Skip to content

Commit

Permalink
Copy MPEG3 plugin from plopp
Browse files Browse the repository at this point in the history
  • Loading branch information
@codefrau
codefrau committed Dec 25, 2023
1 parent a584ede commit 96af425
Show file tree
Hide file tree
Showing 2 changed files with 284 additions and 0 deletions.
1 change: 1 addition & 0 deletions index.html
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@
<script src="jasmine-b3dengine-plugin.js"></script>
<script src="jasmine-opengl.js"></script>
<!-- <script src="https://greggman.github.io/webgl-lint/webgl-lint.js" crossorigin></script> -->
<script src="jasmine-mpeg3-plugin.js"></script>
</head>
<body>
<canvas id="sqCanvas" width="800" height="600"></canvas>
Expand Down
283 changes: 283 additions & 0 deletions jasmine-mpeg3-plugin.js
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,283 @@
// Jasmine Mpeg3Plugin, we play mp3 and mpg (but use mp4 for mpg)
// empty video frames are sent to Squeak, videos are shown as overlay in the browser
// silent audio is sent to Squeak, we play directly via browser
// this is hardcoded to pretend we play videos at 320x240, 25fps
// and audio at 44100Hz, 1 channel
//
// TODO:
// [ ] actually decode video frames and send them to Squeak
// [ ] actually decode audio samples and send them to Squeak

function JasmineMpeg3Plugin() {
"use strict";

var DEBUG = 1; // 0 = off, 1 = some, 2 = lots

return {
getModuleName: function() { return 'Mpeg3Plugin'; },
interpreterProxy: null,
primHandler: null,
vm: null,

setInterpreter: function(anInterpreter) {
this.interpreterProxy = anInterpreter;
this.vm = this.interpreterProxy.vm;
this.primHandler = this.vm.primHandler;
return true;
},

initialiseModule: function() {
// silent audio
this.audioElement = new Audio("data:audio/wav;base64,UklGRigAAABXQVZFZm10IBIAAAABAAEARKwAAIhYAQACABAAAABkYXRhAgAAAAEA");
// for some reason, timing is more accurate on iOS
// if we play through an audio context
var audioCtx = Squeak.startAudioOut();
var node = audioCtx.createMediaElementSource(this.audioElement);
node.connect(audioCtx.destination);
this.audioElement.play();
// empty video
this.videoElement = document.createElement("video");
},

primitiveMPEG3CheckSig: function(argCount) {
// assume any file is valid
return this.primHandler.popNandPushBoolIfOK(argCount + 1, true);
},

primitiveMPEG3Open: function(argCount) {
var pathObj = this.interpreterProxy.stackObjectValue(0);
var path = pathObj.bytesAsString();
// hack to find mp4 in jasmine directory
path = path.replace(/.*\/jasmine\//, "");
path = path.replace(/\.mpg$/, ".mp4");
var isAudio = path.match(/\.mp3$/);
// We use this.audioElement or this.videoElement which have been
// interacted with by the user, so they are allowed to play
var player;
if (isAudio) {
player = this.audioElement;
player.isAudio = true;
} else {
player = this.videoElement;
player.isVideo = true;
player.playsInline = true; // Safari
document.body.appendChild(player);
}
player.src = path; // start playing
player.currentTime = 0; // start at beginning
player.play();
// create handle
var handle = this.primHandler.makeStString("squeakjs-mpeg:" + path);
handle.player = player;
// freeze VM until player is actually playing
this.vm.freeze(function(unfreeze) {
function continueExecution() {
unfreeze();
unfreeze = null; // don't unfreeze twice
}

