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• Matplotlib : ValueError : I/O operation on closed file [duplicate]

  28 septembre 2017, par gopi

  This question is an exact duplicate of :

  • animation.FuncAnimation ValueError : I/O operation on closed file

  %matplotlib inline
  
  import math,os,sys,numpy as np
  
  from numpy.random import random
  
  from matplotlib import pyplot as plt, rcParams, animation, rc
  
  from __future__ import print_function, division
  
  from ipywidgets import interact, interactive, fixed 
  
  from ipywidgets.widgets import *
  
  rc('animation', html='html5')
  
  rcParams['figure.figsize'] = 3,3
  
  %precision 4
  
  np.set_printoptions(precision=4, linewidth=100)
  
  
  
  def lin(a,x,b): return a * x + b
  
  
  
  a = 3.
  
  b = 8.
  
  n = 30
  
  
  
  x = random(n)
  
  y = lin(a,x,b)
  
  
  
  plt.scatter(x,y)
  
  
  
  def sse(y, y_pred): return ((y-y_pred)**2).sum()
  
  def loss(y, a, x, b): return sse(y, lin(a, x, b))
  
  def avg_loss(y, a, x, b): return np.sqrt(loss(y, a, x, b)/n)
  
  
  
  a_guess = -1
  
  b_guess = 1
  
  avg_loss(y, a_guess, x, b_guess)
  
  
  
  lr = 0.01
  
  #d[(y-(a*x+b))**2, b] = 2 (y_pred - y)
  
  #d[(y -(a*x+b)) **2, a] = x * dy/db
  
  
  
  def upd():
  
      global a_guess, b_guess
  
      y_pred = lin(a_guess, x, b_guess)
  
      dydb = 2 * (y_pred - y)
  
      dyda = x * dydb
  
      a_guess -= lr*dyda.mean()
  
      b_guess -= lr*dydb.mean()
  
  
  
  
  
  fig = plt.figure(dpi=100, figsize=(5,5))
  
  plt.scatter(x,y)
  
  line, = plt.plot(x, lin(a_guess, x, b_guess))
  
  plt.close()
  
  
  
  def animate(i):
  
      line.set_ydata(lin(a_guess, x, b_guess))
  
      for i in range(10): upd()
  
      return line,
  
  
  
  
  
  ani = animation.FuncAnimation(fig, animate, np.arange(0, 40), interval=100)
  
  ani

  But when I run it I get the following error,

      ValueError Traceback (most recent call last)
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/IPython/core/formatters.pyc in __call__(self, obj)
  
      309             method = get_real_method(obj, self.print_method)
  
      310             if method is not None:
  
  --> 311                 return method()
  
      312             return None
  
      313         else:
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in _repr_html_(self)
  
     1233         fmt = rcParams['animation.html']
  
     1234         if fmt == 'html5':
  
  -> 1235             return self.to_html5_video()
  
     1236 
  
     1237 
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in to_html5_video(self)
  
     1207                                 bitrate=rcParams['animation.bitrate'],
  
     1208                                 fps=1000. / self._interval)
  
  -> 1209                 self.save(f.name, writer=writer)
  
     1210 
  
     1211             # Now open and base64 encode
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in save(self, filename, writer, fps, dpi, codec, bitrate, extra_args, metadata, extra_anim, savefig_kwargs)
  
     1061                         # TODO: See if turning off blit is really necessary
  
     1062                         anim._draw_next_frame(d, blit=False)
  
  -> 1063                     writer.grab_frame(**savefig_kwargs)
  
     1064 
  
     1065         # Reconnect signal for first draw if necessary
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/contextlib.pyc in __exit__(self, type, value, traceback)
  
       33                 value = type()
  
       34             try:
  
  ---> 35                 self.gen.throw(type, value, traceback)
  
       36                 raise RuntimeError("generator didn't stop after throw()")
  
       37             except StopIteration, exc:
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in saving(self, *args, **kw)
  
      287             yield self
  
      288         finally:
  
  --> 289             self.finish()
  
      290 
  
      291     def _run(self):
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in finish(self)
  
      307     def finish(self):
  
      308         'Finish any processing for writing the movie.'
  
  --> 309         self.cleanup()
  
      310 
  
      311     def grab_frame(self, **savefig_kwargs):
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in cleanup(self)
  
      346     def cleanup(self):
  
      347         'Clean-up and collect the process used to write the movie file.'
  
  --> 348         out, err = self._proc.communicate()
  
      349         self._frame_sink().close()
  
      350         verbose.report('MovieWriter -- '
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in communicate(self, input, timeout)
  
      925 
  
      926         try:
  
  --> 927             stdout, stderr = self._communicate(input, endtime, timeout)
  
      928         finally:
  
      929             self._communication_started = True
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in _communicate(self, input, endtime, orig_timeout)
  
     1711             if _has_poll:
  
     1712                 stdout, stderr = self._communicate_with_poll(input, endtime,
  
  -> 1713                                                              orig_timeout)
  
     1714             else:
  
     1715                 stdout, stderr = self._communicate_with_select(input, endtime,
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in _communicate_with_poll(self, input, endtime, orig_timeout)
  
     1767             select_POLLIN_POLLPRI = select.POLLIN | select.POLLPRI
  
     1768             if self.stdout:
  
  -> 1769                 register_and_append(self.stdout, select_POLLIN_POLLPRI)
  
     1770                 stdout = self._fd2output[self.stdout.fileno()]
  
     1771             if self.stderr:
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in register_and_append(file_obj, eventmask)
  
     1746             poller = select.poll()
  
     1747             def register_and_append(file_obj, eventmask):
  
  -> 1748                 poller.register(file_obj.fileno(), eventmask)
  
     1749                 self._fd2file[file_obj.fileno()] = file_obj
  
     1750 
  
  
  
  ValueError: I/O operation on closed file

  I almost tried everywhere and I couldn’t find a solution, I tried reinstalling ffmpeg from the sources, moved this file to the folder where I installed ffmpeg and gave a try.

