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• Saving an animation using ffmpeg and matplotlib on anaconda3

  21 juin 2016, par Varsha Dyavaiah

  I am trying to create videos of NBA Action with Sportsvu data.

  I was following the steps given in this blog by Dan Vatterott :

  http://www.danvatterott.com/blog/2016/06/16/creating-videos-of-nba-action-with-sportsvu-data/?utm_campaign=Data%2BElixir&utm_medium=email&utm_source=Data_Elixir_84

  I am trying to create a animation and save it using ffmpeg and matplotlib.
  The code snippet is attached below.

   import matplotlib.animation as animation
  
   plt.rcParams['animation.ffmpeg_path'] = '/home/anaconda3/pkgs/ffmpeg-2.1.0-1/bin'
  
  
  
   fig = plt.figure(figsize=(15,7.5)) #create figure object
  
   ax = plt.gca() #create axis object
  
  
  
   draw_court([0,100,0,50]) #draw the court
  
   player_text = list(range(10)) #create player text vector
  
   player_circ = list(range(10)) #create player circle vector
  
   ball_circ = plt.Circle((0,0), 1.1, color=[1, 0.4, 0]) #create circle object for bal
  
   for i in list(range(10)): #create circle object and text object for each player
  
       col=['w','k'] if i<5 else ['k','w'] #color scheme
  
       player_circ[i] = plt.Circle((0,0), 2.2, facecolor=col[0],edgecolor='k') #player circle
  
       player_text[i] =   ax.text(0,0,'',color=col[1],ha='center',va='center') #player jersey # (text)
  
  
  
   ani = animation.FuncAnimation(fig, animate,  frames=np.arange(0,np.size(ball_xy,0)), init_func=init, blit=True, interval=5, repeat=False,\
  
                           save_count=0) #function for making video
  
  
  
   FFwriter = animation.FFMpegWriter()
  
   ani.save('Event_%d.mp4' % (search_id),dpi=100,writer = FFwriter,fps=25) #function for saving video
  
   plt.close('all') #close the plot

  When I try to save the animation ’ani’ , I get Errno 13 (Permission denied).

   ---------------------------------------------------------------------------
  
   PermissionError                           Traceback (most recent call last)
  
   in <module>()
  
       17 
  
       18 FFwriter = animation.FFMpegWriter()
  
  ---> 19 ani.save('Event_%d.mp4' % (search_id),dpi=100,writer = FFwriter,fps=25) #function for saving video
  
   20 plt.close('all') #close the plot
  
  
  
  /home/anaconda3/lib/python3.5/site-packages/matplotlib/animation.py in save(self, filename, writer, fps, dpi, codec, bitrate, extra_args, metadata, extra_anim, savefig_kwargs)
  
      799         # since GUI widgets are gone. Either need to remove extra code to
  
      800         # allow for this non-existant use case or find a way to make it work.
  
  --> 801         with writer.saving(self._fig, filename, dpi):
  
      802             for anim in all_anim:
  
      803                 # Clear the initial frame
  
  
  
  /home/anaconda3/lib/python3.5/contextlib.py in __enter__(self)
  
       57     def __enter__(self):
  
       58         try:
  
  ---> 59             return next(self.gen)
  
       60         except StopIteration:
  
       61             raise RuntimeError("generator didn't yield") from None
  
  
  
  /home/anaconda3/lib/python3.5/site-packages/matplotlib/animation.py in saving(self, *args)
  
      192         '''
  
      193         # This particular sequence is what contextlib.contextmanager wants
  
  --> 194         self.setup(*args)
  
      195         yield
  
      196         self.finish()
  
  
  
  /home/anaconda3/lib/python3.5/site-packages/matplotlib/animation.py in setup(self, fig, outfile, dpi, *args)
  
      182         # Run here so that grab_frame() can write the data to a pipe. This
  
      183         # eliminates the need for temp files.
  
  --> 184         self._run()
  
      185 
  
      186     @contextlib.contextmanager
  
  
  
  /home/anaconda3/lib/python3.5/site-packages/matplotlib/animation.py in _run(self)
  
      210                                       stdout=output, stderr=output,
  
      211                                       stdin=subprocess.PIPE,
  
  --> 212                                       creationflags=subprocess_creation_flags)
  
      213 
  
      214     def finish(self):
  
  
  
  /home/anaconda3/lib/python3.5/subprocess.py in __init__(self, args, bufsize, executable, stdin, stdout, stderr, preexec_fn, close_fds, shell, cwd, env, universal_newlines, startupinfo, creationflags, restore_signals, start_new_session, pass_fds)
  
      948                                 c2pread, c2pwrite,
  
      949                                 errread, errwrite,
  
  --> 950                                 restore_signals, start_new_session)
  
      951         except:
  
      952             # Cleanup if the child failed starting.
  
  
  
  /home/anaconda3/lib/python3.5/subprocess.py in _execute_child(self, args, executable, preexec_fn, close_fds, pass_fds, cwd, env, startupinfo, creationflags, shell, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite, restore_signals, start_new_session)
  
     1542                             else:
  
     1543                                 err_msg += ': ' + repr(orig_executable)
  
  -> 1544                     raise child_exception_type(errno_num, err_msg)
  
     1545                 raise child_exception_type(err_msg)
  
     1546 
  
  
  
  PermissionError: [Errno 13] Permission denied
  
  </module>

  Can someone help me ? Thanks in advance.

