changeset 445:a9fb6590a3dc

Implement a MediaRecorder backed by RecordRTC. Definitely not spec compliant but is at least interface compatible with the methods used in the app.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/app/services/audio-recorder/RecordRtcMediaRecorder.ts	Mon Jun 26 16:16:19 2017 +0100
@@ -0,0 +1,85 @@
+/**
+ * Created by lucast on 26/06/2017.
+ */
+import {
+  BlobEvent as IBlobEvent,
+  MediaRecorder,
+  MediaRecorderErrorEvent,
+  RecordingState
+} from './audio-recorder.service';
+import * as RecordRtc from 'recordrtc';
+
+// safari doesn't implement BlobEvent... this should do
+class BlobEvent extends Event implements IBlobEvent {
+  data: Blob;
+
+  constructor(data: Blob) {
+    super('blob');
+    this.data = data;
+  }
+}
+
+export class RecordRtcMediaRecorder implements MediaRecorder {
+  mimeType: string;
+  state: RecordingState;
+  stream: MediaStream;
+  ignoreMutedMedia: boolean;
+  videoBitsPerSecond: number;
+  audioBitsPerSecond: number;
+  onstart: (evt: Event) => void;
+  onstop: (evt: Event) => void;
+  ondataavailable: (evt: BlobEvent) => void;
+  onpause: (evt: Event) => void;
+  onresume: (evt: Event) => void;
+  onerror: (evt: MediaRecorderErrorEvent) => void;
+
+  private recorder: any; // TODO RecordRTC typings?
+
+  static isTypeSupported(mimeType: string): boolean {
+    return mimeType === 'audio/wav';
+  }
+
+  constructor(stream: MediaStream) {
+    this.state = 'inactive';
+    this.stream = stream;
+    this.recorder = RecordRtc(stream, {
+      type: 'audio',
+      recorderType: RecordRtc.StereoAudioRecorder
+    });
+  }
+
+
+  pause(): void {
+    this.state = 'paused';
+    this.recorder.pauseRecording();
+  }
+
+  requestData(): void {
+    // could probably implement this, but it isn't actually used in the app
+    throw new Error('Not implemented');
+  }
+
+  resume(): void {
+    this.state = 'recording';
+    this.recorder.resumeRecording();
+  }
+
+  start(timeslice?: number): void {
+    this.state = 'recording';
+    this.recorder.startRecording();
+  }
+
+  stop(): void {
+    this.state = 'inactive';
+    this.recorder.stopRecording(() => {
+      if (this.ondataavailable) {
+        const blob = this.recorder.getBlob();
+        this.mimeType = blob.type;
+        this.ondataavailable(new BlobEvent(blob));
+      }
+      if (this.onstop) {
+        this.onstop(new Event('stop'));
+      }
+    });
+  }
+}