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• Revision 33048 : Un flv n’a pas forcément de vidéo associée ... on écrit les metadatas ...

  18 novembre 2009, par kent1@… — Log

  Un flv n’a pas forcément de vidéo associée ... on écrit les metadatas avant pour être sûr

• FFmpeg Easing function doesn't behave as expected [closed]

  11 juin 2024, par Alejandro Sanchez

  What is the simplest way to add an easing function to an animation ? I'm currently trying to animate a zoom value, but for some reason, it goes completely over the final zoom value i constrained it to (my easing function should output values between 0 and 1) : This is the part of a bigger expression which i just cannot understand :

  


  if(gt(in_time\,3.7999999046325685)\,3 - ((0.3) * (((exp((5*(it-3.80)) - 1))/(exp(5*0.80)-1))))\,3)

  


  Note : (exp((5*(it-3.80)) - 1))/(exp(50.80)-1))) are values between 0 and 1 for the animation duration of 0.8 seconds, however the resulting zoom goes way beyond 3-0.31 = 2.7, it just goes crazy in the end.

  


  I tried all kinds of easing functions, all of them behave similarly

  


• Stop JavaCV playback warning

  18 janvier 2018, par Chaoslab

  Problem :
  Receiving a stream of command line warnings as video plays - deprecated pixel format used, make sure you did set range correctly

  Question :
  How can I stop the warnings from happening or being displayed ?

  Update - Fixed :
  The solution was too override the logging callback and don’t do anything in the logging call method. FFmpeg logging is then disabled.

  The reason for the message from FFmpeg is because it is grabbing frames from an old video format so is unavoidable if playing older videos.

  NOTE :
  This solution completely disables all output from FFmpeg. Even FFmpeg errors are muted.

  Code below (just frame grabbing, not timed playback).

  package test.javacv;
  
  
  
  import java.io.File;
  
  
  
  import org.bytedeco.javacv.CanvasFrame;
  
  import org.bytedeco.javacv.FFmpegFrameGrabber;
  
  import org.bytedeco.javacv.Frame;
  
  
  
  import org.bytedeco.javacv.CustomLogCallback;
  
  
  
  public class TestPlay implements Runnable {
  
   private static String      video_loc = null;
  
   private static CanvasFrame canvas    = new CanvasFrame("Test JavaCV player");
  
  
  
   public static void main(String[] args) { new Thread(new TestPlay(args[0])).start(); }
  
  
  
   static {
  
    CustomLogCallback.set();
  
   }
  
  
  
   public void run() { play_video(video_loc); }
  
  
  
   public TestPlay(String loc) {
  
    video_loc = loc;
  
    canvas.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);
  
   }
  
  
  
   public static final void play_video(String vid_loc) {
  
    try {
  
     File               file      = new File(vid_loc);
  
     FFmpegFrameGrabber ffmpeg_fg = new FFmpegFrameGrabber(file.getAbsolutePath());
  
     Frame              frm;
  
     ffmpeg_fg.setAudioChannels(0);
  
     ffmpeg_fg.start();
  
     for(;;)
  
      if((frm = ffmpeg_fg.grab()) != null) canvas.showImage(frm);
  
      else {
  
       ffmpeg_fg.setTimestamp(0);
  
       break;
  
      }
  
     ffmpeg_fg.stop();
  
    } catch(Exception ex) { ex("play_video vid_loc:" + vid_loc, ex); }
  
   }
  
  
  
   public static final void ex(String txt, Exception ex)   {
  
    System.out.println("EXCEPTION: " + txt + " stack..."); ex.printStackTrace(System.out); }
  
  }

  Logging class

  // custom logger to override all logging output
  
  package org.bytedeco.javacv;
  
  
  
  import org.bytedeco.javacpp.BytePointer;
  
  
  
  import static org.bytedeco.javacpp.avutil.LogCallback;
  
  import static org.bytedeco.javacpp.avutil.setLogCallback;
  
  
  
  public class CustomLogCallback extends LogCallback {
  
  
  
   static final CustomLogCallback instance = new CustomLogCallback();
  
  
  
   public static CustomLogCallback getInstance() { return instance; }
  
  
  
   public static void set() { setLogCallback(getInstance()); }
  
  
  
   @Override
  
   public void call(int level, BytePointer msg) {}
  
  }