/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.media.ClosedCaptionParser');
goog.provide('shaka.media.IClosedCaptionParser');
goog.require('shaka.cea.DummyCaptionDecoder');
goog.require('shaka.cea.DummyCeaParser');
goog.require('shaka.log');
goog.require('shaka.util.BufferUtils');
/**
* The IClosedCaptionParser defines the interface to provide all operations for
* parsing the closed captions embedded in Dash videos streams.
* TODO: Remove this interface and move method definitions
* directly to ClosedCaptonParser.
* @interface
* @export
*/
shaka.media.IClosedCaptionParser = class {
/**
* Initialize the caption parser. This should be called whenever new init
* segment arrives.
* @param {BufferSource} initSegment
* @param {boolean=} adaptation True if we just automatically switched active
* variant(s).
*/
init(initSegment, adaptation = false) {}
/**
* Parses embedded CEA closed captions and interacts with the underlying
* CaptionStream, and calls the callback function when there are closed
* captions.
*
* @param {BufferSource} mediaFragment
* @return {!Array<!shaka.extern.ICaptionDecoder.ClosedCaption>}
* An array of parsed closed captions.
*/
parseFrom(mediaFragment) {}
/**
* Resets the CaptionStream.
*/
reset() {}
/**
* Returns the streams that the CEA decoder found.
* @return {!Array.<string>}
*/
getStreams() {}
};
/**
* Closed Caption Parser provides all operations for parsing the closed captions
* embedded in Dash videos streams.
*
* @implements {shaka.media.IClosedCaptionParser}
* @final
* @export
*/
shaka.media.ClosedCaptionParser = class {
/**
* @param {string} mimeType
*/
constructor(mimeType) {
/** @private {!shaka.extern.ICeaParser} */
this.ceaParser_ = new shaka.cea.DummyCeaParser();
const parserFactory =
shaka.media.ClosedCaptionParser.findParser(mimeType.toLowerCase());
if (parserFactory) {
this.ceaParser_ = parserFactory();
}
/**
* Decoder for decoding CEA-X08 data from closed caption packets.
* @private {!shaka.extern.ICaptionDecoder}
*/
this.ceaDecoder_ = new shaka.cea.DummyCaptionDecoder();
const decoderFactory = shaka.media.ClosedCaptionParser.findDecoder();
if (decoderFactory) {
this.ceaDecoder_ = decoderFactory();
}
}
/**
* @override
*/
init(initSegment, adaptation = false) {
shaka.log.debug('Passing new init segment to CEA parser');
if (!adaptation) {
// Reset underlying decoder when new init segment arrives
// to clear stored pts values.
// This is necessary when a new Period comes in DASH or a discontinuity
// in HLS.
this.reset();
}
this.ceaParser_.init(initSegment);
}
/**
* @override
*/
parseFrom(mediaFragment) {
// Parse the fragment.
const captionPackets = this.ceaParser_.parse(mediaFragment);
// Extract the caption packets for decoding.
for (const captionPacket of captionPackets) {
const uint8ArrayData =
shaka.util.BufferUtils.toUint8(captionPacket.packet);
if (uint8ArrayData.length > 0) {
this.ceaDecoder_.extract(uint8ArrayData, captionPacket.pts);
}
}
// Decode and return the parsed captions.
return this.ceaDecoder_.decode();
}
/**
* @override
*/
reset() {
this.ceaDecoder_.clear();
}
/**
* @override
*/
getStreams() {
return this.ceaDecoder_.getStreams();
}
/**
* @param {string} mimeType
* @param {!shaka.extern.CeaParserPlugin} plugin
* @export
*/
static registerParser(mimeType, plugin) {
shaka.media.ClosedCaptionParser.parserMap_[mimeType] = plugin;
}
/**
* @param {string} mimeType
* @export
*/
static unregisterParser(mimeType) {
delete shaka.media.ClosedCaptionParser.parserMap_[mimeType];
}
/**
* @param {string} mimeType
* @return {?shaka.extern.CeaParserPlugin}
* @export
*/
static findParser(mimeType) {
return shaka.media.ClosedCaptionParser.parserMap_[mimeType];
}
/**
* @param {!shaka.extern.CaptionDecoderPlugin} plugin
* @export
*/
static registerDecoder(plugin) {
shaka.media.ClosedCaptionParser.decoderFactory_ = plugin;
}
/**
* @export
*/
static unregisterDecoder() {
shaka.media.ClosedCaptionParser.decoderFactory_ = null;
}
/**
* @return {?shaka.extern.CaptionDecoderPlugin}
* @export
*/
static findDecoder() {
return shaka.media.ClosedCaptionParser.decoderFactory_;
}
};
/** @private {!Object<string, shaka.extern.CeaParserPlugin>} */
shaka.media.ClosedCaptionParser.parserMap_ = {};
/** @private {?shaka.extern.CaptionDecoderPlugin} */
shaka.media.ClosedCaptionParser.decoderFactory_ = null;