Internal documentation¶

This is the documentation of the internals of v4l2ctl

Module ioctlmacros¶

Module v4l2interface¶

Module v4l2device¶

exception v4l2ctl.v4l2device.FeatureNotSupported¶

Bases: Exception

__module__ = 'v4l2ctl.v4l2device'¶

__weakref__¶: list of weak references to the object (if defined)

class v4l2ctl.v4l2device.V4l2Device(device='/dev/video0')¶

Bases: io.IOBase

Initialize the V4l2Device object and read its basic information.

Keyword Arguments:
	device (str, path-like, int) – the video device (default r”/dev/video0”) if an int is given, it is assumed to be number after “video” in “/dev”.
Raises:	`IoctlError` – if a non-video device file is given.

__abstractmethods__ = frozenset()¶

__enter__()¶

__exit__(exc_type, exc, tb)¶

__init__(device='/dev/video0')¶: Initialize self. See help(type(self)) for accurate signature.

__iter__()¶: Implement iter(self).

__module__ = 'v4l2ctl.v4l2device'¶

__next__()¶: Implement next(self).

__repr__()¶: Return repr(self).

_abc_impl = <_abc_data object>¶

_open()¶

buffer_type¶: The buffer type (see V4l2BufferType) required for several operations. This attribute does not change anything in the device itself. It is used by other operations.

bus¶: The bus through which this device is connected (read-only).

capabilities¶: The device specific capabilities (read-only). These are the capabilities associated with this dev-file only. The physical device can have more than one dev-file, and hence more capabilities. See physical_capabilities.

close()¶

Flush and close the IO object.

This method has no effect if the file is already closed.

closed¶

cropping_buffer_types = [<V4l2BufferType.VIDEO_CAPTURE: 1>, <V4l2BufferType.VIDEO_CAPTURE_MPLANE: 9>, <V4l2BufferType.VIDEO_OUTPUT: 2>, <V4l2BufferType.VIDEO_OUTPUT_MPLANE: 10>, <V4l2BufferType.VIDEO_OVERLAY: 3>]¶

cropping_capabilities¶

The cropping capabilities (read-only). These are the cropping capabilities of this video device.

Only valid for these buffer types:

V4l2BufferType.VIDEO_CAPTURE
V4l2BufferType.VIDEO_CAPTURE_MPLANE
V4l2BufferType.VIDEO_OUTPUT
V4l2BufferType.VIDEO_OUTPUT_MPLANE
V4l2BufferType.VIDEO_OVERLAY

cropping_rectangle¶: The cropping rectangle (see V4l2Rectangle).

Note

The cropping rectange is specfic to the set buffer type. (See buffer_type)

device¶: The device file (read-only).

driver¶: The linux driver (read-only).

fileno()¶

Returns underlying file descriptor if one exists.

OSError is raised if the IO object does not use a file descriptor.

flush()¶

Flush write buffers, if applicable.

This is not implemented for read-only and non-blocking streams.

formats¶: A generator for the suported formats by this video device.

Note

The formats are specfic to the set buffer type. (See buffer_type)

isatty()¶

Return whether this is an ‘interactive’ stream.

Return False if it can’t be determined.

iter_buffer_formats(buffer_type)¶

Iterate over the formats supported by a certain buffer.

Keyword Arguments:
	buffer_type – see `V4l2BufferType`.
Returns:	a generator

static iter_devices(skip_links=True)¶

Return an iterator over the available v4l2 devices.

Keyword Arguments:
	skip_links (bool) – skip links and return every device only once (default True)
Returns:	an iterator

name¶: The card name (read-only).

physical_capabilities¶: The general physical capabilities (read-only). These are the capabilities associated with the physical device as a while, and not limited to this dev-file only.

readable()¶

Return whether object was opened for reading.

If False, read() will raise OSError.

readline(size=-1)¶

Read and return a line from the stream.

If size is specified, at most size bytes will be read.

The line terminator is always b’n’ for binary files; for text files, the newlines argument to open can be used to select the line terminator(s) recognized.

readlines(hint=-1)¶

Return a list of lines from the stream.

hint can be specified to control the number of lines read: no more lines will be read if the total size (in bytes/characters) of all lines so far exceeds hint.

seekable()¶

Return whether object supports random access.

If False, seek(), tell() and truncate() will raise OSError. This method may need to do a test seek().

supported_buffer_types¶: The supported buffer types by this video device (read-only).

version¶: The kernel version as a string (read-only).

version_tuple¶: The kernel version as a tuple (read-only).

writable()¶

Return whether object was opened for writing.

If False, write() will raise OSError.

writelines(lines)¶

Write a list of lines to stream.

Line separators are not added, so it is usual for each of the lines provided to have a line separator at the end.

class v4l2ctl.v4l2device.V4l2DeviceIterator(skip_links)¶

Bases: object

__dict__ = mappingproxy({'__module__': 'v4l2ctl.v4l2device', '_v4l2_device_prefixes': ['video', 'radio', 'vbi', 'swradio', 'v4l-subdev'], '__init__': <function V4l2DeviceIterator.__init__>, '__iter__': <function V4l2DeviceIterator.__iter__>, '__dict__': <attribute '__dict__' of 'V4l2DeviceIterator' objects>, '__weakref__': <attribute '__weakref__' of 'V4l2DeviceIterator' objects>, '__doc__': None})¶

__init__(skip_links)¶: Initialize self. See help(type(self)) for accurate signature.

__iter__()¶

__module__ = 'v4l2ctl.v4l2device'¶

__weakref__¶: list of weak references to the object (if defined)

_v4l2_device_prefixes = ['video', 'radio', 'vbi', 'swradio', 'v4l-subdev']¶