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v4l2_device.py
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v4l2_device.py
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import cv2
import os
import sys
#import v4l2 # This import the installed module.
from MyPythonModule import v4l2 # This import the module from user folder. Python wrapper v4l2 API.
from fcntl import ioctl
import mmap
import ctypes
from cStringIO import StringIO # io is slow, use cStringIO instead.
from PIL import Image
import time
import numpy as np
########################################################################################
def print_dict(dict):
for key in dict:
print('{}: {}'.format(key,dict[key]))
# This is a wrapper of ioctl. Return 0 on success, -1 on fail.
def xioctl(fd, VIDIOC_control_word, structure):
try:
rtv = ioctl(fd, VIDIOC_control_word, structure)
return rtv # May return non-negative value other than 0 on success.
except Exception:
return -1
########################################################################################
# This is a v4l2 Camera class.
class Camera():
def __init__(self, device_name):
self.name = device_name
self.fd = None
# Private variables.
# specify the number of buffers.
self._buffer_count = 4
# dictionary to save mmap objects.
self._mmap_dict = {}
# Temperary buffer used in class.
self._buffer = v4l2.v4l2_buffer()
self._buffer.type = v4l2.V4L2_BUF_TYPE_VIDEO_CAPTURE
self._buffer.memory = v4l2.V4L2_MEMORY_MMAP
self._buffer.index = 0
self._buffer_offset = None
self._buffer_size = None
self._buffer_type = None
self._ptr_buffer_type = None
def open(self):
if self.fd is None:
self.fd = os.open(self.name, os.O_RDWR)
print('Device "{}" is opened!'.format(self.name))
else:
print('Error: Can not open device "{}", because it is already opened!'.format(self.name))
def close(self):
if self.fd is not None:
os.close(self.fd)
self.fd = None
print('Device "{}" is closed!'.format(self.name))
else:
print('Error: Can not close device "{}", because it is not opened!'.format(self.name))
# Getting all supported video format for given device.
def get_supported_format(self):
fmtdesc = v4l2.v4l2_fmtdesc()
fmtdesc.index = 0
fmtdesc.type = v4l2.V4L2_BUF_TYPE_VIDEO_CAPTURE
format_dict = {}
while(0 == xioctl(self.fd, v4l2.VIDIOC_ENUM_FMT, fmtdesc)):
format_dict[str(fmtdesc.index)] = {'pixelformat': v4l2.v4l2_fourcc2str(fmtdesc.pixelformat), 'description': fmtdesc.description}
fmtdesc.index += 1
return format_dict
# Set video resolution and pixel format.
def set_video_format(self, frame_width, frame_height, pixelformat_str):
# The following pixel formats are supported by ELP-USBFHD01M-FV board camera.
# ELP-USBFHD01M-FV only accept 'MJPG' or 'YUYV'
# MJPG: V4L2_PIX_FMT_MJPEG
# YUYV: V4L2_PIX_FMT_YUYV.
pixelformat = v4l2.v4l2_fourcc(pixelformat_str[0], pixelformat_str[1], pixelformat_str[2], pixelformat_str[3])
fmt = v4l2.v4l2_format()
fmt.type = v4l2.V4L2_BUF_TYPE_VIDEO_CAPTURE
fmt.fmt.pix.width = frame_width
fmt.fmt.pix.height = frame_height
fmt.fmt.pix.pixelformat = pixelformat
fmt.fmt.pix.field = v4l2.V4L2_FIELD_NONE
if(-1 == xioctl(self.fd, v4l2.VIDIOC_S_FMT, fmt)):
print('Failed to set video format on device "{}".\n'.format(self.name))
return -1
else:
print('Video format of device "{}" is set to:'.format(self.name))
print('resolution : {}x{}.'.format(fmt.fmt.pix.width, fmt.fmt.pix.height))
print('pixelformat : {}\n'.format(v4l2.v4l2_fourcc2str(fmt.fmt.pix.pixelformat)))
