Microphone support

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>

arecord.md

@@ -0,0 +1,50 @@
+```
+Usage: arecord [OPTION]... [FILE]...
+
+-h, --help              help
+    --version           print current version
+-l, --list-devices      list all soundcards and digital audio devices
+-L, --list-pcms         list device names
+-D, --device=NAME       select PCM by name
+-q, --quiet             quiet mode
+-t, --file-type TYPE    file type (voc, wav, raw or au)
+-c, --channels=#        channels
+-f, --format=FORMAT     sample format (case insensitive)
+-r, --rate=#            sample rate
+-d, --duration=#        interrupt after # seconds
+-M, --mmap              mmap stream
+-N, --nonblock          nonblocking mode
+-F, --period-time=#     distance between interrupts is # microseconds
+-B, --buffer-time=#     buffer duration is # microseconds
+    --period-size=#     distance between interrupts is # frames
+    --buffer-size=#     buffer duration is # frames
+-A, --avail-min=#       min available space for wakeup is # microseconds
+-R, --start-delay=#     delay for automatic PCM start is # microseconds
+                        (relative to buffer size if <= 0)
+-T, --stop-delay=#      delay for automatic PCM stop is # microseconds from xrun
+-v, --verbose           show PCM structure and setup (accumulative)
+-V, --vumeter=TYPE      enable VU meter (TYPE: mono or stereo)
+-I, --separate-channels one file for each channel
+-i, --interactive       allow interactive operation from stdin
+-m, --chmap=ch1,ch2,..  Give the channel map to override or follow
+    --disable-resample  disable automatic rate resample
+    --disable-channels  disable automatic channel conversions
+    --disable-format    disable automatic format conversions
+    --disable-softvol   disable software volume control (softvol)
+    --test-position     test ring buffer position
+    --test-coef=#       test coefficient for ring buffer position (default 8)
+                        expression for validation is: coef * (buffer_size / 2)
+    --test-nowait       do not wait for ring buffer - eats whole CPU
+    --max-file-time=#   start another output file when the old file has recorded
+                        for this many seconds
+    --process-id-file   write the process ID here
+    --use-strftime      apply the strftime facility to the output file name
+    --dump-hw-params    dump hw_params of the device
+    --fatal-errors      treat all errors as fatal
+Recognized sample formats are: S8 U8 S16_LE S16_BE U16_LE U16_BE S24_LE S24_BE U24_LE U24_BE S32_LE S32_BE U32_LE U32_BE FLOAT_LE FLOAT_BE FLOAT64_LE FLOAT64_BE IEC958_SUBFRAME_LE IEC958_SUBFRAME_BE MU_LAW A_LAW IMA_ADPCM MPEG GSM SPECIAL S24_3LE S24_3BE U24_3LE U24_3BE S20_3LE S20_3BE U20_3LE U20_3BE S18_3LE S18_3BE U18_3LE U18_3BE G723_24 G723_24_1B G723_40 G723_40_1B DSD_U8 DSD_U16_LE
+Some of these may not be available on selected hardware
+The available format shortcuts are:
+-f cd (16 bit little endian, 44100, stereo)
+-f cdr (16 bit big endian, 44100, stereo)
+-f dat (16 bit little endian, 48000, stereo)
+```

lib/index.js

@@ -1,6 +1,7 @@
 require('./array-includes-shim');
 
 var Camera = require('./camera');
+var Microphone = require('./microphone');
 var Player = require('./player');
 var Speaker = require('./speaker');
 
@@ -18,6 +19,5 @@ module.exports = {
     install('madplay');
     return new Speaker(args);
   },
-  // TODO...
-  Microphone: null,
+  Microphone: Microphone,
 };

lib/install.js

@@ -27,6 +27,8 @@ var cp = require('child_process');
 
 var profile = '/etc/profile';
 var installed = {
+  aplay: true,
+  arecord: true,
   espeak: false,
   fswebcam: true,
   ffmpeg: true,

