shaka-player
Version:
DASH/EME video player library
305 lines (268 loc) • 8.77 kB
JavaScript
/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.media.InitSegmentReference');
goog.provide('shaka.media.SegmentReference');
goog.require('goog.asserts');
goog.require('shaka.util.ArrayUtils');
/**
* Creates an InitSegmentReference, which provides the location to an
* initialization segment.
*
* @export
*/
shaka.media.InitSegmentReference = class {
/**
* @param {function():!Array.<string>} uris A function that creates the URIs
* of the resource containing the segment.
* @param {number} startByte The offset from the start of the resource to the
* start of the segment.
* @param {?number} endByte The offset from the start of the resource to the
* end of the segment, inclusive. A value of null indicates that the
* segment extends to the end of the resource.
*/
constructor(uris, startByte, endByte) {
/** @type {function():!Array.<string>} */
this.getUris = uris;
/** @const {number} */
this.startByte = startByte;
/** @const {?number} */
this.endByte = endByte;
}
/**
* Returns the offset from the start of the resource to the
* start of the segment.
*
* @return {number}
* @export
*/
getStartByte() {
return this.startByte;
}
/**
* Returns the offset from the start of the resource to the end of the
* segment, inclusive. A value of null indicates that the segment extends
* to the end of the resource.
*
* @return {?number}
* @export
*/
getEndByte() {
return this.endByte;
}
/**
* Returns the size of the init segment.
* @return {?number}
*/
getSize() {
if (this.endByte) {
return this.endByte - this.startByte;
} else {
return null;
}
}
/**
* Check if two initSegmentReference have all the same values.
* @param {?shaka.media.InitSegmentReference} reference1
* @param {?shaka.media.InitSegmentReference} reference2
* @return {boolean}
*/
static equal(reference1, reference2) {
const ArrayUtils = shaka.util.ArrayUtils;
if (!reference1 || !reference2) {
return reference1 == reference2;
} else {
return reference1.getStartByte() == reference2.getStartByte() &&
reference1.getEndByte() == reference2.getEndByte() &&
ArrayUtils.equal(reference1.getUris(), reference2.getUris());
}
}
};
/**
* SegmentReference provides the start time, end time, and location to a media
* segment.
*
* @export
*/
shaka.media.SegmentReference = class {
/**
* @param {number} startTime The segment's start time in seconds.
* @param {number} endTime The segment's end time in seconds. The segment
* ends the instant before this time, so |endTime| must be strictly greater
* than |startTime|.
* @param {function():!Array.<string>} uris
* A function that creates the URIs of the resource containing the segment.
* @param {number} startByte The offset from the start of the resource to the
* start of the segment.
* @param {?number} endByte The offset from the start of the resource to the
* end of the segment, inclusive. A value of null indicates that the
* segment extends to the end of the resource.
* @param {shaka.media.InitSegmentReference} initSegmentReference
* The segment's initialization segment metadata, or null if the segments
* are self-initializing.
* @param {number} timestampOffset
* The amount of time, in seconds, that must be added to the segment's
* internal timestamps to align it to the presentation timeline.
* <br>
* For DASH, this value should equal the Period start time minus the first
* presentation timestamp of the first frame/sample in the Period. For
* example, for MP4 based streams, this value should equal Period start
* minus the first segment's tfdt box's 'baseMediaDecodeTime' field (after
* it has been converted to seconds).
* <br>
* For HLS, this value should be 0 to keep the presentation time at the most
* recent discontinuity minus the corresponding media time.
* @param {number} appendWindowStart
* The start of the append window for this reference, relative to the
* presentation. Any content from before this time will be removed by
* MediaSource.
* @param {number} appendWindowEnd
* The end of the append window for this reference, relative to the
* presentation. Any content from after this time will be removed by
* MediaSource.
* @param {!Array.<!shaka.media.SegmentReference>=} partialReferences
* A list of SegmentReferences for the partial segments.
* @param {?string=} tilesLayout
* The value is a grid-item-dimension consisting of two positive decimal
* integers in the format: column-x-row ('4x3'). It describes the
* arrangement of Images in a Grid. The minimum valid LAYOUT is '1x1'.
* @param {?number=} tileDuration
* The explicit duration of an individual tile within the tiles grid.
* If not provided, the duration should be automatically calculated based on
* the duration of the reference.
*/
constructor(
startTime, endTime, uris, startByte, endByte, initSegmentReference,
timestampOffset, appendWindowStart, appendWindowEnd,
partialReferences = [], tilesLayout = '', tileDuration = null) {
// A preload hinted Partial Segment has the same startTime and endTime.
goog.asserts.assert(startTime <= endTime,
'startTime must be less than or equal to endTime');
goog.asserts.assert((endByte == null) || (startByte < endByte),
'startByte must be < endByte');
/** @type {number} */
this.startTime = startTime;
/** @type {number} */
this.endTime = endTime;
/**
* The "true" end time of the segment, without considering the period end
* time. This is necessary for thumbnail segments, where timing requires us
* to know the original segment duration as described in the manifest.
* @type {number}
*/
this.trueEndTime = endTime;
/** @type {function():!Array.<string>} */
this.getUrisInner = uris;
/** @const {number} */
this.startByte = startByte;
/** @const {?number} */
this.endByte = endByte;
/** @type {shaka.media.InitSegmentReference} */
this.initSegmentReference = initSegmentReference;
/** @type {number} */
this.timestampOffset = timestampOffset;
/** @type {number} */
this.appendWindowStart = appendWindowStart;
/** @type {number} */
this.appendWindowEnd = appendWindowEnd;
/** @type {!Array.<!shaka.media.SegmentReference>} */
this.partialReferences = partialReferences;
/** @type {?string} */
this.tilesLayout = tilesLayout;
/** @type {?number} */
this.tileDuration = tileDuration;
}
/**
* Creates and returns the URIs of the resource containing the segment.
*
* @return {!Array.<string>}
* @export
*/
getUris() {
return this.getUrisInner();
}
/**
* Returns the segment's start time in seconds.
*
* @return {number}
* @export
*/
getStartTime() {
return this.startTime;
}
/**
* Returns the segment's end time in seconds.
*
* @return {number}
* @export
*/
getEndTime() {
return this.endTime;
}
/**
* Returns the offset from the start of the resource to the
* start of the segment.
*
* @return {number}
* @export
*/
getStartByte() {
return this.startByte;
}
/**
* Returns the offset from the start of the resource to the end of the
* segment, inclusive. A value of null indicates that the segment extends to
* the end of the resource.
*
* @return {?number}
* @export
*/
getEndByte() {
return this.endByte;
}
/**
* Returns the size of the segment.
* @return {?number}
*/
getSize() {
if (this.endByte) {
return this.endByte - this.startByte;
} else {
return null;
}
}
/**
* Returns true if it contains partial SegmentReferences.
* @return {boolean}
*/
hasPartialSegments() {
return this.partialReferences.length > 0;
}
/**
* Returns the segment's tiles layout. Only defined in image segments.
*
* @return {?string}
* @export
*/
getTilesLayout() {
return this.tilesLayout;
}
/**
* Returns the segment's explicit tile duration.
* Only defined in image segments.
*
* @return {?number}
* @export
*/
getTileDuration() {
return this.tileDuration;
}
};
/**
* A convenient typedef for when either type of reference is acceptable.
*
* @typedef {shaka.media.InitSegmentReference|shaka.media.SegmentReference}
*/
shaka.media.AnySegmentReference;