зеркало из https://github.com/electron/electron.git
499 строки
14 KiB
JavaScript
499 строки
14 KiB
JavaScript
/*
|
|
https://github.com/antimatter15/whammy
|
|
The MIT License (MIT)
|
|
|
|
Copyright (c) 2015 Kevin Kwok
|
|
|
|
Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
of this software and associated documentation files (the "Software"), to deal
|
|
in the Software without restriction, including without limitation the rights
|
|
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
copies of the Software, and to permit persons to whom the Software is
|
|
furnished to do so, subject to the following conditions:
|
|
|
|
The above copyright notice and this permission notice shall be included in all
|
|
copies or substantial portions of the Software.
|
|
|
|
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
SOFTWARE.
|
|
*/
|
|
|
|
function atob (str) {
|
|
return Buffer.from(str, 'base64').toString('binary');
|
|
}
|
|
|
|
// in this case, frames has a very specific meaning, which will be
|
|
// detailed once i finish writing the code
|
|
|
|
function ToWebM (frames) {
|
|
const info = checkFrames(frames);
|
|
|
|
// max duration by cluster in milliseconds
|
|
const CLUSTER_MAX_DURATION = 30000;
|
|
|
|
const EBML = [
|
|
{
|
|
id: 0x1a45dfa3, // EBML
|
|
data: [
|
|
{
|
|
data: 1,
|
|
id: 0x4286 // EBMLVersion
|
|
},
|
|
{
|
|
data: 1,
|
|
id: 0x42f7 // EBMLReadVersion
|
|
},
|
|
{
|
|
data: 4,
|
|
id: 0x42f2 // EBMLMaxIDLength
|
|
},
|
|
{
|
|
data: 8,
|
|
id: 0x42f3 // EBMLMaxSizeLength
|
|
},
|
|
{
|
|
data: 'webm',
|
|
id: 0x4282 // DocType
|
|
},
|
|
{
|
|
data: 2,
|
|
id: 0x4287 // DocTypeVersion
|
|
},
|
|
{
|
|
data: 2,
|
|
id: 0x4285 // DocTypeReadVersion
|
|
}
|
|
]
|
|
},
|
|
{
|
|
id: 0x18538067, // Segment
|
|
data: [
|
|
{
|
|
id: 0x1549a966, // Info
|
|
data: [
|
|
{
|
|
data: 1e6, // do things in millisecs (num of nanosecs for duration scale)
|
|
id: 0x2ad7b1 // TimecodeScale
|
|
},
|
|
{
|
|
data: 'whammy',
|
|
id: 0x4d80 // MuxingApp
|
|
},
|
|
{
|
|
data: 'whammy',
|
|
id: 0x5741 // WritingApp
|
|
},
|
|
{
|
|
data: doubleToString(info.duration),
|
|
id: 0x4489 // Duration
|
|
}
|
|
]
|
|
},
|
|
{
|
|
id: 0x1654ae6b, // Tracks
|
|
data: [
|
|
{
|
|
id: 0xae, // TrackEntry
|
|
data: [
|
|
{
|
|
data: 1,
|
|
id: 0xd7 // TrackNumber
|
|
},
|
|
{
|
|
data: 1,
|
|
id: 0x73c5 // TrackUID
|
|
},
|
|
{
|
|
data: 0,
|
|
id: 0x9c // FlagLacing
|
|
},
|
|
{
|
|
data: 'und',
|
|
id: 0x22b59c // Language
|
|
},
|
|
{
|
|
data: 'V_VP8',
|
|
id: 0x86 // CodecID
|
|
},
|
|
{
|
|
data: 'VP8',
|
|
id: 0x258688 // CodecName
|
|
},
|
|
{
|
|
data: 1,
|
|
id: 0x83 // TrackType
|
|
},
|
|
{
|
|
id: 0xe0, // Video
|
|
data: [
|
|
{
|
|
data: info.width,
|
|
id: 0xb0 // PixelWidth
|
|
},
|
|
{
|
|
data: info.height,
|
|
id: 0xba // PixelHeight
|
|
}
|
|
]
|
|
}
|
|
]
|
|
}
|
|
]
|
|
},
|
|
{
|
|
id: 0x1c53bb6b, // Cues
|
|
data: [
|
|
// cue insertion point
|
|
]
|
|
}
|
|
|
|
// cluster insertion point
|
|
]
|
|
}
|
|
];
|
|
|
|
const segment = EBML[1];
|
|
const cues = segment.data[2];
|
|
|
|
// Generate clusters (max duration)
|
|
let frameNumber = 0;
|
|
let clusterTimecode = 0;
|
|
while (frameNumber < frames.length) {
|
|
const cuePoint = {
|
|
id: 0xbb, // CuePoint
|
|
data: [
|
|
{
|
|
data: Math.round(clusterTimecode),
|
|
id: 0xb3 // CueTime
|
|
},
|
|
{
|
|
id: 0xb7, // CueTrackPositions
