Reference¶

Devices¶

class qamlib.Device¶

Base class for a V4L2 device

get_control(*args, **kwargs)¶

Overloaded function.

get_control(self: qamlib.Device, name: str) -> int

Get current value of control by name

This is only for non-extended controls (eg. integer, menu, etc.)

Parameters:: name – Full name of the control, case is ignored.
Returns:: The integer value of the given control.

get_control(self: qamlib.Device, id: typing.SupportsInt) -> int

Get current value of control by id.

This is only for non-extended controls (eg. integer, menu, etc.)

Parameters:: id – ID of the control, there is no check if a control with that ID actually exists.
Returns:: The integer value of the given control

get_controls(self: qamlib.Device, names: collections.abc.Sequence[str], default_value: bool = False) → dict[str, qamlib.ControlValue]¶

Get current values of a list of (extended) control names

Parameters:

names – List of full control names, case is ignored
default_value – If True the default value of the control is returned.

Returns:

A dictionary with lower-case control names as keys, and a ControlValue with the value of the given control.

get_ext_control(self: qamlib.Device, name: str, default_value: bool = False) → qamlib.ControlValue¶

Get current value of an (extended) control

Parameters:

name – Full name of the control, case is ignored.
default_value – If True the default value of the control is returned.

Returns:

A ControlValue with the value of the given control

list_controls(self: qamlib.Device) → dict[str, qamlib.Control]¶

List all the controls for the device

Returns:: A list of all controls and their information.

set_control(*args, **kwargs)¶

Overloaded function.

set_control(self: qamlib.Device, name: str, value: typing.SupportsInt) -> None

Set a normal named control to desired value.

Parameters:

name – Full name of the control, case is ignored.
value – Integer value to set.

set_control(self: qamlib.Device, id: typing.SupportsInt, value: typing.SupportsInt) -> None

Set a normal control, by id to desired value

Parameters:

id – ID of the control, there is no check if a control with that ID actually exists.
value –
Integer value to set.

NOTE: This function does not do any checks of the control ID or value

set_controls(self: qamlib.Device, values: collections.abc.Mapping[str, qamlib.ControlValue]) → None¶

Set values of (extended) controls by name

Parameters:: values – A dictionary of control names as keys (case is ignored), and a ControlValue derived class with the value to be set for the control.

set_ext_control(self: qamlib.Device, name: str, ctrl_val: qamlib.ControlValue) → None¶

Set value of an (extended) control

Parameters:

name – Full name of the control, case is ignored.
ctrl_val – A ControlValue derived class with the value to set for the control.

property device_info¶: DeviceInfo object

class qamlib.StreamingDevice¶

Base class for devices that support streaming, inherits from Device

__enter__(self: qamlib.StreamingDevice) → None¶: Enter runtime context, starts the device stream

__exit__(self: qamlib.StreamingDevice, arg0: object, arg1: object, arg2: object) → None¶: Exit runtime context, stops the stream

get_crop(self: qamlib.StreamingDevice) → list[qamlib.Rectangle]¶: Get current crop selection (left, top, width, height)

get_crop_bounds(self: qamlib.StreamingDevice) → qamlib.Rectangle¶: Get crop selection bounds (left, top, width, height)

get_crop_default(self: qamlib.StreamingDevice) → qamlib.Rectangle¶: Get default crop selection (left, top, width, height)

list_formats(self: qamlib.StreamingDevice) → dict[str, qamlib.ImageFormat]¶: List all available formats for the device

set_crop(*args, **kwargs)¶

Overloaded function.

set_crop(self: qamlib.StreamingDevice, left: typing.SupportsInt, top: typing.SupportsInt, width: typing.SupportsInt, height: typing.SupportsInt) -> None

Set crop selection using V4L2s selection API. This function will change the resolution if needed.

set_crop(self: qamlib.StreamingDevice, rectangles: qamlib.Rectangle) -> None

Set crop selection using V4L2s selection API. This function will change the resolution if needed.

set_crop(self: qamlib.StreamingDevice, rectangles: collections.abc.Sequence[qamlib.Rectangle]) -> None

Set crop selections, using V4L2s selection API, there are some driver and logic limitations to multi-crop, because of this, the rectangles cannot overlap in the height dimension. This function will change the resolution if needed.

start(self: qamlib.StreamingDevice) → None¶: Starts the device stream

stop(self: qamlib.StreamingDevice) → None¶: Stops the device stream

class qamlib.Camera¶

Class for a V4L2 capture device, inherits from StreamingDevice

__init__(*args, **kwargs)¶

Overloaded function.