return 0
# Get current video format.
def get_video_format(self):
fmt = v4l2.v4l2_format()
fmt.type = v4l2.V4L2_BUF_TYPE_VIDEO_CAPTURE
if (-1 == xioctl(self.fd, v4l2.VIDIOC_G_FMT, fmt)):
print('Failed to get video format for device "{}"!\n'.format(self.name))
return -1
else:
self.frame_width = fmt.fmt.pix.width
self.frame_height = fmt.fmt.pix.height
return {'resolution':{'width':fmt.fmt.pix.width, 'height':fmt.fmt.pix.height},\
'pixelformat':v4l2.v4l2_fourcc2str(fmt.fmt.pix.pixelformat),\
'field':v4l2.v4l2_field_dict[fmt.fmt.pix.field],\
'bytesperline':fmt.fmt.pix.bytesperline,\
'sizeimage':fmt.fmt.pix.sizeimage,\
'colorspace':v4l2.v4l2_colorspace_dict[fmt.fmt.pix.colorspace]}
# Enumerate all control options supported by ELP-USBFHD01M-FV board camera.
def enumerate_all_controls(self):
print('Enumerating all controls for device "{}":'.format(self.name))
queryctrl = v4l2.v4l2_queryctrl()
querymenu = v4l2.v4l2_querymenu()
queryctrl.id = v4l2.V4L2_CTRL_FLAG_NEXT_CTRL
while (0 == xioctl(self.fd, v4l2.VIDIOC_QUERYCTRL, queryctrl)):
if (~(queryctrl.flags & v4l2.V4L2_CTRL_FLAG_DISABLED)):
print('Control item: {}'.format(queryctrl.name))
# If control ID has a type menu, print this menu.
if (queryctrl.type == v4l2.V4L2_CTRL_TYPE_MENU):
# Clear querymenu variable.
querymenu.id = queryctrl.id
print(' menu:')
for querymenu.index in range(queryctrl.minimum, queryctrl.maximum+1):
if (0 == xioctl(self.fd, v4l2.VIDIOC_QUERYMENU, querymenu)):
print(' {}. {}'.format(querymenu.index, querymenu.name))
# Get next control ID.
queryctrl.id |= v4l2.V4L2_CTRL_FLAG_NEXT_CTRL
def get_control_parameter(self, CID):
# Get info of given contro ID, and get current control setting.
# CID means control ID.
queryctrl = v4l2.v4l2_queryctrl()
control = v4l2.v4l2_control()
querymenu = v4l2.v4l2_querymenu()
'''
The following control_ID is supported by ELP-USBFHD01M-FV board camera.
CID_list = [v4l2.V4L2_CID_BRIGHTNESS,
v4l2.V4L2_CID_CONTRAST,
v4l2.V4L2_CID_SATURATION,
v4l2.V4L2_CID_HUE,
v4l2.V4L2_CID_AUTO_WHITE_BALANCE,
v4l2.V4L2_CID_GAMMA,
v4l2.V4L2_CID_GAIN,
v4l2.V4L2_CID_POWER_LINE_FREQUENCY,
v4l2.V4L2_CID_WHITE_BALANCE_TEMPERATURE,
v4l2.V4L2_CID_SHARPNESS,
v4l2.V4L2_CID_BACKLIGHT_COMPENSATION,
v4l2.V4L2_CID_EXPOSURE_AUTO,
v4l2.V4L2_CID_EXPOSURE_ABSOLUTE,
v4l2.V4L2_CID_EXPOSURE_AUTO_PRIORITY
'''
queryctrl.id = CID
control.id = CID
rtv_VIDIOC_QUERYCTRL = xioctl(self.fd, v4l2.VIDIOC_QUERYCTRL, queryctrl)
rtv_VIDIOC_G_CTRL = xioctl(self.fd, v4l2.VIDIOC_G_CTRL, control)
if (-1 == rtv_VIDIOC_QUERYCTRL):
print('Failed to query control parameter for device "{}".'.format(self.name))
print('CID = {}'.format(v4l2.v4l2_CID_dict[CID]))
return -1
elif (-1 == rtv_VIDIOC_G_CTRL):
print('Failed to get control parameter for device "{}".'.format(self.name))
print('CID = {}'.format(v4l2.v4l2_CID_dict[CID]))
return -1
else:
print('Get control parameter for device "{}" successfully.'.format(self.name))
print('CID = {}'.format(v4l2.v4l2_CID_dict[CID]))
print('name = {}'.format(queryctrl.name))
print('minimum = {}'.format(queryctrl.minimum))
print('maximum = {}'.format(queryctrl.maximum))
print('step = {}'.format(queryctrl.step))
print('default_value = {}'.format(queryctrl.default_value))
print('current_value = {}'.format(control.value))
print('flags = {}'.format(v4l2.v4l2_CTRL_FLAG_dict[queryctrl.flags]))
print('type = {}'.format(v4l2.v4l2_ctrl_type_dict[queryctrl.type]))