|
|
data: [
|
|
{
|
|
data: 1,
|
|
id: 0xf7 // CueTrack
|
|
},
|
|
{
|
|
data: 0, // to be filled in when we know it
|
|
size: 8,
|
|
id: 0xf1 // CueClusterPosition
|
|
}
|
|
]
|
|
}
|
|
]
|
|
};
|
|
|
|
cues.data.push(cuePoint);
|
|
|
|
const clusterFrames = [];
|
|
let clusterDuration = 0;
|
|
do {
|
|
clusterFrames.push(frames[frameNumber]);
|
|
clusterDuration += frames[frameNumber].duration;
|
|
frameNumber++;
|
|
} while (frameNumber < frames.length && clusterDuration < CLUSTER_MAX_DURATION);
|
|
|
|
let clusterCounter = 0;
|
|
const cluster = {
|
|
id: 0x1f43b675, // Cluster
|
|
data: [
|
|
{
|
|
data: Math.round(clusterTimecode),
|
|
id: 0xe7 // Timecode
|
|
}
|
|
].concat(clusterFrames.map(function (webp) {
|
|
const block = makeSimpleBlock({
|
|
discardable: 0,
|
|
frame: webp.data.slice(4),
|
|
invisible: 0,
|
|
keyframe: 1,
|
|
lacing: 0,
|
|
trackNum: 1,
|
|
timecode: Math.round(clusterCounter)
|
|
});
|
|
clusterCounter += webp.duration;
|
|
return {
|
|
data: block,
|
|
id: 0xa3
|
|
};
|
|
}))
|
|
};
|
|
|
|
// Add cluster to segment
|
|
segment.data.push(cluster);
|
|
clusterTimecode += clusterDuration;
|
|
}
|
|
|
|
// First pass to compute cluster positions
|
|
let position = 0;
|
|
for (let i = 0; i < segment.data.length; i++) {
|
|
if (i >= 3) {
|
|
cues.data[i - 3].data[1].data[1].data = position;
|
|
}
|
|
const data = generateEBML([segment.data[i]]);
|
|
position += data.size || data.byteLength || data.length;
|
|
if (i !== 2) { // not cues
|
|
// Save results to avoid having to encode everything twice
|
|
segment.data[i] = data;
|
|
}
|
|
}
|
|
|
|
return generateEBML(EBML);
|
|
}
|
|
|
|
// sums the lengths of all the frames and gets the duration, woo
|
|
|
|
function checkFrames (frames) {
|
|
const width = frames[0].width;
|
|
const height = frames[0].height;
|
|
let duration = frames[0].duration;
|
|
for (let i = 1; i < frames.length; i++) {
|
|
if (frames[i].width !== width) throw new Error('Frame ' + (i + 1) + ' has a different width');
|
|
if (frames[i].height !== height) throw new Error('Frame ' + (i + 1) + ' has a different height');
|
|
if (frames[i].duration < 0 || frames[i].duration > 0x7fff) throw new Error('Frame ' + (i + 1) + ' has a weird duration (must be between 0 and 32767)');
|
|
duration += frames[i].duration;
|
|
}
|
|
return {
|
|
duration: duration,
|
|
width: width,
|
|
height: height
|
|
};
|
|
}
|
|
|
|
function numToBuffer (num) {
|
|
const parts = [];
|
|
while (num > 0) {
|
|
parts.push(num & 0xff);
|
|
num = num >> 8;
|
|
}
|
|
return new Uint8Array(parts.reverse());
|
|
}
|
|
|
|
function numToFixedBuffer (num, size) {
|
|
const parts = new Uint8Array(size);
|
|
for (let i = size - 1; i >= 0; i--) {
|
|
parts[i] = num & 0xff;
|
|
num = num >> 8;
|
|
}
|
|
return parts;
|
|
}
|
|
|
|
function strToBuffer (str) {
|
|
// return new Blob([str]);
|
|
|
|
const arr = new Uint8Array(str.length);
|
|
for (let i = 0; i < str.length; i++) {
|
|
arr[i] = str.charCodeAt(i);
|
|
}
|
|
return arr;
|
|
// this is slower
|
|
// return new Uint8Array(str.split('').map(function(e){
|
|
// return e.charCodeAt(0)
|
|
// }))
|
|
}
|
|
|
|
// sorry this is ugly, and sort of hard to understand exactly why this was done
|
|
// at all really, but the reason is that there's some code below that i dont really
|
|
// feel like understanding, and this is easier than using my brain.
