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• matplotlib ArtistAnimation returns a blank video

  28 mars 2017, par Mpaull

  I’m trying to produce an animation of a networkx graph changing over time. I’m using the networkx_draw utilities to create matplotlib figures of the graph, and matplotlib’s ArtistAnimation module to create an animation from the artists networkx produces. I’ve made a minimum reproduction of what I’m doing here :

  import numpy as np
  
  import networkx as nx
  
  import matplotlib.animation as animation
  
  import matplotlib.pyplot as plt
  
  
  
  # Instantiate the graph model
  
  G = nx.Graph()
  
  G.add_edge(1, 2)
  
  
  
  # Keep track of highest node ID
  
  G.maxNode = 2
  
  
  
  fig = plt.figure()
  
  nx.draw(G)
  
  ims = []
  
  
  
  for timeStep in xrange(10):
  
  
  
      G.add_edge(G.maxNode,G.maxNode+1)
  
      G.maxNode += 1
  
  
  
      pos = nx.drawing.spring_layout(G)
  
      nodes = nx.drawing.draw_networkx_nodes(G, pos)
  
      lines = nx.drawing.draw_networkx_edges(G, pos)
  
  
  
      ims.append((nodes,lines,))
  
      plt.pause(.2)
  
      plt.cla()
  
  
  
  im_ani = animation.ArtistAnimation(fig, ims, interval=200,            repeat_delay=3000,blit=True)
  
  im_ani.save('im.mp4', metadata={'artist':'Guido'})

  The process works fine while displaying the figures live, it produces exactly the animation I want. And it even produces a looping animation in a figure at the end of the script, again what I want, which would suggest that the animation process worked. However when I open the "im.mp4" file saved to disk, it is a blank white image which runs for the expected period of time, never showing any of the graph images which were showed live.

  I’m using networkx version 1.11, and matplotlib version 2.0. I’m using ffmpeg for the animation, and am running on a Mac, OSX 10.12.3.

  What am I doing incorrectly ?

• FFmpeg continues to process after time specified at "-to"

  4 août 2020, par Yamahabest

  I have a video, where I want to cut a part from the beginning, and from the end. And I want to apply some fade ins/fade outs, and add some text.

  


  So, I came up with the following syntax :

  


  -ss 10 -to 40 
-i "D:\DATA\Software\VideoProcessor_Files\20171015 Zelhem Tandem Frans met Mirthe.MP4" 
-loop 1 -i "Input_Files\logo maurik large.png" 
-loop 1 -i "Input_Files\logo maurik small.png" 
-filter_complex "
    color=0x7F7F7F@0.95:1920x1080[grey_for_fade_out];
    [grey_for_fade_out]fade=t=out:st=12:d=2:alpha=1[grey_fade_out];
    [0:v][grey_fade_out]overlay[video_grey_fade_out];
    color=0x7F7F7F@0.95:1920x1080[grey_for_fade_in];
    [grey_for_fade_in]fade=t=in:st=37:d=2:alpha=1[grey_fade_in];
    [video_grey_fade_out][grey_fade_in]overlay[video_grey_fade_out_in];
    [1:v]fade=t=out:st=13:d=2:alpha=1[over];
    [over]scale=iw/1.5:-1[scaled];
    [video_grey_fade_out_in][scaled]overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/10[video_grey_fade_out_in_logo];
    [1:v]fade=t=in:st=36:d=2:alpha=1[over2];
    [over2]scale=iw/1.5:-1[scaled2];
    [video_grey_fade_out_in_logo][scaled2]overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2[video_grey_fade_out_in_logo2];
    [2:v]colorchannelmixer=aa=0.5,fade=t=in:st=14:d=2:alpha=1,fade=t=out:st=35:d=2:alpha=1[over3];
    [over3]scale=iw/10:-1[scaled3];
    [video_grey_fade_out_in_logo2][scaled3]overlay=10:10[video_complete];
    [video_complete]drawtext=fontfile=Input_Files/Sansation-Bold.ttf:text='Tandemvlucht met Mirthe':fontsize=96:fontcolor=white:alpha='if(lt(t,11),1,(2-(t-11))/2)':x=(w-text_w)/2:y=((h-text_h)/2)+125,drawtext=fontfile=Input_Files/Sansation-Bold.ttf:text='Zeddam':fontsize=96:fontcolor=white:alpha='if(lt(t,11),1,(2-(t-11))/2)':x=(w-text_w)/2:y=((h-text_h)/2)+250,drawtext=fontfile=Input_Files/Sansation-Bold.ttf:text='4 augustus 2020':fontsize=96:fontcolor=white:alpha='if(lt(t,11),1,(2-(t-11))/2)':x=(w-text_w)/2:y=((h-text_h)/2)+375,drawtext=fontfile=Input_Files/Sansation-Bold.ttf:text='Ook een keer meevliegen?':fontsize=96:fontcolor=white:alpha='if(lt(t,37),0,(t-37)/2)':x=(w-text_w)/2:y=((h-text_h)/6),drawtext=fontfile=Input_Files/Sansation-Bold.ttf:text='Of bel 085 - 049 55 69':fontsize=96:fontcolor=white:alpha='if(lt(t,37),0,(t-37)/2)':x=(w-text_w)/2:y=((h-text_h)/2)+350"
-preset medium 
-crf 18 
-c:a copy 
-y ".\Output_Files\Video\Zeddam\2020-08-04\Mirthe\27ed390a-8497-4550-b93f-4f87d9f2c9f0\MP_Tandemvlucht met_Mirthe_Zeddam_2020-08-04.mp4"


  


  I am quite sure this has worked in the past, but now FFmpeg just keeps on processing endlessly. If I then stop the FFmpeg process, and look at the resulting file, I see that the last frame (of the end of the specified period) just keeps on duplicating.

