrameFormat::MJPEG or FrameFormat::YUYV and Luma8/LumaA8 for FrameFormat::GRAY