Speaker Diarization Configuration Files#

Hydra Configurations for Sortformer Diarizer Training#

Sortformer Diarizer is an end-to-end speaker diarization model that is solely based on Transformer-encoder type of architecture. Model name convention for Sortformer Diarizer: sortformer_diarizer_<loss_type>_<speaker count limit>-<version>.yaml

  • Example <NeMo_root>/examples/speaker_tasks/diarization/neural_diarizer/conf/sortformer_diarizer_hybrid_loss_4spk-v1.yaml.

name: "SortformerDiarizer"
num_workers: 18
batch_size: 8

model:
  sample_rate: 16000
  pil_weight: 0.5 # Weight for Permutation Invariant Loss (PIL) used in training the Sortformer diarizer model
  ats_weight: 0.5 # Weight for Arrival Time Sort (ATS) loss in training the Sortformer diarizer model
  max_num_of_spks: 4 # Maximum number of speakers per model; currently set to 4

  model_defaults:
    fc_d_model: 512 # Hidden dimension size of the Fast-conformer Encoder
    tf_d_model: 192 # Hidden dimension size of the Transformer Encoder

  train_ds:
    manifest_filepath: ???
    sample_rate: ${model.sample_rate}
    num_spks: ${model.max_num_of_spks}
    session_len_sec: 90 # Maximum session length in seconds
    soft_label_thres: 0.5 # Threshold for binarizing target values; higher values make the model more conservative in predicting speaker activity.
    soft_targets: False # If True, use continuous values as target values when calculating cross-entropy loss
    labels: null
    batch_size: ${batch_size}
    shuffle: True
    num_workers: ${num_workers}
    validation_mode: False
    # lhotse config
    use_lhotse: False
    use_bucketing: True
    num_buckets: 10
    bucket_duration_bins: [10, 20, 30, 40, 50, 60, 70, 80, 90]
    pin_memory: True
    min_duration: 10
    max_duration: 90
    batch_duration: 400
    quadratic_duration: 1200
    bucket_buffer_size: 20000
    shuffle_buffer_size: 10000
    window_stride: ${model.preprocessor.window_stride}
    subsampling_factor: ${model.encoder.subsampling_factor}

  validation_ds:
    manifest_filepath: ???
    is_tarred: False
    tarred_audio_filepaths: null
    sample_rate: ${model.sample_rate}
    num_spks: ${model.max_num_of_spks}
    session_len_sec: 90 # Maximum session length in seconds
    soft_label_thres: 0.5 # A threshold value for setting up the binarized labels. The higher the more conservative the model becomes.
    soft_targets: False
    labels: null
    batch_size: ${batch_size}
    shuffle: False
    num_workers: ${num_workers}
    validation_mode: True
    # lhotse config
    use_lhotse: False
    use_bucketing: False
    drop_last: False
    pin_memory: True
    window_stride: ${model.preprocessor.window_stride}
    subsampling_factor: ${model.encoder.subsampling_factor}

  test_ds:
    manifest_filepath: null
    is_tarred: False
    tarred_audio_filepaths: null
    sample_rate: 16000
    num_spks: ${model.max_num_of_spks}
    session_len_sec: 90 # Maximum session length in seconds
    soft_label_thres: 0.5
    soft_targets: False
    labels: null
    batch_size: ${batch_size}
    shuffle: False
    seq_eval_mode: True
    num_workers: ${num_workers}
    validation_mode: True
    # lhotse config
    use_lhotse: False
    use_bucketing: False
    drop_last: False
    pin_memory: True
    window_stride: ${model.preprocessor.window_stride}
    subsampling_factor: ${model.encoder.subsampling_factor}

  preprocessor:
    _target_: nemo.collections.asr.modules.AudioToMelSpectrogramPreprocessor
    normalize: "per_feature"
    window_size: 0.025
    sample_rate: ${model.sample_rate}
    window_stride: 0.01
    window: "hann"
    features: 80
    n_fft: 512
    frame_splicing: 1
    dither: 0.00001

