File Simulators

File simulators are offline .wav file processor utilities to aid in evaluation of the Wake Word engine on pre-recoded audio files. It takes WAV files containing in a mono 16-bit 16 kHz audio format, a wake word model, and outputs detection events to stdout.

The file simulator application is provided only for those architectures where file I/O and stdio C run-time library functionality is readily available (i.e. x86, darwin, linux, etc.).

How to run the application

For an exhaustive list of options, run the application with -h.

Locate the executable in the package

If supplied as part of the PryonLite package, an amazon_ww_filesim application binary will be present in a given <target> subfolder. For example, an Ubuntu x86 version of the filesim application would be found in the x86 folder.

File simulators for V2 API are located in subfolders of the architecture folder. The following table shows locations of file simulator applications built for various API versions:

API / Version	File Simulator Location
v2 PRL1000	./<architecture>/PRL1000/amazon_filesim-PRL1000
v2 PRL2000	./<architecture>/PRL2000/amazon_filesim-PRL2000

Note

Some target subfolders will not contain an amazon filesim application binary. This is due to lack of the target's file i/o capabilities.

Prepare Input Audio List

If you have a directory containing the .wav files to process, run the following command to generate a list file with all the .wav files in that directory:

ls -1 *.wav > all_wavs.list

The wake word engine uses adaptation logic to learn the characteristics of the acoustic environment. This improves detection quality. However if the audio clips are from different environments and do not contain at least 1 second of background noise prior to the wake word, we suggest using -c which will force the engine to clear the adaptation statistics after each file.

Tip

You can also run a single .wav file without a list. Just use the .wav file path instead of a list file path on the command line

Sample input

A sample WAV list file and associated .WAV files can be found in the following package locations:

./sample-wakeword/alexas.list
./sample-wakeword/alexa-*.wav

The list file will look like this:

alexa-01.wav
alexa-02.wav
alexa-03.wav
alexa-04.wav
alexa-05.wav
alexa-06.wav
alexa-07.wav
alexa-08.wav
alexa-09.wav
alexa-10.wav

Select a wake word model

The wake word model must be selected based on the paths specified by a particular architecture's WakewordModelMapping.json configuration file. For example, for the x86 (Ubuntu) architecture, the WakewordModelMapping.json file specifies that the following model is suitable for the x86 Ubuntu PryonLite engine:

common/D.en-US.alexa

The appropriate wake word model is then found in the 'models' subfolder, with a .bin extension. For example:

path_to_model = models/common/D.en-US.alexa.bin

For detailed information on model selection, see this section

Run the application

The application takes the wake word model and an audio list file in as command line parameters:

./<filesim application name> -m <path_to_model> all_wavs.list

To display a full list of options, run the filesim application with the '-h' option.

Reference file simulation output

Reference output from file simulation applications is provided in the package. In the example below, the reference file name is specifically for an x86 Ubuntu architecture using a D.en-US.alexa wake word model. Your package may contain a sample output for a different architecture or model, depending on your package request.

./sample-wakeword/ref-output-x86-D.en-US.alexa-alexas.list

The application output will look similar to the following:

Loaded model from path: models/common/D.en-US.alexa.bin
Decoder instance memory allocated:  266344
Model Version:  en-US_D_ALEXA+STOP_2018SuperBowl_v5.0
Engine Version: 2.9.0
Supported keywords: ALEXA, STOP
Threshold:      500

alexa-01: 'ALEXA' detected during  [0, 9600]
alexa-02: 'ALEXA' detected during  [8640, 17920]
alexa-03: 'ALEXA' detected during  [3680, 13920]
alexa-04: 'ALEXA' detected during  [4480, 14720]
alexa-05: 'ALEXA' detected during  [3040, 13280]
alexa-06: 'ALEXA' detected during  [5440, 15680]
alexa-07: 'ALEXA' detected during  [8800, 20480]
alexa-08: 'ALEXA' detected during  [7840, 19520]
alexa-09: 'ALEXA' detected during  [12000, 24160]
alexa-10: 'ALEXA' detected during  [30400, 43040]

*** 10 wake word(s) detected in 10 files ***

Fingerprinting File Simulator

See the Fingerprinting Integration Guide for instructions on how to pass a fingerprint list to the file simulator.