# If CID is menu type, print this menu.
if (queryctrl.type == v4l2.V4L2_CTRL_TYPE_MENU):
# Clear querymenu variable.
querymenu.id = queryctrl.id;
print('menu: ')
for querymenu.index in range(queryctrl.minimum, queryctrl.maximum+1):
if (0 == xioctl(self.fd, v4l2.VIDIOC_QUERYMENU, querymenu)):
print(' {}. {}'.format(querymenu.index, querymenu.name))
return 0;
def set_control_parameter(self, CID, control_value):
# Set control parameters.
queryctrl = v4l2.v4l2_queryctrl()
old_setting = v4l2.v4l2_control()
new_setting = v4l2.v4l2_control()
querymenu = v4l2.v4l2_querymenu()
'''
The following CID is supported by ELP-USBFHD01M-FV board camera.
CID_list = [v4l2.V4L2_CID_BRIGHTNESS,
v4l2.V4L2_CID_CONTRAST,
v4l2.V4L2_CID_SATURATION,
v4l2.V4L2_CID_HUE,
v4l2.V4L2_CID_AUTO_WHITE_BALANCE,
v4l2.V4L2_CID_GAMMA,
v4l2.V4L2_CID_GAIN,
v4l2.V4L2_CID_POWER_LINE_FREQUENCY,
v4l2.V4L2_CID_WHITE_BALANCE_TEMPERATURE,
v4l2.V4L2_CID_SHARPNESS,
v4l2.V4L2_CID_BACKLIGHT_COMPENSATION,
v4l2.V4L2_CID_EXPOSURE_AUTO,
v4l2.V4L2_CID_EXPOSURE_ABSOLUTE,
v4l2.V4L2_CID_EXPOSURE_AUTO_PRIORITY]
'''
queryctrl.id = CID
old_setting.id = CID
new_setting.id = CID
new_setting.value = control_value
# Query current setting.
rtv_VIDIOC_QUERYCTRL = xioctl(self.fd, v4l2.VIDIOC_QUERYCTRL, queryctrl)
rtv_VIDIOC_G_CTRL = xioctl(self.fd, v4l2.VIDIOC_G_CTRL, old_setting)
if (-1 == rtv_VIDIOC_QUERYCTRL):
print('Before setting, failed to query control parameter for device "{}".'.format(self.name))
print('CID = {}'.format(v4l2.v4l2_CID_dict[CID]))
#print('\n')
return -1
elif (-1 == rtv_VIDIOC_G_CTRL):
print('Before setting, failed to get control parameter for device "{}"'.format(self.name))
print('CID = {}'.format(v4l2.v4l2_CID_dict[CID]))
#print('\n')
return -1
else:
# Set new_setting value.
rtv_VIDIOC_S_CTRL = xioctl(self.fd, v4l2.VIDIOC_S_CTRL, new_setting)
if (-1 == rtv_VIDIOC_S_CTRL):
print('Failed to set control parameter for device "{}".'.format(self.name))
print('CID = {}'.format(v4l2.v4l2_CID_dict[CID]))
print('\n')
return -1
else:
print('Set control parameter for device "{}" successfully.'.format(self.name))