  sortformer_modules:
    _target_: nemo.collections.asr.modules.sortformer_modules.SortformerModules
    num_spks: ${model.max_num_of_spks} # Number of speakers per model. This is currently fixed at 4.
    dropout_rate: 0.5 # Dropout rate
    fc_d_model: ${model.model_defaults.fc_d_model}
    tf_d_model: ${model.model_defaults.tf_d_model} # Hidden layer size for linear layers in Sortformer Diarizer module

  encoder:
    _target_: nemo.collections.asr.modules.ConformerEncoder
    feat_in: ${model.preprocessor.features}
    feat_out: -1
    n_layers: 18
    d_model: ${model.model_defaults.fc_d_model}

    # Sub-sampling parameters
    subsampling: dw_striding # vggnet, striding, stacking or stacking_norm, dw_striding
    subsampling_factor: 8 # must be power of 2 for striding and vggnet
    subsampling_conv_channels: 256 # set to -1 to make it equal to the d_model
    causal_downsampling: false
    # Feed forward module's params
    ff_expansion_factor: 4
    # Multi-headed Attention Module's params
    self_attention_model: rel_pos # rel_pos or abs_pos
    n_heads: 8 # may need to be lower for smaller d_models
    # [left, right] specifies the number of steps to be seen from left and right of each step in self-attention
    att_context_size: [-1, -1] # -1 means unlimited context
    att_context_style: regular # regular or chunked_limited
    xscaling: true # scales up the input embeddings by sqrt(d_model)
    untie_biases: true # unties the biases of the TransformerXL layers
    pos_emb_max_len: 5000
    # Convolution module's params
    conv_kernel_size: 9
    conv_norm_type: 'batch_norm' # batch_norm or layer_norm or groupnormN (N specifies the number of groups)
    conv_context_size: null
    # Regularization
    dropout: 0.1 # The dropout used in most of the Conformer Modules
    dropout_pre_encoder: 0.1 # The dropout used before the encoder
    dropout_emb: 0.0 # The dropout used for embeddings
    dropout_att: 0.1 # The dropout for multi-headed attention modules
    # Set to non-zero to enable stochastic depth
    stochastic_depth_drop_prob: 0.0
    stochastic_depth_mode: linear  # linear or uniform
    stochastic_depth_start_layer: 1

  transformer_encoder:
    _target_: nemo.collections.asr.modules.transformer.transformer_encoders.TransformerEncoder
    num_layers: 18
    hidden_size: ${model.model_defaults.tf_d_model} # Needs to be multiple of num_attention_heads
    inner_size: 768
    num_attention_heads: 8
    attn_score_dropout: 0.5
    attn_layer_dropout: 0.5
    ffn_dropout: 0.5
    hidden_act: relu
    pre_ln: False
    pre_ln_final_layer_norm: True

  loss:
    _target_: nemo.collections.asr.losses.bce_loss.BCELoss
    weight: null # Weight for binary cross-entropy loss. Either `null` or list type input. (e.g. [0.5,0.5])
    reduction: mean

  lr: 0.0001
  optim:
    name: adamw
    lr: ${model.lr}
    # optimizer arguments
    betas: [0.9, 0.98]
    weight_decay: 1e-3

    sched:
      name: InverseSquareRootAnnealing
      warmup_steps: 2500
      warmup_ratio: null
      min_lr: 1e-06

trainer:
  devices: 1 # number of gpus (devices)
  accelerator: gpu
  max_epochs: 800
  max_steps: -1 # computed at runtime if not set
  num_nodes: 1
  strategy: ddp_find_unused_parameters_true # Could be "ddp"
  accumulate_grad_batches: 1
  deterministic: True
  enable_checkpointing: False
  logger: False
  log_every_n_steps: 1  # Interval of logging.
  val_check_interval: 1.0  # Set to 0.25 to check 4 times per epoch, or an int for number of iterations

exp_manager:
  use_datetime_version: False
  exp_dir: null
  name: ${name}
  resume_if_exists: True
  resume_from_checkpoint: null # The path to a checkpoint file to continue the training, restores the whole state including the epoch, step, LR schedulers, apex, etc.
  resume_ignore_no_checkpoint: True
  create_tensorboard_logger: True
  create_checkpoint_callback: True
  create_wandb_logger: False
  checkpoint_callback_params:
    monitor: "val_f1_acc"
    mode: "max"
    save_top_k: 9
    every_n_epochs: 1
  wandb_logger_kwargs:
    resume: True
    name: null
    project: null

