Source: externs/shaka/manifest.js

/*! @license
 * Shaka Player
 * Copyright 2016 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */


/**
 * @externs
 */


/**
 * @typedef {{
 *   presentationTimeline: !shaka.media.PresentationTimeline,
 *   variants: !Array.<shaka.extern.Variant>,
 *   textStreams: !Array.<shaka.extern.Stream>,
 *   imageStreams: !Array.<shaka.extern.Stream>,
 *   offlineSessionIds: !Array.<string>,
 *   minBufferTime: number,
 *   sequenceMode: boolean,
 *   ignoreManifestTimestampsInSegmentsMode: boolean,
 *   type: string,
 *   serviceDescription: ?shaka.extern.ServiceDescription,
 *   nextUrl: ?string,
 *   periodCount: number,
 *   gapCount: number,
 *   isLowLatency: boolean
 * }}
 *
 * @description
 * <p>
 * A Manifest object describes a collection of streams (segmented audio, video,
 * or text data) that share a common timeline. We call the collection of
 * streams "the presentation" and their timeline "the presentation timeline".
 * A Manifest describes one of two types of presentations: live and
 * video-on-demand.
 * </p>
 *
 * <p>
 * A live presentation begins at some point in time and either continues
 * indefinitely or ends when the presentation stops broadcasting. For a live
 * presentation, wall-clock time maps onto the presentation timeline, and the
 * current wall-clock time maps to the live-edge (AKA "the current presentation
 * time"). In contrast, a video-on-demand presentation exists entirely
 * independent of wall-clock time.
 * </p>
 *
 * <p>
 * A variant is a combination of an audio and a video streams that can be played
 * together.
 * </p>
 *
 * <p>
 * A stream has the same logical content as another stream if the only
 * difference between the two is their quality. For example, an SD video stream
 * and an HD video stream that depict the same scene have the same logical
 * content; whereas an English audio stream and a French audio stream have
 * different logical contents. The player can automatically switch between
 * streams which have the same logical content to adapt to network conditions.
 * </p>
 *
 * @property {!shaka.media.PresentationTimeline} presentationTimeline
 *   <i>Required.</i> <br>
 *   The presentation timeline.
 * @property {!Array.<shaka.extern.Variant>} variants
 *   <i>Required.</i> <br>
 *   The presentation's Variants. There must be at least one Variant.
 * @property {!Array.<shaka.extern.Stream>} textStreams
 *   <i>Required.</i> <br>
 *   The presentation's text streams.
 * @property {!Array.<shaka.extern.Stream>} imageStreams
 *   <i>Required.</i> <br>
 *   The presentation's image streams
 * @property {!Array.<string>} offlineSessionIds
 *   <i>Defaults to [].</i> <br>
 *   An array of EME sessions to load for offline playback.
 * @property {number} minBufferTime
 *   <i>Defaults to 0.</i> <br>
 *   The minimum number of seconds of content that must be buffered before
 *   playback can begin.  Can be overridden by a higher value from the Player
 *   configuration.
 * @property {boolean} sequenceMode
 *   If true, we will append the media segments using sequence mode; that is to
 *   say, ignoring any timestamps inside the media files.
 * @property {boolean} ignoreManifestTimestampsInSegmentsMode
 *   If true, don't adjust the timestamp offset to account for manifest
 *   segment durations being out of sync with segment durations. In other
 *   words, assume that there are no gaps in the segments when appending
 *   to the SourceBuffer, even if the manifest and segment times disagree.
 *   Only applies when sequenceMode is <code>false</code>, and only for HLS
 *   streams.
 *   <i>Defaults to <code>false</code>.</i>
 * @property {string} type
 *   Indicates the type of the manifest. It can be <code>'HLS'</code> or
 *   <code>'DASH'</code>.
 * @property {?shaka.extern.ServiceDescription} serviceDescription
 *   The service description for the manifest. Used to adapt playbackRate to
 *   decrease latency.
 * @property {?string} nextUrl
 *   The next url to play.
 * @property {number} periodCount
 *   Number of periods found in a manifest. For DASH, it represents number of
 *   Period elements in a manifest. If streaming protocol does not implement
 *   period-like structure, it should be set to 1.
 *   <i>Defaults to <code>1</code>.</i>
 * @property {number} gapCount
 *   The amount of gaps found in a manifest. For DASH, it represents number of
 *   discontinuities found between periods. For HLS, it is a number of EXT-X-GAP
 *   and GAP=YES occurrences. For MSS, it is always set to 0.
 *   If in src= mode or nothing is loaded, NaN.
 * @property {bolean} isLowLatency
 *   If true, the manifest is Low Latency.
 *
 * @exportDoc
 */
shaka.extern.Manifest;