# Query new setting.
rtv_VIDIOC_QUERYCTRL = xioctl(self.fd, v4l2.VIDIOC_QUERYCTRL, queryctrl)
rtv_VIDIOC_G_CTRL = xioctl(self.fd, v4l2.VIDIOC_G_CTRL, new_setting)
if (-1 == rtv_VIDIOC_QUERYCTRL):
print('After setting, failed to query control parameter for device "{}".'.format(self.name))
print('CID = {}'.format(v4l2.v4l2_CID_dict[CID]))
#print('\n')
return -1
elif (-1 == rtv_VIDIOC_G_CTRL):
print('After setting, failed to get control parameter for device "{}".'.format(self.name))
print('CID = {}'.format(v4l2.v4l2_CID_dict[CID]))
#print('\n')
return -1
else:
print('CID = {}'.format(v4l2.v4l2_CID_dict[CID]))
print('name = {}'.format(queryctrl.name))
print('minimum = {}'.format(queryctrl.minimum))
print('maximum = {}'.format(queryctrl.maximum))
print('step = {}'.format(queryctrl.step))
print('default_value = {}'.format(queryctrl.default_value))
print('current_value = {} (old value = {})'.format(new_setting.value, old_setting.value))
print('flags = {}'.format(v4l2.v4l2_CTRL_FLAG_dict[queryctrl.flags]))
print('type = {}'.format(v4l2.v4l2_ctrl_type_dict[queryctrl.type]))
# If control ID has a type menu, print this menu.
if (queryctrl.type == v4l2.V4L2_CTRL_TYPE_MENU):
querymenu.id = queryctrl.id
print('menu: ')
for querymenu.index in range(queryctrl.minimum, queryctrl.maximum+1):
if (0 == xioctl(self.fd, v4l2.VIDIOC_QUERYMENU, querymenu)):
print(' {}. {}'.format(querymenu.index, querymenu.name))
#print('\n')
return 0;
def print_all_control_parameter(self):
print('Printing all control parameters...\n')
CID_list = [v4l2.V4L2_CID_BRIGHTNESS,
v4l2.V4L2_CID_CONTRAST,
v4l2.V4L2_CID_SATURATION,
v4l2.V4L2_CID_HUE,
v4l2.V4L2_CID_AUTO_WHITE_BALANCE,
v4l2.V4L2_CID_GAMMA,
v4l2.V4L2_CID_GAIN,
v4l2.V4L2_CID_POWER_LINE_FREQUENCY,
v4l2.V4L2_CID_WHITE_BALANCE_TEMPERATURE,
v4l2.V4L2_CID_SHARPNESS,
v4l2.V4L2_CID_BACKLIGHT_COMPENSATION,
v4l2.V4L2_CID_EXPOSURE_AUTO,
v4l2.V4L2_CID_EXPOSURE_ABSOLUTE,
v4l2.V4L2_CID_EXPOSURE_AUTO_PRIORITY]
for CID in CID_list:
self.get_control_parameter(CID)
print('\n')
def get_supported_frame_size_and_fps(self):
print('Supported frame size and fps by device "{}":'.format(self.name))
fmtdesc = v4l2.v4l2_fmtdesc() # Must fill .index and .type before use.
frmsize = v4l2.v4l2_frmsizeenum() # Must fill .index and .pixel_format before use.
frmival = v4l2.v4l2_frmivalenum() # Must fill .index, .pixel_format, .width, and .height before use.
fmtdesc.index = 0
fmtdesc.type = v4l2.V4L2_BUF_TYPE_VIDEO_CAPTURE
while (0 == xioctl(self.fd, v4l2.VIDIOC_ENUM_FMT, fmtdesc)):
print('Pixel Format : {}'.format(v4l2.v4l2_fourcc2str(fmtdesc.pixelformat)))
frmsize.index = 0;
frmsize.pixel_format = fmtdesc.pixelformat;
while ((0 == xioctl(self.fd, v4l2.VIDIOC_ENUM_FRAMESIZES, frmsize))):
if (frmsize.type == v4l2.V4L2_FRMSIZE_TYPE_DISCRETE):
# Fill frmival to check fps.
frmival.index = 0
frmival.pixel_format = fmtdesc.pixelformat
frmival.width = frmsize.discrete.width
frmival.height = frmsize.discrete.height
while (0 == xioctl(self.fd, v4l2.VIDIOC_ENUM_FRAMEINTERVALS, frmival)):
#print('denominator = {}'.format(frmival.discrete.denominator))
#print('numerator = {}'.format(frmival.discrete.numerator))
fps = frmival.discrete.denominator/frmival.discrete.numerator
print (' discrete {: >4}x{: <4} ({: >3} fps)'.format(frmsize.discrete.width, frmsize.discrete.height, fps))
frmival.index += 1 # Get next fps.
