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• How do I remux/transcode a progressive file in ffmpeg ?

  3 décembre 2014, par Levi Roberts

  Here’s what I’m trying to do.

  My primary objective is to remux or transcode a currently downloading media file for AppleTV and iOS compatible streaming.

  I am doing this by looking at the media file and only transcoding when necessary, otherwise it will only alter the container the video/audio lives in. This will reduce overhead for files that are already compatible. The specific compatible output I am looking for is AppleTV3 and iOS.

  I have a file that is progressive, meaning that it is downloading using another download manager or another app without the help of nodejs. This file may or may not have the moov information available in the beginning of the file. It just so happens, that I believe my test file does.

  I have some code that is partially working and it would make sense to be able to get this code fully working. That said, I’m not dismissing alternative ways to do this.

  My primary problem (I think) has to do with the moov header location or that it’s being set incorrectly. I’m hoping the fix is as simple as correcting my poor ffmpeg knowledge with command line parameters.

  I am piping the file to and from ffmpeg via GrowingFile and fs.createWriteStream respectively.

  My code for doing so is :

  var fs = require('fs');
  
  var child = require('child_process');
  
  
  
  var GrowingFile = require('growing-file');
  
  var input_file = GrowingFile.open('./tmp/input.mp4');
  
  var output_file = fs.createWriteStream('./tmp/output.m4v');
  
  
  
  // I've tried various args and ffmpeg params here without success.
  
  var args = ['-re', '-i', 'pipe:0', '-g', '52', '-ab', '64k', '-vcodec', 'libx264', '-vb', '448k', '-f', 'mp4', '-movflags', 'frag_keyframe+faststart', 'pipe:1'];
  
  var trans_proc = child.spawn('ffmpeg', args, null); 
  
  
  
  input_file.pipe(trans_proc.stdin);
  
  trans_proc.stdout.pipe(output_file);

  I am also temporarily trying to make these files work as intended via ffmpeg command line alone, without success. That command is :

  ffmpeg -i original.mp4 -vcodec copy -r 24 output.m4v

  Snippet of original.mp4 via mediainfo :

  General
  
  Format                                   : MPEG-4
  
  Format profile                           : Base Media / Version 2
  
  Codec ID                                 : mp42
  
  File size                                : 9.87 MiB
  
  Duration                                 : 43mn 14s
  
  Overall bit rate mode                    : Variable
  
  Overall bit rate                         : 31.9 Kbp
  
  
  
  Video
  
  Format                                   : AVC
  
  Format/Info                              : Advanced Video Codec
  
  Format profile                           : High@L2.1
  
  Codec ID                                 : avc1
  
  Duration                                 : 43mn 14s
  
  Width                                    : 480 pixels
  
  Height                                   : 268 pixels
  
  Color space                              : YUV
  
  Scan type                                : Progressive
  
  Stream size                              : 67.5 MiB
  
  
  
  Audio
  
  Format                                   : AAC
  
  Format/Info                              : Advanced Audio Codec
  
  Format profile                           : LC
  
  Codec ID                                 : 40
  
  Duration                                 : 43mn 14s
  
  Bit rate mode                            : Variable
  
  Bit rate                                 : 96.0 Kbps

  What’s happening is that output.m4v has an incorrect duration of only the part of the file that’s already downloaded. The video reaches the end or a refresh happens to make the duration longer. This process repeats until the original file is done downloading. What I want is to be able to emulate/clone the duration of the input file to the output file .

• How to compress mp3 file in php

  11 juin 2015, par Wai yan

  I am doing a php project. In my project, I need to compress mp3 files to reduce the file size because I need to store a lot of mp3 files.

  How can I compress it in php ? I am using laravel framework. If possible, I want it without extra installation. I already checked ffmpeg, but I was not able to use it due to the poor documentation. How can I achieve it ?

• Reading a stream of images from rtsp using ffmpeg

  15 février 2015, par Andrew Simpson

  I had been using a wrapper around VLC to stream images from my ip camera to my WinForm Desktop App using the RTSP protocol.

  This works well.

  However, I wanted to see if could achieve the same thing using just FFMPEG.

  I have done so but the results are poor.

  The FPS is slow.

  This is my code :

      private Process process = new Process();
  
      private FileStream baseStream = null;
  
      string file = @"C:\bin\ffmpeg.exe";
  
      string arguments = @" -i rtsp://admin:admin@192.168.0.8:554/video_1 -an -f image2 -s 360x240 -vframes 1 -";
  
  
  
      private void button1_Click(object sender, EventArgs e)
  
      {
  
          try
  
          {
  
              process.StartInfo.FileName = file;
  
              process.StartInfo.Arguments = arguments;
  
              process.StartInfo.CreateNoWindow = true;
  
              process.StartInfo.RedirectStandardError = true;
  
              process.StartInfo.RedirectStandardOutput = true;
  
              process.StartInfo.UseShellExecute = false;
  
  
  
              Task.Run(() => { Feeder(); });
  
          }
  
          catch (Exception ex)
  
          {
  
              //log error here
  
          }
  
      }
  
  
  
      private void Feeder()
  
      {
  
          try
  
          {
  
              process.Start(); 
  
              baseStream = process.StandardOutput.BaseStream as FileStream;
  
              int lastRead = 0;
  
              using (MemoryStream ms = new MemoryStream())
  
              {
  
                  byte[] buffer = new byte[500];
  
                  do
  
                  {
  
                      lastRead = baseStream.Read(buffer, 0, buffer.Length);
  
                      ms.Write(buffer, 0, lastRead);
  
                  } while (lastRead > 0);
  
  
  
                  pictureBox1.Invoke(new Action(() => pictureBox1.Image = Image.FromStream(ms)));
  
                  ms.Close();
  
              }
  
          }
  
          catch (Exception ex)
  
          {
  
              //log error here
  
          }
  
          Task.Run(() => { Feeder(); });
  
      }

  Now I had considered streaming a constant flow of images rather than just taking 1 at a time.
  I can easily identify markers for the JPEG header.

  But, I would have to use

  baseStream.ReadByte

  instead which without trying it would be slow as I would have look at every single byte ?

  Can anyone suggest what I should do ?

  Thanks