/**
 * @typedef {{
*   id: string,
*   audioStreams: !Array.<shaka.extern.Stream>,
*   videoStreams: !Array.<shaka.extern.Stream>,
*   textStreams: !Array.<shaka.extern.Stream>,
*   imageStreams: !Array.<shaka.extern.Stream>
* }}
*
* @description Contains the streams from one DASH period.
* For use in {@link shaka.util.PeriodCombiner}.
*
* @property {string} id
*   The Period ID.
* @property {!Array.<shaka.extern.Stream>} audioStreams
*   The audio streams from one Period.
* @property {!Array.<shaka.extern.Stream>} videoStreams
*   The video streams from one Period.
* @property {!Array.<shaka.extern.Stream>} textStreams
*   The text streams from one Period.
* @property {!Array.<shaka.extern.Stream>} imageStreams
*   The image streams from one Period.
*
* @exportDoc
*/
shaka.extern.Period;

/**
 * @typedef {{
 *   initData: !Uint8Array,
 *   initDataType: string,
 *   keyId: ?string
 * }}
 *
 * @description
 * Explicit initialization data, which override any initialization data in the
 * content. The initDataType values and the formats that they correspond to
 * are specified {@link https://bit.ly/EmeInitTypes here}.
 *
 * @property {!Uint8Array} initData
 *   Initialization data in the format indicated by initDataType.
 * @property {string} initDataType
 *   A string to indicate what format initData is in.
 * @property {?string} keyId
 *   The key Id that corresponds to this initData.
 *
 * @exportDoc
 */
shaka.extern.InitDataOverride;

/**
 * @typedef {{
 *   targetLatency:?number,
 *   maxLatency: ?number,
 *   maxPlaybackRate: ?number,
 *   minLatency: ?number,
 *   minPlaybackRate: ?number
 * }}
 *
 * @description
 * Maximum and minimum latency and playback rate for a manifest. When max
 * latency is reached playbackrate is updated to maxPlaybackRate to decrease
 * latency. When min  latency is reached playbackrate is updated to
 * minPlaybackRate to increase  latency.
 * More information {@link https://dashif.org/docs/CR-Low-Latency-Live-r8.pdf here}.
 *
 * @property {?number} targetLatency
 *  The target latency to aim for.
 * @property {?number} maxLatency
 *  Maximum latency in seconds.
 * @property {?number} maxPlaybackRate
 *  Maximum playback rate.
 * @property {?number} minLatency
 *  Minimum latency in seconds.
 * @property {?number} minPlaybackRate
 *  Minimum playback rate.
 *
 * @exportDoc
 */
shaka.extern.ServiceDescription;


