This is a library of Teensy Arduino classes to provide audio signal processing with 32-bit floating point data transfers.
This parallels the 16-bit integer [Teensy Audio Library](http://www.pjrc.com/teensy/td_libs_Audio.html) but, interconnects blocks using 32-bit floating point data types. Converters for inter-connecting the two types are provided. Both data types can be used in the same sketch. To distinguish the two types, file and class names for this library have a trailing "_F32."
*** Special Note *** 6 January 2021- This library is undergoing revision to make Teensy 4.x compatible and to add functionality. The Tympan Library
files and associated classes output_i2s_f32.h, output_i2s_f32.cpp, input_i2s_f32.h, input_i2s_f32.cpp are now
ready to be used for T3.x and T4.x. There are some restrictions, particularly this should be used with 16-bit I2S codec data. Codec sample rates can be varied. Variable block size is supported, but be sure the settings option is used. More on this to come. Work on the F32 i/o routines is continuing. Thanks to Chip and @jcj83429 .
This library was originally put together by Chip Audette and he summed up the reasons for this:
**Purpose**: The purpose of this library is to build upon the [Teensy Audio Library](http://www.pjrc.com/teensy/td_libs_Audio.html) to enable new functionality for real-time audio processing.
**Approach**: I am attempting to follow the structure and approach of the Teensy Audio Library so that coding techniques, style, and structure that works for the Teensy Audio Library will also work with my library. synth_sine_f32
**Approach**: To follow the structure and approach of the Teensy Audio Library, so that coding techniques, style, and structure that works for the Teensy Audio Library will also work with this library.
**Send Help!**: While I'm hoping to follow the pattern of the Teensy Audio Library, I am not a well trained programmer, so I have difficulty chosing the right path. If you see ways to make my code better aligned with the Teensy Audio Library, send a pull request!
**Send Help!**: If you see ways to make my code better aligned with the Teensy Audio Library, send a pull request!
Contents
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Information
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**Design Tool** Many changes and additions were made in the 2020 time period. Hopefully this has brought this library to the point where blocks can be just assembled and run. To make that practical, there is now an [OpenAudio Library Design Tool](http://www.janbob.com/electron/OpenAudio_Design_Tool/index.html) that again parallels the Teensy Audio Design Tool, that has been borrowed upon for both code and content. This OpenAudio Design Tool is intended to be a temporary design aid with improvements to come, like being able to combine integer and floating point blocks.
As I said, the goal of this library is to extend the functionality of the Teensy Audio Library. My extensions are focused in these areas:
The primary documentation is the Design Tool. Clicking on any of the classes brings up a right-side help panel. This lists the use of the class, the constraints, all the functions and at the botom are general notes. Most classes have example INO files and these are listed and available when this library is installed. Sometimes elements of this documentation is not completed, yet. In some of those cases it is worth looking at the .h include file for the class. At the top of these files are comments with more information.
**Floating Point Audio Processing**: The Teensy Audio Library processes the audio data as fixed-point Int16 values. While very fast for the Teensy 3.0-3.2, it is unnecessarily constraining (IMO) for the Teensy 3.5 and 3.6, which both have floating-point units. To enable floating-point audio processing, I have created:
* **AudioStream_F32: Following the model of Teensy's `AudioStream` class. In addition to the new `AudioStream_F32`, this file includes a new `audio_block_f32_t` in place of `audio_block_t`, as well as a new `AudioConnection_F32` in place of `AudioConnection`.
* **New F32 Audio Processing Blocks**: Using this new floating-point capability, I've written some new audio processing blocks that operate using floating-point audio values instead of fixed-point values. Examples include `AudioEffectGain_F32` and `AudioEffectComperessor_F32`.
* **F32 Versions of Existing Blocks**: To maintain continuity with the Teensy Audio Library, a number of the Audio Library's Audio blocks (which process as Int16 data) to operate on floating-point (ie, Float32) data. Thanks to other people's contributions, examples include `AudioMixer4_F32` and `AudioMultiply_F32`. Feel free to convert more blocks, if you'd like!
