sysfs_devs: add v4l2 video campture device detection
Signed-off-by: Eric Callahan <arksine.code@gmail.com>
This commit is contained in:
Eric Callahan
parent
eb1599fa07
commit
522b4df989
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@ -14,7 +14,7 @@ This module contains of Python port of the macros avaialble in
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"""
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if TYPE_CHECKING:
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IOCParamSize = Union[int, str, Type[ctypes._SimpleCData]]
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IOCParamSize = Union[int, str, Type[ctypes._CData]]
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_IOC_NRBITS = 8
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_IOC_TYPEBITS = 8
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@ -4,7 +4,12 @@
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#
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# This file may be distributed under the terms of the GNU GPLv3 license
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from __future__ import annotations
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import os
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import fcntl
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import ctypes
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import pathlib
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from ..common import ExtendedFlag
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from . import ioctl_macros
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from typing import (
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Dict,
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List,
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@ -18,6 +23,9 @@ USB_DEVICE_PATH = "/sys/bus/usb/devices"
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TTY_PATH = "/sys/class/tty"
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SER_BYPTH_PATH = "/dev/serial/by-path"
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SER_BYID_PATH = "/dev/serial/by-id"
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V4L_DEVICE_PATH = "/sys/class/video4linux"
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V4L_BYPTH_PATH = "/dev/v4l/by-path"
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V4L_BYID_PATH = "/dev/v4l/by-id"
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OPTIONAL_USB_INFO = ["manufacturer", "product", "serial"]
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NULL_DESCRIPTIONS = [
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@ -27,6 +35,19 @@ NULL_DESCRIPTIONS = [
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def read_item(parent: pathlib.Path, filename: str) -> str:
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return parent.joinpath(filename).read_text().strip()
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def find_usb_folder(usb_path: pathlib.Path) -> Optional[str]:
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# Find the sysfs usb folder from a child folder
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while usb_path.is_dir() and usb_path.name:
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dnum_file = usb_path.joinpath("devnum")
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bnum_file = usb_path.joinpath("busnum")
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if not dnum_file.is_file() or not bnum_file.is_file():
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usb_path = usb_path.parent
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continue
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devnum = int(dnum_file.read_text().strip())
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busnum = int(bnum_file.read_text().strip())
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return f"{busnum}:{devnum}"
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return None
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class UsbIdData:
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_usb_info_cache: Dict[str, str] = {
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"DI:1d50": "OpenMoko, Inc",
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@ -204,17 +225,7 @@ def find_serial_devices() -> List[Dict[str, Any]]:
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device_info["device_type"] = "hardware_uart"
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else:
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usb_path = device_folder.resolve()
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usb_location: Optional[str] = None
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while usb_path.is_dir() and usb_path.name:
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dnum_file = usb_path.joinpath("devnum")
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bnum_file = usb_path.joinpath("busnum")
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if not dnum_file.is_file() or not bnum_file.is_file():
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usb_path = usb_path.parent
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continue
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devnum = int(dnum_file.read_text().strip())
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busnum = int(bnum_file.read_text().strip())
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usb_location = f"{busnum}:{devnum}"
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break
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usb_location: Optional[str] = find_usb_folder(usb_path)
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device_info["path_by_hardware"] = usb_devs_by_path.get(device_name)
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device_info["path_by_id"] = usb_devs_by_id.get(device_name)
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device_info["usb_location"] = None
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@ -224,3 +235,122 @@ def find_serial_devices() -> List[Dict[str, Any]]:
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serial_devs.append(device_info)
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return serial_devs
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class struct_v4l2_capability(ctypes.Structure):
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_fields_ = [
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("driver", ctypes.c_char * 16),
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("card", ctypes.c_char * 32),
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("bus_info", ctypes.c_char * 32),
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("version", ctypes.c_uint32),
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("capabilities", ctypes.c_uint32),
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("device_caps", ctypes.c_uint32),
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("reserved", ctypes.c_uint32 * 3),
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]
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class V4L2Capability(ExtendedFlag):
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VIDEO_CAPTURE = 0x00000001 # noqa: E221
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VIDEO_OUTPUT = 0x00000002 # noqa: E221
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VIDEO_OVERLAY = 0x00000004 # noqa: E221
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VBI_CAPTURE = 0x00000010 # noqa: E221
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VBI_OUTPUT = 0x00000020 # noqa: E221
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SLICED_VBI_CAPTURE = 0x00000040 # noqa: E221
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SLICED_VBI_OUTPUT = 0x00000080 # noqa: E221
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RDS_CAPTURE = 0x00000100 # noqa: E221
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VIDEO_OUTPUT_OVERLAY = 0x00000200
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HW_FREQ_SEEK = 0x00000400 # noqa: E221
