Add HOTWORD as an AudioSource

- This is a low-priority source that can be preempted by others
- This is required for scenarios where someone wants an alway-on
  graceful microphone

Bug: 10640877.

Change-Id: Idb3577541103717cb713a7a93d3762ad2c2f4710

3 files changed, 15 insertions, 11 deletions

diff --git a/media/java/android/media/AudioManager.java b/media/java/android/media/AudioManager.java
index 1dcf0e9..9bda852f 100644
--- a/media/java/android/media/AudioManager.java
+++ b/media/java/android/media/AudioManager.java
@@ -1532,16 +1532,6 @@ public class AudioManager {
 
     /**
      * @hide
-     * Checks whether speech recognition is active
-     * @return true if a recording with source {@link MediaRecorder.AudioSource#VOICE_RECOGNITION}
-     *    is underway.
-     */
-    public boolean isSpeechRecognitionActive() {
-        return AudioSystem.isSourceActive(MediaRecorder.AudioSource.VOICE_RECOGNITION);
-    }
-
-    /**
-     * @hide
      * Checks whether the current audio focus is exclusive.
      * @return true if the top of the audio focus stack requested focus
      *     with {@link #AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE}
diff --git a/media/java/android/media/AudioRecord.java b/media/java/android/media/AudioRecord.java
index d20f5b9..f49ef2e 100644
--- a/media/java/android/media/AudioRecord.java
+++ b/media/java/android/media/AudioRecord.java
@@ -252,7 +252,8 @@ public class AudioRecord
         //--------------
         // audio source
         if ( (audioSource < MediaRecorder.AudioSource.DEFAULT) ||
-             (audioSource > MediaRecorder.getAudioSourceMax()) )  {
+             ((audioSource > MediaRecorder.getAudioSourceMax()) &&
+              (audioSource != MediaRecorder.AudioSource.HOTWORD)) )  {
             throw new IllegalArgumentException("Invalid audio source.");
         }
         mRecordSource = audioSource;
diff --git a/media/java/android/media/MediaRecorder.java b/media/java/android/media/MediaRecorder.java
index 1d2b889..8dcbd6b 100644
--- a/media/java/android/media/MediaRecorder.java
+++ b/media/java/android/media/MediaRecorder.java
@@ -200,6 +200,19 @@ public class MediaRecorder
          * </p>
          */
         public static final int REMOTE_SUBMIX = 8;
+
+        /**
+         * Audio source for preemptible, low-priority software hotword detection
+         * It presents the same gain and pre processing tuning as {@link #VOICE_RECOGNITION}.
+         * <p>
+         * An application should use this audio source when it wishes to do
+         * always-on software hotword detection, while gracefully giving in to any other application
+         * that might want to read from the microphone.
+         * </p>
+         * This is a hidden audio source.
+         * @hide
+         */
+        protected static final int HOTWORD = 1999;
     }
 
     /**