/**
 * @typedef {{
 *   keySystem: string,
 *   encryptionScheme: string,
 *   keySystemUris: (Set.<string>|undefined),
 *   licenseServerUri: string,
 *   distinctiveIdentifierRequired: boolean,
 *   persistentStateRequired: boolean,
 *   audioRobustness: string,
 *   videoRobustness: string,
 *   serverCertificate: Uint8Array,
 *   serverCertificateUri: string,
 *   sessionType: string,
 *   initData: Array.<!shaka.extern.InitDataOverride>,
 *   keyIds: Set.<string>
 * }}
 *
 * @description
 * DRM configuration for a single key system.
 *
 * @property {string} keySystem
 *   <i>Required.</i> <br>
 *   The key system, e.g., "com.widevine.alpha".
 * @property {string} encryptionScheme
 *   <i>Required.</i> <br>
 *   The encryption scheme, e.g., "cenc", "cbcs", "cbcs-1-9".
 * @property {(Set.<string>|undefined)} keySystemUris
 *   <i>Optional.</i> <br>
 *   The key system uri, e.g., "skd://" for fairplay.
 * @property {string} licenseServerUri
 *   <i>Filled in by DRM config if missing.</i> <br>
 *   The license server URI.
 * @property {boolean} distinctiveIdentifierRequired
 *   <i>Defaults to false.  Can be filled in by advanced DRM config.</i> <br>
 *   True if the application requires the key system to support distinctive
 *   identifiers.
 * @property {boolean} persistentStateRequired
 *   <i>Defaults to false.  Can be filled in by advanced DRM config.</i> <br>
 *   True if the application requires the key system to support persistent
 *   state, e.g., for persistent license storage.
 * @property {string} sessionType
 *   <i>Defaults to 'temporary' if Shaka wasn't initiated for storage.
 *   Can be filled in by advanced DRM config sessionType parameter.</i> <br>
 * @property {string} audioRobustness
 *   <i>Defaults to '', e.g., no specific robustness required.  Can be filled in
 *   by advanced DRM config.</i> <br>
 *   A key-system-specific string that specifies a required security level.
 * @property {string} videoRobustness
 *   <i>Defaults to '', e.g., no specific robustness required.  Can be filled in
 *   by advanced DRM config.</i> <br>
 *   A key-system-specific string that specifies a required security level.
 * @property {Uint8Array} serverCertificate
 *   <i>Defaults to null, e.g., certificate will be requested from the license
 *   server if required.  Can be filled in by advanced DRM config.</i> <br>
 *   A key-system-specific server certificate used to encrypt license requests.
 *   Its use is optional and is meant as an optimization to avoid a round-trip
 *   to request a certificate.
 * @property {string} serverCertificateUri
 *   <i>Defaults to '', e.g., server certificate will be requested from the
 *   given URI if serverCertificate is not provided. Can be filled in by
 *   advanced DRM config.</i>
 * @property {Array.<!shaka.extern.InitDataOverride>} initData
 *   <i>Defaults to [], e.g., no override.</i> <br>
 *   A list of initialization data which override any initialization data found
 *   in the content.  See also shaka.extern.InitDataOverride.
 * @property {Set.<string>} keyIds
 *   <i>Defaults to the empty Set</i> <br>
 *   If not empty, contains the default key IDs for this key system, as
 *   lowercase hex strings.
 * @exportDoc
 */
shaka.extern.DrmInfo;


/**
 * @typedef {{
 *   id: number,
 *   language: string,
 *   disabledUntilTime: number,
 *   primary: boolean,
 *   audio: ?shaka.extern.Stream,
 *   video: ?shaka.extern.Stream,
 *   bandwidth: number,
 *   allowedByApplication: boolean,
 *   allowedByKeySystem: boolean,
 *   decodingInfos: !Array.<MediaCapabilitiesDecodingInfo>
 * }}
 *
 * @description
 * A Variant describes a combination of an audio and video streams which
 * could be played together. It's possible to have a video/audio only
 * variant.
 *
 * @property {number} id
 *   <i>Required.</i> <br>
 *   A unique ID among all Variant objects within the same Manifest.
 * @property {string} language
 *   <i>Defaults to '' (i.e., unknown).</i> <br>
 *   The Variant's language, specified as a language code. <br>
 *   See {@link https://tools.ietf.org/html/rfc5646} <br>
 *   See {@link http://www.iso.org/iso/home/standards/language_codes.htm}
 * @property {number} disabledUntilTime
 *   <i>Defaults to 0.</i> <br>
 *   0 means the variant is enabled. The Player will set this value to
 *   "(Date.now() / 1000) + config.streaming.maxDisabledTime" and once this
 *   maxDisabledTime has passed Player will set the value to 0 in order to
 *   reenable the variant.
 * @property {boolean} primary
 *   <i>Defaults to false.</i> <br>
 *   True indicates that the player should use this Variant over others if user
 *   preferences cannot be met.  The player may still use another Variant to
 *   meet user preferences.
 * @property {?shaka.extern.Stream} audio
 *   The audio stream of the variant.
 * @property {?shaka.extern.Stream} video
 *   The video stream of the variant.
 * @property {number} bandwidth
 *   The variant's required bandwidth in bits per second.
 * @property {boolean} allowedByApplication
 *   <i>Defaults to true.</i><br>
 *   Set by the Player to indicate whether the variant is allowed to be played
 *   by the application.
 * @property {boolean} allowedByKeySystem
 *   <i>Defaults to true.</i><br>
 *   Set by the Player to indicate whether the variant is allowed to be played
 *   by the key system.
 * @property {!Array.<MediaCapabilitiesDecodingInfo>} decodingInfos
 *   <i>Defaults to [].</i><br>
 *   Set by StreamUtils to indicate the results from MediaCapabilities
 *   decodingInfo.
 *
 * @exportDoc
 */
shaka.extern.Variant;