lib/microphone.js

@@ -0,0 +1,204 @@
+// Dependencies: Built-in
+var cp = require('child_process');
+var Emitter = require('events').EventEmitter;
+
+// Dependencies: Internal
+var CaptureStream = require('./capture-stream');
+
+// Program specific
+var priv = new WeakMap();
+
+function Microphone(options) {
+  Emitter.call(this);
+
+  options = options || {};
+
+  var state = {
+    arecord: null,
+    aplay: null,
+    currentTime: 0,
+    isListening: false,
+    interval: null,
+    cs: new CaptureStream(),
+    time: null,
+  };
+
+  priv.set(this, state);
+
+  Object.defineProperties(this, {
+    currentTime: {
+      get: () => Number(state.currentTime.toFixed(3)),
+    },
+    isListening: {
+      get: () => state.isListening,
+    },
+  });
+}
+
+Microphone.prototype = Object.create(Emitter.prototype, {
+  constructor: {
+    value: Microphone
+  }
+});
+
+var defaults = ['-f', 'cd', '-c', '1', '-r', '41100', '-D', 'plughw:0,0'];
+
+Microphone.prototype.listen = function(options) {
+  var state = priv.get(this);
+  var args = [];
+  var offset = null;
+  var time = 0;
+
+  if (state.isListening) {
+    return state.cs;
+  }
+
+  options = options || {};
+
+  if (Array.isArray(options)) {
+    // mic.listen(['-f', 'cd', '-c', 1, '-r', 41100 ]);
+    args = options;
+  } else {
+    // Don't need to check for null, since those are handled above
+    if (typeof options === 'object') {
+      //  mic.listen({
+      //    ...
+      //  });
+      //
+      args = Object.keys(options).reduce((accum, key) => {
+        var value = options[key];
+        var option = '';
+
+        if (key.length === 1) {
+          //  mic.listen({
+          //    c: 1,
+          //    f: 'cd',
+          //  });
+          //
+          option = '-';
+        }
+
+        //  mic.listen({
+        //    '-c': 1,
+        //    '-f': 'cd',
+        //  });
+        //
+        option += key;
+
+        accum.push(option, value);
+
+        return accum;
+      }, []);
+    }
+  }
+
+  if (args.length === 0) {
+    args = defaults.slice();
+  }
+
+  if (state.arecord === null) {
+    state.isListening = true;
+    state.currentTime = 0;
+    state.startTime = Date.now();
+    state.interval = setInterval(() => {
+      var now = Date.now();
+      if (offset === null) {
+        offset = now - state.startTime;
+      }
+      state.currentTime = time + (now - state.startTime - offset) / 1000;
+
+      this.emit('timeupdate', this.currentTime);
+    }, 100);
+
+    // Apply some reasonable defaults...
+    Object.keys(arecord.options).forEach(key => {
+      if (!args.includes(key)) {
+        args.push(key, arecord.options[key]);
+      }
+    });
+
+    state.arecord = cp.spawn('arecord', args);
+
+    if (this.debug) {
+      state.arecord.stderr.on('data', (data) => {
+        var lines = data.toString().split('\n').filter(Boolean).map(line => line.trim());
+        lines.forEach(line => {
+          console.error(line);
+        });
+      });
+    }
+
+    state.arecord.stdout.on('data', (data) => {
+      state.cs.push(data);
+      this.emit('data', data);
+      this.emit('timeupdate', this.currentTime);
+    });
+
+    state.arecord.on('close', (code, signal) => {
+      if (code !== null && signal === null) {
+        if (state.interval) {
+          clearInterval(state.interval);
+        }
+        state.arecord = null;
+        state.currentTime = 0;
+        state.startTime = 0;
+        state.isListening = false;
+
+        this.emit('close');
+      }
+    });
+
+    this.emit('listen');
+  }
+
+  return state.cs;
+};
+
+Microphone.prototype.monitor = function(catpureStream) {
+  var state = priv.get(this);
+
+  if (state.isListening) {
+    state.aplay = cp.spawn('aplay', ['-D', 'plughw:0,0']);
+  }
+
+  if (catpureStream) {
+    return catpureStream.pipe(state.aplay.stdin);
+  } else {
+    return state.cs.pipe(state.aplay.stdin);
+  }
+};
+
+Microphone.prototype.stop = function() {
+  var state = priv.get(this);
+  if (!state.isListening) {
+    return this;
+  }
+  state.isListening = false;
+  if (state.interval) {
+    clearInterval(state.interval);
+  }
+  if (state.arecord) {
+    state.arecord.kill('SIGTERM');
+    state.arecord = null;
+  }
+  if (state.aplay) {
+    state.aplay.kill('SIGTERM');
+    state.aplay = null;
+  }
+  this.emit('stop');
+  return this;
+};
+
+
+var arecord = {
+  options: {
+    '-f': 'cd',
+    '-c': 1,
+    '-r': 41100,
+    '-D': 'plughw:0,0',
+  },
+};
+
+arecord.keys = Object.keys(arecord.options);
+
+module.exports = Microphone;

test/.jshintrc

@@ -28,10 +28,11 @@
     "Writable": true,
     "bindings": true,
     "sinon": true,
-    "MemoryStream": true,
+    "CaptureStream": true,
     "av": true,
     "Camera": true,
     "Player": true,
-    "Speaker": true
+    "Speaker": true,
+    "Microphone": true
   }
 }

test/common/bootstrap.js

@@ -21,6 +21,7 @@ global.sinon = require('sinon');
 global.av = require('../../lib/index');
 global.CaptureStream = require('../../lib/capture-stream');
 global.Camera = require('../../lib/camera');
+global.Microphone = require('../../lib/microphone');
 global.Player = require('../../lib/player');
 global.Speaker = require('../../lib/speaker');
 

test/unit/camera.js

@@ -51,6 +51,7 @@ exports['av.Camera'] = {
     });
 
     capture.on('end', function() {
+      cam.stop();
       test.done();
     });
 
@@ -69,6 +70,7 @@ exports['av.Camera'] = {
 
     writable.on('pipe', () => {
       test.ok(true);
+      cam.stop();
       test.done();
     });