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105 lines
4.4 KiB
105 lines
4.4 KiB
/* This is a direct translation of the Teensy Audio Library RMS Analyze
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* to use floating point f32. This is intended to be compatible with
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* Chip Audette's floating point libraries.
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* Bob Larkin 23 April 2020 - AudioAnalyze_RMS_F32
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*
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* Regard the copyright and licensing:
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* Audio Library for Teensy 3.X
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* Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
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*
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* Development of this audio library was funded by PJRC.COM, LLC by sales of
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* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop
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* open source software by purchasing Teensy or other PJRC products.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice, development funding notice, and this permission
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* notice shall be included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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/* Input is a block of f32 numbers. Output is the signal RMS amplitude
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* calculated over multiple blocks. Useful for audio level response projects,
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* and general troubleshooting.
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*
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* Status: Tested 3.6 and T4.0 No known bugs.
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* Functions:
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* available(); Returns true if new RMS data is available.
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* read(); Read the new RMS value. Return is rms value in float.
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* Examples:
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* TestPeakRMS.ino
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* Similar: File > Examples > Audio > Analysis > PeakAndRMSMeterStereo
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* Time: Measured time for the update of F32 RMS is 7 microseconds
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* for 128 block size.
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*
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* The average "power" is found by squaring the sample values, adding them
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* together and dividing by the number of samples. The RMS value is a "voltage"
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* found by taking the square root of the power. This is in DSP lingo, and
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* the units are vague. But, since usually, only relative values are important,
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* the units will cancel out!
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*
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* The two variables, accum and count, keep adding to the power sum until
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* a read() takes place. This is fine if the statistics of the input data are
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* stationary, i.e., not changing with time. But, if the process is not
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* stationary, be aware and do read() at appropriate times.
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*/
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#ifndef analyze_rms_f32_h_
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#define analyze_rms_f32_h_
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#include "Arduino.h"
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#include "AudioStream_F32.h"
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class AudioAnalyzeRMS_F32 : public AudioStream_F32 {
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//GUI: inputs:1, outputs:0 //this line used for automatic generation of GUI node
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//GUI: shortName: AnalyzeRMS
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public:
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AudioAnalyzeRMS_F32(void) : AudioStream_F32(1, inputQueueArray_f32) {
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// default values from initialization below
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}
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// Alternate specification of block size. Sample rate does not apply for analyze_rms
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AudioAnalyzeRMS_F32(const AudioSettings_F32 &settings) : AudioStream_F32(1, inputQueueArray_f32) {
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block_size = settings.audio_block_samples;
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}
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bool available(void) {
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return count > 0;
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}
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void showError(uint16_t e) { // 0/1 Disables/Enables printing of update() errors
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errorPrint = e;
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}
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float read(void);
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virtual void update(void);
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private:
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audio_block_f32_t *inputQueueArray_f32[1];
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uint16_t block_size = AUDIO_BLOCK_SAMPLES;
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// double for accum is very safe, but needed? Well, power dynamic Range x 1 sec of data =~ 1E7 x 4E4 = 4E11
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// whereas float range for positive numbers is 2^23 =~ 1E7 so double is easily justified for accuracy.
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// The timing 7 microseconds per 128, includes using double for accum, so the price is reasonable.
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double accum = 0.0;
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uint32_t count = 0;
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// Control error printing in update(). Should never be enabled
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// until all audio objects have been initialized.
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// Only used as 0 or 1 now, but 16 bits are available.
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uint16_t errorPrint = 0;
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};
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#endif
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