/**
 * Creates a SegmentIndex; returns a Promise that resolves after the
 * SegmentIndex has been created.
 *
 * @typedef {function(): !Promise}
 * @exportDoc
 */
shaka.extern.CreateSegmentIndexFunction;


/**
 * @typedef {{
 *   bitsKey: number,
 *   blockCipherMode: string,
 *   cryptoKey: (webCrypto.CryptoKey|undefined),
 *   fetchKey: (shaka.extern.CreateSegmentIndexFunction|undefined),
 *   iv: (!Uint8Array|undefined),
 *   firstMediaSequenceNumber: number
 * }}
 *
 * @description
 * AES key and iv info from the manifest.
 *
 * @property {number} bitsKey
 *   The number of the bit key (eg: 128, 256).
 * @property {string} blockCipherMode
 *   The block cipher mode of operation. Possible values: 'CTR' or 'CBC'.
 * @property {webCrypto.CryptoKey|undefined} cryptoKey
 *   Web crypto key object of the AES key. If unset, the "fetchKey"
 *   property should be provided.
 * @property {shaka.extern.FetchCryptoKeysFunction|undefined} fetchKey
 *   A function that fetches the key.
 *   Should be provided if the "cryptoKey" property is unset.
 *   Should update this object in-place, to set "cryptoKey".
 * @property {(!Uint8Array|undefined)} iv
 *   The IV in the manifest, if defined. For HLS see HLS RFC 8216 Section 5.2
 *   for handling undefined IV.
 * @property {number} firstMediaSequenceNumber
 *   The starting Media Sequence Number of the playlist, used when IV is
 *   undefined.
 *
 * @exportDoc
 */
shaka.extern.aesKey;


/**
 * A function that fetches the crypto keys for AES-128.
 * Returns a promise that resolves when the keys have been fetched.
 *
 * @typedef {function(): !Promise}
 * @exportDoc
 */
shaka.extern.FetchCryptoKeysFunction;


/**
 * SegmentIndex minimal API.
 * @interface
 * @exportDoc
 */
shaka.extern.SegmentIndex = class {
  /**
   * Get number of references.
   * @return {number}
   * @exportDoc
   */
  getNumReferences() {}

  /**
   * Finds the position of the segment for the given time, in seconds, relative
   * to the start of the presentation.  Returns the position of the segment
   * with the largest end time if more than one segment is known for the given
   * time.
   *
   * @param {number} time
   * @return {?number} The position of the segment, or null if the position of
   *   the segment could not be determined.
   * @exportDoc
   */
  find(time) {}

  /**
   * Gets the SegmentReference for the segment at the given position.
   *
   * @param {number} position The position of the segment as returned by find().
   * @return {shaka.media.SegmentReference} The SegmentReference, or null if
   *   no such SegmentReference exists.
   * @exportDoc
   */
  get(position) {}

  /**
   * Gets number of already evicted segments.
   * @return {number}
   * @exportDoc
   */
  getNumEvicted() {}
};


