Recherche avancée

Sur d’autres sites (9862)

• how to set ffmpeg bitrate, frame per second when scalling from low to high resolution/ high to low

  21 janvier 2015, par user2303069

  I’m developing a video sharing app for mobile device users. I noticed if I convert video with ffmpeg from a low(ex 240x320) to a higher resolution(ex 480x-1) the video looses quality and also there is no sound at the end. My question to you is how should I filter(how many fps,bitrate ect) the converted file ? In terms of parameters, how should I convert to make sure the video comes out in good quality at it’s destination(the user who will play it on their mobile device[Android/BlackBerry]).

  Here is my current code(java) :

  /************************  CONVERTING    TIME   *************************
  
                         method to convert video-clip
  
  */
  
  if(sn.toString().trim().startsWith("<>")){
  
      String info=sn.toString().trim().substring(2);
  
      String scale=info.substring(0, info.indexOf("."));
  
      String width=scale.substring(0, scale.indexOf("x"));
  
      String name=info.substring(info.indexOf(".")+1, info.length());
  
      String to = null;
  
      String from;
  
  
  
      try{
  
          //calculate to and from
  
          to=name.substring(0, name.indexOf("$"));
  
          from=name.substring(name.indexOf("$")+1, name.lastIndexOf("$"));
  
          gui.textArea1.append("\nStart converting...: to="+to+" from="+from+" fileName="+name);
  
      }catch(NullPointerException npe){
  
          gui.textArea1.append("\nNullpointer in calculate name in converting: "+npe.getMessage());
  
      }
  
  
  
      final Path videoIn = Paths.get("c:\\wamp\\www\\iclips\\videoMessages\\"+name);
  
      final Path encodingFile = Paths.get("c:\\wamp\\www\\iclips\\videoMessages\\scaled-"+name);
  
      final Path errorFile = Paths.get("c:\\ffmpeg\\bin\\error.txt");
  
      String pro;
  
      int w=Integer.parseInt(width);
  
  
  
      if(w<=240){
  
          pro="baseline";
  
      }else if(w>240&&w<=480){
  
          pro="main";
  
      }else if(w>480){
  
          pro="high";
  
      }else{
  
          pro="baseline";
  
      }
  
      //int retCode;
  
  
  
      try {
  
          Files.deleteIfExists(encodingFile);
  
          Files.deleteIfExists(errorFile);
  
  
  
          final ProcessBuilder pb 
  
              = new ProcessBuilder("c:\\ffmpeg\\bin\\ffmpeg.exe",
  
                  "-i", videoIn.toString(),
  
                  "-y", 
  
                  "-vf", "scale="+width+":-1", 
  
                  // "-pix_fmt","yuv420p",   
  
                  "-vcodec", "libx264",
  
                  "-vprofile", pro,    
  
                  "c:\\wamp\\www\\iclips\\videoMessages\\scaled-"+name
  
          ); //or other command....                    
  
  
  
          pb.redirectError(errorFile.toFile());
  
          pb.redirectOutput(encodingFile.toFile());
  
  
  
          final Process p = pb.start();
  
          try {
  
              p.waitFor();
  
              if(p.exitValue()==0){
  
                  gui.textArea1.append("\n+++++++++++++Vic-^clip converted successfully:"
  
                          + " ExitValue=["+String.valueOf(p.exitValue())+"] ++++++++++++++");
  
                  if(Files.deleteIfExists(videoIn)){
  
                      gui.textArea1.append("\n"+videoIn.toString()+" deleted!");
  
                  }
  
                  sendMsg("Scalling successfull:-)   Video-clip name=scaled-"+name+"_", "\nSent scaled successfull "+username);
  
                  NotifyClientOfScaledVideoMessage(to,"^scaled-"+name+"_");
  
              }else{
  
                  gui.textArea1.append("\nSomething went wrong with process-convert: ExitValue="+String.valueOf(p.exitValue()));
  
                  sendMsg("Unable to scale video, try again._", "\nSent scaled failed to "+username);
  
              }
  
          } catch (InterruptedException e) {
  
              gui.textArea1.append("\nInterrupted process convert: "+e.getMessage());
  
          }
  
      } catch (IOException e) {
  
          // deal with e here
  
          gui.textArea1.append("\nIOException in Convert Video: "+e.getMessage());
  
      }
  
  }

  Thank you very much.

• how to make high latency in ffmpeg ?

  2 mars 2023, par Joe Cola

  I want to live stream with ffmpeg to YouTube, but I want to wait for it to make high latency, which is to wait for the encode for 2-3 minutes and then stream it to YouTube. How to ? I can't get an answer on the internet, because most are looking for low latency, while I need normal latency - high latency

  


• ffmpeg convert from H.264 (High 4:4:4 Profile) to H.265 (Main Profile)

  30 novembre 2022, par David Alonso Ruiz

  How can I convert a video from H.264 (High 4:4:4 Profile) to H.265 (Main Profile 4:2:0) using ffmpeg ?

  


  I can't do that with this command : ffmpeg -i input.mkv -c:v hevc_nvenc -c:a copy output2.mkv

  


  That'd return an error, does not recognize the source format