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• libx264 : Allow full-range yuv422 and yuv444 pixel formats

  17 mars 2015, par Carl Eugen Hoyos

  libx264 : Allow full-range yuv422 and yuv444 pixel formats
  Signed-off-by : Vittorio Giovara <vittorio.giovara@gmail.com>
  

  • [DBH] libavcodec/libx264.c

• How to set yuv to full range in a mpeg2video ?

  7 mai 2021, par Jefferson Villasan Josol

  I've found out that YUV420P has a limited range based on MediaInfo. How can I set that into Full range using ffmpeg ? Does anyone know how to set it into Full ?
I'm currently using mpeg2video -q:v 0 because it has an acceptable quality and small file sizes compared to x264 -crf 0.
Thanks in advance for those who can help me !

  


  Edit : I prefer mpeg2video because it is much faster compared to x264 encoding. And I've also noticed that -q:v 0 is better than -q:v 2. I don't know if it sounds strange but on my phone, the quality is really better if I use the -c:v mpeg2video -q:v 0

  


• How can I get matplotlib to show full subplots in an animation ?

  12 mars 2015, par Matt Stone

  I’m trying to write a simple immune system simulator. I’m modeling infected tissue as a simple grid of cells and various intracellular signals, and I’d like to animate movement of cells in one plot and the intensity of viral presence in another as the infection progresses. I’m doing so with the matshow function provided by matplotlib. However, when I plot the two next to each other, the full grid gets clipped unless I stretch out the window myself. I can’t address the problem at all when saving to an mp4.

  Here’s the default view, which is identical to what I observe when saving to mp4 :
  

  And here’s what it looks like after stretching out the viewer window
  

  I’m running Python 2.7.9 with matplotlib 1.4.2 on OS X 10.10.2, using ffmpeg 2.5.2 (installed via Homebrew). Below is the code I’m using to generate the animation. I tried using plt.tight_layout() but it didn’t affect the problem. If anyone has any advice as to how to solve this, I’d really appreciate it ! I’d especially like to be able to save it without viewing with plt.show(). Thanks !

  def animate(self, fname=None, frames=100):
  
      fig, (agent_ax, signal_ax) = plt.subplots(1, 2, sharey=True)
  
  
  
      agent_ax.set_ylim(0, self.grid.shape[0])
  
      agent_ax.set_xlim(0, self.grid.shape[1])
  
      signal_ax.set_ylim(0, self.grid.shape[0])
  
      signal_ax.set_xlim(0, self.grid.shape[1])
  
  
  
      agent_mat = agent_ax.matshow(self.display_grid(),
  
                                   vmin=0, vmax=10)
  
      signal_mat = signal_ax.matshow(self.signal_display(virus),
  
                                     vmin=0, vmax=20)
  
      fig.colorbar(signal_mat)
  
  
  
      def anim_update(tick):
  
          self.update()
  
          self.diffuse()
  
          agent_mat.set_data(self.display_grid())
  
          signal_mat.set_data(self.signal_display(virus))
  
          return agent_mat, signal_mat
  
  
  
      anim = animation.FuncAnimation(fig, anim_update, frames=frames,
  
                                     interval=3000, blit=False)
  
  
  
      if fname:
  
          anim.save(fname, fps=5, extra_args=['-vcodec', 'libx264'])
  
      else:
  
          plt.show()