Hydra Configurations for Streaming Sortformer Diarizer Training#

Model name convention for Streaming Sortformer Diarizer: streaming_sortformer_diarizer_<speaker count limit>-<version>.yaml

  • Example <NeMo_root>/examples/speaker_tasks/diarization/neural_diarizer/conf/streaming_sortformer_diarizer_4spk-v2.yaml.

name: "StreamingSortformerDiarizer"
num_workers: 18
batch_size: 4

model:
  sample_rate: 16000
  pil_weight: 0.5 # Weight for Permutation Invariant Loss (PIL) used in training the Sortformer diarizer model
  ats_weight: 0.5 # Weight for Arrival Time Sort (ATS) loss in training the Sortformer diarizer model
  max_num_of_spks: 4 # Maximum number of speakers per model; currently set to 4
  streaming_mode: True

  model_defaults:
    fc_d_model: 512 # Hidden dimension size of the Fast-conformer Encoder
    tf_d_model: 192 # Hidden dimension size of the Transformer Encoder

  train_ds:
    manifest_filepath: ???
    sample_rate: ${model.sample_rate}
    num_spks: ${model.max_num_of_spks}
    session_len_sec: 90 # Maximum session length in seconds
    soft_label_thres: 0.5 # Threshold for binarizing target values; higher values make the model more conservative in predicting speaker activity.
    soft_targets: False # If True, use continuous values as target values when calculating cross-entropy loss
    labels: null
    batch_size: ${batch_size}
    shuffle: True
    num_workers: ${num_workers}
    validation_mode: False
    # lhotse config
    use_lhotse: False
    use_bucketing: True
    num_buckets: 10
    bucket_duration_bins: [10, 20, 30, 40, 50, 60, 70, 80, 90]
    pin_memory: True
    min_duration: 10
    max_duration: 90
    batch_duration: 400
    quadratic_duration: 1200
    bucket_buffer_size: 20000
    shuffle_buffer_size: 10000
    window_stride: ${model.preprocessor.window_stride}
    subsampling_factor: ${model.encoder.subsampling_factor}

  validation_ds:
    manifest_filepath: ???
    is_tarred: False
    tarred_audio_filepaths: null
    sample_rate: ${model.sample_rate}
    num_spks: ${model.max_num_of_spks}
    session_len_sec: 90 # Maximum session length in seconds
    soft_label_thres: 0.5 # A threshold value for setting up the binarized labels. The higher the more conservative the model becomes.
    soft_targets: False
    labels: null
    batch_size: ${batch_size}
    shuffle: False
    num_workers: ${num_workers}
    validation_mode: True
    # lhotse config
    use_lhotse: False
    use_bucketing: False
    drop_last: False
    pin_memory: True
    window_stride: ${model.preprocessor.window_stride}
    subsampling_factor: ${model.encoder.subsampling_factor}

  test_ds:
    manifest_filepath: null
    is_tarred: False
    tarred_audio_filepaths: null
    sample_rate: 16000
    num_spks: ${model.max_num_of_spks}
    session_len_sec: 90 # Maximum session length in seconds
    soft_label_thres: 0.5
    soft_targets: False
    labels: null
    batch_size: ${batch_size}
    shuffle: False
    seq_eval_mode: True
    num_workers: ${num_workers}
    validation_mode: True
    # lhotse config
    use_lhotse: False
    use_bucketing: False
    drop_last: False
    pin_memory: True
    window_stride: ${model.preprocessor.window_stride}
    subsampling_factor: ${model.encoder.subsampling_factor}