elif(frmsize.type == v4l2.V4L2_FRMSIZE_TYPE_STEPWISE):
print(' stepwise {}x{}'.format(frmsize.stepwise.min_width, frmsize.stepwise.min_height))
print(' min_width = {}'.format(frmsize.stepwise.min_width))
print(' max_width = {}'.format(frmsize.stepwise.max_width))
print(' step_width = {}'.format(frmsize.stepwise.step_width))
print(' min_height = {}'.format(frmsize.stepwise.min_height))
print(' max_height = {}'.format(frmsize.stepwise.max_height))
print(' step_height = {}'.format(frmsize.stepwise.step_height))
frmsize.index += 1 # Get next frame size.
fmtdesc.index += 1 # Get next video format.
return 0;
def get_frame_rate(self):
parm = v4l2.v4l2_streamparm()
parm.type = v4l2.V4L2_BUF_TYPE_VIDEO_CAPTURE
rtv = xioctl(self.fd, v4l2.VIDIOC_G_PARM, parm)
if (-1 == rtv):
print('Failed to get stream parameters for device "{}".'.format(self.name))
return -1
if (parm.parm.capture.capability != v4l2.V4L2_CAP_TIMEPERFRAME):
print('The frame skipping/repeating controlled by the timeperframe field is not supported for device "{}".'.format(self.name))
return -1
return (parm.parm.capture.timeperframe.denominator)/(parm.parm.capture.timeperframe.numerator)
def get_frame_width_height(self):
fmt = v4l2.v4l2_format()
fmt.type = v4l2.V4L2_BUF_TYPE_VIDEO_CAPTURE
if (-1 == xioctl(self.fd, v4l2.VIDIOC_G_FMT, fmt)):
print('Failed to get video format for device "{}"!\n'.format(self.name))
return (-1, -1)
return (fmt.fmt.pix.width, fmt.fmt.pix.height)
def get_device_capability(self):
# Query camera capability.
capability = v4l2.v4l2_capability()
rtv = xioctl(self.fd, v4l2.VIDIOC_QUERYCAP, capability)
if (-1 == rtv):
print('Failed to get device capability for device "{}".'.format(self.name))
return -1
# Get capability variables.
bus_info = capability.bus_info
capabilities = capability.capabilities
card = capability.card
driver = capability.driver
reserved = capability.reserved
version = capability.version
print('bus_info : {}'.format(bus_info))
# capabilities: A 32-bit longer integer withholding your device's capabilities (one bit per capability).
# You can use a bitwise & to check for a particular one
print('capabilities : ({})'.format(hex(capabilities)))
for key in v4l2.v4l2_capabilities_dict:
if (capabilities & key):
print(' {}'.format(v4l2.v4l2_capabilities_dict[key]))
print('card : {}'.format(card))
print('driver : {}'.format(driver))
print('version : {}'.format(version))
return 0
def init_device(self, resolution=(480,270), pixel_format='MJPG', exposure='AUTO', white_balance='AUTO'):
time.sleep(1) # Wait for device warm up.
# Power line frequency. # 2 = 60 Hz (USA frequency), 0 = disable, 1 = 50 Hz.
counter = 1
while ((-1 == self.set_control_parameter(v4l2.V4L2_CID_POWER_LINE_FREQUENCY, 2)) and counter<=3):
print('Setting power line frequency {} times.'.format(counter))
counter += 1
time.sleep(1)
# Set camera resolution and pixel format.
counter = 1
while ((-1 == self.set_video_format(resolution[0], resolution[1], pixel_format)) and counter<=3):
print('Setting resolution {} times.'.format(counter))
counter += 1
time.sleep(1)
# Set exposure.
if (exposure=='AUTO'):
self.set_control_parameter(v4l2.V4L2_CID_EXPOSURE_AUTO, 3) # 1 = Manual Mode, 3 = Aperture Priority Mode
self.set_control_parameter(v4l2.V4L2_CID_EXPOSURE_AUTO_PRIORITY, 0) # Do not vary frame rate according to exposure.