  


  The drop counter in the console output of FFmpeg also starts increasing at the end of the specified period :

  


  frame=  987 fps= 15 q=-1.0 Lsize=   31357kB time=00:00:41.04 bitrate=6259.0kbits/s dup=0 drop=10 speed=0.644x


  


  I am kind of lost on why this doesn't work anymore. I might have upgraded the FFmpeg executable in the mean time. Maybe my syntax was/is not correct, but I believe it just worked.

  


  It has to be in the complex filter, because when I remove that, it works alright.
It is not in the drawtext part of the complex filter, because it still occurs when I remove that. And when I only do the drawtext, FFmpeg stops correctly at the specified time.

  


  I have tried this, but then it still occurs :

  


  -filter_complex "
    color=0x7F7F7F@0.95:1920x1080[grey_for_fade_out];
    [grey_for_fade_out]fade=t=out:st=12:d=2:alpha=1[grey_fade_out];
    [0:v][grey_fade_out]overlay[video_grey_fade_out];
    color=0x7F7F7F@0.95:1920x1080[grey_for_fade_in];
    [grey_for_fade_in]fade=t=in:st=37:d=2:alpha=1[grey_fade_in];
    [video_grey_fade_out][grey_fade_in]overlay"


  


  Also with this, it still occurs :

  


  -filter_complex "
    [1:v]fade=t=out:st=13:d=2:alpha=1[over];
    [over]scale=iw/1.5:-1[scaled];
    [0:v][scaled]overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/10[video_grey_fade_out_in_logo];
    [1:v]fade=t=in:st=36:d=2:alpha=1[over2];
    [over2]scale=iw/1.5:-1[scaled2];
    [video_grey_fade_out_in_logo][scaled2]overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2[video_grey_fade_out_in_logo2];
    [2:v]colorchannelmixer=aa=0.5,fade=t=in:st=14:d=2:alpha=1,fade=t=out:st=35:d=2:alpha=1[over3];
    [over3]scale=iw/10:-1[scaled3];
    [video_grey_fade_out_in_logo2][scaled3]overlay=10:10"


  


  I just don't understand. All my fade-ins/-outs seem to be within the specified range :

  


  

  • fade=t=out:st=12:d=2 : start at 12 seconds, duration 2 seconds. This ends at 14 seconds, which is smaller than 40 seconds.

  


  • fade=t=in:st=37:d=2 : start at 37 seconds, duration 2 seconds. This ends at 39 seconds, which is smaller than 40 seconds.

  


  • fade=t=out:st=13:d=2 : start at 13 seconds, duration 2 seconds. This ends at 15 seconds, which is smaller than 40 seconds.

  


  • fade=t=in:st=36:d=2 : start at 36 seconds, duration 2 seconds. This ends at 38 seconds, which is smaller than 40 seconds.

  


  


  It is just like some sequence is not ended properly, which is causing FFmpeg to just continue.

  


• FFmpeg scale and watermark filters with VAAP gives error "Cannot allocate memory." [closed]

  8 février 2024, par Diz-X

  I'm attempting to transcode any uploaded video on our website into H.264 using an ARC GPU (VAAPI). While I've achieved functionality, ffmpeg crashes after a certain period, displaying the error message : "Error while filtering : Cannot allocate memory."

  


  The following is the ffmpeg command is used transcode videos to H.264 :

  


  


  ffmpeg -hwaccel vaapi -hwaccel_output_format vaapi -vaapi_device /dev/dri/renderD129 -y -i '/Media/001.mp4' -codec:v h264_vaapi -movflags +faststart -f mp4 -b:v 500k -maxrate 1000k -bufsize 500k -vf "movie=/Watermarks/video-watermark.png,hwupload [watermark] ; [in] scale_vaapi=trunc(iw/2)*2:trunc(ih/2)*2 [scale] ; [scale][watermark] overlay_vaapi=main_w-overlay_w:main_h-overlay_h [out]" -an -pass 1 -passlogfile /tmp/91f13b11b0ccd5195b588fb204da6626 -map_metadata -1 /dev/null

  


  


  We ensure that the video is scaled to the appropriate video dimensions expected by H.264 codec , we use the "scale_vaapi=trunc(iw/2)*2:trunc(ih/2)*2" filter for this. We also apply a watermark to the video using the "overlay_vaapi=main_w-overlay_w:main_h-overlay_h" filter.

  


  If I omit the ",hwupload" after the "movie=" statement, I encounter the following error : "Impossible to convert between the formats supported by the filter 'Parsed_movie_0' and the filter 'auto_scale_0'."

  


  The "-filter-complex" results in the identical error : "Error while filtering : Cannot allocate memory.".

  


  Does anyone have insights on how to enable hardware-accelerated transcoding for this ?