Merge pull request #1 from noblesamurai/init

Initial implementation.

package.json

@@ -1,7 +1,7 @@
 {
-  "name": "rms-amplitude",
+  "name": "@noblesam/rms-amplitude",
   "description": "Get RMS amplitude of an audio file.",
-  "version": "0.0.1",
+  "version": "1.0.0-init.3",
   "author": "Tim Allen <tim@noblesamurai.com>",
   "license": "BSD",
   "main": "src/index.js",
@@ -27,7 +27,9 @@
     "node": "10.x",
     "npm": "6.x"
   },
-  "dependencies": {},
+  "dependencies": {
+    "tempy": "^0.3.0"
+  },
   "devDependencies": {
     "chai": "^4.2.0",
     "chai-as-promised": "^7.1.1",

src/index.js

@@ -0,0 +1,19 @@
+const util = require('util');
+const exec = util.promisify(require('child_process').exec);
+const tempy = require('tempy');
+
+/**
+ * @param {string} filename
+ * @param {object} opts
+ * @param {string} opts.ffmpeg ffmpeg full path
+ * @param {string} opts.sox sox full path
+ */
+module.exports = async function sox (filename, opts = {}) {
+  const { ffmpeg = 'ffmpeg', sox = 'sox' } = opts;
+  const tempfile = tempy.file({ extension: 'wav' });
+  await exec(`${ffmpeg} -i ${filename} ${tempfile}`);
+  const { stderr } = await exec(`${sox} ${tempfile} -n stat`);
+  const rms = stderr.match(/RMS[ ]+amplitude:[ ]+([\d.]+)/);
+  const max = stderr.match(/Maximum[ ]+amplitude:[ ]+([\d.]+)/);
+  return rms && max && { rms: parseFloat(rms[1]), max: parseFloat(max[1]) };
+};

test/index.js

@@ -0,0 +1,17 @@
+const expect = require('chai').expect;
+const path = require('path');
+const rmsAmplitude = require('..');
+
+describe('rms-amplitude', function () {
+  it('gives the RMS amplitude of an audio file', async function () {
+    const result = await rmsAmplitude(path.join(__dirname, 'fixtures/Allure10.mp3'));
+    expect(result.max).to.be.a('number');
+    expect(result.rms).to.be.a('number');
+    expect(result.rms).to.be.lessThan(result.max);
+  });
+  it('handles a .mp4 file', async function () {
+    const result = await rmsAmplitude(path.join(__dirname, 'fixtures/user_video-30.mp4'));
+    expect(result.max).to.be.a('number');
+    expect(result.rms).to.be.a('number');
+  });
+});