|
|
|
|
function bitsToBuffer (bits) {
|
|
const data = [];
|
|
const pad = (bits.length % 8) ? (new Array(1 + 8 - (bits.length % 8))).join('0') : '';
|
|
bits = pad + bits;
|
|
for (let i = 0; i < bits.length; i += 8) {
|
|
data.push(parseInt(bits.substr(i, 8), 2));
|
|
}
|
|
return new Uint8Array(data);
|
|
}
|
|
|
|
function generateEBML (json) {
|
|
const ebml = [];
|
|
for (let i = 0; i < json.length; i++) {
|
|
if (!('id' in json[i])) {
|
|
// already encoded blob or byteArray
|
|
ebml.push(json[i]);
|
|
continue;
|
|
}
|
|
|
|
let data = json[i].data;
|
|
if (typeof data === 'object') data = generateEBML(data);
|
|
if (typeof data === 'number') data = ('size' in json[i]) ? numToFixedBuffer(data, json[i].size) : bitsToBuffer(data.toString(2));
|
|
if (typeof data === 'string') data = strToBuffer(data);
|
|
|
|
const len = data.size || data.byteLength || data.length;
|
|
const zeroes = Math.ceil(Math.ceil(Math.log(len) / Math.log(2)) / 8);
|
|
const sizeStr = len.toString(2);
|
|
const padded = (new Array((zeroes * 7 + 7 + 1) - sizeStr.length)).join('0') + sizeStr;
|
|
const size = (new Array(zeroes)).join('0') + '1' + padded;
|
|
|
|
// i actually dont quite understand what went on up there, so I'm not really
|
|
// going to fix this, i'm probably just going to write some hacky thing which
|
|
// converts that string into a buffer-esque thing
|
|
|
|
ebml.push(numToBuffer(json[i].id));
|
|
ebml.push(bitsToBuffer(size));
|
|
ebml.push(data);
|
|
}
|
|
|
|
// convert ebml to an array
|
|
const buffer = toFlatArray(ebml);
|
|
return new Uint8Array(buffer);
|
|
}
|
|
|
|
function toFlatArray (arr, outBuffer) {
|
|
if (outBuffer == null) {
|
|
outBuffer = [];
|
|
}
|
|
for (let i = 0; i < arr.length; i++) {
|
|
if (typeof arr[i] === 'object') {
|
|
// an array
|
|
toFlatArray(arr[i], outBuffer);
|
|
} else {
|
|
// a simple element
|
|
outBuffer.push(arr[i]);
|
|
}
|
|
}
|
|
return outBuffer;
|
|
}
|
|
|
|
function makeSimpleBlock (data) {
|
|
let flags = 0;
|
|
if (data.keyframe) flags |= 128;
|
|
if (data.invisible) flags |= 8;
|
|
if (data.lacing) flags |= (data.lacing << 1);
|
|
if (data.discardable) flags |= 1;
|
|
if (data.trackNum > 127) {
|
|
throw new Error('TrackNumber > 127 not supported');
|
|
}
|
|
const out = [data.trackNum | 0x80, data.timecode >> 8, data.timecode & 0xff, flags].map(function (e) {
|
|
return String.fromCharCode(e);
|
|
}).join('') + data.frame;
|
|
|
|
return out;
|
|
}
|
|
|
|
// here's something else taken verbatim from weppy, awesome rite?
