Source: lib/util/mime_utils.js

  1. /*! @license
  2.  * Shaka Player
  3.  * Copyright 2016 Google LLC
  4.  * SPDX-License-Identifier: Apache-2.0
  5.  */
  7. goog.provide('shaka.util.MimeUtils');
  9. goog.require('shaka.transmuxer.TransmuxerEngine');
  10. goog.require('shaka.util.ManifestParserUtils');
  12. /**
  13.  * @summary A set of utility functions for dealing with MIME types.
  14.  * @export
  15.  */
  16. shaka.util.MimeUtils = class {
  17.   /**
  18.    * Takes a MIME type and optional codecs string and produces the full MIME
  19.    * type. Also remove the codecs for raw formats.
  20.    *
  21.    * @param {string} mimeType
  22.    * @param {string=} codecs
  23.    * @return {string}
  24.    * @export
  25.    */
  26.   static getFullType(mimeType, codecs) {
  27.     let fullMimeType = mimeType;
  28.     if (codecs && !shaka.util.MimeUtils.RAW_FORMATS.includes(mimeType)) {
  29.       fullMimeType += '; codecs="' + codecs + '"';
  30.     }
  31.     return fullMimeType;
  32.   }
  34.   /**
  35.    * Takes a MIME type and optional codecs string and produces the full MIME
  36.    * type.
  37.    *
  38.    * @param {string} mimeType
  39.    * @param {string=} codecs
  40.    * @return {string}
  41.    * @export
  42.    */
  43.   static getFullTypeWithAllCodecs(mimeType, codecs) {
  44.     let fullMimeType = mimeType;
  45.     if (codecs) {
  46.       fullMimeType += '; codecs="' + codecs + '"';
  47.     }
  48.     return fullMimeType;
  49.   }
  51.   /**
  52.    * Takes a MIME type and a codecs string and produces the full MIME
  53.    * type. If it's a transport stream, convert its codecs to MP4 codecs.
  54.    * Otherwise for multiplexed content, convert the video MIME types to
  55.    * their audio equivalents if the content type is audio.
  56.    *
  57.    * @param {string} mimeType
  58.    * @param {string} codecs
  59.    * @param {string} contentType
  60.    * @return {string}
  61.    */
  62.   static getFullOrConvertedType(mimeType, codecs, contentType) {
  63.     const MimeUtils = shaka.util.MimeUtils;
  64.     const fullMimeType = MimeUtils.getFullType(mimeType, codecs);
  65.     const fullMimeTypeWithAllCodecs = MimeUtils.getFullTypeWithAllCodecs(
  66.         mimeType, codecs);
  67.     const ContentType = shaka.util.ManifestParserUtils.ContentType;
  68.     const TransmuxerEngine = shaka.transmuxer.TransmuxerEngine;
  70.     if (TransmuxerEngine.isSupported(fullMimeTypeWithAllCodecs, contentType)) {
  71.       return TransmuxerEngine.convertCodecs(
  72.           contentType, fullMimeTypeWithAllCodecs);
  73.     } else if (mimeType != 'video/mp2t' && contentType == ContentType.AUDIO) {
  74.       // video/mp2t is the correct mime type for TS audio, so only replace the
  75.       // word "video" with "audio" for non-TS audio content.
  76.       return fullMimeType.replace('video', 'audio');
  77.     }
  78.     return fullMimeType;
  79.   }
  82.   /**
  83.    * Takes a Stream object and produces an extended MIME type with information
  84.    * beyond the container and codec type, when available.
  85.    *
  86.    * @param {shaka.extern.Stream} stream
  87.    * @return {string}
  88.    */
  89.   static getExtendedType(stream) {
  90.     const components = [stream.mimeType];
  92.     const extendedMimeParams = shaka.util.MimeUtils.EXTENDED_MIME_PARAMETERS_;
  93.     extendedMimeParams.forEach((mimeKey, streamKey) => {
  94.       const value = stream[streamKey];
  95.       if (streamKey == 'codecs' &&
  96.           shaka.util.MimeUtils.RAW_FORMATS.includes(stream.mimeType)) {
  97.         // Skip codecs for raw formats
  98.       } else if (value) {
  99.         components.push(mimeKey + '="' + value + '"');
  100.       }
  101.     });
  102.     if (stream.hdr == 'PQ') {
  103.       components.push('eotf="smpte2084"');
  104.     }
  106.     return components.join(';');
  107.   }
  109.   /**
  110.    * Takes a full MIME type (with codecs) or basic MIME type (without codecs)
  111.    * and returns a container type string ("mp2t", "mp4", "webm", etc.)
  112.    *
  113.    * @param {string} mimeType
  114.    * @return {string}
  115.    */
  116.   static getContainerType(mimeType) {
  117.     return mimeType.split(';')[0].split('/')[1];
  118.   }
  120.   /**
  121.    * Split a list of codecs encoded in a string into a list of codecs.
  122.    * @param {string} codecs
  123.    * @return {!Array.<string>}
  124.    */
  125.   static splitCodecs(codecs) {
  126.     return codecs.split(',');
  127.   }
  129.   /**
  130.    * Get the normalized codec from a codec string,
  131.    * independently of their container.
