streamium/app/components/streamer.js

Decentralized trustless video streaming using bitcoin payment channels.

'use strict';

// 2013, Muaz Khan - www.MuazKhan.com
// MIT License     - www.WebRTC-Experiment.com/licence
// Documentation   - github.com/muaz-khan/WebRTC-Experiment/tree/master/Pre-recorded-Media-Streaming

angular.module('streamium.streamer', [])
.factory('Streamer', function() { return function Streamer() {
  var SEND_FREQUENCY = 1000;
  var queue = function(f) {
    setTimeout(f, SEND_FREQUENCY);
  };

  var prefix = !!navigator.webkitGetUserMedia ? '' : 'moz';
  var self = this;

  self.isStatic = true;

  self.stream = streamPreRecordedMedia;

  window.MediaSource = window.MediaSource || window.WebKitMediaSource;
  if (!window.MediaSource) throw 'Chrome >=M28 (or Firefox with flag "media.mediasource.enabled=true") is mandatory to test this experiment.';

  function streamPreRecordedMedia(file) {
      if (!self.push) throw '<push> method is mandatory.';
      
      var reader = new window.FileReader();
      reader.readAsArrayBuffer(file);
      reader.onload = function (e) {
          startStreaming(new window.Blob([new window.Uint8Array(e.target.result)]));
      };

      var sourceBuffer, mediaSource = new MediaSource();
      mediaSource.addEventListener(prefix +'sourceopen', function () {
          sourceBuffer = mediaSource.addSourceBuffer('video/webm; codecs="vorbis,vp8"');
          console.debug('MediaSource readyState: <', this.readyState, '>');
      }, false);

      mediaSource.addEventListener(prefix+'sourceended', function () {
          console.debug('MediaSource readyState: <', this.readyState, '>');
      }, false);

      function startStreaming(blob) {
        if(!blob) return;
              var size = blob.size,
                  startIndex = 0,
                  plus = 200000;

              console.debug('one chunk size: <', plus, '>');

              function inner_streamer() {
                  reader = new window.FileReader();
                  reader.onload = function (e) {
                      self.push(new window.Uint8Array(e.target.result));

                      startIndex += plus;
                      if (startIndex <= size) {
                        queue(function() {
                          reader.readAsArrayBuffer(blob.slice(startIndex, startIndex + plus));
                          inner_streamer();
                        });
                      }
                      else
                          self.push({
                              end: true
                          });
                  };
                  if (startIndex === 0) {
                    reader.readAsArrayBuffer(blob.slice(startIndex, startIndex + plus));
                  }
              }

              inner_streamer();
      }

      startStreaming();
  }

  self.receive = receive;
  function receive() {
      var sourceBuffer, mediaSource = new MediaSource();

      self.video.src = window.URL.createObjectURL(mediaSource);
      mediaSource.addEventListener(prefix+'sourceopen', function () {
          self.receiver = mediaSource.addSourceBuffer('video/webm; codecs="vorbis,vp8"');
          self.mediaSource = mediaSource;
          self.receiver.addEventListener('update', function() {
            if (appendQueue.length) {
              var newQueue = appendQueue.splice(1)
              self.receiver.appendBuffer(appendQueue[0]);
              appendQueue = newQueue;
            }
          });

          console.debug('MediaSource readyState: <', this.readyState, '>');
      }, false);
  

      mediaSource.addEventListener(prefix+'sourceended', function () {
          console.warn('MediaSource readyState: <', this.readyState, '>');
      }, false);
  }

  var appendQueue = [];

  this.append = function (data) {
    if (self.receiver.updating) {
      appendQueue.push(data);
    } else {
      self.receiver.appendBuffer(data);
    }
  };

  this.end = function (data) {
      self.mediaSource.endOfStream();
  };
};});