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RDS_OUTPUT = 0x00000800 # noqa: E221
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VIDEO_CAPTURE_MPLANE = 0x00001000
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VIDEO_OUTPUT_MPLANE = 0x00002000 # noqa: E221
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VIDEO_M2M_MPLANE = 0x00004000 # noqa: E221
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VIDEO_M2M = 0x00008000 # noqa: E221
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TUNER = 0x00010000 # noqa: E221
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AUDIO = 0x00020000 # noqa: E221
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RADIO = 0x00040000 # noqa: E221
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MODULATOR = 0x00080000 # noqa: E221
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SDR_CAPTURE = 0x00100000 # noqa: E221
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EXT_PIX_FORMAT = 0x00200000 # noqa: E221
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SDR_OUTPUT = 0x00400000 # noqa: E221
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META_CAPTURE = 0x00800000 # noqa: E221
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READWRITE = 0x01000000 # noqa: E221
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STREAMING = 0x04000000 # noqa: E221
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META_OUTPUT = 0x08000000 # noqa: E221
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TOUCH = 0x10000000 # noqa: E221
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IO_MC = 0x20000000 # noqa: E221
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SET_DEVICE_CAPS = 0x80000000 # noqa: E221
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V4L2_QUERYCAP = ioctl_macros.IOR(ord("V"), 0, struct_v4l2_capability)
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def find_video_devices() -> List[Dict[str, Any]]:
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v4lpath = pathlib.Path(V4L_DEVICE_PATH)
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if not v4lpath.is_dir():
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return []
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v4l_by_path_dir = pathlib.Path(V4L_BYPTH_PATH)
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v4l_by_id_dir = pathlib.Path(V4L_BYID_PATH)
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dev_root_folder = pathlib.Path("/dev")
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v4l_devs_by_path: Dict[str, str] = {}
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v4l_devs_by_id: Dict[str, str] = {}
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if v4l_by_path_dir.is_dir():
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v4l_devs_by_path = {
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dev.resolve().name: str(dev) for dev in v4l_by_path_dir.iterdir()
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}
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if v4l_by_id_dir.is_dir():
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v4l_devs_by_id = {
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dev.resolve().name: str(dev) for dev in v4l_by_id_dir.iterdir()
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}
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v4l_devices: List[Dict[str, Any]] = []
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for v4ldev_path in v4lpath.iterdir():
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devfs_name = v4ldev_path.name
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devfs_path = dev_root_folder.joinpath(devfs_name)
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# The video4linux sysfs implmentation provides limited device
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# info. Use the VIDEOC_QUERYCAPS ioctl to retreive extended
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# information about the v4l2 device.
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fd: int = -1
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try:
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fd = os.open(str(devfs_path), os.O_RDONLY | os.O_NONBLOCK)
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cap_info = struct_v4l2_capability()
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fcntl.ioctl(fd, V4L2_QUERYCAP, cap_info)
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except Exception:
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continue
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finally:
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if fd != -1:
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os.close(fd)
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capabilities = V4L2Capability(cap_info.device_caps)
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if not capabilities & V4L2Capability.VIDEO_CAPTURE:
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# Skip devices that do not capture video
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continue
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ver_tuple = tuple(
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[str((cap_info.version >> (i)) & 0xFF) for i in range(16, -1, -8)]
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)
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video_device: Dict[str, Any] = {
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"device_name": devfs_name,
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"device_path": str(devfs_path),
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"camera_name": cap_info.card.decode(),
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"driver_name": cap_info.driver.decode(),
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"hardware_bus": cap_info.bus_info.decode(),
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"capabilities": [cap.name for cap in capabilities],
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"version": ".".join(ver_tuple),
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"path_by_hardware": v4l_devs_by_path.get(devfs_name),
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"path_by_id": v4l_devs_by_id.get(devfs_name),
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"alt_name": None,
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"usb_location": None,
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}
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name_file = v4ldev_path.joinpath("name")
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if name_file.is_file():
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video_device["alt_name"] = read_item(v4ldev_path, "name")
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device_path = v4ldev_path.joinpath("device")
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if device_path.is_dir():
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usb_location = find_usb_folder(device_path.resolve())
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if usb_location is not None:
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video_device["usb_location"] = usb_location
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v4l_devices.append(video_device)
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def idx_sorter(item: Dict[str, Any]) -> int:
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try:
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return int(item["device_name"][5:])
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except ValueError:
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return -1
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# Sort by string first, then index
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v4l_devices.sort(key=lambda item: item["device_name"])
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v4l_devices.sort(key=idx_sorter)
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return v4l_devices
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