mirror of https://bitbucket.org/ausocean/av.git
132 lines
3.3 KiB
JavaScript
132 lines
3.3 KiB
JavaScript
/*
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AUTHOR
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Trek Hopton <trek@ausocean.org>
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LICENSE
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This file is Copyright (C) 2020 the Australian Ocean Lab (AusOcean)
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It is free software: you can redistribute it and/or modify them
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under the terms of the GNU General Public License as published by the
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Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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It is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License in gpl.txt.
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If not, see http://www.gnu.org/licenses.
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*/
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let frameRate = 25; //Keeps track of the frame rate, default is 25fps.
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self.importScripts('./lex-mjpeg.js');
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self.importScripts('./hlsjs/mts-demuxer.js');
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const codecs = {
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MJPEG: 1,
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MTS_MJPEG: 2,
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}
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// onmessage is called whenever the main thread sends this worker a message.
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onmessage = e => {
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switch (e.data.msg) {
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case "setFrameRate":
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frameRate = e.data.data;
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break;
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case "loadMjpeg":
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player = new PlayerWorker();
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player.init(codecs.MJPEG);
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player.append(e.data.data);
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player.setFrameRate(frameRate);
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player.start();
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break;
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case "loadMtsMjpeg":
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player = new PlayerWorker();
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player.init(codecs.MTS_MJPEG);
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player.append(e.data.data);
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player.start();
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break;
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case "appendMtsMjpeg":
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player.append(e.data.data);
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break;
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default:
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console.error("unknown message from main thread");
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break;
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}
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};
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// PlayerWorker has a FrameBuffer to hold frames and once started, passes them one at a time to the main thread.
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class PlayerWorker {
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init(codec) {
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this.frameRate = frameRate;
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this.codec = codec;
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switch (codec) {
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case codecs.MJPEG:
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this.frameSrc = new MJPEGLexer();
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break;
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case codecs.MTS_MJPEG:
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this.frameSrc = new FrameBuffer();
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break;
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}
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}
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setFrameRate(rate) {
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this.frameRate = rate;
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}
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start() {
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let frame = this.frameSrc.read();
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if (frame != null) {
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postMessage({ msg: "frame", data: frame.buffer }, [frame.buffer]);
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setTimeout(() => { this.start(); }, 1000 / this.frameRate);
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}
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}
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append(data) {
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this.frameSrc.append(data);
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}
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}
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// FrameBuffer allows an array of subarrays (MJPEG frames) to be read one at a time.
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class FrameBuffer {
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constructor() {
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this.segments = [];
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this.off = { segment: 0, frame: 0 };
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this.demuxer = new MTSDemuxer();
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}
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// read returns the next single frame.
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read() {
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let off = this.off;
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let prevOff = off;
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if (this.incrementOff()) {
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return this.segments[prevOff.segment][prevOff.frame];
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} else {
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return null;
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}
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}
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append(data) {
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let demuxed = this.demuxer.demux(new Uint8Array(data));
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this.segments.push(demuxed.data);
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}
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incrementOff() {
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if (!this.segments || !this.segments[this.off.segment]) {
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return false;
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}
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if (this.off.frame + 1 >= this.segments[this.off.segment].length) {
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if (this.off.segment + 1 >= this.segments.length) {
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return false;
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} else {
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this.off.segment++;
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this.off.frame = 0;
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return true;
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}
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} else {
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this.off.frame++;
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return true;
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}
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}
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} |