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• download video fragment by size usnig ffmpeg

  6 mars 2023, par Ivan Dobryaev

  Suppose I have some video url. I want to download video fragment by size (equal time intervals may have different sizes).

  


  I have some different ways :

  


  


  1. The best one. Get list of start and finish time points for each fragment (without download full video). For example : [(0, 15, 10Mb), (15, 40, 10Mb), etc]

     


  


  2. Parallel download each fragment with size 10Mb

     


  


  


• What is the full code to execute a ffmpeg command in java [on hold]

  16 janvier 2015, par user2303069

  I did the following and only got 0kb output file :
  File encodingFile = new File("c :\ffmpeg\bin\output.mp4") ;
  encodingFile.createNewFile() ;

                      Process process = new ProcessBuilder("c:\\ffmpeg\\bin\\ffmpeg.exe", "-i", "c:\\ffmpeg\\bin\\input.mp4", 
  
                              "-y", "-s", "1440" + "x" + "-1", "-vcodec", "libx264", "c:\\ffmpeg\\bin\\outfile.mp4").start();
  
  
  
                      is = process.getInputStream();
  
  
  
                      byte[] resultBuff = new byte[0];
  
                      byte[] buff = new byte[1024];
  
                      int k = -1;
  
                      while((k = is.read(buff, 0, buff.length)) > -1) {
  
                          byte[] tbuff = new byte[resultBuff.length + k]; // temp buffer size = bytes already read + bytes last read
  
                          System.arraycopy(resultBuff, 0, tbuff, 0, resultBuff.length); // copy previous bytes
  
                          System.arraycopy(buff, 0, tbuff, resultBuff.length, k);  // copy current lot
  
                          resultBuff = tbuff; // call the temp buffer as your result buff
  
                      }
  
                      fos=new FileOutputStream(encodingFile);
  
                      fos.write(resultBuff, 0,resultBuff.length );
  
                      gui.textArea1.append("\n"+resultBuff.length + " bytes read.");
  
                      //return resultBuff;
  
                      try {
  
                          // if you want to wait for the process to finish
  
                          process.waitFor();
  
                           gui.textArea1.append("\n+++++++Finished while converting!++++++++\n");
  
                      } catch (InterruptedException ex) {
  
                           gui.textArea1.append("\nInterruptedException: "+ex.getMessage());
  
                      }
  
  
  
                  }catch(IOException ex){
  
                      gui.textArea1.append("\nIOException converting: "+ex.getMessage());
  
                  }finally{
  
                      try{
  
                          if(is!=null){
  
                              is.close();
  
                          }
  
                          if(fos!=null){
  
                              fos.close();
  
                          }
  
                      }catch(IOException ioe){
  
                          gui.textArea1.append("\nClosing streams while converting:"+ioe.getMessage());
  
                      }
  
                  }

  My question is how to get back a converted file using ffmpeg in java. So far I got empty files. It’s like nothing happens during the converting process. I got the code from web(here) and modified it according to my desire so can you just tell me how to do this correctly ? Thanks a lot.

• rtmppkt : Repeat the full 32 bit timestamp for chunking continuation packets

  14 janvier 2015, par Martin Storsjö

  rtmppkt : Repeat the full 32 bit timestamp for chunking continuation packets
  This fixes sending chunked packets (packets larger than the output
  
  chunk size, which often can be e.g. 4096 bytes) with a timestamp delta
  
  (or absolute timstamp, if it’s a timestamp step backwards, or the
  
  first packet of the stream) larger than 0xffffffff.
  The RTMP spec explicitly says (in section 5.3.1.3.) that packets of
  
  type 3 (continuation packets) should include this field, if the
  
  previous non-continuation packet had it included.
  The receiving code handles these packets correctly.
  Pointed out by Cheolho Park.
  CC : libav-stable@libav.org
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavformat/rtmppkt.c