/**
 * @typedef {{
 *   id: number,
 *   originalId: ?string,
 *   groupId: ?string,
 *   createSegmentIndex: shaka.extern.CreateSegmentIndexFunction,
 *   closeSegmentIndex: (function()|undefined),
 *   segmentIndex: shaka.media.SegmentIndex,
 *   mimeType: string,
 *   codecs: string,
 *   frameRate: (number|undefined),
 *   pixelAspectRatio: (string|undefined),
 *   hdr: (string|undefined),
 *   colorGamut: (string|undefined),
 *   videoLayout: (string|undefined),
 *   bandwidth: (number|undefined),
 *   width: (number|undefined),
 *   height: (number|undefined),
 *   kind: (string|undefined),
 *   encrypted: boolean,
 *   drmInfos: !Array.<shaka.extern.DrmInfo>,
 *   keyIds: !Set.<string>,
 *   language: string,
 *   originalLanguage: ?string,
 *   label: ?string,
 *   type: string,
 *   primary: boolean,
 *   trickModeVideo: ?shaka.extern.Stream,
 *   emsgSchemeIdUris: ?Array.<string>,
 *   roles: !Array.<string>,
 *   accessibilityPurpose: ?shaka.media.ManifestParser.AccessibilityPurpose,
 *   forced: boolean,
 *   channelsCount: ?number,
 *   audioSamplingRate: ?number,
 *   spatialAudio: boolean,
 *   closedCaptions: Map.<string, string>,
 *   tilesLayout: (string|undefined),
 *   matchedStreams:
 *      (!Array.<shaka.extern.Stream>|!Array.<shaka.extern.StreamDB>|
 *      undefined),
 *   mssPrivateData: (shaka.extern.MssPrivateData|undefined),
 *   external: boolean,
 *   fastSwitching: boolean,
 *   fullMimeTypes: !Set.<string>
 * }}
 *
 * @description
 * A Stream object describes a single stream (segmented media data).
 *
 * @property {number} id
 *   <i>Required.</i> <br>
 *   A unique ID among all Stream objects within the same Manifest.
 * @property {?string} originalId
 *   <i>Optional.</i> <br>
 *   The original ID, if any, that appeared in the manifest.  For example, in
 *   DASH, this is the "id" attribute of the Representation element.  In HLS,
 *   this is the "NAME" attribute.
 * @property {?string} groupId
 *   <i>Optional.</i> <br>
 *   The ID of the stream's parent element. In DASH, this will be a unique
 *   ID that represents the representation's parent adaptation element
 * @property {shaka.extern.CreateSegmentIndexFunction} createSegmentIndex
 *   <i>Required.</i> <br>
 *   Creates the Stream's segmentIndex (asynchronously).
 * @property {(function()|undefined)} closeSegmentIndex
 *   <i>Optional.</i> <br>
 *   Closes the Stream's segmentIndex.
 * @property {shaka.media.SegmentIndex} segmentIndex
 *   <i>Required.</i> <br>
 *   May be null until createSegmentIndex() is complete.
 * @property {string} mimeType
 *   <i>Required.</i> <br>
 *   The Stream's MIME type, e.g., 'audio/mp4', 'video/webm', or 'text/vtt'.
 *   In the case of a stream that adapts between different periods with
 *   different MIME types, this represents only the first period.
 * @property {string} codecs
 *   <i>Defaults to '' (i.e., unknown / not needed).</i> <br>
 *   The Stream's codecs, e.g., 'avc1.4d4015' or 'vp9', which must be
 *   compatible with the Stream's MIME type. <br>
 *   In the case of a stream that adapts between different periods with
 *   different codecs, this represents only the first period.
 *   See {@link https://tools.ietf.org/html/rfc6381}
 * @property {(number|undefined)} frameRate
 *   <i>Video streams only.</i> <br>
 *   The Stream's framerate in frames per second
 * @property {(string|undefined)} pixelAspectRatio
 *   <i>Video streams only.</i> <br>
 *   The Stream's pixel aspect ratio
 * @property {(string|undefined)} hdr
 *   <i>Video streams only.</i> <br>
 *   The Stream's HDR info
 * @property {(string|undefined)} colorGamut
 *   <i>Video streams only.</i> <br>
 *   The Stream's color gamut info
 * @property {(string|undefined)} videoLayout
 *   <i>Video streams only.</i> <br>
 *   The Stream's video layout info.
 * @property {(number|undefined)} bandwidth
 *   <i>Audio and video streams only.</i> <br>
 *   The stream's required bandwidth in bits per second.
 * @property {(number|undefined)} width
 *   <i>Video streams only.</i> <br>
 *   The stream's width in pixels.
 * @property {(number|undefined)} height
 *   <i>Video streams only.</i> <br>
 *   The stream's height in pixels.
 * @property {(string|undefined)} kind
 *   <i>Text streams only.</i> <br>
 *   The kind of text stream.  For example, 'caption' or 'subtitle'.
 *   @see https://bit.ly/TextKind
 * @property {boolean} encrypted
 *   <i>Defaults to false.</i><br>