player.addEventListener('timeupdate',
function() {
if (player.currentTime < 0.1) return; // not playing yet
if (!unfreeze) return; // already failed or started
DEBUG > 0 && console.log("primitiveMPEG3Open: "
+ (player.isVideo? player.videoWidth + "x" + player.videoHeight + ", " : "")
+ player.duration + "s " + player.src);
if (player.isAudio) {
// we pretend to send samples so Squeak can track time
player.sentSamples = 0;
player.totalSamples = Math.floor(player.duration * 44100);
}
continueExecution();
},
);
player.onerror = function(err) {
if (!unfreeze) return; // too late
console.error("primitiveMPEG3Open: error", err);
continueExecution();
};
}.bind(this));
// the primitive will succeeed now, but then the VM
// will pause execution until unfreeze() is called
this.interpreterProxy.popthenPush(argCount + 1, handle);
return true;
},

primitiveMPEG3Close: function(argCount) {
var player = this.playerFromStackArg(0);
if (!player) return false;
DEBUG > 0 && console.log("primitiveMPEG3Close", player.src);
player.pause();
if (player.isVideo) player.remove();
try {
player.removeAttribute('src');
player.load();
} catch (err) {}
this.interpreterProxy.pop(argCount);
return true;
},

playerFromStackArg: function(n) {
var handle = this.interpreterProxy.stackObjectValue(n);
if (this.interpreterProxy.failed()) return null;
return handle.player;
},

primitiveMPEG3HasAudio: function(argCount) {
var player = this.playerFromStackArg(0);
return this.primHandler.popNandPushBoolIfOK(argCount + 1, player && player.isAudio);
},

primitiveMPEG3HasVideo: function(argCount) {
var player = this.playerFromStackArg(0);
return this.primHandler.popNandPushBoolIfOK(argCount + 1, player && player.isVideo);
},

//////////// VIDEO /////////////

primitiveMPEG3TotalVStreams: function(argCount) {
var player = this.playerFromStackArg(0);
return this.primHandler.popNandPushIntIfOK(argCount + 1, player && player.isVideo ? 1 : 0);
},

primitiveMPEG3FrameRate: function(argCount) {
return this.primHandler.popNandPushIntIfOK(argCount + 1, 25);
},

primitiveMPEG3VideoWidth: function(argCount) {
return this.primHandler.popNandPushIntIfOK(argCount + 1, 320);
},

primitiveMPEG3VideoHeight: function(argCount) {
return this.primHandler.popNandPushIntIfOK(argCount + 1, 240);
},

primitiveMPEG3ReadFrame: function(argCount) {
DEBUG > 1 && console.log("primitiveMPEG3ReadFrame");
this.interpreterProxy.pop(argCount);
return true;
},

primitiveMPEG3GetFrame: function(argCount) {
var player = this.playerFromStackArg(1);
if (!player) return false;
var frame = Math.floor(player.currentTime * 25);
var frames = Math.floor(player.duration * 25);
DEBUG > 1 && console.log("primitiveMPEG3GetFrame", frame, "of", frames);
if (frame >= frames) frame = frames - 1;
return this.primHandler.popNandPushIntIfOK(argCount + 1, frame);
},

primitiveMPEG3VideoFrames: function(argCount) {
var player = this.playerFromStackArg(1);
if (!player) return false;
var frames = Math.floor(player.duration * 25);
DEBUG > 1 && console.log("primitiveMPEG3VideoFrames", frames);
return this.primHandler.popNandPushIntIfOK(argCount + 1, frames);
},

primitiveMPEG3SetFrame: function(argCount) {
var player = this.playerFromStackArg(2);
if (!player) return false;
var frame = this.interpreterProxy.stackIntegerValue(1);
player.currentTime = frame / 25;
DEBUG > 0 && console.log("primitiveMPEG3SetFrame", frame, "(current time now " + player.currentTime.toFixed(1) + ")");
this.interpreterProxy.pop(argCount);
return true;
},

primitiveMPEG3DropFrames: function(argCount) {
// var count = this.interpreterProxy.stackIntegerValue(1);
DEBUG > 1 && console.log("primitiveMPEG3DropFrames", count);
this.interpreterProxy.pop(argCount);
return true;
},

primitiveMPEG3ReadFrameBufferOffset: function(argCount) {
return this.primHandler.popNandPushIntIfOK(argCount + 1, 0);
},

primitiveMPEG3EndOfVideo: function(argCount) {
var player = this.playerFromStackArg(1);
if (!player) return false;
DEBUG > 1 && console.log("primitiveMPEG3EndOfVideo:", player.ended);
return this.primHandler.popNandPushBoolIfOK(argCount + 1, player.ended);
},