  I’m using python 3.5,
  Ubuntu 16.04
  Anaconda 4.4
  Matplotlib 2.02

  actually this particular course was taught using python 2.7 so I created a virenv installed 2.7 along with all related dependencies. So will it be the problem ?? I mean using python 2.7 on top of 3.5 ?

• Convert images into video

  24 septembre 2017, par Disha Shukla

  I have some images in the folder. I want to convert all images into videos. But the problem is that when the resolution is different it shows the error. I don’t want to stretch the images in the video. I just want to keep image size as it is. But it shows this error.

  My Command :

  ffmpeg -framerate 1/3 -pattern_type glob -i "images/*.jpg" -i trinity.MP3 -shortest -c:v libx264 -r 30 -vf "scale=iw*sar:ih , pad=max(iw\,ih*(16/9)):ow/(16/9):(ow-iw)/2:(oh-ih)/2" -aspect 16:9 -pix_fmt yuv420p out.mp4 -y

  Logs :

  [mjpeg @ 0x6b3820] Changeing bps to 8
  
  Input #0, image2, from 'images/*.jpg':
  
    Duration: 00:00:24.00, start: 0.000000, bitrate: N/A
  
      Stream #0:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 1:1 DAR 16:9], 0.33 fps, 0.33 tbr, 0.33 tbn, 0.33 tbc
  
  [mp3 @ 0x6b4ca0] Estimating duration from bitrate, this may be inaccurate
  
  Input #1, mp3, from 'trinity.MP3':
  
    Metadata:
  
      encoded_by      : Lavf52.9.0
  
    Duration: 00:09:02.35, start: 0.000000, bitrate: 128 kb/s
  
      Stream #1:0: Audio: mp3, 44100 Hz, stereo, s16p, 128 kb/s
  
  [swscaler @ 0x68a3c0] deprecated pixel format used, make sure you did set range correctly
  
  [libx264 @ 0x6bada0] using SAR=1/1
  
  [libx264 @ 0x6bada0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX AVX2 FMA3 LZCNT BMI2
  
  [libx264 @ 0x6bada0] profile High, level 3.1
  
  [libx264 @ 0x6bada0] 264 - core 142 r2438 af8e768 - H.264/MPEG-4 AVC codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=3 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to 'out.mp4':
  
    Metadata:
  
      encoder         : Lavf56.25.101
  
      Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 30 fps, 15360 tbn, 30 tbc
  
      Metadata:
  
        encoder         : Lavc56.26.100 libx264
  
      Stream #0:1: Audio: aac (libfaac) ([64][0][0][0] / 0x0040), 44100 Hz, stereo, s16, 128 kb/s
  
      Metadata:
  
        encoder         : Lavc56.26.100 libfaac
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (libx264))
  
    Stream #1:0 -> #0:1 (mp3 (native) -> aac (libfaac))
  
  Press [q] to stop, [?] for help
  
  Input stream #0:0 frame changed from size:1280x720 fmt:yuvj420p to size:596x913 fmt:yuvj420p
  
  [Parsed_pad_1 @ 0x697940] Input area 512:0:1108:913 not within the padded area 0:0:1622:912 or zero-sized
  
  [Parsed_pad_1 @ 0x697940] Failed to configure input pad on Parsed_pad_1

  Is there any way to keep resolution as it is and make a video of all images ?

• python cv2 BackgroundSubtractor imshow function error

  16 septembre 2017, par Vincent Yuan

  problem

  I want to detect the motional object in a video, but the cap seems not to read the video. I use conda jupyter and have install the ffmpeg with brew and I use macOS. Still, I am unable to capture the video.

  code :

  import numpy as np
  
  import cv2
  
  import time
  
  
  
  cap = cv2.VideoCapture('test.avi')
  
  time.sleep(2)
  
  fgbg = cv2.createBackgroundSubtractorKNN(detectShadows=True)
  
  
  
  while(1):
  
  ret, frame = cap.read()
  
  
  
  fgmask = fgbg.apply(frame)
  
  
  
  cv2.imshow('original',frame)
  
  cv2.imshow('fg',fgmask)
  
  
  
  k = cv2.waitKey(30) & 0xff
  
  for c in contours:
  
          # 获取矩形框边界坐标
  
          x, y, w, h = cv2.boundingRect(c)
  
          # 计算矩形框的面积
  
          area = cv2.contourArea(c)
  
          if 500 < area < 3000:
  
              cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 0), 2)
  
  
  
  cv2.imshow("detection", frame)
  
  cv2.imshow("back", dilated)
  
  
  
  
  
  if k == 27:
  
      break
  
  
  
  
  
  cap.release()
  
  cv2.destroyAllWindows()

  error

  Couldn’t read video stream from file "test.avi"