PLCTestbench

PLCTestbench is a companion tool for researchers and developers working on Packet Loss Concealment (PLC). It greatly simplifies the process of measuring the reconstruction quality of PLC algorithms and allows to easily test the effects of different packet loss models and distributions.

It features the implementation of some of the most common packet loss models, PLC algorithms and metrics:

Packet Loss Simulation

• Binomial: uniform distribution of packet losses, governed by the Packet Error Ratio (PER) parameter.
• Gilbert-Elliot: bursty distribution of packet losses, governed by the four probabilities associated to its two states (For each state, the probability of packet loss and the probability of transitioning to the other state) [1].

PLC Algorithms

• Zeros: the lost samples are replaced by zeros.
• Last Packet: the lost samples are replaced by the last received packet.
• Low-Cost: implementation of the algorithm proposed in [2].
• Burg: Python bindings for the C++ implementation of the Burg method.
• Deep Learning: implementation of the algorithm proposed in [3].
• External: Python bindings for C++ to simplify the integration of existing algorithms.

Metrics

• Mean Square Error: the mean square error between the original and reconstructed signal.
• PEAQ: the Perceptual Evaluation of Audio Quality (PEAQ) metric, as defined in [4].

Basic Usage

You will need a mongoDB database to store the results. You can install it locally or use a cloud service like MongoDB Atlas. It is recomended however to use the Docker image provided by MongoDB.

Pull the image

    docker pull mongo:6.0.8

Then run the container setting the port to 27017 and the name to mongodb. Also set the username and password for the database.

    docker run -d -p 27017:27017 --name mongodb \
    -e MONGO_INITDB_ROOT_USERNAME=myUserAdmin \
    -e MONGO_INITDB_ROOT_PASSWORD=admin \
    mongo:6.0.8

Clone this repository, install the requirements and the plctestbench package:

    git clone https://github.com/LucaVignati/plc-testbench.git
    cd plc-testbench
    pip install -r requirements.txt
    pip install .

If you want to use it inside Jupyter Notebook you also need to install the ipywidgets package:

    pip install ipywidgets

Clone and install the burg-python-bindings:

    git clone https://github.com/LucaVignati/burg-python-bindings.git
    cd burg-python-bindings
    python setup.py install

Clone and install the cpp_plc_template:

    git clone https://github.com/LucaVignati/cpp_plc_template.git
    cd cpp_plc_template
    python setup.py install

If you want to use the PEAQ metric, you also need to install the GSTREAMER library and the PEAQ plugin:

    sudo apt-get install libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev libgstreamer-plugins-bad1.0-dev gstreamer1.0-plugins-base gstreamer1.0-plugins-good gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly gstreamer1.0-libav gstreamer1.0-tools gstreamer1.0-x gstreamer1.0-alsa gstreamer1.0-gl gstreamer1.0-gtk3 gstreamer1.0-qt5 gstreamer1.0-pulseaudio git gtk-doc-tools git2cl automake libtool
    mkdir gstpeaq && git clone https://github.com/HSU-ANT/gstpeaq.git gstpeaq
    cd gstpeaq
    aclocal && autoheader && ./autogen.sh && sed -i 's/SUBDIRS = src doc/SUBDIRS = src/' Makefile.am && ./configure --libdir=/usr/lib && automake && make && make install

The file plctestbench.ipynb contains a Jupyter Notebook with a basic example of how to use the tool.

Input the settings of the testbench as follows:

    testbench_settings = {
        'root_folder': 'path/to/root/folder',
        'db_ip': 'ip.of.the.database',
        'db_port': 27017,
        'db_username': 'myUserAdmin',
        'db_password': 'admin',
}

List the audio files you want to input as follows (path relative to root_folder):

original_audio_tracks = [(OriginalAudio, OriginalAudioSettings('Blues_Drums.wav')),
                         (OriginalAudio, OriginalAudioSettings('Blues_Piano.wav'))]

List the packet loss models you want to test as follows:

packet_loss_simulators = [(GilbertElliotPLS, GilbertElliotPLSSettings()),
                          (BinomialPLS, BinomialPLSSettings())]

List the PLC algorithms you want to test as follows:

plc_algorithms = [(ZerosPLC, ZerosPLCSettings()),
                  (LastPacketPLC, LastPacketPLCSettings()),
                  (LowCostPLC, LowCostPLCSettings()),
                  (BurgPLC, BurgPLCSettings()),
                  (DeepLearningPLC, DeepLearningPLCSettings()),
                  (ExternalPLC, ExternalPLCSettings())]

❗The DeepLearningPLC algorithm requires the bufer_size to be set to 128 in the Settings of the PacketLossSimulator of choice.

