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• avcodec/bitstream : Remove outdated comment

  29 août 2020, par Andreas Rheinhardt

  avcodec/bitstream : Remove outdated comment
  The comment referred to the INIT_VLC_USE_STATIC flag which has been
  
  removed in 2009 in 595324e143b57a52e2329eb47b84395c70f93087 ; the
  
  function it referred to was removed even earlier in commit
  
  83422c1940d963d395a64bee0cbb9c637192ce8c in 2008.
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/bitstream.c

• Use fluent-ffmpeg to tell if a file is a video or audio

  8 mai 2021, par afterglowlee

  I am using node-fluent-ffmpeg module in NodeJS. It is very good that fluent-ffmpeg provides functions to get the metadata of a video and audio file.

  



  https://github.com/schaermu/node-fluent-ffmpeg#reading-video-metadata

  



  I have tried on Mac OS to use the "resolution" attribute in the metadata to tell if a file is audio only or video, i.e. if both resolution.w and resolution.h are 0, then this file is an audio. This work fine on Mac OS. But some strange things happened that this doesn't work on Windows platform (I have tried Windows 7 64bit and Windows 2008) using the latest ffmpeg. Even though I put a .mp3 file through fluent-ffmpeg,the result looks something like this :

  



  video:
{
  container:'mp3',
  ...
  resolution: {w:300,h:300},
  resolutionSquare: {w:300,h:300},
  aspectString: '1:1',
  ...
}
audio:
{
  codec:'mp3',
  bitrate:64,
  sample_rate:44100,
  stream:0,
  channels:1
}


  



  I am not why there is a "resolution" since it is a pure audio file. So is there any solid way to find out if the file is audio only or video from the metadata ? Or should I use ffmpeg commandline to find it out ?

  


• 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)