• libx265 motion compensation and CU traverse

  17 juin 2016, par Ariana

  I’m trying to play with the H.265 motion compensation and search (HEVC- libx265 implementation from here : https://bitbucket.org/multicoreware/x265/downloads). I need to slightly extend the edge extension search, and fill the macro block with left-most pixels as if my sample videos are like cylinder (rightmost is connected to leftmost).

  What I need to do is basically this :

  

  One way to do that is to modify the edge extension area (which is already in the code, in the frameFilter.cpp), and do that for rightmost and fill parts of blocks which are out with leftmost pixels. I identified the piece of code here which apparently is responsible for that. Can someone help me with implementing this feature ?

  if ((col == 0) | (col == m_frameFilter->m_numCols - 1))
  
      {
  
          // TODO: improve by process on Left or Right only
  
          primitives.extendRowBorder(reconPic->getLumaAddr(m_rowAddr), stride, reconPic->m_picWidth, realH, reconPic->m_lumaMarginX);
  
  
  
          if (m_frameFilter->m_param->internalCsp != X265_CSP_I400)
  
          {
  
              primitives.extendRowBorder(reconPic->getCbAddr(m_rowAddr), strideC, reconPic->m_picWidth >> hChromaShift, realH >> vChromaShift, reconPic->m_chromaMarginX);
  
              primitives.extendRowBorder(reconPic->getCrAddr(m_rowAddr), strideC, reconPic->m_picWidth >> hChromaShift, realH >> vChromaShift, reconPic->m_chromaMarginX);
  
          }
  
      }
  
  
  
      // Extra Left and Right border on first and last CU
  
      if ((col == 0) | (col == m_frameFilter->m_numCols - 1))
  
      {
  
          copySizeY += lumaMarginX;
  
          copySizeC += chromaMarginX;
  
      }
  
  
  
      // First column need extension left padding area and first CU
  
      if (col == 0)
  
      {
  
          pixY -= lumaMarginX;
  
          pixU -= chromaMarginX;
  
          pixV -= chromaMarginX;
  
      }

• FFMPEG Motion Compensation and Search

  20 juin 2016, par Tina Jasmin

  I’m trying to modify the motion detection part of FFMPEG. What I want to do is to extend the search space, so that whenever the macroblock hit the right most edge of the frame, I need it to still move the block towards the left-most as if they are connected (in my example videos, the right edge is actually a continue of the left edge). Can someone help me to point where exactly I can modify it within FFMPEG source code or x265, or x264 ?

  

  I took H265 as an example from here. It has a motion.cpp file which nicely specifies the possible block sizes as below. But I can’t find the specific loop that traverses the frame. A help is highly appreciated.

  #define SETUP_SCALE(W, H) \
  
      sizeScale[LUMA_ ## W ## x ## H] = (H * H) >> 4;
  
      SETUP_SCALE(4, 4);
  
      SETUP_SCALE(8, 8);
  
      SETUP_SCALE(8, 4);
  
      SETUP_SCALE(4, 8);
  
      SETUP_SCALE(16, 16);
  
      SETUP_SCALE(16, 8);
  
      SETUP_SCALE(8, 16);
  
      SETUP_SCALE(16, 12);
  
      SETUP_SCALE(12, 16);
  
      SETUP_SCALE(4, 16);
  
      SETUP_SCALE(16, 4);
  
      SETUP_SCALE(32, 32);
  
      SETUP_SCALE(32, 16);
  
      SETUP_SCALE(16, 32);
  
      SETUP_SCALE(32, 24);
  
      SETUP_SCALE(24, 32);
  
      SETUP_SCALE(32, 8);
  
      SETUP_SCALE(8, 32);
  
      SETUP_SCALE(64, 64);
  
      SETUP_SCALE(64, 32);
  
      SETUP_SCALE(32, 64);
  
      SETUP_SCALE(64, 48);
  
      SETUP_SCALE(48, 64);
  
      SETUP_SCALE(64, 16);
  
      SETUP_SCALE(16, 64);
  
  #undef SETUP_SCALE

  UPDATE :

  One way to do that (in x265) is to modify the edge extension area (which is already in the code, in the frameFilter.cpp), and do that for rightmost and fill blocks with leftmost pixels. I identified the piece of code here. Can someone help me to add this feature for right-to-left extension ?

  if ((col == 0) | (col == m_frameFilter->m_numCols - 1))
  
      {
  
          // TODO: improve by process on Left or Right only
  
          primitives.extendRowBorder(reconPic->getLumaAddr(m_rowAddr), stride, reconPic->m_picWidth, realH, reconPic->m_lumaMarginX);
  
  
  
          if (m_frameFilter->m_param->internalCsp != X265_CSP_I400)
  
          {
  
              primitives.extendRowBorder(reconPic->getCbAddr(m_rowAddr), strideC, reconPic->m_picWidth >> hChromaShift, realH >> vChromaShift, reconPic->m_chromaMarginX);
  
              primitives.extendRowBorder(reconPic->getCrAddr(m_rowAddr), strideC, reconPic->m_picWidth >> hChromaShift, realH >> vChromaShift, reconPic->m_chromaMarginX);
  
          }
  
      }
  
  
  
      // Extra Left and Right border on first and last CU
  
      if ((col == 0) | (col == m_frameFilter->m_numCols - 1))
  
      {
  
          copySizeY += lumaMarginX;
  
          copySizeC += chromaMarginX;
  
      }
  
  
  
      // First column need extension left padding area and first CU
  
      if (col == 0)
  
      {
  
          pixY -= lumaMarginX;
  
          pixU -= chromaMarginX;
  
          pixV -= chromaMarginX;
  
      }