BJ_web_developers / cityOperationCenter

/**
 * @file flash-source-buffer.js
 */
'use strict';

Object.defineProperty(exports, '__esModule', {
  value: true
});

var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();

var _get = function get(_x, _x2, _x3) { var _again = true; _function: while (_again) { var object = _x, property = _x2, receiver = _x3; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x = parent; _x2 = property; _x3 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }

function _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }

var _globalWindow = require('global/window');

var _globalWindow2 = _interopRequireDefault(_globalWindow);

var _videoJs = require('video.js');

var _videoJs2 = _interopRequireDefault(_videoJs);

var _muxJsLibFlv = require('mux.js/lib/flv');

var _muxJsLibFlv2 = _interopRequireDefault(_muxJsLibFlv);

var _removeCuesFromTrack = require('./remove-cues-from-track');

var _removeCuesFromTrack2 = _interopRequireDefault(_removeCuesFromTrack);

var _createTextTracksIfNecessary = require('./create-text-tracks-if-necessary');

var _createTextTracksIfNecessary2 = _interopRequireDefault(_createTextTracksIfNecessary);

var _addTextTrackData = require('./add-text-track-data');

var _flashTransmuxerWorker = require('./flash-transmuxer-worker');

var _flashTransmuxerWorker2 = _interopRequireDefault(_flashTransmuxerWorker);

var _webwackify = require('webwackify');

var _webwackify2 = _interopRequireDefault(_webwackify);

var _flashConstants = require('./flash-constants');

var _flashConstants2 = _interopRequireDefault(_flashConstants);

var resolveFlashTransmuxWorker = function resolveFlashTransmuxWorker() {
  var result = undefined;

  try {
    result = require.resolve('./flash-transmuxer-worker');
  } catch (e) {
    // no result
  }

  return result;
};

/**
 * A wrapper around the setTimeout function that uses
 * the flash constant time between ticks value.
 *
 * @param {Function} func the function callback to run
 * @private
 */
var scheduleTick = function scheduleTick(func) {
  // Chrome doesn't invoke requestAnimationFrame callbacks
  // in background tabs, so use setTimeout.
  _globalWindow2['default'].setTimeout(func, _flashConstants2['default'].TIME_BETWEEN_CHUNKS);
};

/**
 * Generates a random string of max length 6
 *
 * @return {String} the randomly generated string
 * @function generateRandomString
 * @private
 */
var generateRandomString = function generateRandomString() {
  return Math.random().toString(36).slice(2, 8);
};

/**
 * Round a number to a specified number of places much like
 * toFixed but return a number instead of a string representation.
 *
 * @param {Number} num A number
 * @param {Number} places The number of decimal places which to
 * round
 * @private
 */
var toDecimalPlaces = function toDecimalPlaces(num, places) {
  if (typeof places !== 'number' || places < 0) {
    places = 0;
  }

  var scale = Math.pow(10, places);

  return Math.round(num * scale) / scale;
};

/**
 * A SourceBuffer implementation for Flash rather than HTML.
 *
 * @link https://developer.mozilla.org/en-US/docs/Web/API/MediaSource
 * @param {Object} mediaSource the flash media source
 * @class FlashSourceBuffer
 * @extends videojs.EventTarget
 */

var FlashSourceBuffer = (function (_videojs$EventTarget) {
  _inherits(FlashSourceBuffer, _videojs$EventTarget);

  function FlashSourceBuffer(mediaSource) {
    var _this = this;

    _classCallCheck(this, FlashSourceBuffer);

    _get(Object.getPrototypeOf(FlashSourceBuffer.prototype), 'constructor', this).call(this);
    var encodedHeader = undefined;

    // Start off using the globally defined value but refine
    // as we append data into flash
    this.chunkSize_ = _flashConstants2['default'].BYTES_PER_CHUNK;

    // byte arrays queued to be appended
    this.buffer_ = [];

    // the total number of queued bytes
    this.bufferSize_ = 0;

    // to be able to determine the correct position to seek to, we
    // need to retain information about the mapping between the
    // media timeline and PTS values
    this.basePtsOffset_ = NaN;

    this.mediaSource_ = mediaSource;

    this.audioBufferEnd_ = NaN;
    this.videoBufferEnd_ = NaN;

