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• FFmpeg how generate a sequence of videos with bash

  27 janvier 2018, par Massimo Vantaggio

  i try to write an .sh that read a folder create a playlist of mp4 files and then generate an only big video with a sequence of all videos find in the folder, and encode it for dash :

  printf "file '%s'\n" ./*.mp4 > playlist.sh
  
  ffmpeg -f concat -safe 0 -i playlist.sh -c copy concat.mp4

  Till now i follow the demux concat official guido to ffmpeg website.
  Without result, also the following give me "more than 1000 frames duplicated between videos of the sequence"

  ffmpeg -f concat -i playlist.sh -c:a aac -b:a 384k -ar 48000 -ac 2 -c:v libx264 -x264opts 'keyint=50:min-keyint=50:no-scenecut' -r 25 -b:v 2400k -maxrate 2400k -bufsize 1200k -vf "scale=-1:432 " out.mp4

  Thanks a lot

• CBR libx265, constant bitrate with HEVC

  8 novembre 2022, par user1722669

  I was trying to use FFmpeg and libx265, but actually, I can't find any working solution for HEVC and Constant bitrate

  



  *ffmpeg -i "D:\video\Mixer test.mp4" -c:v libx265 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v 1M -minrate 1M -maxrate 1M -bufsize 2M output.ts*


  



  or

  



  ffmpeg -i "D:\video\Mixer test.mp4" -c:v libx265 -preset medium  -pass 1 -b:v 5000k -preset 5 -x265-params -strict-cbr -crf 28 -c:a aac -b:a 128k output.mp4


  



  Is it possible to get CBR with h265 ?

  



  If it isn't possible can you share some official information about it

  



  Thank you.

  


• matplotlib funcanimation save issue

  20 avril 2015, par Richie Abraham

  I have been trying some animation recently using matplotlib animations. It has been going great, i create an ffmpeg writer and save it as a video file. However i face an issue whenever the function that FuncAnimation calls returns more than one object.

  Below is a small snippet of my code base. When I return both im0 and im1, the video file created only has im1 , although the plt.show command works as expected ( showing both the videos ). If i return just a single im0, then it works as expected. IT also works as expected if i return both im0 and im1 with alpha=0.5.

  Can anyone shed some light on what is happening underneath the hood ?

  fig, ax = plt.subplots(1)
  
  def animate(i):
  
      im0=ax.imshow(np.ma.masked_array(imgl[i][:,:,0], mask=get_blob(i)),cmap='cubehelix')
  
  
  
      im1=ax.imshow(imgl[(i-100)%len(imgl)][:,:,0],cmap='cubehelix')
  
  
  
      return [im1,im0]
  
  
  
  
  
  
  
  ani = animation.FuncAnimation(fig, animate, frames=200,
  
                                interval=10, blit=True,repeat=False)
  
  ani.save('ps.mp4', writer=writer)
  
  plt.show()