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• ffmpeg - put video atop of second and center it while keeping aspect ratio

  25 août 2022, par artolini

  I'm trying to put 16:9 video atop of same blurred 1:1 video just like on the photos.
I'm looking a wise guy with ffmpeg knowledge to help me with think of about the command which will :

  


  

  1. rescale 16:9 (sharp video) accordingly to blurred one height (keeping the width automatically to ratio)

  


  2. center the 16:9 (sharp video) to x position = (blurredVideoWidth / 2) - (sharpVideoWidth / 2)

  


  


  My current comment looks like this :

  


  ffmpeg -y -i ${squareBlurredVideoUri} -i ${square169VideoUri} -filter_complex "[1:v]scale=620:-1[v2];[0:v][v2]overlay=0:0" -codec:a copy ${squareFinalVideoUri}

  


  As you can see scale is hardcoded to 620 which is wrong because we should rescale it accordingly to blurred video height.

  


  Overlay is set to 0:0 which places sharp video to x = 0 and y = 0 and should center it

  


  Thank you in advance.

  


  Current result :

Desired result :


  


• Python Matplotlib Basemap animation with FFMpegwriter stops after 820 Frames ?

  5 août 2013, par cpaulik

  If I run the following code it just stops after 820 Frames. I tested this on both a Ubuntu 12.04 VM and on Linux Mint 15. Unfortunately there is no error message. The program just hangs after printing 2012-06-02T16:54:00

  import os, sys
  
  import matplotlib.pyplot as plt
  
  from mpl_toolkits.basemap import Basemap
  
  import matplotlib.animation as animation
  
  from datetime import datetime,timedelta
  
  
  
  def animation_test(start,end,fps=10,save_path='/home/username/animation_test/',\
  
  save_name="test.mp4",dpi=80):
  
  
  
      step = timedelta(minutes = 3)
  
  
  
      current = start
  
  
  
      dates =[]
  
  
  
      frame = 0
  
  
  
      while current <=end:
  
          dates.append(current)
  
          current += step
  
  
  
      fig = plt.figure(figsize=(16,9),facecolor='k',edgecolor='k')
  
      ax = fig.add_subplot(111)
  
  
  
      metadata = dict(title='Movie Test', artist='Matplotlib',
  
              comment='Movie support!')
  
      writer = animation.FFMpegWriter(fps=fps, metadata=metadata,bitrate=20000)
  
  
  
      direction = -0.5
  
      lat_current = 0
  
      lon_current = 0
  
  
  
      with writer.saving(fig,os.path.join(save_path,save_name),dpi):
  
  
  
          for current in dates:
  
  
  
              ax.cla()
  
              if direction > 0 and lat_current > 40 or \
  
                     direction < 0 and lat_current < -40:
  
                      direction = - direction
  
  
  
              lat_current = lat_current + direction
  
              lon_current = lon_current - 0.75
  
              if lon_current < -180 :
  
                  lon_current += 360
  
              basem = Basemap(projection='ortho', lat_0=lat_current, lon_0=lon_current, resolution='l',ax=ax)
  
              basem.drawcoastlines()
  
  
  
              #plt.show()
  
  
  
              plt.savefig(os.path.join(save_path, 'frame%d.png'%frame),
  
                  dpi=dpi,facecolor='w',edgecolor='k')
  
  
  
              writer.grab_frame()
  
              frame += 1
  
              print current.isoformat()
  
  
  
  start = datetime.now()
  
  animation_test(datetime(2012,6,1,0,0,0),datetime(2012,6,4,0,0,0),fps=10,dpi=80)
  
  print datetime.now() - start

  To explain the code a little bit :
  I want to make an animation of satellite data which comes in small 3 minute files and show it on a rotating globe. This is why I chose to make the loop in the following example code step through the animation in 3 minute steps. I just removed the reading and plotting of the satellite data in order to make the code executable by anyone.

  When I removed basemap from the program and just plotted a scatterplot of random data the program ran all the way through.

  I'm not sure but I don't think that it is a memory issue since my RAM is only utilized approx. 20% while the program is running.

  Thanks for any help in getting to the bottom of this.

• Revision cdffeaaae0 : Add mode info arrays and mode info index. In non frame-parallel decoding, this

  10 juin 2014, par hkuang

  Changed Paths :
   Modify /vp9/common/vp9_alloccommon.c

  
   Modify /vp9/common/vp9_onyxc_int.h

  
  
  Add mode info arrays and mode info index.

  In non frame-parallel decoding, this works the same way as
  current decoding scheme. Every time after decoder finish
  decoding a frame, it will swap the current mode info pointer
  and previous mode info pointer if the decoded frame needs
  to be shown. Both mode info pointer and previous mode info
  pointer are from mode info arrays.

  In frame-parallel decoding, this will become more complicated
  as current frame’s mode info pointer will be shared with next
  frame as previous mode info pointer. But when one decoder
  thread finishes decoding one frame and starts to work on next
  available frame, it needs to retain the decoded frame’s mode
  info pointers until next frame finishes decoding. The mode info
  index will serve this purpose. The decoder will use different
  buffer in the mode info arrays and use the other buffer to save
  previous decoded frame’s mode info.

  Change-Id : If11d57d8eb0ee38c8876158e5482177fcb229428