    // indicates whether the asynchronous continuation of an operation
    // is still being processed
    // see https://w3c.github.io/media-source/#widl-SourceBuffer-updating
    this.updating = false;
    this.timestampOffset_ = 0;

    encodedHeader = _globalWindow2['default'].btoa(String.fromCharCode.apply(null, Array.prototype.slice.call(_muxJsLibFlv2['default'].getFlvHeader())));

    // create function names with added randomness for the global callbacks flash will use
    // to get data from javascript into the swf. Random strings are added as a safety
    // measure for pages with multiple players since these functions will be global
    // instead of per instance. When making a call to the swf, the browser generates a
    // try catch code snippet, but just takes the function name and writes out an unquoted
    // call to that function. If the player id has any special characters, this will result
    // in an error, so safePlayerId replaces all special characters to '_'
    var safePlayerId = this.mediaSource_.player_.id().replace(/[^a-zA-Z0-9]/g, '_');

    this.flashEncodedHeaderName_ = 'vjs_flashEncodedHeader_' + safePlayerId + generateRandomString();
    this.flashEncodedDataName_ = 'vjs_flashEncodedData_' + safePlayerId + generateRandomString();

    _globalWindow2['default'][this.flashEncodedHeaderName_] = function () {
      delete _globalWindow2['default'][_this.flashEncodedHeaderName_];
      return encodedHeader;
    };

    this.mediaSource_.swfObj.vjs_appendChunkReady(this.flashEncodedHeaderName_);

    this.transmuxer_ = (0, _webwackify2['default'])(_flashTransmuxerWorker2['default'], resolveFlashTransmuxWorker());
    this.transmuxer_.postMessage({ action: 'init', options: {} });
    this.transmuxer_.onmessage = function (event) {
      if (event.data.action === 'data') {
        _this.receiveBuffer_(event.data.segment);
      }
    };

    this.one('updateend', function () {
      _this.mediaSource_.tech_.trigger('loadedmetadata');
    });

    Object.defineProperty(this, 'timestampOffset', {
      get: function get() {
        return this.timestampOffset_;
      },
      set: function set(val) {
        if (typeof val === 'number' && val >= 0) {
          this.timestampOffset_ = val;
          // We have to tell flash to expect a discontinuity
          this.mediaSource_.swfObj.vjs_discontinuity();
          // the media <-> PTS mapping must be re-established after
          // the discontinuity
          this.basePtsOffset_ = NaN;
          this.audioBufferEnd_ = NaN;
          this.videoBufferEnd_ = NaN;

          this.transmuxer_.postMessage({ action: 'reset' });
        }
      }
    });

    Object.defineProperty(this, 'buffered', {
      get: function get() {
        if (!this.mediaSource_ || !this.mediaSource_.swfObj || !('vjs_getProperty' in this.mediaSource_.swfObj)) {
          return _videoJs2['default'].createTimeRange();
        }

        var buffered = this.mediaSource_.swfObj.vjs_getProperty('buffered');

        if (buffered && buffered.length) {
          buffered[0][0] = toDecimalPlaces(buffered[0][0], 3);
          buffered[0][1] = toDecimalPlaces(buffered[0][1], 3);
        }
        return _videoJs2['default'].createTimeRanges(buffered);
      }
    });

    // On a seek we remove all text track data since flash has no concept
    // of a buffered-range and everything else is reset on seek
    this.mediaSource_.player_.on('seeked', function () {
      (0, _removeCuesFromTrack2['default'])(0, Infinity, _this.metadataTrack_);
      if (_this.inbandTextTracks_) {
        for (var track in _this.inbandTextTracks_) {
          (0, _removeCuesFromTrack2['default'])(0, Infinity, _this.inbandTextTracks_[track]);
        }
      }
    });

    var onHlsReset = this.onHlsReset_.bind(this);

    // hls-reset is fired by videojs.Hls on to the tech after the main SegmentLoader
    // resets its state and flushes the buffer
    this.mediaSource_.player_.tech_.on('hls-reset', onHlsReset);

    this.mediaSource_.player_.tech_.hls.on('dispose', function () {
      _this.transmuxer_.terminate();
      _this.mediaSource_.player_.tech_.off('hls-reset', onHlsReset);
    });
  }