  132.    *
  133.    * @param {string} codecString
  134.    * @return {string}
  135.    */
  136.   static getNormalizedCodec(codecString) {
  137.     const parts =
  138.       shaka.util.MimeUtils.getCodecParts_(codecString);
  139.     const base = parts[0];
  140.     const profile = parts[1].toLowerCase();
  141.     switch (true) {
  142.       case base === 'mp4a' && profile === '69':
  143.       case base === 'mp4a' && profile === '6b':
  144.       case base === 'mp4a' && profile === '40.34':
  145.         return 'mp3';
  146.       case base === 'mp4a' && profile === '66':
  147.       case base === 'mp4a' && profile === '67':
  148.       case base === 'mp4a' && profile === '68':
  149.       case base === 'mp4a' && profile === '40.2':
  150.       case base === 'mp4a' && profile === '40.02':
  151.       case base === 'mp4a' && profile === '40.5':
  152.       case base === 'mp4a' && profile === '40.05':
  153.       case base === 'mp4a' && profile === '40.29':
  154.       case base === 'mp4a' && profile === '40.42': // Extended HE-AAC
  155.         return 'aac';
  156.       case base === 'mp4a' && profile === 'a5':
  157.         return 'ac-3'; // Dolby Digital
  158.       case base === 'mp4a' && profile === 'a6':
  159.         return 'ec-3'; // Dolby Digital Plus
  160.       case base === 'mp4a' && profile === 'b2':
  161.         return 'dtsx'; // DTS:X
  162.       case base === 'mp4a' && profile === 'a9':
  163.         return 'dtsc'; // DTS Digital Surround
  164.       case base === 'avc1':
  165.       case base === 'avc3':
  166.         return 'avc'; // H264
  167.       case base === 'hvc1':
  168.       case base === 'hev1':
  169.         return 'hevc'; // H265
  170.       case base === 'dvh1':
  171.       case base === 'dvhe':
  172.         return 'dovi'; // Dolby Vision
  173.     }
  174.     return base;
  175.   }
  177.   /**
  178.    * Get the base codec from a codec string.
  179.    *
  180.    * @param {string} codecString
  181.    * @return {string}
  182.    */
  183.   static getCodecBase(codecString) {
  184.     const parts = shaka.util.MimeUtils.getCodecParts_(codecString);
  185.     return parts[0];
  186.   }
  188.   /**
  189.    * Takes a full MIME type (with codecs) or basic MIME type (without codecs)
  190.    * and returns a basic MIME type (without codecs or other parameters).
  191.    *
  192.    * @param {string} mimeType
  193.    * @return {string}
  194.    */
  195.   static getBasicType(mimeType) {
  196.     return mimeType.split(';')[0];
  197.   }
  199.   /**
  200.    * Takes a MIME type and returns the codecs parameter, or an empty string if
  201.    * there is no codecs parameter.
  202.    *
  203.    * @param {string} mimeType
  204.    * @return {string}
  205.    */
  206.   static getCodecs(mimeType) {
  207.     // Parse the basic MIME type from its parameters.
  208.     const pieces = mimeType.split(/ *; */);
  209.     pieces.shift();  // Remove basic MIME type from pieces.
  211.     const codecs = pieces.find((piece) => piece.startsWith('codecs='));
  212.     if (!codecs) {
  213.       return '';
  214.     }
  216.     // The value may be quoted, so remove quotes at the beginning or end.
  217.     const value = codecs.split('=')[1].replace(/^"|"$/g, '');
  218.     return value;
  219.   }
  221.   /**
  222.    * Checks if the given MIME type is HLS MIME type.
  223.    *
  224.    * @param {string} mimeType
  225.    * @return {boolean}
  226.    */
  227.   static isHlsType(mimeType) {
  228.     return mimeType === 'application/x-mpegurl' ||
  229.         mimeType === 'application/vnd.apple.mpegurl';
  230.   }
  232.   /**
  233.    * Get the base and profile of a codec string. Where [0] will be the codec
  234.    * base and [1] will be the profile.
  235.    * @param {string} codecString
  236.    * @return {!Array.<string>}
  237.    * @private
  238.    */
  239.   static getCodecParts_(codecString) {
  240.     const parts = codecString.split('.');
  242.     const base = parts[0];
  244.     parts.shift();
  245.     const profile = parts.join('.');
  247.     // Make sure that we always return a "base" and "profile".
  248.     return [base, profile];
  249.   }
  250. };
  253. /**
  254.  * A map from Stream object keys to MIME type parameters.  These should be
  255.  * ignored by platforms that do not recognize them.
  256.  *
  257.  * This initial set of parameters are all recognized by Chromecast.
  258.  *
  259.  * @const {!Map.<string, string>}
  260.  * @private
  261.  */
  262. shaka.util.MimeUtils.EXTENDED_MIME_PARAMETERS_ = new Map()
  263.     .set('codecs', 'codecs')
  264.     .set('frameRate', 'framerate')  // Ours is camelCase, theirs is lowercase.
  265.     .set('bandwidth', 'bitrate')  // They are in the same units: bits/sec.
  266.     .set('width', 'width')
  267.     .set('height', 'height')
  268.     .set('channelsCount', 'channels');
  271. /**
  272.  * A mimetype created for CEA-608 closed captions.
  273.  * @const {string}
  274.  */
  275. shaka.util.MimeUtils.CEA608_CLOSED_CAPTION_MIMETYPE = 'application/cea-608';
  277. /**
  278.  * A mimetype created for CEA-708 closed captions.
  279.  * @const {string}
  280.  */
  281. shaka.util.MimeUtils.CEA708_CLOSED_CAPTION_MIMETYPE = 'application/cea-708';
  283. /**
  284.  * MIME types of raw formats.
  285.  *
  286.  * @const {!Array.<string>}
  287.  */
  288. shaka.util.MimeUtils.RAW_FORMATS = [
  289.   'audio/aac',
  290.   'audio/ac3',
  291.   'audio/ec3',
  292.   'audio/mpeg',
  293. ];