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• Ffmpeg deletes my file ?

  9 janvier 2018, par Melvin Roest

  Does anyone know why ffmpeg sometimes seemingly deletes my files ? It mostly happens when I put my laptop to sleep and wait for quite a bit after opening my Finder window.

  Here is an example command.

  ffmpeg -i  Rec\ 01-9-18\ 1.trec  -c:a aac -c:v libx264 tutorial.mp4

  It never happens when I don’t let my laptop sleep and open it immediately after finishing.

  I’m on Mac OS X.

• Can I stream WebM video to a video element through WebSocket ?

  5 février 2015, par Ravenstine

  I’d like to be able to capture my desktop using FFmpeg and send the video through a WebSocket to the client where the video stream can be played in an HTML5 video tag. It seems that the current way to accomplish this is by sending JPG data and placing it on a canvas element. I would rather stream actual video and audio data before resorting to that.

  Below is my server code. Note that I am running Ruby 2.2.0 on Linux(Debian Stable).

  require 'bundler'
  
  Bundler.require
  
  
  
  EM.run do
  
    EM::WebSocket.run host: "0.0.0.0", port: 9393 do |ws|
  
  
  
      cmd = "ffmpeg -y -f x11grab -s 1600x900 -r 15 -i :0.0 -tune fastdecode -b:v 150k -threads 4 -f webm -"
  
      @handler = EM.popen3(cmd, stdout: Proc.new { |data| 
  
        puts(data)
  
        ws.send(Base64.encode64(data))
  
      }, stderr: Proc.new{|err|})
  
  
  
      @handler.callback do
  
        puts "hey"
  
      end
  
  
  
      @handler.errback do |err_code|
  
        puts err_code
  
      end
  
  
  
      ws.onopen do |handshake|
  
        puts "WebSocket connection open"
  
      end
  
  
  
      ws.onclose do
  
        puts "Connection closed"
  
        # @handler.kill('TERM', true)
  
      end
  
  
  
    end
  
  
  
    class SimpleView < Sinatra::Base
  
      set :public_folder, './'
  
      configure do
  
        set :threaded, false
  
      end
  
      get '/' do
  
        send_file
  
      end
  
    end
  
  
  
    EM.run do
  
      Rack::Server.start({
  
        app:    Rack::Builder.app{map('/'){ run SimpleView.new }},
  
        server: 'thin',
  
        Host:   '0.0.0.0',
  
        Port:   '8181'
  
      })
  
    end
  
  
  
  end

  Here is the client code(JavaScript) :

  var stream = new WebSocket('ws://localhost:9393')
  
  var videoElement = document.querySelector("#desktop")
  
  var videoSource = document.querySelector("source")
  
  window.MediaSource = window.MediaSource || window.WebKitMediaSource;
  
  var mediaSource = new MediaSource()
  
  videoElement.src = window.URL.createObjectURL(mediaSource)
  
  
  
  stream.onopen = function(){
  
    console.log('connection open')
  
  }
  
  
  
  stream.onclose = function(){
  
    console.log('connection closed')
  
  }
  
  
  
  mediaSource.addEventListener('sourceopen', function(e){
  
    var sourceBuffer = mediaSource.addSourceBuffer('video/webm; codecs="vp8,vorbis"')
  
  
  
    stream.onmessage = function(e){
  
      var byteCharacters = atob(e.data)
  
  
  
      var byteNumbers = new Array(byteCharacters.length)
  
      for (var i = 0; i < byteCharacters.length; i++) {
  
        byteNumbers[i] = byteCharacters.charCodeAt(i)
  
      }
  
  
  
      var byteArray = new Uint8Array(byteNumbers)
  
  
  
      sourceBuffer.appendStream(byteArray)
  
  
  
    }
  
  
  
  }, false)

  What’s happening is I’m capturing the stdout of FFmpeg, converting each chunk of data to base64, sending it through the websocket, then the client tries to decode the base64 chunk into something a source buffer can understand and play the mediasource in the video element.

  Though it doesn’t surprise me that this doesn’t work, I would still like it to and I’m hoping maybe there’s just one little thing that I’m missing. I get nothing except black inside the video element.

  NOTE : I am using the original FFmpeg, and NOT Avconv. I compiled it with all codecs enabled.

  The full source is available at https://github.com/Ravenstine/simpleview.

• How to deal with whitespace in foldernames

  27 mars 2015, par FlashSolutions

  I am trying to use ffmpeg to process input files with spaces in them.

  To check the syntax, I try using Dir in a cmd window and get "file not found".

  Dir "C:/DigitalSignageManager/LLRA photos/SpinningTop.mp4"

  I have tried escaping with \ and ^ and used double and single quotes, but nothing seems to work.

  What is the proper syntax to make this work ?