  /**
   * Append bytes to the sourcebuffers buffer, in this case we
   * have to append it to swf object.
   *
   * @link https://developer.mozilla.org/en-US/docs/Web/API/SourceBuffer/appendBuffer
   * @param {Array} bytes
   */

  _createClass(FlashSourceBuffer, [{
    key: 'appendBuffer',
    value: function appendBuffer(bytes) {
      var error = undefined;

      if (this.updating) {
        error = new Error('SourceBuffer.append() cannot be called ' + 'while an update is in progress');
        error.name = 'InvalidStateError';
        error.code = 11;
        throw error;
      }
      this.updating = true;
      this.mediaSource_.readyState = 'open';
      this.trigger({ type: 'update' });

      this.transmuxer_.postMessage({
        action: 'push',
        data: bytes.buffer,
        byteOffset: bytes.byteOffset,
        byteLength: bytes.byteLength
      }, [bytes.buffer]);
      this.transmuxer_.postMessage({ action: 'flush' });
    }

    /**
     * Reset the parser and remove any data queued to be sent to the SWF.
     *
     * @link https://developer.mozilla.org/en-US/docs/Web/API/SourceBuffer/abort
     */
  }, {
    key: 'abort',
    value: function abort() {
      this.buffer_ = [];
      this.bufferSize_ = 0;
      this.mediaSource_.swfObj.vjs_abort();

      // report any outstanding updates have ended
      if (this.updating) {
        this.updating = false;
        this.trigger({ type: 'updateend' });
      }
    }

    /**
     * Flash cannot remove ranges already buffered in the NetStream
     * but seeking clears the buffer entirely. For most purposes,
     * having this operation act as a no-op is acceptable.
     *
     * @link https://developer.mozilla.org/en-US/docs/Web/API/SourceBuffer/remove
     * @param {Double} start start of the section to remove
     * @param {Double} end end of the section to remove
     */
  }, {
    key: 'remove',
    value: function remove(start, end) {
      (0, _removeCuesFromTrack2['default'])(start, end, this.metadataTrack_);
      if (this.inbandTextTracks_) {
        for (var track in this.inbandTextTracks_) {
          (0, _removeCuesFromTrack2['default'])(start, end, this.inbandTextTracks_[track]);
        }
      }
      this.trigger({ type: 'update' });
      this.trigger({ type: 'updateend' });
    }

    /**
     * Receive a buffer from the flv.
     *
     * @param {Object} segment
     * @private
     */
  }, {
    key: 'receiveBuffer_',
    value: function receiveBuffer_(segment) {
      var _this2 = this;

      // create an in-band caption track if one is present in the segment
      (0, _createTextTracksIfNecessary2['default'])(this, this.mediaSource_, segment);
      (0, _addTextTrackData.addTextTrackData)(this, segment.captions, segment.metadata);

      // Do this asynchronously since convertTagsToData_ can be time consuming
      scheduleTick(function () {
        var flvBytes = _this2.convertTagsToData_(segment);

        if (_this2.buffer_.length === 0) {
          scheduleTick(_this2.processBuffer_.bind(_this2));
        }

        if (flvBytes) {
          _this2.buffer_.push(flvBytes);
          _this2.bufferSize_ += flvBytes.byteLength;
        }
      });
    }

    /**
     * Append a portion of the current buffer to the SWF.
     *
     * @private
     */
  }, {
    key: 'processBuffer_',
    value: function processBuffer_() {
      var _this3 = this;

      var chunkSize = _flashConstants2['default'].BYTES_PER_CHUNK;

      if (!this.buffer_.length) {
        if (this.updating !== false) {
          this.updating = false;
          this.trigger({ type: 'updateend' });
        }
        // do nothing if the buffer is empty
        return;
      }

      // concatenate appends up to the max append size
      var chunk = this.buffer_[0].subarray(0, chunkSize);

      // requeue any bytes that won't make it this round
      if (chunk.byteLength < chunkSize || this.buffer_[0].byteLength === chunkSize) {
        this.buffer_.shift();
      } else {
        this.buffer_[0] = this.buffer_[0].subarray(chunkSize);
      }

      this.bufferSize_ -= chunk.byteLength;

