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• Video playing, how to play a video back a a rapid rate at random timestamp locations

  10 avril 2020, par Zarc Rowden

  Note : this is a mildly general question that is looking more for pointers in the right direction and not exactly requiring a concise coded answer. I appreciate any and all input, thank you for lending your brain power to me for this moment :)

  



  I have a script that receives midi messages in real time and triggers playback of a single video on various timestamps that are changed/selected regularly and randomly by a user. Currently this is working in the browser, however, I've realized that there is some noticeable latency between (i'm guessing the cause here so please correct me) the moment a request to play a video at a specific time is made(note : the video is not being requested over the wire, this action does not take place until a JS Blob Url is loaded into the player) and the moment where that request is fulfilled and delivered from storage to pixels on the screen.

  



  My question is : Is it reasonable to assume that there is a tool out there, that given the correct video format and optimizations both in the code and in the file that could load an entire, say : 1 gb video into memory and play it back at random timestamps every 60 milliseconds at completely random, constantly changing timestamps.

  



  If you're now all the way down here... Thanks for reading this far, or scanning ! Please let me know if this question makes any sense / could be improved, I'm happy to clarify further.

  


• Adding outro video to multiple video files using ffmpeg

  31 août 2017, par jasan

  I can successfully merge files using the following command using ffmpeg :

  ffmpeg -f concat -i mylist.txt -c copy output.mp4

  the mylist.txt looks like this :

  file './video.mp4'
  
  file './outro.mp4'

  However what I want to do is the following :

  • I have 100 video files ( video1.mp4, video2.mp4, video3.mp4,...)

  • i have one outro file(outro.mp4)

  I want to concat outro.mp4 to the end of each of the 100 files and save each of concatenated video file with the same filename as the original videofile( i.e video1, video2....)

  I’m on a windows machine. any way I can achieve this ? code snippet would be really helpful.

• How to speed up processing for FFmpeg video overlay on a video source file in Android ?

  28 décembre 2017, par Iffat Fatima

  I am working on an Android application to add a video file as an overlay on another video file, along with adding an audio stream to it, using FFmpeg library for Android.

  I am using the following command to apply the overlay, but for a video of 2 seconds, it takes 55 seconds to process. Is there a way to speed up this process ?

      String[] complexCmd = new String[]{ "-y",    
  
              "-i",               
  
              originalVideoPath,        
  
              "-i",               
  
              overlayVideoPath ,       
  
              "-i",               
  
              audioPath,              
  
              "-filter_complex",  
  
              "[0:v]setpts=PTS-STARTPTS[top];[1:v]setpts=PTS-STARTPTS, scale="+newOverlayWidth+"x"+newOverlayHeight+",format=yuva420p,colorchannelmixer=aa=0.5[bottom];[top][bottom]overlay=shortest=1:x="+left+":y="+top+"" ,
  
              "-c:v",
  
              "libx264",
  
              "-preset",
  
              "ultrafast",
  
              "-crf",
  
              "28",  
  
              "-map",  
  
              "2:a",  
  
              "-shortest",
  
              destVideoPath,
  
      };