shaka-player
Version:
DASH/EME video player library
270 lines (248 loc) • 6.91 kB
JavaScript
/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.util.CmsdManager');
goog.require('shaka.log');
/**
* @summary
* A CmsdManager maintains CMSD state as well as a collection of utility
* functions.
* @export
*/
shaka.util.CmsdManager = class {
/**
* @param {shaka.extern.CmsdConfiguration} config
*/
constructor(config) {
/** @private {shaka.extern.CmsdConfiguration} */
this.config_ = config;
/** @private {?Map<string, (boolean | number | string)>} */
this.staticParams_ = null;
/** @private {?Map<string, (boolean | number | string)>} */
this.dynamicParams_ = null;
}
/**
* Called by the Player to provide an updated configuration any time it
* changes.
*
* @param {shaka.extern.CmsdConfiguration} config
*/
configure(config) {
this.config_ = config;
}
/**
* Resets the CmsdManager.
*/
reset() {
this.staticParams_ = null;
this.dynamicParams_ = null;
}
/**
* Called by the Player to provide the headers of the latest request.
*
* @param {!Object<string, string>} headers
*/
processHeaders(headers) {
if (!this.config_.enabled) {
return;
}
const CmsdManager = shaka.util.CmsdManager;
const cmsdStatic = headers[CmsdManager.CMSD_STATIC_HEADER_NAME_];
if (cmsdStatic) {
const staticParams = this.parseCMSDStatic_(cmsdStatic);
if (staticParams) {
this.staticParams_ = staticParams;
}
}
const cmsdDynamic = headers[CmsdManager.CMSD_DYNAMIC_HEADER_NAME_];
if (cmsdDynamic) {
const dynamicParams = this.parseCMSDDynamic_(cmsdDynamic);
if (dynamicParams) {
this.dynamicParams_ = dynamicParams;
}
}
}
/**
* Returns the max bitrate in bits per second. If there is no max bitrate or
* it's not enabled, it returns null.
*
* @return {?number}
* @export
*/
getMaxBitrate() {
const key = shaka.util.CmsdManager.KEYS_.MAX_SUGGESTED_BITRATE;
if (!this.config_.enabled || !this.config_.applyMaximumSuggestedBitrate ||
!this.dynamicParams_ || !this.dynamicParams_.has(key)) {
return null;
}
return /** @type {number} */(this.dynamicParams_.get(key)) * 1000;
}
/**
* Returns the estimated throughput in bits per second. If there is no
* estimated throughput or it's not enabled, it returns null.
*
* @return {?number}
* @export
*/
getEstimatedThroughput() {
const key = shaka.util.CmsdManager.KEYS_.ESTIMATED_THROUGHPUT;
if (!this.config_.enabled || !this.dynamicParams_ ||
!this.dynamicParams_.has(key)) {
return null;
}
return /** @type {number} */(this.dynamicParams_.get(key)) * 1000;
}
/**
* Returns the response delay in milliseconds. If there is no response delay
* or it's not enabled, it returns null.
*
* @return {?number}
* @export
*/
getResponseDelay() {
const key = shaka.util.CmsdManager.KEYS_.RESPONSE_DELAY;
if (!this.config_.enabled || !this.dynamicParams_ ||
!this.dynamicParams_.has(key)) {
return null;
}
return /** @type {number} */(this.dynamicParams_.get(key));
}
/**
* Returns the RTT in milliseconds. If there is no RTT or it's not enabled,
* it returns null.
*
* @return {?number}
* @export
*/
getRoundTripTime() {
const key = shaka.util.CmsdManager.KEYS_.ROUND_TRIP_TIME;
if (!this.config_.enabled || !this.dynamicParams_ ||
!this.dynamicParams_.has(key)) {
return null;
}
return /** @type {number} */(this.dynamicParams_.get(key));
}
/**
* Gets the current bandwidth estimate.
*
* @param {number} defaultEstimate
* @return {number} The bandwidth estimate in bits per second.
* @export
*/
getBandwidthEstimate(defaultEstimate) {
const estimatedThroughput = this.getEstimatedThroughput();
if (!estimatedThroughput) {
return defaultEstimate;
}
const etpWeightRatio = this.config_.estimatedThroughputWeightRatio;
if (etpWeightRatio > 0 && etpWeightRatio <= 1) {
return (defaultEstimate * (1 - etpWeightRatio)) +
(estimatedThroughput * etpWeightRatio);
}
return defaultEstimate;
}
/**
* @param {string} headerValue
* @return {?Map<string, (boolean | number | string)>}
* @private
*/
parseCMSDStatic_(headerValue) {
try {
const params = new Map();
const items = headerValue.split(',');
for (let i = 0; i < items.length; i++) {
// <key>=<value>
const substrings = items[i].split('=');
const key = substrings[0];
const value = this.parseParameterValue_(substrings[1]);
params.set(key, value);
}
return params;
} catch (e) {
shaka.log.warning(
'Failed to parse CMSD-Static response header value:', e);
return null;
}
}
/**
* @param {string} headerValue
* @return {?Map<string, (boolean | number | string)>}
* @private
*/
parseCMSDDynamic_(headerValue) {
try {
const params = new Map();
const items = headerValue.split(';');
// Server identifier as 1st item
for (let i = 1; i < items.length; i++) {
// <key>=<value>
const substrings = items[i].split('=');
const key = substrings[0];
const value = this.parseParameterValue_(substrings[1]);
params.set(key, value);
}
return params;
} catch (e) {
shaka.log.warning(
'Failed to parse CMSD-Dynamic response header value:', e);
return null;
}
}
/**
* @param {string} value
* @return {(boolean|number|string)}
* @private
*/
parseParameterValue_(value) {
// If the value type is BOOLEAN and the value is TRUE, then the equals
// sign and the value are omitted
if (!value) {
return true;
}
// Check if boolean 'false'
if (value.toLowerCase() === 'false') {
return false;
}
// Check if a number
if (/^[-0-9]/.test(value)) {
return parseInt(value, 10);
}
// Value is a string, remove double quotes from string value
return value.replace(/["]+/g, '');
}
};
/**
* @const {string}
* @private
*/
shaka.util.CmsdManager.CMSD_STATIC_HEADER_NAME_ = 'cmsd-static';
/**
* @const {string}
* @private
*/
shaka.util.CmsdManager.CMSD_DYNAMIC_HEADER_NAME_ = 'cmsd-dynamic';
/**
* @enum {string}
* @private
*/
shaka.util.CmsdManager.KEYS_ = {
AVAILABILITY_TIME: 'at',
DURESS: 'du',
ENCODED_BITRATE: 'br',
ESTIMATED_THROUGHPUT: 'etp',
HELD_TIME: 'ht',
INTERMEDIARY_IDENTIFIER: 'n',
MAX_SUGGESTED_BITRATE: 'mb',
NEXT_OBJECT_RESPONSE: 'nor',
NEXT_RANGE_RESPONSE: 'nrr',
OBJECT_DURATION: 'd',
OBJECT_TYPE: 'ot',
RESPONSE_DELAY: 'rd',
ROUND_TRIP_TIME: 'rtt',
STARTUP: 'su',
STREAM_TYPE: 'st',
STREAMING_FORMAT: 'sf',
VERSION: 'v',
};