  preprocessor:
    _target_: nemo.collections.asr.modules.AudioToMelSpectrogramPreprocessor
    normalize: "NA"
    window_size: 0.025
    sample_rate: ${model.sample_rate}
    window_stride: 0.01
    window: "hann"
    features: 128
    n_fft: 512
    frame_splicing: 1
    dither: 0.00001

  sortformer_modules:
    _target_: nemo.collections.asr.modules.sortformer_modules.SortformerModules
    num_spks: ${model.max_num_of_spks} # Maximum number of speakers the model can handle
    dropout_rate: 0.5 # Dropout rate
    fc_d_model: ${model.model_defaults.fc_d_model} # Hidden dimension size for Fast Conformer encoder
    tf_d_model: ${model.model_defaults.tf_d_model} # Hidden dimension size for Transformer encoder
    # Streaming mode parameters
    spkcache_len: 188 # Length of speaker cache buffer (total number of frames for all speakers)
    fifo_len: 0 # Length of FIFO buffer for streaming processing (0 = disabled)
    chunk_len: 188 # Number of frames processed in each streaming chunk
    spkcache_update_period: 188 # Speaker cache update period in frames
    chunk_left_context: 1 # Number of previous frames for each streaming chunk
    chunk_right_context: 1 # Number of future frames for each streaming chunk
    # Speaker cache update parameters
    spkcache_sil_frames_per_spk: 3 # Number of silence frames allocated per speaker in the speaker cache
    scores_add_rnd: 0 # Standard deviation of random noise added to scores in speaker cache update (training only)
    pred_score_threshold: 0.25 # Probability threshold for internal scores processing in speaker cache update
    max_index: 99999 # Maximum allowed index value for internal processing in speaker cache update
    scores_boost_latest: 0.05 # Gain for scores for recently added frames in speaker cache update
    sil_threshold: 0.2 # Threshold for determining silence frames to calculate average silence embedding
    strong_boost_rate: 0.75 # Rate determining number of frames per speaker that receive strong score boosting
    weak_boost_rate: 1.5 # Rate determining number of frames per speaker that receive weak score boosting
    min_pos_scores_rate: 0.5 # Rate threshold for dropping overlapping frames when enough non-overlapping exist
    # Self-attention parameters (training only)
    causal_attn_rate: 0.5 # Proportion of batches that use self-attention with limited right context
    causal_attn_rc: 7 # Right context size for self-attention with limited right context

  encoder:
    _target_: nemo.collections.asr.modules.ConformerEncoder
    feat_in: ${model.preprocessor.features}
    feat_out: -1
    n_layers: 17
    d_model: ${model.model_defaults.fc_d_model}

    # Sub-sampling parameters
    subsampling: dw_striding # vggnet, striding, stacking or stacking_norm, dw_striding
    subsampling_factor: 8 # must be power of 2 for striding and vggnet
    subsampling_conv_channels: 256 # set to -1 to make it equal to the d_model
    causal_downsampling: false
    # Feed forward module's params
    ff_expansion_factor: 4
    # Multi-headed Attention Module's params
    self_attention_model: rel_pos # rel_pos or abs_pos
    n_heads: 8 # may need to be lower for smaller d_models
    # [left, right] specifies the number of steps to be seen from left and right of each step in self-attention
    att_context_size: [-1, -1] # -1 means unlimited context
    att_context_style: regular # regular or chunked_limited
    xscaling: true # scales up the input embeddings by sqrt(d_model)
    untie_biases: true # unties the biases of the TransformerXL layers
    pos_emb_max_len: 5000
    # Convolution module's params
    conv_kernel_size: 9
    conv_norm_type: 'batch_norm' # batch_norm or layer_norm or groupnormN (N specifies the number of groups)
    conv_context_size: null
    # Regularization
    dropout: 0.1 # The dropout used in most of the Conformer Modules
    dropout_pre_encoder: 0.1 # The dropout used before the encoder
    dropout_emb: 0.0 # The dropout used for embeddings
    dropout_att: 0.1 # The dropout for multi-headed attention modules
    # Set to non-zero to enable stochastic depth
    stochastic_depth_drop_prob: 0.0
    stochastic_depth_mode: linear  # linear or uniform
    stochastic_depth_start_layer: 1

