1 files changed, 98 insertions, 0 deletions
diff --git a/src/com/android/speechrecorder/MicrophoneInputStream.java b/src/com/android/speechrecorder/MicrophoneInputStream.java
new file mode 100644
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+++ b/src/com/android/speechrecorder/MicrophoneInputStream.java
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2006 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.speechrecorder;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import android.media.AudioRecord;
+
+import static android.media.AudioFormat.CHANNEL_IN_MONO;
+import static android.media.AudioFormat.ENCODING_PCM_16BIT;
+import static android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION;
+
+/**
+ * Provides an InputStream like API over {@code android.media.AudioRecord}.
+ *
+ * <b>Not thread safe.</b>
+ */
+public final class MicrophoneInputStream extends InputStream {
+
+    private final int mSampleRate;
+    private final int mBufferSize;
+    private final AudioRecord mAudioRecord;
+
+    private boolean mRecording;
+
+    public MicrophoneInputStream(int sampleRate) throws IOException {
+        mSampleRate = sampleRate;
+        mBufferSize = AudioRecord.getMinBufferSize(sampleRate,
+            CHANNEL_IN_MONO, ENCODING_PCM_16BIT);
+        mAudioRecord = createAudioRecord();
+        mRecording = false;
+    }
+
+    private AudioRecord createAudioRecord() throws IOException {
+        AudioRecord ar = new AudioRecord(VOICE_RECOGNITION,
+            mSampleRate, CHANNEL_IN_MONO, ENCODING_PCM_16BIT, mBufferSize);
+
+        if (ar.getState() != AudioRecord.STATE_INITIALIZED) {
+            ar.release();
+            throw new IOException("Unable to create AudioRecord");
+        }
+
+        return ar;
+    }
+
+    private void maybeStartRecording() throws IOException {
+        if (mRecording) {
+            return;
+        }
+
+        mAudioRecord.startRecording();
+
+        int recordingState = mAudioRecord.getRecordingState();
+        if (recordingState != AudioRecord.RECORDSTATE_RECORDING) {
+            throw new IOException("Unexpected recordingState: " + recordingState);
+        }
+        mRecording = true;
+    }
+
+    @Override
+    public int read() throws IOException {
+        throw new UnsupportedOperationException("Single byte read.");
+    }
+
+    @Override
+    public int read(byte[] b, int offset, int length) throws IOException {
+        maybeStartRecording();
+
+        final int ret = mAudioRecord.read(b, offset, length);
+        if (ret == AudioRecord.ERROR_INVALID_OPERATION ||
+                ret == AudioRecord.ERROR_BAD_VALUE) {
+            throw new IOException("AudioRecord.read returned: " + ret);
+        }
+
+        return ret;
+    }
+
+    @Override
+    public void close() throws IOException {
+        mAudioRecord.stop();
+        mAudioRecord.release();
+    }
+}