Raspberry pi Video Capture 在写入视频时冻结

Question

我正在尝试同时显示网络摄像头流以及将视频写入文件。但是在写入时，它会冻结实时流。问题是 OpenCV 使用循环录制视频，程序卡在 OpenCV 循环中，用户无法继续。它不听用户响应。如何同时录制视频并听取用户响应？

我正在使用的代码：

import wx
import vlc
import os
import user
import numpy as np
import time
import cv, cv2

class MainWindow(wx.Panel):

    def __init__(self, parent,capture):  
        wx.Panel.__init__(self, parent)        
        mainSizer = wx.BoxSizer(wx.VERTICAL)

# video    
        videoWarper = wx.StaticBox(self,size=(640,480)        
        videoBoxSizer = wx.StaticBoxSizer(videoWarper, wx.VERTICAL)     
        videoFrame = wx.Panel(self, -1,size=(640,480))        
        capture = ShowCapture(videoFrame, capture)       
        videoBoxSizer.Add(videoFrame,0)       
        mainSizer.Add(videoBoxSizer,0)      

        parent.Centre()        
        self.Show()        
        self.SetSizerAndFit(mainSizer)       

# Panels

# The first panel holds the video and it's all black

        self.videopanel = wx.Panel(self, -1)        
        self.videopanel.SetBackgroundColour(wx.BLACK)

# The second panel holds controls

        ctrlpanel = wx.Panel(self, -1 )      
        self.timeslider = wx.Slider(ctrlpanel, -1, 0, 0, 1000)        
        self.timeslider.SetRange(0, 1000)        
        record = wx.Button(ctrlpanel, label="Record")       
        end = wx.Button(ctrlpanel, label="End")

# Bind controls to events

        self.Bind(wx.EVT_BUTTON, self.OnRecord, record)      
        self.Bind(wx.EVT_BUTTON, self.OnEnd, end)

# Give a pretty layout to the controls

        ctrlbox = wx.BoxSizer(wx.VERTICAL)        
        box = wx.BoxSizer(wx.HORIZONTAL)

# box contains some buttons and the volume controls

        box.Add(record)       
        box.Add(end)

# Merge box to the ctrlsizer

        ctrlbox.Add(box, flag=wx.EXPAND, border=10)        
        ctrlpanel.SetSizer(ctrlbox)

# Put everything togheter

        sizer = wx.BoxSizer(wx.VERTICAL)        
        sizer.Add(ctrlpanel, flag=wx.EXPAND | wx.BOTTOM | wx.TOP, border=10)        
        self.SetSizer(sizer)        
        self.SetMinSize((350, 300))

# VLC player controls

        self.Instance = vlc.Instance()       
        self.player = self.Instance.media_player_new()   

    def OnRecord(self, evt):

        fourcc = cv2.cv.CV_FOURCC('D', 'I', 'V', 'X')     
        out = cv2.VideoWriter('video.avi', fourcc, 8.0, (640, 480))    
        counter = 0     
        while counter < 1:                        
            ret,frame = capture.read()           
            out.write(frame)

    def OnEnd(self, evt):
        out = cv2.VideoWriter('video.avi', fourcc, 8.0, (640, 480))      
        out.release()        
        cv2.destroyAllWindows()

class ShowCapture(wx.Panel):

    def __init__(self, parent, capture, fps=8):

        wx.Panel.__init__(self, parent, wx.ID_ANY, (0,0), (640,480))        
        self.capture = capture       
        ret, frame = capture.read()        
        height, width = frame.shape[:2]        
        parent.SetSize((width, height))        
        frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)    
        self.bmp = wx.BitmapFromBuffer(width, height, frame)        
        self.timer = wx.Timer(self)       
        self.timer.Start(1000./fps)    
        self.Bind(wx.EVT_PAINT, self.OnPaint)        
        self.Bind(wx.EVT_TIMER, self.NextFrame)

    def OnPaint(self, evt):
        dc = wx.BufferedPaintDC(self)        
        dc.DrawBitmap(self.bmp, 0, 0)

    def NextFrame(self, event):
        ret, frame = self.capture.read()       
        if ret:           
            frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)            
            self.bmp.CopyFromBuffer(frame)            
            self.Refresh()

capture = cv2.VideoCapture(-1)

app = wx.App(False) 
frame = wx.Frame(None, title='CamGUI')
panel = MainWindow(frame, capture)
frame.Show()
app.MainLoop()

树莓派是否能够并行读取/写入视频或者它会损害 pi 的性能？

希望高手指点:)

Answer 1

添加timer，这将允许您在应用程序执行期间测试输入和其他更改。
wx.timer