* **New Hardware Controls**: The Teensy Audio Library does a great job of wrapping up the complicated control of hardware elements (such as the SGTL5000 audio codec) into a nice easy-to-use classes. But, sometimes, certain features of the hardware were not exposed in those classes. Here, I've extended the default classes to expose the extra features that I want. See `AudioControlSGTL5000_Extended` as an example.
**Teensy 3 and 4** During 2020 this library has undergone revision to make Teensy 4.x compatible. Much of this related to using multiple sampling rates with the I2S clocks and the interrupt/DMA code for data transfer. The files and associated classes output_i2s_f32.h, output_i2s_f32.cpp, input_i2s_f32.h, input_i2s_f32.cpp are now
ready to be used for T3.x and T4.x. There are some restrictions, particularly this should be used with 16-bit I2S codec data. Codec sample rates can be varied. Variable block size is supported, but be sure the settings option is used. Thanks to Chip, @jcj83429 and all the Teensy development work.
After installing this library into your Arduino->Libraries direction, you can have access to any of these capabilities simply by including the following command in your Arduino sketch: `#include <OpenAudio_ArduinoLibrary.h>`.
**Tympan Project** Many of the classes in this library were put together as part of the [Tympan Project.](https://github.com/Tympan) That is oriented towards open-source hearing aid and hearing aid development tools. It has its own [Tympan Design Tool](https://tympan.github.io/Tympan_Audio_Design_Tool/) as well as some custom Teensy-based hardware. Additionally, there are a few classes in this library that use terminology and variables that are specific to audiology. It is intended that these, in time, be replaced by similar classes with more conventional descriptors. And, of course, if your interest is in hearing aids, you should spend time at the Tympan project!
Installation
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@ -33,90 +31,13 @@ Download (and unzip) this library into the Arduino libraries directory on your c
Restart your Arduino IDE and you should now see this libraries example sketches under File->Examples->OpenAudio_ArduinoLibrary
After installing this library into your Arduino->Libraries direction, you can have access to any of these capabilities simply by including the following command in your Arduino sketch: `#include <OpenAudio_ArduinoLibrary.h>`.
As an alternative to the ZIP download, you can use git to maintain a local copy of the library. This has the advantage of easy updating. See GitHub and git documentation on how to do this.
Dependencies
------------
This library extends the functionality of the [Teensy Audio Library](http://www.pjrc.com/teensy/td_libs_Audio.html), so you'll need to install it per its instructions.
The floating-point processing takes advantage of the DSP acceleration afforded by the ARM M4F core inside the Teensy 3.5/3.6 processor. Therefore, it uses `arm_math.h`. This dependencies is installed automatically when you install the Teensy Audio Library, so you don't need to take any extra steps. It's there already.
Status
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The following table summarizes the status, as of 24 November 2020. I will try to keep this up-to-date as work continues, but tere will be lags.
Thus there may be more T4.x compatibility than shown here. A blank entry for status does not indicate a problem, but rather a lack
of verification. Further examples will come to test some of these objects.
Update 29 Jan 2021: Replaced WDRC2 with AudioEffectCompressor2_F32. See Example testCompressor2.ino
Update 18 Feb 2021: Added analyze_fft1024_F32.h and .cpp that parallels analyze_fft1024.h and .cpp in the Teensy Audio Library, but F32.
Update 8 March 2021 Complex input FFT classes have been added for 256, 1024 and 2048 input points. These see use in Software Designed
Radios for double Fs spectral analysis with I-Q inputs.
