diff options
author | Andrew Comminos <andrew@comminos.com> | 2016-02-22 12:40:11 +0300 |
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committer | Andrew Comminos <andrew@comminos.com> | 2016-02-22 12:40:11 +0300 |
commit | a1bbf51f867c2ac96d542d20433ccadb411a2733 (patch) | |
tree | cf649bd71738d09a75613c9ed056d08b9fd3be3d | |
parent | 7780c62022b044de5ccaf0ad62c1f7dc8d814458 (diff) |
Properly clip amplitude boosted input.
-rw-r--r-- | src/main/java/com/morlunk/jumble/audio/AudioInput.java | 30 |
1 files changed, 20 insertions, 10 deletions
diff --git a/src/main/java/com/morlunk/jumble/audio/AudioInput.java b/src/main/java/com/morlunk/jumble/audio/AudioInput.java index 91a7215..ed44938 100644 --- a/src/main/java/com/morlunk/jumble/audio/AudioInput.java +++ b/src/main/java/com/morlunk/jumble/audio/AudioInput.java @@ -195,11 +195,18 @@ public class AudioInput implements Runnable { int shortsRead = mAudioRecord.read(mAudioBuffer, 0, mFrameSize); if(shortsRead > 0) { // Boost/reduce amplitude based on user preference + // TODO: perhaps amplify to the largest value that does not result in clipping. if(mAmplitudeBoost != 1.0f) { for(int i = 0; i < mFrameSize; i++) { - mAudioBuffer[i] *= mAmplitudeBoost; - if(mAudioBuffer[i] > Short.MAX_VALUE) mAudioBuffer[i] = Short.MAX_VALUE; - else if(mAudioBuffer[i] < Short.MIN_VALUE) mAudioBuffer[i] = Short.MIN_VALUE; + // Java only guarantees the bounded preservation of sign in a narrowing + // primitive conversion from float -> int, not float -> int -> short. + float val = mAudioBuffer[i] * mAmplitudeBoost; + if (val > Short.MAX_VALUE) { + val = Short.MAX_VALUE; + } else if (val < Short.MIN_VALUE) { + val = Short.MIN_VALUE; + } + mAudioBuffer[i] = (short) val; } } @@ -209,21 +216,24 @@ public class AudioInput implements Runnable { // Use a logarithmic energy-based scale for VAD. float sum = 1.0f; for (int i = 0; i < mFrameSize; i++) { - sum += mAudioBuffer[i] * mAudioBuffer[i]; + sum += Math.pow(mAudioBuffer[i], 2); } float micLevel = (float) Math.sqrt(sum / (float)mFrameSize); float peakSignal = (float) (20.0f*Math.log10(micLevel / 32768.0f))/96.0f; talking = (peakSignal+1) >= mVADThreshold; /* Record the last time where VAD was detected in order to prevent speech dropping. */ - if(talking) vadLastDetectedTime = System.nanoTime(); + if(talking) { + vadLastDetectedTime = System.nanoTime(); + } else { + talking = (System.nanoTime() - vadLastDetectedTime) < SPEECH_DETECT_THRESHOLD; + } -// Log.v(Constants.TAG, String.format("Signal: %2f, Threshold: %2f", peakSignal+1, mVADThreshold)); - talking |= (System.nanoTime() - vadLastDetectedTime) < SPEECH_DETECT_THRESHOLD; + // Update the service with the new talking state if we detected voice. + if(talking ^ vadLastDetected) { + mListener.onTalkStateChange(talking ? TalkState.TALKING : TalkState.PASSIVE); + } - if(talking ^ vadLastDetected) // Update the service with the new talking state if we detected voice. - mListener.onTalkStateChange(talking ? TalkState.TALKING : - TalkState.PASSIVE); vadLastDetected = talking; } |