 *   True if the stream is encrypted.
 * @property {!Array.<!shaka.extern.DrmInfo>} drmInfos
 *   <i>Defaults to [] (i.e., no DRM).</i> <br>
 *   An array of DrmInfo objects which describe DRM schemes are compatible with
 *   the content.
 * @property {!Set.<string>} keyIds
 *   <i>Defaults to empty (i.e., unencrypted or key ID unknown).</i> <br>
 *   The stream's key IDs as lowercase hex strings. These key IDs identify the
 *   encryption keys that the browser (key system) can use to decrypt the
 *   stream.
 * @property {string} language
 *   The Stream's language, specified as a language code. <br>
 *   Audio stream's language must be identical to the language of the containing
 *   Variant.
 * @property {?string} originalLanguage
 *   <i>Optional.</i> <br>
 *   The original language, if any, that appeared in the manifest.
 * @property {?string} label
 *   The Stream's label, unique text that should describe the audio/text track.
 * @property {string} type
 *   <i>Required.</i> <br>
 *   Content type (e.g. 'video', 'audio' or 'text', 'image')
 * @property {boolean} primary
 *   <i>Defaults to false.</i> <br>
 *   True indicates that the player should use this Stream over others if user
 *   preferences cannot be met.  The player may still use another Variant to
 *   meet user preferences.
 * @property {?shaka.extern.Stream} trickModeVideo
 *   <i>Video streams only.</i> <br>
 *   An alternate video stream to use for trick mode playback.
 * @property {?Array.<string>} emsgSchemeIdUris
 *   <i>Defaults to empty.</i><br>
 *   Array of registered emsg box scheme_id_uri that should result in
 *   Player events.
 * @property {!Array.<string>} roles
 *   The roles of the stream as they appear on the manifest,
 *   e.g. 'main', 'caption', or 'commentary'.
 * @property {?shaka.media.ManifestParser.AccessibilityPurpose}
 *     accessibilityPurpose
 *   The DASH accessibility descriptor, if one was provided for this stream.
 * @property {boolean} forced
 *   <i>Defaults to false.</i> <br>
 *   Whether the stream set was forced
 * @property {?number} channelsCount
 *   The channel count information for the audio stream.
 * @property {?number} audioSamplingRate
 *   Specifies the maximum sampling rate of the content.
 * @property {boolean} spatialAudio
 *   <i>Defaults to false.</i> <br>
 *   Whether the stream set has spatial audio
 * @property {Map.<string, string>} closedCaptions
 *   A map containing the description of closed captions, with the caption
 *   channel number (CC1 | CC2 | CC3 | CC4) as the key and the language code
 *   as the value. If the channel number is not provided by the description,
 *   we'll set a 0-based index as the key. If the language code is not
 *   provided by the description we'll set the same value as channel number.
 *   Example: {'CC1': 'eng'; 'CC3': 'swe'}, or {'1', 'eng'; '2': 'swe'}, etc.
 * @property {(string|undefined)} tilesLayout
 *   <i>Image streams only.</i> <br>
 *   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'.
 * @property {(!Array.<shaka.extern.Stream>|!Array.<shaka.extern.StreamDB>|
 *   undefined)} matchedStreams
 *   The streams in all periods which match the stream. Used for Dash.
 * @property {(shaka.extern.MssPrivateData|undefined)} mssPrivateData
 *   <i>Microsoft Smooth Streaming only.</i> <br>
 *   Private MSS data that is necessary to be able to do transmuxing.
 * @property {boolean} external
 *   Indicate if the stream was added externally.
 *   Eg: external text tracks.
 * @property {boolean} fastSwitching
 *   Indicate if the stream should be used for fast switching.
 * @property {!Set.<string>} fullMimeTypes
 *   A set of full MIME types (e.g. MIME types plus codecs information), that
 *   represents the types used in each period of the original manifest.
 *   Meant for being used by compatibility checking, such as with
 *   MediaSource.isTypeSupported.
 *
 * @exportDoc
 */
shaka.extern.Stream;


/**
 * @typedef {{
 *   duration: number,
 *   timescale: number,
 *   codecPrivateData: ?string
 * }}
 *
 * @description
 * Private MSS data that is necessary to be able to do transmuxing.
 *
 * @property {number} duration
 *   <i>Required.</i> <br>
 *   MSS Stream duration.
 * @property {number} timescale
 *   <i>Required.</i> <br>
 *   MSS timescale.
 * @property {?string} codecPrivateData
 *   MSS codecPrivateData.
 *
 * @exportDoc
 */
shaka.extern.MssPrivateData;