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• How can I encode RGB images into HDR10 videos in ffmpeg command-line ? [closed]

  5 juin 2024, par F.X.

  How can I encode HDR10 videos from RGB images using the ffmpeg command-line, with the proper color and luminance metadata ?

  


  There are a lot of ffmpeg command-line examples floating around when searching information about how to encode HDR10 streams properly, but I didn't find any that has a comprehensive list of all the parameters you can tune when using RGB frames as inputs.

  


  For example :

  


  

  • This article has a lot of information, but uses an existing video as input.

  


  • Similarly, this article uses an existing video as input

  


  


• How do I get the last line of a popen() callback in every iteration ?

  29 mai 2017, par Mike

  I’m trying to create a progress bar with FFMPEG using php and AJAX. When a user uploads a video file I want to be able to display the current percent until completion. I have managed to get everything working but I have one issue.

  The data returns what I want, but it also returns all the data from the previous iterations... like it just keeps stacking everything on top rather than flushing out the data from previous iterations. I tried to work with tail thinking it would return only the last line, but it did not return anything.

  Here is the code I’m working with :

  encode.php

  $video_path = 'test.mp4';
  
  $cmd        = 'ffmpeg -i ' . $video_path .' -y -hide_banner output.mp4 2>&1';
  
  
  
  while (@ ob_end_flush());
  
  
  
  $proc = popen($cmd, 'r');
  
  
  
  while (!feof($proc))
  
  {
  
  
  
      $file = escapeshellarg(fread($proc, 4096));
  
      //$line = `tail -n 1 $file`; // <-tried this with no luck
  
      echo fread($file, 4096) . "\n";
  
      @ flush();
  
  }
  
  return 'complete';
  
  pclose($proc);

  The above code returns :

  // first iteration
  
  frame=   52 fps= 13 q=29.0 size=     279kB time=00:00:00.10 bitrate=22856.9kbits/s
  
  
  
  // second iteration
  
  frame=   52 fps= 13 q=29.0 size=     279kB time=00:00:00.10 bitrate=22856.9kbits/s    
  
  frame=   54 fps= 12 q=29.0 size=     329kB time=00:00:00.16 bitrate=16146.6kbits/s 
  
  
  
  // third iteration
  
  frame=   52 fps= 13 q=29.0 size=     279kB time=00:00:00.10 bitrate=22856.9kbits/s    
  
  frame=   54 fps= 12 q=29.0 size=     329kB time=00:00:00.16 bitrate=16146.6kbits/s    
  
  frame=   57 fps= 11 q=29.0 size=     464kB time=00:00:00.26 bitrate=14233.2kbits/s 

  As you can see the data stacks, I need only the new line of data, not the data stacking.

  ** EDIT ** this has been marked as a duplicate, rather than me explain how it’s different, I’d like to hear how this is the same thing ? I am not writing to a log file and, like most people, do not feel that’s a good solution.

• Animated line chart with pandas, matplotlib and ffmpeg

  10 avril 2020, par Mark K

  In producing an animated line chart, I have below data and codes.

  



  But when the chart produced, it shows no line. What did I do wrong ?

  



  Thank you.

  



  import numpy as np
import pandas as pd
import seaborn as sns
import matplotlib
import matplotlib.pyplot as plt
import matplotlib.animation as animation

title = 'Heroin Overdoses'

data = {'Year' : ["1999","2000","2001","2002","2003","2004","2005","2006","2007","2008","2009","2010","2011","2012","2013","2014","2015","2016"], 
'Heroin Overdoses' : [280,443,413,486,475,148,197,170,448,103,137,160,483,356,352,300,466,278]}
overdose = pd.DataFrame(data)

Writer = animation.writers['ffmpeg']
writer = Writer(fps=20, metadata=dict(artist='Me'), bitrate=1800)

fig = plt.figure(figsize=(10,6))
plt.xlim(1999, 2016)
plt.ylim(np.min(overdose)[0], np.max(overdose)[0])
plt.xlabel('Year',fontsize=20)
plt.ylabel(title,fontsize=20)
plt.title('Heroin Overdoses per Year',fontsize=20)

def animate(i):
    data = overdose.iloc[:int(i+1)] #select data range
    p = sns.lineplot(x=data.index, y=data[title], data=data, color="r")
    p.tick_params(labelsize=17)
    plt.setp(p.lines,linewidth=7)

ani = matplotlib.animation.FuncAnimation(fig, animate, frames=17, repeat=True)

ani.save('C:\\folder\\line chart.mp4', writer=writer)