我正在尝试从 USB 相机中每 x 秒拍摄一帧。相机名称为:ELP-USBFHD06H-SFV(5-50)。 代码尚未 100% 完成,但我现在就这样使用它 ↓ (
shot
fn 在循环中从 main.py
调用)
import cv2
import subprocess
from time import sleep
from collections import namedtuple
from errors import *
class Camera:
def __init__(self, cam_index, res_width, res_height, pic_format, day_time_exposure_ms, night_time_exposure_ms):
Resolution = namedtuple("resolution", ["width", "height"])
self.manual_mode(True)
self.cam_index = cam_index
self.camera_resolution = Resolution(res_width, res_height)
self.picture_format = pic_format
self.day_time_exposure_ms = day_time_exposure_ms
self.night_time_exposure_ms = night_time_exposure_ms
self.started: bool = False
self.night_mode = False
self.cap = cv2.VideoCapture(self.cam_index, cv2.CAP_V4L2)
self.cap.set(cv2.CAP_PROP_FRAME_WIDTH, self.camera_resolution.width)
self.cap.set(cv2.CAP_PROP_FRAME_HEIGHT, self.camera_resolution.height)
self.cap.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc(*self.picture_format))
def start(self):
sleep(1)
if not self.cap.isOpened():
return CameraCupError()
self.set_exposure_time(self.day_time_exposure_ms)
self.set_brightness(0)
sleep(0.1)
self.started = True
def shot(self, picture_name, is_night):
if not self.started:
return InitializationError()
self.configure_mode(is_night)
# Clear buffer
for _ in range(5):
ret, _ = self.cap.read()
ret, frame = self.cap.read()
sleep(0.1)
if ret:
print(picture_name)
cv2.imwrite(picture_name, frame)
return True
else:
print("No photo")
return False
def release(self):
self.set_exposure_time(156)
self.set_brightness(0)
self.manual_mode(False)
self.cap.release()
def manual_mode(self, switch: bool):
if switch:
subprocess.run(["v4l2-ctl", "--set-ctrl=auto_exposure=1"])
else:
subprocess.run(["v4l2-ctl", "--set-ctrl=auto_exposure=3"])
sleep(1)
def configure_mode(self, is_night):
if is_night == self.night_mode:
return
if is_night:
self.night_mode = is_night
self.set_exposure_time(self.night_time_exposure_ms)
self.set_brightness(64)
else:
self.night_mode = is_night
self.set_exposure_time(self.day_time_exposure_ms)
self.set_brightness(0)
sleep(0.1)
def set_exposure_time(self, ms: int):
ms = int(ms)
default_val = 156
if ms < 1 or ms > 5000:
ms = default_val
self.cap.set(cv2.CAP_PROP_EXPOSURE, ms)
def set_brightness(self, value: int):
value = int(value)
default_val = 0
if value < -64 or value > 64:
value = default_val
self.cap.set(cv2.CAP_PROP_BRIGHTNESS, value)
这是相机的设置(yaml 文件)
camera:
camera_index: 0
res_width: 1920
res_height: 1080
picture_format: "MJPG"
day_time_exposure_ms: 5
night_time_exposure_ms: 5000
photos_format: "jpg"
我做了一些配置,例如为相机设置手动模式、更改曝光/亮度和保存帧。 另外,相机可能正在将帧捕获到缓冲区(它没有实时保存最新帧:它更滞后),所以我每次都必须清除缓冲区。像这样
# Clear buffer from old frames
for _ in range(5):
ret, _ = self.cap.read()
# Get a new frame
ret, frame = self.cap.read()
我真的不喜欢,但我可以找到更好的方法(tldr:设置 1 帧的缓冲区在我的相机上不起作用)。
此方法保存的帧在 1920x1080 分辨率下看起来不错。但是当我尝试运行
ffmpeg
命令来从保存的 jpg
文件中进行延时拍摄时,如下所示
ffmpeg -framerate 20 -pattern_type glob -i "*.jpg" -c:v libx264 output.mp4
我遇到了这样的错误
[image2 @ 0x555609c45240] Could not open file : 08:59:20.jpg
[image2 @ 0x555609c45240] Could not find codec parameters for stream 0 (Video: mjpeg, none(bt470bg/unknown/unknown)): unspecified size
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Input #0, image2, from '*.jpg':
Duration: 00:00:00.05, start: 0.000000, bitrate: N/A
Stream #0:0: Video: mjpeg, none(bt470bg/unknown/unknown), 20 fps, 20 tbr, 20 tbn
Output #0, mp4, to 'output.mp4':
Output file #0 does not contain any stream
此外,当我尝试将文件从 Linux 复制到 Windows 时,我收到一些奇怪的复制失败错误和跳过图片的选项。但即使我按下跳过按钮,图片也会被复制并可以打开。我不确定格式有什么问题,但相机支持 1920x1080 的 MPEG。
>>> v4l2-ctl --all
Driver Info:
Driver name : uvcvideo
