Newest 'ffmpeg' Questions - Stack Overflow

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• build python opencv with ffmpeg support on Heroku

  4 mars 2017, par Dzung Nguyen

  I am using this buildpacks to install ffmpeg on heroku

  heroku buildpacks:add --index 2 https://github.com/shunjikonishi/heroku-buildpack-ffmpeg.git
  

  and this buildpacks to install python opencv on heroku

  heroku buildpacks:add --index 3 https://github.com/diogojc/heroku-buildpack-python-opencv-scipy.git
  

  I can use ffmpeg command and python opencv on heroku separately. Using python opencv, I can open and read image. However I cannot read video. Somehow opencv is not compiled with ffmpeg. My question is how can I compile python opencv with ffmpeg support.

• Python FuncAnimation is saved only 30%

  4 mars 2017, par cvut

  I am trying to make a movie out of data I've calculated. I am using ffmpeg writer. When I start the animation in Spyder it is working fine and goes to the end, but when I try to save it it goes only for first 30% of animation. How can I make it to save the whole animation?

  Here is a bit of code( it's long); MM is place where the matrices are stored (1200 of them).

  import matplotlib
  matplotlib.use("Agg")
  from mpl_toolkits.mplot3d import axes3d
  import matplotlib.animation as animation
  import numpy as np
  import matplotlib.pyplot as plt
  import matplotlib.cm as cm
  nx = 10
  ny = 10
  X=np.linspace(0, Lx, nx)
  Y=np.linspace(0, Ly, ny)   
  Writer = animation.writers['ffmpeg']
  writer = Writer(fps=15, metadata=dict(artist='Me'), bitrate=1)
  
  plt.ion()
  fig = plt.figure()
  im = plt.contourf(X, Y, MM[0], np.linspace(T_ok,np.max(MM[-1]),150), cmap =     cm.hot)
  ax = fig.add_subplot(111, projection='3d')  
  plt.colorbar(im)
  
  def anime(i):
      ax.cla()
      im = ax.contourf(X, Y, MM[i], np.linspace(T_ok,np.max(MM[-1]),150), cmap = cm.hot)
      plt.title('%5.3f'%i)
      return im,
  
  anim = animation.FuncAnimation(fig, anime)
  anim.save('anime.mp4', writer=writer)
  

  EDIT: I just set frames to 10000 and it's working, but I would like to know why. There are 1200 matrices that should be plotted.

• How to create a webm video file ?

  4 mars 2017, par Marneau

  After looking over the web project I see no evidence of a way to generate a webm video. I see drivers for Windows and Quicktime, but no evidence that the most common utility ffmpeg is being supported.

  Is there any open source converter that produces webm?

  Thanks.

• avformat_alloc_context returns null

  4 mars 2017, par dk123

  I'm currently trying to play a video from a stream through FFMPEG. I'm currently stuck however on a particular section: regardless of what I do, avformat_alloc_context(); seems to return null.

  Would anyone perhaps know what might be going on?

  I've been referencing the link below: Reading a file located in memory with libavformat

• Stream MMS/ASX link on IOS app

  4 mars 2017, par Seb78

  I have an app streaming mp3/aac link and working well (using avaudioplayer)

  I would like to stream MMS/ASX link. I found and tried Radiotunes SDK and working well but i dont wanna pay 99$ to use it.

  I heard about libmms and ffmpeg library but it seems complicated to implement. Do you have another solution or a tutorial (step by step) to stream mms/asx link.

  Thanks Regards