elif (isinstance(exposure, (int, long))):
if ((exposure<1)or(exposure>5000)):
print('Value Error: exposure range is from 1 to 5000.')
return -1
else:
self.set_control_parameter(v4l2.V4L2_CID_EXPOSURE_AUTO, 1) # 1 = Manual Mode, 3 = Aperture Priority Mode
self.set_control_parameter(v4l2.V4L2_CID_EXPOSURE_ABSOLUTE, exposure) # Default 177.
else:
print('Value Error: please specify "AUTO" or exposure value (int).')
return -1
# Set white balance.
if (white_balance=='AUTO'):
self.set_control_parameter(v4l2.V4L2_CID_AUTO_WHITE_BALANCE, 1) # 1 = auto, 0 = manual.
elif (isinstance(white_balance, (int, long))): # white balance temperature range = (2800 ~ 6500), 4600 by default.
if ((white_balance<2800)or(white_balance>6500)):
print('Range Error: white balance temperature range is from 2800 to 6500.')
return -1
else:
self.set_control_parameter(v4l2.V4L2_CID_AUTO_WHITE_BALANCE, 0) # 1 = auto, 0 = manual.
self.set_control_parameter(v4l2.V4L2_CID_WHITE_BALANCE_TEMPERATURE, white_balance)
else:
print('Value Error: please specify "AUTO" or white balance temperature value (int).')
return -1
return 0
def init_mmap(self):
# Inform the device about your future buffers.
bufrequest = v4l2.v4l2_requestbuffers()
bufrequest.count = self._buffer_count
bufrequest.type = v4l2.V4L2_BUF_TYPE_VIDEO_CAPTURE
bufrequest.memory = v4l2.V4L2_MEMORY_MMAP
if (-1 == xioctl(self.fd, v4l2.VIDIOC_REQBUFS, bufrequest)):
print('init_mmap() failed. Can not request buffers.\n')
return -1
for i in xrange(self._buffer_count):
self._buffer.index = i
if (-1 == xioctl(self.fd, v4l2.VIDIOC_QUERYBUF, self._buffer)): # self._buffer.index will automatically increased by 1.
print('init_mmap() failed. Can not query buffers.\n')
return -1
self._buffer_offset = self._buffer.m.offset
self._buffer_size = self._buffer.length
#print('self._buffer_offset = {}'.format(self._buffer_offset))
#print('self._buffer_size = {}\n'.format(self._buffer_size))
# After calling the xioctl above, the structure's length and m.offset fields are ready.
# We can therefore map our memory.
buffer_mmap = mmap.mmap(self.fd,
self._buffer.length,
mmap.MAP_SHARED,
mmap.PROT_READ | mmap.PROT_WRITE,
offset=self._buffer.m.offset)
# Add buffer_mmap to buffer_mmap_list.
self._mmap_dict[i] = buffer_mmap
def stream_on(self):
for i in xrange(self._buffer_count):
self._buffer.index = i
if (-1 == xioctl(self.fd, v4l2.VIDIOC_QBUF, self._buffer)): # Queue buffer won't increase buffer index.
print('stream_on() failed. Can not queue buffers.\n')
return -1
self._buffer_type = v4l2.V4L2_BUF_TYPE_VIDEO_CAPTURE
self._ptr_buffer_type = ctypes.cast(self._buffer_type, ctypes.c_void_p)
if (-1 == xioctl(self.fd, v4l2.VIDIOC_STREAMON, self._ptr_buffer_type)):
print('stream_on() failed. Can not turn stream on.\n')
return -1
self.retrieve() # Release the first frame grabbed in this function.
