/*! @license * Shaka Player * Copyright 2016 Google LLC * SPDX-License-Identifier: Apache-2.0 */goog.provide('shaka.polyfill.MediaSource');goog.require('shaka.log');goog.require('shaka.polyfill');goog.require('shaka.util.MimeUtils');goog.require('shaka.util.Platform');/** * @summary A polyfill to patch MSE bugs. */shaka.polyfill.MediaSource = class { /** * Install the polyfill if needed. */ static install() { shaka.log.debug('MediaSource.install'); // MediaSource bugs are difficult to detect without checking for the // affected platform. SourceBuffer is not always exposed on window, for // example, and instances are only accessible after setting up MediaSource // on a video element. Because of this, we use UA detection and other // platform detection tricks to decide which patches to install. const safariVersion = shaka.util.Platform.safariVersion(); if (!window.MediaSource) { shaka.log.info('No MSE implementation available.'); } else if (window.cast && cast.__platform__ && cast.__platform__.canDisplayType) { shaka.log.info('Patching Chromecast MSE bugs.'); // Chromecast cannot make accurate determinations via isTypeSupported. shaka.polyfill.MediaSource.patchCastIsTypeSupported_(); } else if (safariVersion) { // TS content is broken on Safari in general. // See https://github.com/google/shaka-player/issues/743 // and https://bugs.webkit.org/show_bug.cgi?id=165342 shaka.polyfill.MediaSource.rejectTsContent_(); // NOTE: shaka.Player.isBrowserSupported() has its own restrictions on // Safari version. if (safariVersion <= 12) { shaka.log.info('Patching Safari 11 & 12 MSE bugs.'); // Safari 11 & 12 do not correctly implement abort() on SourceBuffer. // Calling abort() before appending a segment causes that segment to be // incomplete in the buffer. // Bug filed: https://bugs.webkit.org/show_bug.cgi?id=165342 shaka.polyfill.MediaSource.stubAbort_(); // If you remove up to a keyframe, Safari 11 & 12 incorrectly will also // remove that keyframe and the content up to the next. // Offsetting the end of the removal range seems to help. // Bug filed: https://bugs.webkit.org/show_bug.cgi?id=177884 shaka.polyfill.MediaSource.patchRemovalRange_(); } else { shaka.log.info('Patching Safari 13 MSE bugs.'); // Safari 13 does not correctly implement abort() on SourceBuffer. // Calling abort() before appending a segment causes that segment to be // incomplete in the buffer. // Bug filed: https://bugs.webkit.org/show_bug.cgi?id=165342 shaka.polyfill.MediaSource.stubAbort_(); } } else if (shaka.util.Platform.isTizen2() || shaka.util.Platform.isTizen3() || shaka.util.Platform.isTizen4()) { shaka.log.info('Rejecting Opus.'); // Tizen's implementation of MSE does not work well with opus. To prevent // the player from trying to play opus on Tizen, we will override media // source to always reject opus content. shaka.polyfill.MediaSource.rejectCodec_('opus'); } else { shaka.log.info('Using native MSE as-is.'); } if (window.MediaSource && MediaSource.isTypeSupported('video/webm; codecs="vp9"') && !MediaSource.isTypeSupported('video/webm; codecs="vp09.00.10.08"')) { shaka.log.info('Patching vp09 support queries.'); // Only the old, deprecated style of VP9 codec strings is supported. // This occurs on older smart TVs. // Patch isTypeSupported to translate the new strings into the old one. shaka.polyfill.MediaSource.patchVp09_(); } } /** * Stub out abort(). On some buggy MSE implementations, calling abort() * causes various problems. * * @private */ static stubAbort_() { /* eslint-disable no-restricted-syntax */ const addSourceBuffer = MediaSource.prototype.addSourceBuffer; MediaSource.prototype.addSourceBuffer = function(...varArgs) { const sourceBuffer = addSourceBuffer.apply(this, varArgs); sourceBuffer.abort = function() {}; // Stub out for buggy implementations. return sourceBuffer; }; /* eslint-enable no-restricted-syntax */ } /** * Patch remove(). On Safari 11, if you call