/**
* @license
* Copyright 2016 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
goog.provide('shaka.util.MimeUtils');
/**
* @summary A set of utility functions for dealing with MIME types.
*/
shaka.util.MimeUtils = class {
/**
* Takes a MIME type and optional codecs string and produces the full MIME
* type.
*
* @param {string} mimeType
* @param {string=} codecs
* @return {string}
*/
static getFullType(mimeType, codecs) {
let fullMimeType = mimeType;
if (codecs) {
fullMimeType += '; codecs="' + codecs + '"';
}
return fullMimeType;
}
/**
* Takes a Stream object and produces an extended MIME type with information
* beyond the container and codec type, when available.
*
* @param {shaka.extern.Stream} stream
* @return {string}
*/
static getExtendedType(stream) {
const components = [stream.mimeType];
const extendedMimeParams = shaka.util.MimeUtils.EXTENDED_MIME_PARAMETERS_;
extendedMimeParams.forEach((mimeKey, streamKey) => {
const value = stream[streamKey];
if (value) {
components.push(mimeKey + '="' + value + '"');
}
});
return components.join(';');
}
/**
* Split a list of codecs encoded in a string into a list of codecs.
* @param {string} codecs
* @return {!Array.<string>}
*/
static splitCodecs(codecs) {
return codecs.split(',');
}
/**
* Get the base codec from a codec string.
*
* @param {string} codecString
* @return {string}
*/
static getCodecBase(codecString) {
const parts = shaka.util.MimeUtils.getCodecParts_(codecString);
return parts[0];
}
/**
* Takes a full MIME type (with codecs) or basic MIME type (without codecs)
* and returns a basic MIME type (without codecs or other parameters).
*
* @param {string} mimeType
* @return {string}
*/
static getBasicType(mimeType) {
return mimeType.split(';')[0];
}
/**
* Takes a MIME type and returns the codecs parameter, or an empty string if
* there is no codecs parameter.
*
* @param {string} mimeType
* @return {string}
*/
static getCodecs(mimeType) {
// Parse the basic MIME type from its parameters.
const pieces = mimeType.split(/ *; */);
pieces.shift(); // Remove basic MIME type from pieces.
const codecs = pieces.find((piece) => piece.startsWith('codecs='));
if (!codecs) {
return '';
}
// The value may be quoted, so remove quotes at the beginning or end.
const value = codecs.split('=')[1].replace(/^"|"$/g, '');
return value;
}
/**
* Get the base and profile of a codec string. Where [0] will be the codec
* base and [1] will be the profile.
* @param {string} codecString
* @return {!Array.<string>}
* @private
*/
static getCodecParts_(codecString) {
const parts = codecString.split('.');
const base = parts[0];
parts.pop();
const profile = parts.join('.');
// Make sure that we always return a "base" and "profile".
return [base, profile];
}
};
/**
* A map from Stream object keys to MIME type parameters. These should be
* ignored by platforms that do not recognize them.
*
* This initial set of parameters are all recognized by Chromecast.
*
* @const {!Map.<string, string>}
* @private
*/
shaka.util.MimeUtils.EXTENDED_MIME_PARAMETERS_ = new Map()
.set('codecs', 'codecs')
.set('frameRate', 'framerate') // Ours is camelCase, theirs is lowercase.
.set('bandwidth', 'bitrate') // They are in the same units: bits/sec.
.set('width', 'width')
.set('height', 'height')
.set('channelsCount', 'channels');
/**
* A mimetype created for CEA closed captions.
* @const {string}
*/
shaka.util.MimeUtils.CLOSED_CAPTION_MIMETYPE = 'application/cea-608';