      // base64 encode the bytes
      var binary = [];
      var length = chunk.byteLength;

      for (var i = 0; i < length; i++) {
        binary.push(String.fromCharCode(chunk[i]));
      }
      var b64str = _globalWindow2['default'].btoa(binary.join(''));

      _globalWindow2['default'][this.flashEncodedDataName_] = function () {
        // schedule another processBuffer to process any left over data or to
        // trigger updateend
        scheduleTick(_this3.processBuffer_.bind(_this3));
        delete _globalWindow2['default'][_this3.flashEncodedDataName_];
        return b64str;
      };

      // Notify the swf that segment data is ready to be appended
      this.mediaSource_.swfObj.vjs_appendChunkReady(this.flashEncodedDataName_);
    }

    /**
     * Turns an array of flv tags into a Uint8Array representing the
     * flv data. Also removes any tags that are before the current
     * time so that playback begins at or slightly after the right
     * place on a seek
     *
     * @private
     * @param {Object} segmentData object of segment data
     */
  }, {
    key: 'convertTagsToData_',
    value: function convertTagsToData_(segmentData) {
      var segmentByteLength = 0;
      var tech = this.mediaSource_.tech_;
      var videoTargetPts = 0;
      var segment = undefined;
      var videoTags = segmentData.tags.videoTags;
      var audioTags = segmentData.tags.audioTags;

      // Establish the media timeline to PTS translation if we don't
      // have one already
      if (isNaN(this.basePtsOffset_) && (videoTags.length || audioTags.length)) {
        // We know there is at least one video or audio tag, but since we may not have both,
        // we use pts: Infinity for the missing tag. The will force the following Math.min
        // call will to use the proper pts value since it will always be less than Infinity
        var firstVideoTag = videoTags[0] || { pts: Infinity };
        var firstAudioTag = audioTags[0] || { pts: Infinity };

        this.basePtsOffset_ = Math.min(firstAudioTag.pts, firstVideoTag.pts);
      }

      if (tech.seeking()) {
        // Do not use previously saved buffer end values while seeking since buffer
        // is cleared on all seeks
        this.videoBufferEnd_ = NaN;
        this.audioBufferEnd_ = NaN;
      }

      if (isNaN(this.videoBufferEnd_)) {
        if (tech.buffered().length) {
          videoTargetPts = tech.buffered().end(0) - this.timestampOffset;
        }

        // Trim to currentTime if seeking
        if (tech.seeking()) {
          videoTargetPts = Math.max(videoTargetPts, tech.currentTime() - this.timestampOffset);
        }

        // PTS values are represented in milliseconds
        videoTargetPts *= 1e3;
        videoTargetPts += this.basePtsOffset_;
      } else {
        // Add a fudge factor of 0.1 to the last video pts appended since a rendition change
        // could append an overlapping segment, in which case there is a high likelyhood
        // a tag could have a matching pts to videoBufferEnd_, which would cause
        // that tag to get appended by the tag.pts >= targetPts check below even though it
        // is a duplicate of what was previously appended
        videoTargetPts = this.videoBufferEnd_ + 0.1;
      }

      // filter complete GOPs with a presentation time less than the seek target/end of buffer
      var currentIndex = videoTags.length;

      // if the last tag is beyond videoTargetPts, then do not search the list for a GOP
      // since our videoTargetPts lies in a future segment
      if (currentIndex && videoTags[currentIndex - 1].pts >= videoTargetPts) {
        // Start by walking backwards from the end of the list until we reach a tag that
        // is equal to or less than videoTargetPts
        while (--currentIndex) {
          var currentTag = videoTags[currentIndex];

          if (currentTag.pts > videoTargetPts) {
            continue;
          }

          // if we see a keyFrame or metadata tag once we've gone below videoTargetPts,
          // exit the loop as this is the start of the GOP that we want to append
          if (currentTag.keyFrame || currentTag.metaDataTag) {
            break;
          }
        }