|
|
|
|
function parseWebP (riff) {
|
|
const VP8 = riff.RIFF[0].WEBP[0];
|
|
|
|
const frameStart = VP8.indexOf('\x9d\x01\x2a'); // A VP8 keyframe starts with the 0x9d012a header
|
|
const c = [];
|
|
for (let i = 0; i < 4; i++) c[i] = VP8.charCodeAt(frameStart + 3 + i);
|
|
|
|
// the code below is literally copied verbatim from the bitstream spec
|
|
let tmp = (c[1] << 8) | c[0];
|
|
const width = tmp & 0x3FFF;
|
|
const horizontalScale = tmp >> 14;
|
|
tmp = (c[3] << 8) | c[2];
|
|
const height = tmp & 0x3FFF;
|
|
const verticalScale = tmp >> 14;
|
|
return {
|
|
width: width,
|
|
height: height,
|
|
data: VP8,
|
|
riff: riff
|
|
};
|
|
}
|
|
|
|
// i think i'm going off on a riff by pretending this is some known
|
|
// idiom which i'm making a casual and brilliant pun about, but since
|
|
// i can't find anything on google which conforms to this idiomatic
|
|
// usage, I'm assuming this is just a consequence of some psychotic
|
|
// break which makes me make up puns. well, enough riff-raff (aha a
|
|
// rescue of sorts), this function was ripped wholesale from weppy
|
|
|
|
function parseRIFF (string) {
|
|
let offset = 0;
|
|
const chunks = {};
|
|
|
|
while (offset < string.length) {
|
|
const id = string.substr(offset, 4);
|
|
chunks[id] = chunks[id] || [];
|
|
if (id === 'RIFF' || id === 'LIST') {
|
|
const len = parseInt(string.substr(offset + 4, 4).split('').map(function (i) {
|
|
const unpadded = i.charCodeAt(0).toString(2);
|
|
return (new Array(8 - unpadded.length + 1)).join('0') + unpadded;
|
|
}).join(''), 2);
|
|
const data = string.substr(offset + 4 + 4, len);
|
|
offset += 4 + 4 + len;
|
|
chunks[id].push(parseRIFF(data));
|
|
} else if (id === 'WEBP') {
|
|
// Use (offset + 8) to skip past "VP8 "/"VP8L"/"VP8X" field after "WEBP"
|
|
chunks[id].push(string.substr(offset + 8));
|
|
offset = string.length;
|
|
} else {
|
|
// Unknown chunk type; push entire payload
|
|
chunks[id].push(string.substr(offset + 4));
|
|
offset = string.length;
|
|
}
|
|
}
|
|
return chunks;
|
|
}
|
|
|
|
// here's a little utility function that acts as a utility for other functions
|
|
// basically, the only purpose is for encoding "Duration", which is encoded as
|
|
// a double (considerably more difficult to encode than an integer)
|
|
function doubleToString (num) {
|
|
return [].slice.call(
|
|
new Uint8Array(
|
|
(
|
|
new Float64Array([num]) // create a float64 array
|
|
).buffer) // extract the array buffer
|
|
, 0) // convert the Uint8Array into a regular array
|
|
.map(function (e) { // since it's a regular array, we can now use map
|
|
return String.fromCharCode(e); // encode all the bytes individually
|
|
})
|
|
.reverse() // correct the byte endianness (assume it's little endian for now)
|
|
.join(''); // join the bytes in holy matrimony as a string
|
|
}
|
|
|
|
function WhammyVideo (speed, quality = 0.8) { // a more abstract-ish API
|
|
this.frames = [];
|
|
this.duration = 1000 / speed;
|
|
this.quality = quality;
|
|
}
|
|
|
|
/**
|
|
*
|
|
* @param {string} frame
|
|
* @param {number} [duration]
|
|
*/
|
|
WhammyVideo.prototype.add = function (frame, duration) {
|
|
if (typeof duration !== 'undefined' && this.duration) throw new Error("you can't pass a duration if the fps is set");
|
|
if (typeof duration === 'undefined' && !this.duration) throw new Error("if you don't have the fps set, you need to have durations here.");
|
|
if (frame.canvas) { // CanvasRenderingContext2D
|
|
frame = frame.canvas;
|
|
}
|
|
if (frame.toDataURL) {
|
|
// frame = frame.toDataURL('image/webp', this.quality);
|
|
// quickly store image data so we don't block cpu. encode in compile method.
|
|
frame = frame.getContext('2d').getImageData(0, 0, frame.width, frame.height);
|
|
} else if (typeof frame !== 'string') {
|
|
throw new Error('frame must be a a HTMLCanvasElement, a CanvasRenderingContext2D or a DataURI formatted string');
|
|
}
|
|
if (typeof frame === 'string' && !(/^data:image\/webp;base64,/ig).test(frame)) {
|
|
throw new Error('Input must be formatted properly as a base64 encoded DataURI of type image/webp');
|
|
}
|
|
this.frames.push({
|
|
image: frame,
|
|
duration: duration || this.duration
|
|
});
|
|
};
|
|
|
|
WhammyVideo.prototype.compile = function (callback) {
|
|
const webm = new ToWebM(this.frames.map(function (frame) {
|
|
const webp = parseWebP(parseRIFF(atob(frame.image.slice(23))));
|
|
webp.duration = frame.duration;
|
|
return webp;
|
|
}));
|
|
callback(webm);
|
|
};
|
|
|
|
export const WebmGenerator = WhammyVideo;
|