The example files (from the Examples directory) are
1. AudioTestAnalyzePhase_F32
2. AudioTestPeakRMS
3. AudioTestSinCos
4. BasicCompressor_Float
5. BasicGain_Float
6. FineFreqShift_OA
7. FormantShifter_FD_OA
8. FrequencyShifter_FD_OA
9. LowpassFilter_FD_OA
10. MixStereoToMono_Float
11. MyAudioEffect_Float
12. OscillatorWithPitchmod_Float
13. ReceiverFM
14. ReceiverPart1
15. ReceiverPart2
16. Repair audio mixer_F32
17. SignalNoise_float
18. Switches_float
19. TestEqualizer1
20. TestEqualizer1Audio
21. TestFIRGeneral3
22. TestFIRGeneralLarge4
23. TestFIRGeneralLarge5
24. TestInputOutput_float
28. Tympan_TLV320AIC3206
29. testWDRC2 (not supported)
30. testCompressor2
WORKING NOTES - For now, here are some temporary notes:
---------------
1. synth_sine_f32.h & .cpp allowed both KINETISK and__IMXRT1062__ to support T4.x. Tested 3.6, 4.0
2. Fix synth_pinknoise_f32.h & .cpp built in I16 to F32. Now T3 and T4.
3. Fix synth_whitenoise_f32.cpp to include IMXRT1062 and built in I16 to F32. Now T3 and T4.
4. Added Gaussian White Noise F32. This is T3 and T4.
5. Renamed 3206 codec to .xxx to stop collisions with Teensy I16 library. Needs work.
6. Added new examples/SignalNoise_float.ino to test white, pink, Gaussian noise and sine. Audio out.
7. Disabled output_i2s_f32.h, .cpp by .xxxfile type. These need rework for T4. Use Convert_F32toI16.
8. Disabled control_tlv320aic3206.h, .cpp by .xxxfile type. These collide with Teensy I16 Audio.
9. Added new analyze_peak_f32.h and .cpp that parallel similar classes in the Teensy I16 library.
10. Added new analyze_rms_f32.h and .cpp that parallel similar classes in the Teensy I16 library.
11. Moved AudioSwitch_F32 from Tympan, added 8-channel version.
12. Added /examples/Switches_float.ino for 4 and 8 channel switches.
13. Moved FFT_Overlapped_F32 files from Tympan, revised for T4.0, added _OA name isolation.
14. Moved Overlapped FFT LPF .INO from Tympan to OA. Working T3.6 and T4.0
15. Moved Overlapped FFT AudioFormantShifter INO and related from Tympan to _OA Open Audio. Tested 3.6 and 4.0.
16. Moved AudioFrequencyShifter INO and related from Tympan to _OA Open Audio. Tested 3.6 and 4.0.
17. Working on SdFatWriter and related SdFat files. DO NOT USE.
18. Modified AudioEffectDelay for T4.0.
19. Moved in radio function AudioFilter90Deg_F32.
20. Moved in radio function RadioIQMixer_F32.
21. Added Example INO, FineFreqShift_OA.ino with Hilbert shifter and delay stereo.
22. Brought in support stuff mathDSP_F32 and sinTable512_F32.h.
23. Brought in AudioAnalyzePhase_F32 and Example
24. Brought in AudioFilterEqualyzer_F32 and 2 Example
25. Brought in AudioFilterFIRGeneral_F32 and 2 Example INOs
26. Brought in RadioFMDetector_F32 and Example
27. Brought in synth_sin_cos_F32 and test example
28. Brought in RadioNoiseBlanker_F32 and Example
29. Created output_i2s_OA_F32.h and .cpp to have F32 input. SEE 31 below
30. Repaired Audio Mixers 4 & 8. These are adders, NOT RF DBM's---see Multiplier_F32.
31. I2S Input and Output made T4 compatible, both supporting variable sample rate
32. Added AudioEffectCompressor2_F32 quite general audio compressor.
33. Added analyze_fft1024_F32 that does audio in and rms volts, power or dBFS out.
34. Added analyze_fft256_iq_F32 that does complex (I-Q) in and rms volts, power or dBFS out.
35. Added analyze_fft1024_iq_F32 that does complex (I-Q) in and rms volts, power or dBFS out.
36. Added analyze_fft2048_iq_F32 that does complex (I-Q) in and rms volts, power or dBFS out.
The floating-point processing takes advantage of the DSP acceleration afforded by the ARM core inside the Teensy 3.x and 4.x processor. Therefore, it uses `arm_math.h`. This dependencies is installed automatically when you install the Teensy Audio Library, so you don't need to take any extra steps. It's there already.
boblark
3 years ago