Recherche avancée

Sur d’autres sites (5314)

• How Many Default Languages ?

  26 janvier 2012, par Multimedia Mike — Programming

  I was thinking back to my childhood, when my family first owned a computer. It was an MS-DOS-powered IBM PC. The default OS came with 2 programming environments, such as they were : GW-BASIC and batch files. It was a start, I suppose. I guess most any microcomputer you can name from that era came with some kind of BASIC interpreter. That defined the computer’s “out of the box” programmability.

  Then I started wondering how this compares to computers (operating systems/distributions, really) these days. So I installed a fresh version of the latest Ubuntu Linux version (11.10 as of this writing ; x86_32) and looked for programmability (without installing anything else). This is what I came up with :

  1. gcc/C (only the C compiler ; other components of the GNU compiler collection are installed separately)
  2. Perl
  3. Python
  4. C#, as furnished by Mono
  5. Bash — can’t forget about the shell as a full-featured programming language (sh is also present, but not t/csh)
  6. JavaScript — since Firefox is installed per default, JS counts
  7. GNU Assember — thanks to Reimar for the reminder that if gcc is present, gas necessarily needs to be there as well

  I checked on C++, Objective C, Java, Ada, Fortran, Go, Lua, Ruby, Tcl, PHP, R and other languages I could think of, but the above items were the only ones present by default. At the same time, I checked my Mac OS X (10.6) box and it also has Ruby and PHP installed. It has a bunch of other languages, courtesy of Xcode, so I can’t certify anything about its out of the box programmability.

  Still, I think “embarrassment of riches” pretty well sums it up. I try not to be crotchety old fogey complaining that kids these days don’t know how good they have it ; rather, I’m genuinely excited for anyone who wants to leap into computer programming in this day and age.

• FFmpeg libx264 Llicense

  2 juillet 2014, par user416472

  We have Java Spring application. The application interacts with FFmpeg through Java Runtime.exec() call in order to encode video into mp4 format. Are we ok with the commercial aspect of our application, having in mind that libx264 is released under GPL license, ffmpeg under LGPL license and we are using ffmpeg as external command line utility already installed and hosted on the client’s computer ?

• Getting video metadata in ruby script using ffmpeg, ffprobe or rvideo

  24 janvier 2013, par alex

  I want to get metadata of videos referenced by a URL using Ruby. At this point, I found many related posts, but could not find out how to solve my problem.

  I tried to use RVideo, but when I do :

  file = RVideo::Inspector.new(:file => 'http://www.agreatsite.com/avideo.mp4' ;)

  It throws

  'ArgumentError : File not found (http://www.agreatsite.com/avideo.mp4)...

  So I can't get the information using RVideo (but it works well when I have the file hosted on my local computer).

  I then tried to use ffprobe, but I don't know how to read the output.
  So far, I have the following method, which "shows" the information I want when I run it in the console, but it actually returns "true" and I can't find out how to capture the output I need...

    def media_info
  
      source = self
  
      command = <<-end_command
  
        ffprobe -v quiet -print_format json -show_format -show_streams  #{source}
  
      end_command
  
      command.gsub!(/\s+/, " ")
  
      system(command)
  
    end

  Would love some help, to make this work with either ffprobe or RVideo !

  UPDATE :
  I found a way to get what I needed. Not sure this is the best way to do it :

  def get_media_duration

  source = self.media[0][:url]    
  
  
  
  command = <<-end_command
  
    ffprobe -v quiet  -show_streams  #{source}
  
  end_command
  
  command.gsub!(/\s+/, " ")
  
  
  
  duration = ""
  
  IO.popen(command) { |io| while (line = io.gets) do
  
                          puts "++ "+line.inspect
  
                          duration = line.split("duration=")[1].gsub("\n", "") if line.split("duration=").length > 1
  
                        end
  
                    }
  
  duration   

  end

  I guess I could make it work that way, but doesn't seem very elegant to me. Better suggestions would be greatly appreciated !