audioform
Version:
Extract waveform data from audio files in NodeJS
155 lines (154 loc) • 7.09 kB
JavaScript
;
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
return new (P || (P = Promise))(function (resolve, reject) {
function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
var __generator = (this && this.__generator) || function (thisArg, body) {
var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
function verb(n) { return function (v) { return step([n, v]); }; }
function step(op) {
if (f) throw new TypeError("Generator is already executing.");
while (_) try {
if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
if (y = 0, t) op = [op[0] & 2, t.value];
switch (op[0]) {
case 0: case 1: t = op; break;
case 4: _.label++; return { value: op[1], done: false };
case 5: _.label++; y = op[1]; op = [0]; continue;
case 7: op = _.ops.pop(); _.trys.pop(); continue;
default:
if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
if (t[2]) _.ops.pop();
_.trys.pop(); continue;
}
op = body.call(thisArg, _);
} catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
}
};
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
exports.__esModule = true;
exports.normalizeData = exports.getMultiplier = exports.filteredData = exports.decodeAudio = void 0;
var web_audio_api_1 = require("web-audio-api");
var ffmpeg_1 = require("@ffmpeg-installer/ffmpeg");
var child_process_1 = require("child_process");
var tempy_1 = require("tempy");
var promises_1 = __importDefault(require("fs/promises"));
function audioToWaveformData(buffer, _a) {
var _b = _a === void 0 ? {} : _a, _c = _b.channel, channel = _c === void 0 ? 0 : _c, samples = _b.samples;
return __awaiter(this, void 0, void 0, function () {
var audioBuffer, data;
return __generator(this, function (_d) {
switch (_d.label) {
case 0: return [4 /*yield*/, decodeAudio(buffer)];
case 1:
audioBuffer = _d.sent();
data = audioBuffer.getChannelData(channel);
return [2 /*return*/, normalizeData(filteredData(data, samples))];
}
});
});
}
exports["default"] = audioToWaveformData;
function decodeAudio(buffer, mayConvert) {
if (mayConvert === void 0) { mayConvert = true; }
var context = new web_audio_api_1.AudioContext();
return new Promise(function (resolve, reject) {
context.decodeAudioData(buffer, resolve, function (err) {
if (mayConvert) {
tryConvert(buffer).then(resolve, reject);
}
else {
reject(err);
}
});
});
}
exports.decodeAudio = decodeAudio;
function tryConvert(buffer) {
return __awaiter(this, void 0, void 0, function () {
var f, o, ffmpeg_2, out, _a;
return __generator(this, function (_b) {
switch (_b.label) {
case 0:
_b.trys.push([0, , 4, 6]);
o = (0, tempy_1.file)({ extension: 'mp3' });
return [4 /*yield*/, (0, tempy_1.write)(buffer)];
case 1:
f = _b.sent();
ffmpeg_2 = (0, child_process_1.spawn)(ffmpeg_1.path, [
'-i',
f,
'-vn',
'-ar',
'44100',
'-ac',
'2',
'-b:a',
'192k',
o,
]);
return [4 /*yield*/, new Promise(function (resolve, reject) {
ffmpeg_2.on('error', reject);
ffmpeg_2.on('exit', resolve);
})];
case 2:
_b.sent();
_a = decodeAudio;
return [4 /*yield*/, promises_1["default"].readFile(o)];
case 3:
out = _a.apply(void 0, [_b.sent(), false]);
return [3 /*break*/, 6];
case 4: return [4 /*yield*/, Promise.all([f, o].map(function (t) {
return new Promise(function (resolve) {
if (t) {
promises_1["default"].unlink(t).then(resolve, resolve);
}
else {
resolve();
}
});
}))];
case 5:
_b.sent();
return [7 /*endfinally*/];
case 6: return [2 /*return*/, out];
}
});
});
}
function filteredData(rawData, samples) {
if (samples === void 0) { samples = 70; }
var blockSize = Math.floor(rawData.length / samples);
var filteredData = [];
for (var i = 0; i < samples; i++) {
var blockStart = blockSize * i;
var sum = 0;
for (var j = 0; j < blockSize; j++) {
sum = sum + Math.abs(rawData[blockStart + j]);
}
filteredData.push(sum / blockSize);
}
return filteredData;
}
exports.filteredData = filteredData;
function getMultiplier(data) {
return Math.pow(Math.max.apply(Math, data), -1);
}
exports.getMultiplier = getMultiplier;
function normalizeData(filteredData, multiplier) {
if (multiplier === void 0) { multiplier = getMultiplier(filteredData); }
return filteredData.map(function (n) { return n * multiplier; });
}
exports.normalizeData = normalizeData;