Added [email protected], Merged & Closed #85 (PCM RAW Audio)

Returning Blob rather than ArrayBuffer. You can use FileReader API to
get original buffer.

Author: muaz-khan

AudioStreamRecorder/StereoAudioRecorderHelper.js

@@ -23,6 +23,10 @@ function StereoAudioRecorderHelper(mediaStream, root) {
     var volume;
     var audioInput;
     var sampleRate = root.sampleRate || deviceSampleRate;
+
+    var mimeType = root.mimeType || 'audio/wav';
+    var isPCM = mimeType.indexOf('audio/pcm') > -1;
+
     var context;
 
     var numChannels = root.audioChannels || 2;
@@ -66,6 +70,17 @@ function StereoAudioRecorderHelper(mediaStream, root) {
             interleaved = interleave(leftBuffer, rightBuffer);
         }
 
+        if (isPCM) {
+            // our final binary blob
+            var blob = new Blob([convertoFloat32ToInt16(interleaved)], {
+                type: 'audio/pcm'
+            });
+
+            console.debug('audio recorded blob size:', bytesToSize(blob.size));
+            root.ondataavailable(blob);
+            return;
+        }
+
         // we create our wav file
         var buffer = new ArrayBuffer(44 + interleaved.length * 2);
         var view = new DataView(buffer);
@@ -151,6 +166,16 @@ function StereoAudioRecorderHelper(mediaStream, root) {
         }
     }
 
+    function convertoFloat32ToInt16(buffer) {
+        var l = buffer.length;
+        var buf = new Int16Array(l)
+
+        while (l--) {
+            buf[l] = buffer[l] * 0xFFFF; //convert to 16 bit
+        }
+        return buf.buffer
+    }
+
     // creates the audio context
     var context = ObjectStore.AudioContextConstructor;
 

MediaStreamRecorder.js

@@ -1,4 +1,4 @@
-// Last time updated: 2016-07-03 8:17:15 AM UTC
+// Last time updated: 2016-07-03 8:51:35 AM UTC
 
 // links:
 // Open-Sourced: https://github.com/streamproc/MediaStreamRecorder
@@ -51,7 +51,8 @@ function MediaStreamRecorder(mediaStream) {
         }
 
         // audio/wav is supported only via StereoAudioRecorder
-        if (this.mimeType === 'audio/wav') {
+        // audio/pcm (int16) is supported only via StereoAudioRecorder
+        if (this.mimeType === 'audio/wav' || this.mimeType === 'audio/pcm') {
             Recorder = StereoAudioRecorder;
         }
 
@@ -988,6 +989,10 @@ function StereoAudioRecorderHelper(mediaStream, root) {
     var volume;
     var audioInput;
     var sampleRate = root.sampleRate || deviceSampleRate;
+
+    var mimeType = root.mimeType || 'audio/wav';
+    var isPCM = mimeType.indexOf('audio/pcm') > -1;
+
     var context;
 
     var numChannels = root.audioChannels || 2;
@@ -1031,6 +1036,17 @@ function StereoAudioRecorderHelper(mediaStream, root) {
             interleaved = interleave(leftBuffer, rightBuffer);
         }
 
+        if (isPCM) {
+            // our final binary blob
+            var blob = new Blob([convertoFloat32ToInt16(interleaved)], {
+                type: 'audio/pcm'
+            });
+
+            console.debug('audio recorded blob size:', bytesToSize(blob.size));
+            root.ondataavailable(blob);
+            return;
+        }
+
         // we create our wav file
         var buffer = new ArrayBuffer(44 + interleaved.length * 2);
         var view = new DataView(buffer);
@@ -1116,6 +1132,16 @@ function StereoAudioRecorderHelper(mediaStream, root) {
         }
     }
 
+    function convertoFloat32ToInt16(buffer) {
+        var l = buffer.length;
+        var buf = new Int16Array(l)
+
+        while (l--) {
+            buf[l] = buffer[l] * 0xFFFF; //convert to 16 bit
+        }
+        return buf.buffer
+    }
+
     // creates the audio context
     var context = ObjectStore.AudioContextConstructor;
 

MediaStreamRecorder.min.js

@@ -78,7 +78,7 @@ Then link single/standalone "MediaStreamRecorder.js" file:
 <script src="https://www.webrtc-experiment.com/MediaStreamRecorder.js"> </script>
 
 <!-- or link specific release -->
-<script src="https://github.com/streamproc/MediaStreamRecorder/releases/download/1.3.3/MediaStreamRecorder.js"></script>
+<script src="https://github.com/streamproc/MediaStreamRecorder/releases/download/1.3.4/MediaStreamRecorder.js"></script>
 ```
 
 ## Record audio+video
@@ -406,6 +406,7 @@ videoRecorder.mimeType = 'video/mp4';
 audioRecorder.mimeType = 'audio/webm'; // MediaRecorderWrapper
 audioRecorder.mimeType = 'audio/ogg'; // MediaRecorderWrapper
 audioRecorder.mimeType = 'audio/wav'; // StereoAudioRecorder
+audioRecorder.mimeType = 'audio/pcm'; // StereoAudioRecorder
 
 // gif:
 gifRecorder.mimeType = 'image/gif'; // GifRecorder

README.md

@@ -1,6 +1,6 @@
 {
     "name": "msr",
-    "version": "1.3.3",
+    "version": "1.3.4",
     "authors": [
         {
             "name": "Muaz Khan",

bower.json

@@ -27,7 +27,8 @@ function MediaStreamRecorder(mediaStream) {
         }
 
         // audio/wav is supported only via StereoAudioRecorder
-        if (this.mimeType === 'audio/wav') {
+        // audio/pcm (int16) is supported only via StereoAudioRecorder
+        if (this.mimeType === 'audio/wav' || this.mimeType === 'audio/pcm') {
             Recorder = StereoAudioRecorder;
         }
 

common/MediaStreamRecorder.js

@@ -76,7 +76,8 @@ <h1>
             <select id="audio-recorderType" style="font-size:22px;vertical-align: middle;margin-right: 5px;">
                 <option>[Best Available Recorder]</option>
                 <option>MediaRecorder API</option>
-                <option>WebAudio API</option>
+                <option>WebAudio API (WAV)</option>
+                <option>WebAudio API (PCM)</option>
             </select>
             <br>
 
@@ -167,8 +168,14 @@ <h1>
                     mediaRecorder.recorderType = MediaRecorderWrapper;
                 }
 
-                if (recorderType === 'WebAudio API') {
+                if (recorderType === 'WebAudio API (WAV)') {
                     mediaRecorder.recorderType = StereoAudioRecorder;
+                    mediaRecorder.mimeType = 'audio/wav';
+                }
+
+                if (recorderType === 'WebAudio API (PCM)') {
+                    mediaRecorder.recorderType = StereoAudioRecorder;
+                    mediaRecorder.mimeType = 'audio/pcm';
                 }
 
                 // don't force any mimeType; use above "recorderType" instead.

demos/audio-recorder.html

@@ -1,7 +1,7 @@
 {
   "name": "msr",
   "preferGlobal": false,
-  "version": "1.3.3",
+  "version": "1.3.4",
   "author": {
     "name": "Muaz Khan",
     "email": "[email protected]",