__init__(self: qamlib.Camera, path: str, buffers: typing.SupportsInt | None = None, overflow_exception: bool = True) -> None

Open V4L2 device at path.

Parameters:

path – Path to the V4L2 capture device
buffers – The size of the userspace ring-buffer. qamlib will request a small amount >buffers so the driver always has a buffer ready. See get_frame for when and how the buffer is used.
overflow_exception – Whether to throw DroppedFrameException when frames are dropped in get_frame(buffered=True)

__init__(self: qamlib.Camera, device_num: typing.SupportsInt, buffers: typing.SupportsInt | None = None, overflow_exception: bool = True) -> None

Open V4L2 device number: device_num.

Parameters:

device_num – Video device number. (/dev/videoX)
buffers – The size of the userspace ring-buffer. qamlib will request a small amount >buffers so the driver always has a buffer ready. See get_frame for when and how the buffer is used.
overflow_exception – Whether to throw DroppedFrameException when frames are dropped in get_frame(buffered=True)

__init__(self: qamlib.Camera, overflow_exception: bool = True) -> None

Opens /dev/qtec/video0

Parameters:: overflow_exception – Whether to throw DroppedFrameException when frames are dropped in get_frame(buffered=True)

get_format(self: qamlib.Camera) → qamlib.Format¶: Get the currently set format

get_frame(self: qamlib.Camera, timeout: SupportsFloat | None = None, buffered: bool = False) → tuple[qamlib.FrameMetadata, numpy.ndarray]¶

Get frame from camera.

Parameters:

timeout – Time in seconds to wait before throwing a:class:TimeoutException if no frame is ready. Negative timeouts are allowed, and results in immediate timeout if no frame is ready.
buffered – If True then the next frame in the buffer is returned, otherwise the newest frame in the buffer is returned.

Returns:

The FrameMetadata for the frame and the frame as a NumPy ndarray

Raises:

TimeoutException – If the timeout is reached.
DroppedFrameException – If buffered=True and the buffer has overrun.

get_framerate(self: qamlib.Camera) → float¶: Get current framerate in frames per second (FPS)

get_framerates(*args, **kwargs)¶

Overloaded function.

get_framerates(self: qamlib.Camera) -> qamlib.FrameRate

Get possible framerates for current resolution and format

Returns:: A FrameRate derived object with the possible framerates.

get_framerates(self: qamlib.Camera, width: typing.SupportsInt, height: typing.SupportsInt) -> qamlib.FrameRate

Get possible framerates for current format at the given resolution

Parameters:

width – Frame width.
height – Frame height.

Returns:

A FrameRate derived object with the possible framerates.

get_framerates(self: qamlib.Camera, width: typing.SupportsInt, height: typing.SupportsInt, pixelformat: str, big_endian: bool = False) -> qamlib.FrameRate

Get possible framerates for the given format at the given resolution

Parameters:

width – Frame width.
height – Frame height.
pixelformat – FourCC name of the format (eg. “RGB”)
big_endian – Whether the format is big endian. This is also true if the pixelformat name has “_BE” appended to it

Returns:

A FrameRate derived object with the possible framerates.

get_resolution(self: qamlib.Camera) → tuple[int, int]¶: Get current resolution

set_format(*args, **kwargs)¶

Overloaded function.

set_format(self: qamlib.Camera, format: qamlib.Format) -> qamlib.Format

Set image format

set_format(self: qamlib.Camera, format: str, big_endian: bool = False) -> qamlib.Format

Set image format by format name, this function alsoscales selection for the new format

set_framerate(self: qamlib.Camera, framerate: SupportsFloat) → float¶: Tries to set the desired framerate, returns the actual framerate that we got

set_resolution(self: qamlib.Camera, width: SupportsInt, height: SupportsInt) → tuple[int, int]¶: Try to set the desired resolution, and returns the resolution that was set

class qamlib.EventDevice¶

Class for getting events from a V4L2 device

__init__(*args, **kwargs)¶

Overloaded function.