remove() to remove the content * up to a keyframe, Safari will also remove the keyframe and all of the data * up to the next one. For example, if the keyframes are at 0s, 5s, and 10s, * and you tried to remove 0s-5s, it would instead remove 0s-10s. * * Offsetting the end of the range seems to be a usable workaround. * * @private */ static patchRemovalRange_() { // eslint-disable-next-line no-restricted-syntax const originalRemove = SourceBuffer.prototype.remove; // eslint-disable-next-line no-restricted-syntax SourceBuffer.prototype.remove = function(startTime, endTime) { // eslint-disable-next-line no-restricted-syntax return originalRemove.call(this, startTime, endTime - 0.001); }; } /** * Patch isTypeSupported() to reject TS content. Used to avoid TS-related MSE * bugs on Safari. * * @private */ static rejectTsContent_() { const originalIsTypeSupported = MediaSource.isTypeSupported; MediaSource.isTypeSupported = (mimeType) => { // Parse the basic MIME type from its parameters. const pieces = mimeType.split(/ *; */); const basicMimeType = pieces[0]; const container = basicMimeType.split('/')[1]; if (container.toLowerCase() == 'mp2t') { return false; } return originalIsTypeSupported(mimeType); }; } /** * Patch |MediaSource.isTypeSupported| to always reject |codec|. This is used * when we know that we are on a platform that does not work well with a given * codec. * * @param {string} codec * @private */ static rejectCodec_(codec) { const isTypeSupported = MediaSource.isTypeSupported; MediaSource.isTypeSupported = (mimeType) => { const actualCodec = shaka.util.MimeUtils.getCodecBase(mimeType); return actualCodec != codec && isTypeSupported(mimeType); }; } /** * Patch isTypeSupported() to chain to a private API on the Chromecast which * can query for support of detailed content parameters. * * @private */ static patchCastIsTypeSupported_() { const originalIsTypeSupported = MediaSource.isTypeSupported; MediaSource.isTypeSupported = (mimeType) => { // Parse the basic MIME type from its parameters. const pieces = mimeType.split(/ *; */); pieces.shift(); // Remove basic MIME type from pieces. const hasCodecs = pieces.some((piece) => piece.startsWith('codecs=')); if (!hasCodecs) { // Though the original reason for this special case was not documented, // it is presumed to be because the platform won't accept a MIME type // without codecs in canDisplayType. It is valid, however, in // isTypeSupported. return originalIsTypeSupported(mimeType); } // Only canDisplayType can check extended MIME type parameters on this // platform (such as frame rate, resolution, etc). // In previous versions of this polyfill, the MIME type parameters were // manipulated, filtered, or extended. This is no longer true, so we pass // the full MIME type to the platform as we received it. return cast.__platform__.canDisplayType(mimeType); }; } /** * Patch isTypeSupported() to translate vp09 codec strings into vp9, to allow * such content to play on older smart TVs. * * @private */ static patchVp09_() { const originalIsTypeSupported = MediaSource.isTypeSupported; MediaSource.isTypeSupported = (mimeType) => { // Split the MIME type into its various parameters. const pieces = mimeType.split(/ *; */); const codecsIndex = pieces.findIndex((piece) => piece.startsWith('codecs=')); if (codecsIndex < 0) { // No codec? Call the original without modifying the MIME type. return originalIsTypeSupported(mimeType); } const codecsParam = pieces[codecsIndex]; const codecs = codecsParam .replace('codecs=', '').replace(/"/g, '').split(/\s*,\s*/); const vp09Index = codecs.findIndex( (codecName) => codecName.startsWith('vp09')); if (vp09Index >= 0) { // vp09? Replace it with vp9. codecs[vp09Index] = 'vp9'; pieces[codecsIndex] = 'codecs="' + codecs.join(',') + '"'; mimeType = pieces.join('; '); } return originalIsTypeSupported(mimeType); }; }};shaka.polyfill.register(shaka.polyfill.MediaSource.install);