--- /dev/null
+/*
+ * 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.
+ */
+
+#ifndef GLITCH_TEST_H
+#define GLITCH_TEST_H
+
+class Fft;
+class Window;
+
+class GlitchTest {
+public:
+ GlitchTest(void);
+
+ virtual ~GlitchTest(void) {
+ cleanup();
+ }
+
+ /* Set up the instance to operate on input test signals sampled at
+ sample_rate that contain a stimulis tone of stim_freq frequency.
+ The signal will be considered on during the interval it exceeds
+ onset_thresh (dB re 1.0). Any frames containing a tone that have
+ a signal energy to out-of-band energy ratio less than
+ db_snr_thresh are counted as bad frames. Init must be called
+ before CheckToneSnr. */
+ void init(float sample_rate, float stim_freq, float onset_thresh,
+ float db_snr_thresh);
+
+ /* Analyze the n_samples of the lin16 signal in pcm. This signal is
+ assumed sampled at sample_rate, and to contain a sinusoid with
+ center frequency stim_freq, embedded somewhere in time, with
+ "silence" intervals before and after. The contiguous duration of
+ the tone that exceeds onset_thresh (in dB re 1.0) is returned as
+ seconds in duration. The number of frames for which the ratio of
+ the energy at the tone frequency to the energy in the rest of the
+ spectrum is less than db_snr_thresh is returned in n_bad_frames.
+ If the test succeed, the method returns 1, else it returns a
+ negative number that reflects the cause of failure as follows:
+ -1 The instance is not initialized.
+ -2 There are not enough samples to do a reasonable check.
+ -3 The tone signal onset was not found.
+ -4 The tone signal end was not found. */
+ int checkToneSnr(short* pcm, int n_samples, float* duration,
+ int* n_bad_frames);
+
+private:
+ // Free memory, etc.
+ void cleanup(void);
+
+ /* Do a real FFT on the n_input samples in data, and return n_output
+ power spectral density points in output. The output points include
+ DC through the Nyquist frequency (i.e. 1 + fft_size/2). output
+ must be large enough to accommodate this size. If n_input==0 or
+ n_input > fft_size, return 0; else return 1. */
+ int realMagSqSpectrum(float* data, int n_input,
+ float* output, int* n_output);
+
+ /* Find the largest value in data starting at start_search and ending
+ at end_search-1. The values in data are assumed to be magnitude
+ squared values from a spectrum computation based on window_size
+ sample points. Return the index where the largest value was found,
+ and return the dB (re 1.0) equivalent of the highest magnitude. */
+ void findPeak(float* data, int start_search, int end_search,
+ int* max_loc, float* max_value);
+
+ // Real and Imaginary analysis arrays.
+ float* mRe;
+ float* mIm;
+ // Fourier transform and window.
+ Fft* mFt;
+ Window* mWind;
+ // Derived parameters and other variables.
+ float mSampleRate;
+ int mFrameStep;
+ int mWindowSize;
+ int mFftSize;
+ float mOnsetThresh;
+ float mDbSnrThresh;
+ int mLowestSpectrumBin;
+ int mLowToneBin;
+ int mHighToneBin;
+};
+
+#endif // GLITCH_TEST_H
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