__init__(self: qamlib.EventDevice) -> None
__init__(self: qamlib.EventDevice, arg0: str) -> None
__init__(self: qamlib.EventDevice, arg0: typing.SupportsInt) -> None

set_callback(self: qamlib.EventDevice, arg0: collections.abc.Callable[[qamlib::BaseEvent], None]) → None¶: Set the callback function

start(self: qamlib.EventDevice) → None¶: Start capturing events

stop(self: qamlib.EventDevice) → None¶: Stop capturing events

subscribe(self: qamlib.EventDevice, type: SupportsInt, id: SupportsInt = 0) → None¶: Subscribe to event

unsubscribe(self: qamlib.EventDevice, type: SupportsInt, id: SupportsInt = 0) → None¶: Unsubscribe from event

Controls¶

class qamlib.Control¶

This class represents the information about a camera control.

to_json(self: qamlib.Control) → json¶

property dimensions¶: The dimensions of the element array

property element_size¶: The size of the control elements

property elements¶: The number of control elemets

property flags¶: Class representing the control flags

property id¶: ID of the camera control

property name¶: Name of the camera control

property type¶: Type of the camera control

class qamlib.ValueControl¶

Inherits from Control, represents a normal control with a single value

to_json(self: qamlib.ValueControl) → json¶

property default_value¶: The default value of the camera control

property max¶: The maximum value of the camera control

property min¶: The minimum value of the camera control

property step¶: The step size of the camera control

class qamlib.MenuControl¶

Inherits from ValueControl. Represents a menu control, with the names of the items

to_json(self: qamlib.MenuControl) → json¶

property items¶: Names of the menu items

class qamlib.IntegerMenuControl¶

Inherits from ValueControl. Reprenests an integer menu control, with the values of the items

to_json(self: qamlib.IntegerMenuControl) → json¶

property items¶: Values of the menu items

class qamlib.ControlFlags¶

Class that represents the flags of a control. For more information about their meaning see here.

to_json(self: qamlib.ControlFlags) → json¶

property disabled¶

property dynamic_array¶

property execute_on_write¶

property grabbed¶

property has_payload¶

property inactive¶

property is_volatile¶

property modify_layout¶

property raw_flags¶: The integer containing the V4L2 control flags

property read_only¶

property slider¶

property update¶

property write_only¶

ControlValue classes¶

class qamlib.ControlValue¶: Base class for extended control values

class qamlib.IntegerControlValue¶

Class that represents a integer control value

__init__(self: qamlib.IntegerControlValue, value: SupportsInt) → None¶

to_json(self: qamlib.IntegerControlValue) → json¶

property value¶

class qamlib.StringControlValue¶

Class that represents a string control value

__init__(self: qamlib.StringControlValue, value: str) → None¶

to_json(self: qamlib.StringControlValue) → json¶

property value¶

class qamlib.ArrayControlValue¶

Class that represents an array control value

__init__(self: qamlib.ArrayControlValue, array: numpy.ndarray) → None¶

to_json(self: qamlib.ArrayControlValue) → json¶

property value¶

class qamlib.TriggerSequenceValue¶

Class that represents the values of a trigger sequence

NOTE: Qtec specific control at the moment. The trigger sequence control is not implemented for all Qtec cameras and/or sensors configurations.