print('Stream is turned on on device "{}".'.format(self.name))
return 0
def stream_off(self):
if (-1 == xioctl(self.fd, v4l2.VIDIOC_STREAMOFF, self._ptr_buffer_type)):
print('stream_off fialed. Either not turn stream on or failed turn off.')
return -1
print('Stream is turned off on device "{}".'.format(self.name))
return 0
def retrieve(self):
# In VIDIOC_DQBUF, buffer.index does not accept user specify value.
if (-1 == xioctl(self.fd, v4l2.VIDIOC_DQBUF, self._buffer)): # Dequeue buffer will increase buffer.index by 1.
print('retrieve() failed. Can not dequeue buffers.\n')
return None
try:
raw_img = np.asarray(bytearray(self._mmap_dict[self._buffer.index].read(self._buffer_size)), dtype=np.uint8)
self._mmap_dict[self._buffer.index].seek(0) # Rollback buffer pointer.
return raw_img
except Exception:
return None
def decode_MJPG(self, raw_img, color=True):
# cv2.IMREAD_COLOR
# cv2.IMREAD_GRAYSCALE
# cv2.IMREAD_UNCHANGED
try:
if color:
return cv2.imdecode(raw_img, cv2.IMREAD_COLOR)
else:
return cv2.imdecode(raw_img, cv2.IMREAD_GRAYSCALE)
except Exception:
return None
def decode_MJPG_downsample(self, raw_img, (width, height), color=True):
try:
# Need import Image from PIL.
PIL_img = Image.open(StringIO(raw_img)) # 8.04901123047 ms to load 1920x1080.
#PIL_img = Image.open(io.BytesIO(raw_frameL)) # 11.7862224579 ms to load 1920x1080.
if color:
PIL_img.draft('P', (width, height)).convert('RGB')
return cv2.cvtColor(np.array(PIL_img), cv2.COLOR_RGB2BGR)
else:
PIL_img.draft('L', (width, height))
return np.array(PIL_img)
except Exception:
return None
def decode_YUYV(self, raw_img, (width, height)):
try:
return cv2.cvtColor(np.reshape(raw_img, (height, width, 2)), cv2.COLOR_YUV2BGR_YUY2)
except Exception:
return None
def grab(self):
if (-1 == xioctl(self.fd, v4l2.VIDIOC_QBUF, self._buffer)):
print('grab() failed. Can not queue buffers.\n')
return -1
#========================= main ===========================
'''
The following resolution is supported by ELP-USBFHD01M-FV board camera.
Pixel Format : MJPG
discrete 1920x1080 ( 30 fps) # Good. FPS=10.24. decode_time=58ms. Full hardward resolution. Largest view angle.
discrete 1280x1024 ( 30 fps) # Good. FPS=15.66. decode_time=40ms. View angel is slightly larger than 320X240
discrete 1280x720 ( 60 fps) # Good. FPS=23.23. decode_time=27ms. View angel is equal to 320X240
discrete 1024x768 ( 30 fps) # Dark. FPS=26.50. decode_time=22ms. View angel is slightly larger than 320X240
discrete 800x600 ( 60 fps) # Good. FPS=38.64. decode_time=17ms. Very Narrow.
discrete 640x480 (120 fps) # Dark. FPS=58.74. decode_time=11ms. View angel is equal to 320X240
discrete 320x240 (120 fps) # Good. FPS=99.14. decode_time= 3ms.
Pixel Format : YUYV
discrete 1920x1080 ( 6 fps) # FPS= 4.97. decode_time=12 ms.
discrete 1280x1024 ( 6 fps) # FPS= 4.97. decode_time=8.0ms. Narrow.
discrete 1280x720 ( 9 fps) # FPS= 9.21. decode_time=6.5ms.
discrete 1024x768 ( 6 fps) # FPS= 4.96. decode_time=5.5ms. Dark.
discrete 800x600 ( 20 fps) # FPS=19.90. decode_time=2.7ms. Narrow.
discrete 640x480 ( 30 fps) # FPS=29.83. decode_time=1.8ms. View angel is smaller than 320x240.
discrete 320x240 ( 30 fps) # FPS=29.82. decode_time=0.8ms. View angel is equal to 1920x1080, white ballence differ too much.
'''