List the metrics you want to use as follows:

metrics = [(MSECalculator, MSECalculatorSettings()),
           (PEAQCalculator, PEAQCalculatorSettings())]

Finally, run the testbench:

testbench = Testbench(testbench_settings, user, original_audio_tracks, packet_loss_simulators, plc_algorithms, metrics)
testbench.run()

If you want to change the parameters of any of the modules, you can do so by passing the settings as a parameter to the constructor of the module. For example, to change the PER of the Binomial packet loss model:

packet_loss_simulators = [(BinomialPLS, BinomialPLSSettings(per=0.1))]

For the full list of settings, check the settings.py file.

To plot the results:

testbench.plot(to_file=True, original_tracks=True, lost_samples_masks=True, output_analyses=True)

You can also plot the waveform of the reconstructed audio tracks, however since we're plotting the entire duration of the audio file, the differences with the original tracks are not going to be visible. This is why we developed a user interface for this application.

You will find both the audio files and the results in the folder specified in the root_folder setting.

User Interface

This user interface is an ongoing thesis project carried out by Stefano Dallona under the supervision of Luca Vignati. It is a web application developed using the React framework. The code is available in the following two repositories:

• plc-testbench-ui
• react-test

The easiest way to try it out is to use the Docker image provided by Stefano Dallona:

    docker pull cimil/plc-testbench-ui:latest

This Docker image already contains the code of PLCTestbench so it only requires a running MongoDB instance (see previous section).

Run the following command to start the container:

    docker run -e DB_USERNAME=$DB_USERNAME \
               -e DB_PASSWORD=$DB_PASSWORD \
               -e DB_HOST=$DB_HOST \
               -e DB_CONN_STRING=$DB_CONN_STRING \
               -e GEVENT_SUPPORT=$GEVENT_SUPPORT \
               -e FLASK_APP=$FLASK_APP \
               -e FLASK_DEBUG=$FLASK_DEBUG \
               -e FRONTEND_DATA_FOLDER=$FRONTEND_DATA_FOLDER \
               -e SECURITY_ENABLED=$SECURITY_ENABLED \
               -p 5000:5000 \
               -v /path/to/root/folder:/original_tracks \
               --name plc-testbench-ui \
               cimil/plc-testbench-ui:latest

Where the environment variables are:

Variable	Value	Description
DB_USERNAME	myUserAdmin	Username of the database
DB_PASSWORD	admin	Password of the database
DB_HOST	ip.of.the.database	IP address of the database
DB_CONN_STRING	mongodb://ip:27017	Connection string of the database
GEVENT_SUPPORT	True	Enable gevent support
FLASK_APP	app.py	Flask application
FLASK_DEBUG	True	Enable Flask debug mode
FRONTEND_DATA_FOLDER	/original_tracks	Path to the folder containing the audio files
SECURITY_ENABLED	False	Enable security

Then open your browser and go to localhost:5000.

❗Please consider the pre-release status of this user interface when using it.

References

[1] Elliott, Edwin O. "Estimates of error rates for codes on burst-noise channels." The Bell System Technical Journal 42.5 (1963): 1977-1997.

[2] Fink, Marco, and Udo Zölzer. "Low-Delay Error Concealment with Low Computational Overhead for Audio over IP Applications." DAFx. 2014.

[3] Verma, Prateek, et al. "A deep learning approach for low-latency packet loss concealment of audio signals in networked music performance applications." 2020 27th Conference of open innovations association (FRUCT). IEEE, 2020.

[4] Thiede, Thilo, et al. "PEAQ-The ITU standard for objective measurement of perceived audio quality." Journal of the Audio Engineering Society 48.1/2 (2000): 3-29.