add-text-track-data.js
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/**
* @file add-text-track-data.js
*/
import window from 'global/window';
import videojs from 'video.js';
/**
* Define properties on a cue for backwards compatability,
* but warn the user that the way that they are using it
* is depricated and will be removed at a later date.
*
* @param {Cue} cue the cue to add the properties on
* @private
*/
const deprecateOldCue = function(cue) {
Object.defineProperties(cue.frame, {
id: {
get() {
videojs.log.warn(
'cue.frame.id is deprecated. Use cue.value.key instead.'
);
return cue.value.key;
}
},
value: {
get() {
videojs.log.warn(
'cue.frame.value is deprecated. Use cue.value.data instead.'
);
return cue.value.data;
}
},
privateData: {
get() {
videojs.log.warn(
'cue.frame.privateData is deprecated. Use cue.value.data instead.'
);
return cue.value.data;
}
}
});
};
const durationOfVideo = function(duration) {
let dur;
if (isNaN(duration) || Math.abs(duration) === Infinity) {
dur = Number.MAX_VALUE;
} else {
dur = duration;
}
return dur;
};
/**
* Add text track data to a source handler given the captions and
* metadata from the buffer.
*
* @param {Object} sourceHandler the flash or virtual source buffer
* @param {Array} captionArray an array of caption data
* @param {Array} metadataArray an array of meta data
* @private
*/
const addTextTrackData = function(sourceHandler, captionArray, metadataArray) {
let Cue = window.WebKitDataCue || window.VTTCue;
if (captionArray) {
captionArray.forEach(function(caption) {
let track = caption.stream;
this.inbandTextTracks_[track].addCue(
new Cue(
caption.startTime + this.timestampOffset,
caption.endTime + this.timestampOffset,
caption.text
));
}, sourceHandler);
}
if (metadataArray) {
let videoDuration = durationOfVideo(sourceHandler.mediaSource_.duration);
metadataArray.forEach(function(metadata) {
let time = metadata.cueTime + this.timestampOffset;
metadata.frames.forEach(function(frame) {
let cue = new Cue(
time,
time,
frame.value || frame.url || frame.data || '');
cue.frame = frame;
cue.value = frame;
deprecateOldCue(cue);
this.metadataTrack_.addCue(cue);
}, this);
}, sourceHandler);
// Updating the metadeta cues so that
// the endTime of each cue is the startTime of the next cue
// the endTime of last cue is the duration of the video
if (sourceHandler.metadataTrack_ &&
sourceHandler.metadataTrack_.cues &&
sourceHandler.metadataTrack_.cues.length) {
let cues = sourceHandler.metadataTrack_.cues;
let cuesArray = [];
// Create a copy of the TextTrackCueList...
// ...disregarding cues with a falsey value
for (let i = 0; i < cues.length; i++) {
if (cues[i]) {
cuesArray.push(cues[i]);
}
}
// Group cues by their startTime value
let cuesGroupedByStartTime = cuesArray.reduce((obj, cue) => {
let timeSlot = obj[cue.startTime] || [];
timeSlot.push(cue);
obj[cue.startTime] = timeSlot;
return obj;
}, {});
// Sort startTimes by ascending order
let sortedStartTimes = Object.keys(cuesGroupedByStartTime)
.sort((a, b) => Number(a) - Number(b));
// Map each cue group's endTime to the next group's startTime
sortedStartTimes.forEach((startTime, idx) => {
let cueGroup = cuesGroupedByStartTime[startTime];
let nextTime = Number(sortedStartTimes[idx + 1]) || videoDuration;
// Map each cue's endTime the next group's startTime
cueGroup.forEach((cue) => {
cue.endTime = nextTime;
});
});
}
}
};
export default {
addTextTrackData,
durationOfVideo
};