Recherche avancée

Sur d’autres sites (6703)

• Sending video from images through wifi on Android device [closed]

  26 novembre 2012, par user1853766

  I have a bit of a specific question, I'm currently working on a solution that is supposed to send video data through wifi from an Android device.

  This video must but generate from images generate during at a runtime, and I want the smallest latency possible.

  To begin with this, I was wondering what kind of library I could use, and what kind of protocol. I'm very new with this kind of programs...

  I've look around ffmpeg, which seems fine for video compression, but I'm not sure it's exactly what I need since I start the work with images. As it is quite complicate to build it and make it work, I wanted to be sure it's what I need to do before...

  Any help or advice would be greatly appreciated !

• Capture FFMPEG output in PHP

  22 novembre 2012, par Andrew

  I need to read the output from ffmpeg in order to even try the solution to my question from yesterday. This is a separate issue from my problem there, so I made a new question.

  How the heck do I get the output from an ffmpeg -i command in PHP ?

  This is what I've been trying :

  <?PHP
  
      error_reporting(E_ALL);
  
      $src = "/var/videos/video1.wmv";
  
      $command = "/usr/bin/ffmpeg -i " . $src;
  
      echo "<b>",$command,"</b><br />";
  
      $command = escapeshellcmd($command);
  
  
  
      echo "backtick:<br /><pre>";
  
      `$command`;
  
  
  
      echo "</pre><br />system:<br /><pre>";
  
      echo system($command);
  
  
  
      echo "</pre><br />shell_exec:<br /><pre>";
  
      echo shell_exec($command);
  
  
  
      echo "</pre><br />passthru:<br /><pre>";
  
      passthru($command);
  
  
  
      echo "</pre><br />exec:<br /><pre>";
  
      $output = array();
  
      exec($command,$output,$status);
  
      foreach($output AS $o)
  
      {
  
              echo $o , "<br />";
  
      }
  
      echo "</pre><br />popen:<br /><pre>";
  
      $handle = popen($command,&#39;r&#39;);
  
      echo fread($handle,1048576);
  
      pclose($handle);
  
      echo "</pre><br />";
  
  ?>

  This is my output :

  <b>/usr/bin/ffmpeg -i /var/videos/video1.wmv</b><br />
  
  backtick:<br />
  
      <pre></pre><br />
  
  system:<br />
  
      <pre></pre><br />
  
  shell_exec:<br />
  
      <pre></pre><br />
  
  passthru:<br />
  
      <pre></pre><br />
  
  exec:<br />
  
      <pre></pre><br />
  
  popen:<br />
  
      <pre></pre><br />

  I don't get it. safe_mode is off. There's nothing in disable_functions. The directory is owned by www-data (the apache user on my Ubuntu system). I get a valid status back from exec() and system() and running the same command from the command line give me tons of output. I feel like I must be missing something obvious but I have no idea what it is.

  Help. Please.

• ffmpeg video streaming deep understanding

  14 novembre 2012, par Stefan Alexandru

  The main question is if it is possible to somehow go around the frame index checking that ffmpeg does when writing the frame to a file.

  Now I will explain my exact problem so you can understand better what I need or maybe think of an alternative solution.

  Problem n0.1 : I am getting video stream from two independent cameras and for some reason I want to save it in the same video file. First the frames from the first camera and then the frames from the second. When writing the frames from the second camera av_write_frame would return the error code -22 and will fail to add the frame. That's because the writing context is expecting a frame index following the index of the previously written frame (the last frame from camera 1) but he receives a frame with the index 0, the first frame from the second camera.

  Problem no.2 : Consider the following problem independently to the first one.
  I am trying to save a video stream to a file but the frame rate is double the real speed. So because I couldn't find any working solution to speed down the frame rate i thought to write every frame twice in the video file. But it won't make any difference to the frame rate.
  I also tried a different approach on the frame rate problem but it also failed(question here).

  Any kind of working solution would be highly appreciated.

  Also it's important that I can't use console commands, I need C code, as I need to integrate those functionalities in an Android application that is automated.