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• How can I use ffmpeg to create a seamless looping gif ? [closed]

  27 juin 2024, par DavidNyan10

  I have an MP4 file which contains animation repeating in a loop. Let's just say, for example, a video of rain. However, when loop is turned on, the video cuts off at the wrong place and does not make a nice smooth animation. The part where it loops is obvious. It's just that the video contains more than one cycle of the loop, but not an exact integer of the full cycle.

  


  My goal is to turn this video into a gif with a seamless loop. In other words, I want the last frame of the video to match the first frame.

  


  My approach : I found a "Seamless loop creator" website on Google, tried it out, and it worked REALLY well. I thought all my problems have been solved. But little did I know, I've been only looking at the few seconds at the beginning and at the end of the video, not paying attention to what's in the middle. The sneaky pesky little website cuts off the video right in the middle, stitch the "seamless transition" at the beginning and end of the video, and put an ugly cross-fade in the middle where the frames don't line up. That is stupid. This of course, isn't noticable on rain videos, but on videos like a character jumping, the crossfade is very visible.

  


  My second approach : I'd use FFMPEG to get the first frame of the video, then starting from the last frame of the video and backwards, it'd try to find a frame that matches exactly with the first frame.

  


  Steps :

  


  

  1. Get the first frame and save it as a PNG or something I don't know

  


  2. Reverse the original video

  


  3. Match the image to each frame of the video in step 2. It is now easier because it's not doing it backwards frame by frame.

  


  4. When a frame match is found, cut off all the frames before this matched frame.

  


  5. Reverse back the video

  


  


  Can I achieve something like this in ffmpeg, preferably a one-liner in windows cmd ?

  


  Follow-up question : Would it be better to leave the last frame the same as first frame or should I remove it ? For example, when it's looping, it would repeat that exact frame two times, is that good ? Or which one provides better results ? And if it's better to not include the last frame (the one that matches), how would I do it in my process above ?

  


  I tried ChatGPT, expecting a ready-made code. Put it in the command prompt and lost my original video file. Had to use a recovery tool because the file was overwritten.

  


• Android ffmpeg : create video from sequence of images using jni

  22 novembre 2018, par Sameer Z.

  I have successfully build ffmpeg for Android and now I need to create video from sequence images so it look like animation video with some default audio. I have found some solution but it all says using command like.

  How to do same thing using jni on Android ?

• create a movie in python [on hold]

  22 mai 2017, par masoud

  I have some files with names (’Den_car_resample’ +’sdf’+ str(n)+’.dat’) where n changes from 0 to 25. I wrote a code to read these files and plots the results.
  now I want to create a movie from these plots. at the end of the program, I used the avconv command to do that.
  but, unfortunately my code creates a movie but it is empty.
  I don’t know the reason exactly but I think, first, I have to define a frame to each plot and then create a movie.
  can anyone please tell me how can I define a frame and also the add bit_rate of the movie.

  import sys
  
  import subprocess   
  
  import sdf
  
  import numpy as np
  
  import matplotlib.pyplot as plt  
  
  import time
  
  import matplotlib.animation as Animation
  
  from matplotlib.font_manager import FontProperties
  
  fp = FontProperties('Symbola')
  
  
  
  ##################### information from EPOCH input.deck
  
  nx,ny= 1200, 1600
  
  xmin=-100e-6
  
  xmax = 110e-6
  
  ymin = -200e-6
  
  ymax = 200e-6
  
  X =np.linspace(xmin,xmax,nx)   
  
  Y =np.linspace(ymin,ymax,ny)
  
  
  
  #################
  
  for n in range(0,25):
  
    nstr = str(n)
  
  
  
  ######################..... reading Density of carbon
  
    filename ="Den_car_resample" +'_sdf_'+ str(n)+'.dat'
  
  
  
    with open(filename, 'rb') as f:                        
  
      data = np.fromfile(f, dtype='float64', count=nx*ny)  
  
  
  
    Den_car  = np.reshape(data, [ny, nx], order='F')
  
    Den_car= np.log10(Den_car)
  
  
  
    ######################  Display Carbon density
  
  
  
    fig = plt.imshow(Den_car,  extent=[X.min()*1e6, X.max()*1e6, Y.min()*1e6,Y.max()*1e6], vmin=24, vmax=29, cmap='brg', aspect='auto') 
  
    plt.suptitle('Den_car')
  
    plt.title('sdf '+ str(n)+'; Time= '+str(n*50)+'ps',color='green', fontsize=15)
  
    plt.xlabel('x($\mu$m)')
  
    plt.ylabel('y($\mu$m)')
  
    plt.text(-80,-40,'Den_Carbon',color='red', fontsize=15)
  
    plt.colorbar()
  
    plt.savefig( 'fig%06d.png' % n, bbox_inches='tight')          
  
  
  
    plt.pause(.1)
  
    plt.clf()  
  
    plt.close()
  
  
  
    ######################  Create movie
  
  
  
    subprocess.call("avconv -framerate 1 -i fig%06d.png -c:v libx264 -profile:v high -crf 20".split())
  
  
  
  sys.exit()