Pyramic Demo at IWAENC 2018

This repository contains C++ code to run real-time adaptive beamforming suitable for a large number of channels. We use it with the Pyramic microphone array, which makes use of the DE1-SoC FPGA/ARM combo.

This is the code that was used for our demo at IWAENC 2018 in Tokyo.

Compile and run the demo

# prepare the environment
source start_demo_env.sh

# compile the demo (make sure SPEEDFLAGS is used in the Makefile)
make demos

# After placing the microphone array and target speaker run the calibration
# when the room is relatively silent and the target source playing the
# calibration signal `data/calibration_signal.wav`
# Usage: demo_gsc_calibration <config_file> <weight_output_file> <recording_time>
./bin/demo_gsc_calibration config/demo_gsc.json config/my_weights.json 15

# Now you can run the demo specifying the same config and weight files
./bin/demo_gsc config/demo_gsc.json config/my_weights.json

Compile and run tests

# build the tests
make tests

# this won't be needed when we move the shared library to /usr/lib
export LD_LIBRARY_PATH=./lib:$LD_LIBRARY_PATH

# test correctness of STFT output
./tests/bin/test_stft

# speed to execture two-way STFT
./tests/bin/test_stft_speed

Use the STFT

#include "src/e3e_detection.h"
#include "src/stft.h"

// We'll need these to store sample, etc
float audio_input_buffer[FRAME_SIZE];
float audio_output_buffer[FRAME_SIZE];

// We only need a pointer for this one, the array
// will be allocated by the STFT engine
e3e_complex *spectrum;

STFT engine(FRAME_SIZE, FFT_SIZE, ZB, ZF, CHANNELS, WFLAG);

while (1)
{
  // get FRAME_SIZE new audio samples
  get_new_audio_samples(audio_input_buffer, FRAME_SIZE);

  // Analyze them. Spectrum contains (FFT_SIZE / 2 + 1) complex numbers
  spectrum = engine.analysis(audio_input_buffer);

  // Run some processing on spectrum
  ...

  // Now synthesize into the output buffer
  engine.synthesis(audio_output_buffer);

  // Send the processed samples to the output
  play_audio_samples(audio_output_buffer, FRAME_SIZE);
}

The docstring for the STFT constructor

STFT(int shift, int fft_size, int zpb, int zpf, int channels, int flags)
/**
  Constructor for the STFT engine.

  @param shift The frame shift
  @param fft_size The size of the FFT (including padding, if any)
  @param zpb The zero-padding at the end of the array
  @param zpf The zero-padding at the front of the array
  @param channels The number of channels
  @param flags Specify which window scheme to use (STFT_NO_WINDOW, STFT_WINDOW_ANALYSIS, STFT_WINDOW_BOTH)
  */

Dependencies

Install compile tools

apt-get install build-essential gfortran manpages-dev

To run the code, one needs to install

FFTW

These other libraries are used, but are distributed with the code

The Eigen library is distributed with the code for convenience (in include/Eigen). It is licensed under MPL2. For more information see the official website.

The nolehmann/json header file is distributed with the code for convenience (in include/json.hpp). It is licensed under MIT License. More information can be found on the official github page.

The AudioFile header and source files are distributed with the code for convenience (in include/AudioFile.h and src/AudioFile.cpp). It is licensed under GPL License. More information can be found on the official github page.

Install GCC with std14 support (v4.9)

The code uses some C++14 specific commands and requires g++-4.9 minimum to be compiled. The current Pyramic image is Ubuntu 14.04 which requires some patching to get the right compiler.

source

# install the add-apt-repository command
apt-get install software-properties-common python-software-properties

# now try to upgrade g++
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install g++-4.9 gfortran-4.9

Set the default gcc version used

update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 10
update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.9 20
update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.8 10
update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.9 20
update-alternatives --install /usr/bin/gfortran gfortran /usr/bin/gfortran-4.8 10
update-alternatives --install /usr/bin/gfortran gfortran /usr/bin/gfortran-4.9 20

update-alternatives --set cc /usr/bin/gcc
update-alternatives --install /usr/bin/cc cc /usr/bin/gcc 30
update-alternatives --set c++ /usr/bin/g++
update-alternatives --install /usr/bin/c++ c++ /usr/bin/g++ 30

Check that version 4.9 is called when running

g++ --version

Compile FFTW

Compile FFTW on ARM with floating point NEON support

apt-get install gfortran

wget http://www.fftw.org/fftw-3.3.4.tar.gz
tar xzfv fftw-3.3.4.tar.gz
cd fftw-3.3.4
./configure --enable-single --enable-neon ARM_CPU_TYPE=<ARCH> --enable-shared
make
make install
ldconfig

Replace <ARCH> by

cortex-a8 for BBB
cortex-a9 for DE1-SoC

Compile OpenBLAS (not actually used)

Note that you should have the same gfortran version than gcc

wget https://github.com/xianyi/OpenBLAS/archive/v0.3.3.tar.gz
tar xzfv v0.3.3.tar.gz
cd OpenBLAS-0.3.3
make TARGET=CORTEXA9
make PREFIX=/path/to/pyramic-demo install

fakufaku/pyramic-demo