capture and playback

qt_scikit_capture.py

import os
import sys
import time
import numpy as np
import matplotlib as mpl

mpl.use('Qt4Agg')
mpl.rcParams['backend.qt4']='PySide'
mpl.rcParams['toolbar'] = 'None'

#from PySide import
from PySide.QtGui import QApplication
from PySide.QtCore import QObject

from skimage.io import ImageCollection
from skimage.io.video import CvVideo

import matplotlib.pyplot as plt
import matplotlib.image as mpimg

import cv


class WebcamVideo(CvVideo):
    """
    Opencv-based video loader.

    Parameters
    ----------
    source : str
        Camera number.
    size: tuple, optional
        Size of returned array.
    """
    def __init__(self, source=None, size=None, backend=None):
        if source is None:
            source = -1
        self.source = source
        self.capture = cv.CreateCameraCapture(source)
        self.width = int(cv.GetCaptureProperty(self.capture,
                                               cv.CV_CAP_PROP_FRAME_WIDTH))
        self.height = int(cv.GetCaptureProperty(self.capture,
                                                cv.CV_CAP_PROP_FRAME_HEIGHT))
        self.size = size


# Note: color-intensive applications may require a different color allocation
# strategy.

FRAMES = 120

class BlitQT(QApplication):
    def __init__(self):
        QApplication.__init__(self,sys.argv)

        self.v = WebcamVideo()
        fourcc = cv.CV_FOURCC('I','4','2','0')
        self.writer = cv.CreateVideoWriter('capture.avi', fourcc, 30,
                                           (self.v.width, self.v.height),
                                           is_color=1)
        self.fig = plt.figure()
        self.ax = self.fig.add_subplot(111)
        self.ax.get_xaxis().set_visible(False)
        self.ax.get_yaxis().set_visible(False)

        self.im = self.ax.imshow(self.v.get())

        self.cnt = 0

        self.fig.canvas.draw()

    def timerEvent(self, evt):
        self.im.set_data(self.v.get())
        self.fig.canvas.draw()
        cv.GrabFrame(self.v.capture)
        frame = cv.RetrieveFrame(self.v.capture)
        cv.WriteFrame(self.writer, frame)

        if self.cnt==FRAMES:
            # print the timing info and quit
            print 'FPS:' , FRAMES/(time.time()-self.tstart)
            self.closeAllWindows()

        else:
            self.cnt += 1


if __name__ == "__main__":
    app = BlitQT()
# for profiling
    app.tstart = time.time()
    app.startTimer(0)
    plt.show()