| /* |
| * Copyright (C) 2010 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.cts.verifier.audioquality.experiments; |
| |
| import com.android.cts.verifier.R; |
| import com.android.cts.verifier.audioquality.AudioQualityVerifierActivity; |
| import com.android.cts.verifier.audioquality.Utils; |
| |
| import android.content.Context; |
| |
| /** |
| * Experiment to test the linearity of the microphone gain response. |
| * |
| * This plays a sequence of identical stimuli at increasing volumes and then |
| * analyzes the set of recordings. |
| */ |
| public class GainLinearityExperiment extends SequenceExperiment { |
| private static final int LEVELS = 4; |
| private static final float DB_STEP_SIZE = 10.0f; |
| private static final float TOLERANCE = 2.0f; // Maximum allowed deviation from linearity in dB |
| private static final int STIM_NUM = 31; |
| |
| private short[] mReference = null; |
| |
| public GainLinearityExperiment() { |
| super(true); |
| } |
| |
| @Override |
| protected String lookupName(Context context) { |
| return context.getString(R.string.aq_linearity_exp); |
| } |
| |
| @Override |
| protected int getTrials() { |
| return LEVELS; |
| } |
| |
| @Override |
| protected byte[] getStim(Context context, int trial) { |
| float db = (trial - (LEVELS - 1)) * DB_STEP_SIZE; |
| if (mReference == null) { |
| mReference = Utils.byteToShortArray(Utils.getStim(context, STIM_NUM)); |
| } |
| short[] samples = Utils.scale(mReference, db); |
| return Utils.shortToByteArray(samples); |
| } |
| |
| @Override |
| protected void compare(byte[][] stim, byte[][] record) { |
| short[][] pcms = new short[LEVELS][]; |
| for (int i = 0; i < LEVELS; i++) { |
| pcms[i] = Utils.byteToShortArray(record[i]); |
| } |
| // We specify the middle stimulus (LEVELS / 2) as the "reference": |
| float deviation = mNative.linearityTest(pcms, AudioQualityVerifierActivity.SAMPLE_RATE, |
| DB_STEP_SIZE, LEVELS / 2); |
| if (deviation < 0.0f) { |
| setScore(getString(R.string.aq_fail)); |
| setReport(String.format(getString(R.string.aq_linearity_report_error), deviation)); |
| } else if (deviation > TOLERANCE) { |
| setScore(getString(R.string.aq_fail)); |
| setReport(String.format(getString(R.string.aq_linearity_report_normal), |
| deviation, TOLERANCE)); |
| } else { |
| setScore(getString(R.string.aq_pass)); |
| setReport(String.format(getString(R.string.aq_linearity_report_normal), |
| deviation, TOLERANCE)); |
| } |
| } |
| } |