__init__(self: qamlib.TriggerSequenceValue) → None¶

add_exposure(self: qamlib.TriggerSequenceValue, exposure_time: SupportsInt, flash_time: SupportsInt, frame_delay: SupportsInt, trigger_delay: SupportsInt, flash_time_delay: bool = False) → None¶: Add an exposure to the sequence

clear(self: qamlib.TriggerSequenceValue) → None¶: Clear the sequences

to_json(self: qamlib.TriggerSequenceValue) → json¶

property value¶: The list of sequences

Formats¶

class qamlib.ImageFormat¶

Class that represents an image format

to_json(self: qamlib.ImageFormat) → json¶

property description¶

property flags¶

property index¶

property pixelformat¶

class qamlib.ImageFormatFlags¶

Class that represents the flags for an image format. For more information see here.

to_json(self: qamlib.ImageFormatFlags) → json¶

property compressed¶

property continuous_bytestream¶

property csc_colorspace¶

property csc_hsv_enc¶

property csc_quantization¶

property csc_xfer_func¶

property csc_ycbcr_enc¶

property dyn_resolution¶

property emulated¶

property enc_cap_frame_interval¶

class qamlib.Format¶

Class that represents the format

property type¶

class qamlib.SinglePlaneFormat¶

Class that represents a single plane pixel format

to_json(self: qamlib.SinglePlaneFormat) → json¶

property bytesperline¶

property colorspace¶

property field¶

property flags¶

property height¶

property pixelformat¶

property priv¶

property quantization¶

property sizeimage¶

property width¶

property xfer_func¶

class qamlib.PixelFormat¶

Class that represents a V4L2 fourcc code

get_code(self: qamlib.PixelFormat) → int¶

property big_endian¶

property fourcc¶

class qamlib.PixelFormatFlags¶

Class that represents the flags for a pixel format. For more information see here.

to_json(self: qamlib.PixelFormatFlags) → json¶

Framerates¶

class qamlib.FrameRate¶

Base class for FrameRate types

property type¶

class qamlib.DiscreteFrameRate¶

Represents a list of discrete framerates

to_json(self: qamlib.DiscreteFrameRate) → json¶

property values¶: FPS values

class qamlib.ContinuousFrameRate¶

Represents a continous framerate

to_json(self: qamlib.ContinuousFrameRate) → json¶

property max¶: Maximum FPS

property min¶: Minimum FPS

class qamlib.StepwiseFrameRate¶

Inherits from ContinuousFrameRate. Represents a stepwise framerate

to_json(self: qamlib.StepwiseFrameRate) → json¶

property step¶: FPS step size

Events¶

class qamlib.BaseEvent¶

Base class for Event types

property id¶: Control ID associated with the event source. If the event does not have an associated ID, this value is 0.

property pending¶: Number of pending events

property sequence¶: Event sequence number

property timestamp¶: Event timestamp

property type¶: Type of the event

class qamlib.ControlEvent¶

Class that represents a control event

property changes¶: Flags that show what has changed for the control

property control_type¶: Type of the control

property default_value¶: Potentially new default_value of the control

property flags¶: Potentially new flags of the control

property max¶: Potentially new maximum of the control

property min¶: Potentially new minimum of the control

property step¶: Potentially new step of the control

property value¶: Potentially new value of the control

class qamlib.EventType¶

Members:

ALL

VSYNC

EOS

CTRL

FRAME_SYNC

SOURCE_CHANGE

MOTION_DET

ALL = <EventType.ALL: 0>¶

CTRL = <EventType.CTRL: 3>¶

EOS = <EventType.EOS: 2>¶

FRAME_SYNC = <EventType.FRAME_SYNC: 4>¶

MOTION_DET = <EventType.MOTION_DET: 6>¶

SOURCE_CHANGE = <EventType.SOURCE_CHANGE: 5>¶

VSYNC = <EventType.VSYNC: 1>¶

property name¶

property value¶

class qamlib.ControlChangesFlags¶

Class that represents the flags for a control event. For more information see here.

property flags¶

property range¶

property value¶

Misc¶

class qamlib.FrameMetadata¶

This class contains the frame metadata.

property clock¶: CLOCKID for which kernel clock was used

property sequence¶: The sequence number of the frame

property time¶: Kernel time for when the frame was taken

class qamlib.Rectangle¶

Class to represent a selection rectangle

property height¶

property left¶

property top¶

property width¶

class qamlib.DeviceInfo¶

Class containing information about the video device

property bus_info¶: String

property card¶: String

property driver¶: String

Exceptions¶

exception qamlib.V4L2Exception¶

exception qamlib.TimeoutException¶

exception qamlib.DroppedFrameException¶