//////////// AUDIO /////////////

primitiveMPEG3AudioChannels: function(argCount) {
DEBUG > 1 && console.log("primitiveMPEG3AudioChannels", 1);
// even if it was stereo - we're not sending samples to Squeak
// so it doesn't matter
return this.primHandler.popNandPushIntIfOK(argCount + 1, 1);
},

primitiveMPEG3SampleRate: function(argCount) {
DEBUG > 1 && console.log("primitiveMPEG3SampleRate", 44100);
return this.primHandler.popNandPushIntIfOK(argCount + 1, 44100);
},

primitiveMPEG3SetSample: function(argCount) {
var player = this.playerFromStackArg(2);
if (!player) return false;
var sample = this.interpreterProxy.stackIntegerValue(1);
player.currentTime = sample / 44100;
DEBUG > 0 && console.log("primitiveMPEG3SetSample", sample, "(current time now " + player.currentTime.toFixed(1) + ")");
this.interpreterProxy.pop(argCount);
return true;
},

primitiveMPEG3GetSample: function(argCount) {
var player = this.playerFromStackArg(1);
if (!player) return false;
var sent = player.sentSamples;
var actual = Math.floor(player.currentTime * 44100);
var total = player.totalSamples;
var samples = sent;
if (samples > total) samples = total;
if (actual > total || player.ended) actual = total;
DEBUG > 1 && console.log("primitiveMPEG3GetSample sent:", sent, "/", total, "(todo:", total - sent, "), actual:", actual, "todo:", total - actual, "ended:", player.ended);
return this.primHandler.popNandPushIntIfOK(argCount + 1, samples);
},

primitiveMPEG3AudioSamples: function(argCount) {
var player = this.playerFromStackArg(1);
if (!player) return false;
var total = player.totalSamples;
DEBUG > 1 && console.log("primitiveMPEG3AudioSamples", total);
return this.primHandler.popNandPushIntIfOK(argCount + 1, total);
},

primitiveMPEG3ReadAudio: function(argCount) {
// args: handle, buffer, channel, samples, stream
var player = this.playerFromStackArg(4);
var sending = this.interpreterProxy.stackIntegerValue(1);
// we need to keep track of the number of samples we sent
player.sentSamples += sending;
DEBUG > 1 && console.log("primitiveMPEG3ReadAudio: sending", sending, "=", player.sentSamples, "/", player.totalSamples, "todo:", player.totalSamples - player.sentSamples);
this.interpreterProxy.pop(argCount);
return true;
},

primitiveMPEG3EndOfAudio: function(argCount) {
var player = this.playerFromStackArg(1);
if (!player) return false;
var sent = player.sentSamples;
var actual = Math.floor(player.currentTime * 44100);
var total = player.totalSamples;
var samples = sent > actual ? sent : actual; // in case Squeak is behind
var ended = samples >= total || player.ended;
if (ended) DEBUG > 1 && console.log("primitiveMPEG3EndOfAudio:", ended);
return this.primHandler.popNandPushBoolIfOK(argCount + 1, ended);
},
};
}

function registerMpeg3Plugin() {
if (typeof Squeak === "object" && Squeak.registerExternalModule) {
Squeak.registerExternalModule('Mpeg3Plugin', JasmineMpeg3Plugin());
} else self.setTimeout(registerMpeg3Plugin, 100);
}

registerMpeg3Plugin();

0 comments on commit 96af425

Please sign in to comment.