bbc-speech-segmenter: Voice Activity Detection & Speaker Diarization

A complete speech segmentation system using Kaldi and x-vectors for voice activity detection (VAD) and speaker diarisation.

The x-vector-vad system is described in the paper; Ogura, M. & Haynes, M. (2021) X-vector-vad for Multi-genre Broadcast Speech-to-text. The paper has been submitted to 2021 IEEE Automatic Speech Recognition and Understanding Workshop (ASRU) and is currently under review as of June 2021.

• ASRU 2021 website

Quickstart

$ docker pull bbcrd/bbc-speech-segmenter

# Test

$ docker run -w /wrk -v `pwd`:/wrk bbcrd/bbc-speech-segmenter ./test.sh

# Segmentation help

$ docker run bbcrd/bbc-speech-segmenter ./run-segmentation.sh --help
usage: run-segmentation.sh [options] input.wav input.stm output-dir

options:
  --nj NUM                 Maximum number of CPU cores to use
  --stage STAGE            Start from this stage
  --cluster-threshold THR  Cluster stopping criteria. Default: -0.3
  --vad-threshold THR      Xvector classifier threshold. Lower the number the
                           more speech segments shall be returned at the
                           expense of accuracy. Default: 0.2
  --vad-method             Filter segments on an individual or segment basis.
                           Default: individual
  --no-vad                 Skip xvector vad stages. Default: false
  --help                   Print this message

# Run segmentation (VAD + diarisation), results are in output-dir/diarize.stm

$ docker run -v `pwd`:/data bbcrd/bbc-speech-segmenter \
  ./run-segmentation.sh /data/audio.wav /data/audio.stm /data/output-dir

$ cat output-dir/diarize.stm
audio 0 audio_S00004 3.750 10.125 <speech>
audio 0 audio_S00003 10.125 13.687 <speech>
audio 0 audio_S00004 13.688 16.313 <speech>
...

# Train x-vector classifier

$ docker run -w /wrk/recipe -v `pwd`:/wrk bbcrd/bbc-speech-segmenter \
  local/xvector_utils.py data/bbc-vad-train/reference.stm            \
  data/bbc-vad-train/xvectors.ark new_model.pkl

# Evaluate x-vector classifier

$ docker run -w /wrk/recipe -v `pwd`:/wrk bbcrd/bbc-speech-segmenter \
  local/xvector_utils.py evaluate data/bbc-vad-eval/reference.stm    \
  data/bbc-vad-eval/xvectors.ark model/xvector-classifier.pkl

Audio & STM file format

In order to run the segmentation script you need your audio in 16Khz Mono WAV format. You also need an STM file describing the segments you want to apply voice activity detection and speaker diarization to.

For more information on the STM file format see XVECTOR_UTILS.md.

# Convert audio file to 16Khz mono wav

$ ffmpeg audio.mp3 -vn -ac 1 -ar 16000 audio.wav

# Create STM file for input

$ DURATION=$(ffprobe -i audio.wav -show_entries format=duration -v quiet -of csv="p=0")
$ DURATION=$(printf "%0.2f\n" $DURATION)

$ FILENAME=$(basename audio.wav)

$ echo "${FILENAME%.*} 0 ${FILENAME%.*} 0.00 $DURATION <label> _" > audio.stm

$ cat audio.stm
audio 0 audio 0.00 60.00 <label> _

Use Docker image to run code in local checkout

# Bulid Docker image

$ docker build -t bbc-speech-segmenter .

# Spin up a Docker container in an interactive mode

$ docker run -it -v `pwd`:/wrk bbc-speech-segmenter /bin/bash

# Inside a Docker container

$ cd /wrk/

# Run test

$ ./test.sh
All checks passed

Training and evaluation

X-vector utility

xvector_utils.py can be used to train and evaluate x-vector classifier, as well as o extract and visualize x-vectors. For more detailed information, see XVECTOR_UTILS.md.

The documentation also gives details on file formats such as ARK, SCP or STM, which are required to use this tool.

Run x-vector VAD training

Two files are required for x-vector-vad training:

• Reference STM file
• X-vectors ARK file

For example, from inside the Docker container:

$ cd /wrk/recipe

$ python3 local/xvector_utils.py train \
  data/bbc-vad-train/reference.stm     \
  data/bbc-vad-train/xvectors.ark      \
  new_model.pkl

The model will be saved as new_model.pkl.

Run x-vector VAD evaluation

Three files are needed in order to run VAD evaluation:

• Reference STM file
• X-vectors ARK file
• x-vector-vad classifier model

For example, from inside the Docker container:

$ cd /wrk/recipe

$ python3 local/xvector_utils.py evaluate \
  data/bbc-vad-eval/reference.stm        \
  data/bbc-vad-eval/xvectors.ark         \
  model/xvector-classifier.pkl

WebRTC baseline

The code for the baseline WebRTC system referenced in the paper is available in the directory recipe/baselines/denoising_DIHARD18_webrtc.

Request access to bbc-vad-train

Due to size restriction, only bbc-vad-eval is included in the repository. If you'd like access to bbc-vad-train, please contact Matt Haynes.

Authors

• Misa Ogura misa.ogura01@gmail.com
• Matt Haynes matt.haynes@bbc.co.uk