Card type : H264 USB Camera: USB Camera
Bus info : usb-xhci-hcd.1-1
Driver version : 6.6.51
Capabilities : 0x84a00001
Video Capture
Metadata Capture
Streaming
Extended Pix Format
Device Capabilities
Device Caps : 0x04200001
Video Capture
Streaming
Extended Pix Format
Media Driver Info:
Driver name : uvcvideo
Model : H264 USB Camera: USB Camera
Serial : 2020032801
Bus info : usb-xhci-hcd.1-1
Media version : 6.6.51
Hardware revision: 0x00000100 (256)
Driver version : 6.6.51
Interface Info:
ID : 0x03000002
Type : V4L Video
Entity Info:
ID : 0x00000001 (1)
Name : H264 USB Camera: USB Camera
Function : V4L2 I/O
Flags : default
Pad 0x0100000d : 0: Sink
Link 0x0200001a: from remote pad 0x1000010 of entity 'Extension 4' (Video Pixel Formatter): Data, Enabled, Immutable
Priority: 2
Video input : 0 (Camera 1: ok)
Format Video Capture:
Width/Height : 1920/1080
Pixel Format : 'MJPG' (Motion-JPEG)
Field : None
Bytes per Line : 0
Size Image : 4147789
Colorspace : sRGB
Transfer Function : Default (maps to sRGB)
YCbCr/HSV Encoding: Default (maps to ITU-R 601)
Quantization : Default (maps to Full Range)
Flags :
Crop Capability Video Capture:
Bounds : Left 0, Top 0, Width 1920, Height 1080
Default : Left 0, Top 0, Width 1920, Height 1080
Pixel Aspect: 1/1
Selection Video Capture: crop_default, Left 0, Top 0, Width 1920, Height 1080, Flags:
Selection Video Capture: crop_bounds, Left 0, Top 0, Width 1920, Height 1080, Flags:
Streaming Parameters Video Capture:
Capabilities : timeperframe
Frames per second: 15.000 (15/1)
Read buffers : 0
User Controls
brightness 0x00980900 (int) : min=-64 max=64 step=1 default=0 value=64
contrast 0x00980901 (int) : min=0 max=64 step=1 default=32 value=32
saturation 0x00980902 (int) : min=0 max=128 step=1 default=56 value=56
hue 0x00980903 (int) : min=-40 max=40 step=1 default=0 value=0
white_balance_automatic 0x0098090c (bool) : default=1 value=1
gamma 0x00980910 (int) : min=72 max=500 step=1 default=100 value=100
gain 0x00980913 (int) : min=0 max=100 step=1 default=0 value=0
power_line_frequency 0x00980918 (menu) : min=0 max=2 default=1 value=1 (50 Hz)
0: Disabled
1: 50 Hz
2: 60 Hz
white_balance_temperature 0x0098091a (int) : min=2800 max=6500 step=1 default=4600 value=4600 flags=inactive
sharpness 0x0098091b (int) : min=0 max=6 step=1 default=3 value=3
backlight_compensation 0x0098091c (int) : min=0 max=2 step=1 default=1 value=1
Camera Controls
auto_exposure 0x009a0901 (menu) : min=0 max=3 default=3 value=1 (Manual Mode)
1: Manual Mode
3: Aperture Priority Mode
exposure_time_absolute 0x009a0902 (int) : min=1 max=5000 step=1 default=156 value=5000
exposure_dynamic_framerate 0x009a0903 (bool) : default=0 value=0
我还尝试使用
ffmpeg
保存图片,以防 opencv
出现问题,如下所示:
ffmpeg -f v4l2 -framerate 30 -video_size 1920x1080 -i /dev/video0 -c:v libx264 -preset fast -crf 23 -t 00:01:00 output.mp4
它正在保存图片,但也改变了它的格式
[video4linux2,v4l2 @ 0x555659ed92b0] The V4L2 driver changed the video from 1920x1080 to 800x600
[video4linux2,v4l2 @ 0x555659ed92b0] The driver changed the time per frame from 1/30 to 1/15
但是当使用
v4l2
将其设置回 FHD 时,格式看起来正确
>>> v4l2-ctl --device=/dev/video0 --set-fmt-video=width=1920,height=1080,pixelformat=MJPG
>>> v4l2-ctl --get-fmt-video
Format Video Capture:
Width/Height : 1920/1080
Pixel Format : 'MJPG' (Motion-JPEG)
Field : None
Bytes per Line : 0
Size Image : 4147789
Colorspace : sRGB
Transfer Function : Default (maps to sRGB)
YCbCr/HSV Encoding: Default (maps to ITU-R 601)
Quantization : Default (maps to Full Range)
Flags :
我不确定格式/相机可能有什么问题,而且我认为我没有足够的信息来弄清楚。
我尝试使用
ffmpeg
而不是 opencv
并更改了 opencv's cup
配置中的一些设置。
明白了。问题出在保存的 .jpg 文件的名称上。 从
11:50:45.jpg
到 11-50-45.jpg
成功了。