        // We need to check if there are any metadata tags that come before currentIndex
        // as those will be metadata tags associated with the GOP we are appending
        // There could be 0 to 2 metadata tags that come before the currentIndex depending
        // on what videoTargetPts is and whether the transmuxer prepended metadata tags to this
        // key frame
        while (currentIndex) {
          var nextTag = videoTags[currentIndex - 1];

          if (!nextTag.metaDataTag) {
            break;
          }

          currentIndex--;
        }
      }

      var filteredVideoTags = videoTags.slice(currentIndex);

      var audioTargetPts = undefined;

      if (isNaN(this.audioBufferEnd_)) {
        audioTargetPts = videoTargetPts;
      } else {
        // Add a fudge factor of 0.1 to the last video pts appended since a rendition change
        // could append an overlapping segment, in which case there is a high likelyhood
        // a tag could have a matching pts to videoBufferEnd_, which would cause
        // that tag to get appended by the tag.pts >= targetPts check below even though it
        // is a duplicate of what was previously appended
        audioTargetPts = this.audioBufferEnd_ + 0.1;
      }

      if (filteredVideoTags.length) {
        // If targetPts intersects a GOP and we appended the tags for the GOP that came
        // before targetPts, we want to make sure to trim audio tags at the pts
        // of the first video tag to avoid brief moments of silence
        audioTargetPts = Math.min(audioTargetPts, filteredVideoTags[0].pts);
      }

      // skip tags with a presentation time less than the seek target/end of buffer
      currentIndex = 0;

      while (currentIndex < audioTags.length) {
        if (audioTags[currentIndex].pts >= audioTargetPts) {
          break;
        }

        currentIndex++;
      }

      var filteredAudioTags = audioTags.slice(currentIndex);

      // update the audio and video buffer ends
      if (filteredAudioTags.length) {
        this.audioBufferEnd_ = filteredAudioTags[filteredAudioTags.length - 1].pts;
      }
      if (filteredVideoTags.length) {
        this.videoBufferEnd_ = filteredVideoTags[filteredVideoTags.length - 1].pts;
      }

      var tags = this.getOrderedTags_(filteredVideoTags, filteredAudioTags);

      if (tags.length === 0) {
        return;
      }

      // If we are appending data that comes before our target pts, we want to tell
      // the swf to adjust its notion of current time to account for the extra tags
      // we are appending to complete the GOP that intersects with targetPts
      if (tags[0].pts < videoTargetPts && tech.seeking()) {
        var fudgeFactor = 1 / 30;
        var currentTime = tech.currentTime();
        var diff = (videoTargetPts - tags[0].pts) / 1e3;
        var adjustedTime = currentTime - diff;

        if (adjustedTime < fudgeFactor) {
          adjustedTime = 0;
        }

        try {
          this.mediaSource_.swfObj.vjs_adjustCurrentTime(adjustedTime);
        } catch (e) {
          // no-op for backwards compatability of swf. If adjustCurrentTime fails,
          // the swf may incorrectly report currentTime and buffered ranges
          // but should not affect playback over than the time displayed on the
          // progress bar is inaccurate
        }
      }

      // concatenate the bytes into a single segment
      for (var i = 0; i < tags.length; i++) {
        segmentByteLength += tags[i].bytes.byteLength;
      }
      segment = new Uint8Array(segmentByteLength);
      for (var i = 0, j = 0; i < tags.length; i++) {
        segment.set(tags[i].bytes, j);
        j += tags[i].bytes.byteLength;
      }

      return segment;
    }

    /**
     * Assemble the FLV tags in decoder order.
     *
     * @private
     * @param {Array} videoTags list of video tags
     * @param {Array} audioTags list of audio tags
     */
  }, {
    key: 'getOrderedTags_',
    value: function getOrderedTags_(videoTags, audioTags) {
      var tag = undefined;
      var tags = [];

      while (videoTags.length || audioTags.length) {
        if (!videoTags.length) {
          // only audio tags remain
          tag = audioTags.shift();
        } else if (!audioTags.length) {
          // only video tags remain
          tag = videoTags.shift();
        } else if (audioTags[0].dts < videoTags[0].dts) {
          // audio should be decoded next
          tag = audioTags.shift();
        } else {
          // video should be decoded next
          tag = videoTags.shift();
        }

        tags.push(tag);
      }

      return tags;
    }
  }, {
    key: 'onHlsReset_',
    value: function onHlsReset_() {
      this.transmuxer_.postMessage({ action: 'resetCaptions' });
    }
  }]);

  return FlashSourceBuffer;
})(_videoJs2['default'].EventTarget);

exports['default'] = FlashSourceBuffer;
module.exports = exports['default'];