mirror of
https://github.com/shaka-project/shaka-player.git
synced 2026-06-17 16:26:39 +03:00
Muhammad Haris
480d4a801a
This is an MP4 Parser which extracts CEA-708 packets from Fragmented MP4 streams. The Closed Caption Parser (shaka.media.ClosedCaptionParser) will own this MP4 Parser, and will initialize it and call it as shown. As data comes in, the parser will parse this data, and the caption packets data then be returned in a callback (on708Data), as shown. Here, a theoretical decoder (future pull request, mentioned as a Todo comment) will decode and extract the parsed captions from these packets. Issue #2648
57 lines
1.4 KiB
JavaScript
57 lines
1.4 KiB
JavaScript
/*! @license
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* Shaka Player
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* Copyright 2016 Google LLC
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* SPDX-License-Identifier: Apache-2.0
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*/
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goog.provide('shaka.cea.ICeaParser');
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/**
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* Interface for parsing inband closed caption data from MP4 streams.
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* @interface
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*/
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shaka.cea.ICeaParser = class {
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/**
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* Initializes the parser with init segment data.
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* @param {!BufferSource} initSegment init segment to parse.
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*/
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init(initSegment) {}
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/**
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* Parses the stream and extracts closed captions packets.
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* @param {!BufferSource} mediaSegment media segment to parse.
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* @return {!Array<!shaka.cea.ICeaParser.CaptionPacket>}
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*/
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parse(mediaSegment) {}
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};
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/**
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* NALU type for Supplemental Enhancement Information (SEI).
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* @const {number}
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*/
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shaka.cea.ICeaParser.NALU_TYPE_SEI = 0x06;
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/**
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* Default timescale value for a track.
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*/
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shaka.cea.ICeaParser.DEFAULT_TIMESCALE_VALUE = 90000;
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/**
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* @typedef {{
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* packet: !Uint8Array,
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* pts: !number
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* }}
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*
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* @description Parsed Caption Packet.
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* @property {!Uint8Array} packet
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* Caption packet. More specifically, it contains a "User data
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* registered by Recommendation ITU-T T.35 SEI message", from section D.1.6
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* and section D.2.6 of Rec. ITU-T H.264 (06/2019).
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* @property {!number} pts
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* The presentation timestamp (pts) at which the ITU-T T.35 data shows up,
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* in seconds.
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* @exportDoc
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*/
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shaka.cea.ICeaParser.CaptionPacket;
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