  transformer_encoder:
    _target_: nemo.collections.asr.modules.transformer.transformer_encoders.TransformerEncoder
    num_layers: 18
    hidden_size: ${model.model_defaults.tf_d_model} # Needs to be multiple of num_attention_heads
    inner_size: 768
    num_attention_heads: 8
    attn_score_dropout: 0.5
    attn_layer_dropout: 0.5
    ffn_dropout: 0.5
    hidden_act: relu
    pre_ln: False
    pre_ln_final_layer_norm: True

  loss:
    _target_: nemo.collections.asr.losses.bce_loss.BCELoss
    weight: null # Weight for binary cross-entropy loss. Either `null` or list type input. (e.g. [0.5,0.5])
    reduction: mean

  lr: 0.0001
  optim:
    name: adamw
    lr: ${model.lr}
    # optimizer arguments
    betas: [0.9, 0.98]
    weight_decay: 1e-3

    sched:
      name: InverseSquareRootAnnealing
      warmup_steps: 500
      warmup_ratio: null
      min_lr: 1e-06

trainer:
  devices: 1 # number of gpus (devices)
  accelerator: gpu
  max_epochs: 800
  max_steps: -1 # computed at runtime if not set
  num_nodes: 1
  strategy: ddp_find_unused_parameters_true # Could be "ddp"
  accumulate_grad_batches: 1
  deterministic: True
  enable_checkpointing: False
  logger: False
  log_every_n_steps: 1  # Interval of logging.
  val_check_interval: 1.0  # Set to 0.25 to check 4 times per epoch, or an int for number of iterations

exp_manager:
  use_datetime_version: False
  exp_dir: null
  name: ${name}
  resume_if_exists: True
  resume_from_checkpoint: null # The path to a checkpoint file to continue the training, restores the whole state including the epoch, step, LR schedulers, apex, etc.
  resume_ignore_no_checkpoint: True
  create_tensorboard_logger: True
  create_checkpoint_callback: True
  create_wandb_logger: False
  checkpoint_callback_params:
    monitor: "val_f1_acc"
    mode: "max"
    save_top_k: 9
    every_n_epochs: 1
  wandb_logger_kwargs:
    resume: True
    name: null
    project: null

Hydra Configurations for (Streaming) Sortformer Diarization Post-processing#

Post-processing converts the floating point number based Tensor output to time stamp output. While generating the speaker-homogeneous segments, onset and offset threshold, paddings can be considered to render the time stamps that can lead to the lowest diarization error rate (DER). This post-processing can be applied to both offline and streaming Sortformer diarizer.

By default, post-processing is bypassed, and only binarization is performed. If you want to reproduce DER scores reported on NeMo model cards, you need to apply post-processing steps. Use batch_size = 1 to have the longest inference window and the highest possible accuracy.

parameters:
  onset: 0.64  # Onset threshold for detecting the beginning of a speech segment
  offset: 0.74  # Offset threshold for detecting the end of a speech segment
  pad_onset: 0.06  # Adds the specified duration at the beginning of each speech segment
  pad_offset: 0.0  # Adds the specified duration at the end of each speech segment
  min_duration_on: 0.1  # Removes short speech segments if the duration is less than the specified minimum duration
  min_duration_off: 0.15  # Removes short silences if the duration is less than the specified minimum duration

Hydra Configurations for Diarization Inference#

Example configuration files for speaker diarization inference can be found in <NeMo_root>/examples/speaker_tasks/diarization/conf/inference/. Choose a yaml file that fits your targeted domain. For example, if you want to diarize audio recordings of telephonic speech, choose diar_infer_telephonic.yaml.

The configurations for all the components of diarization inference are included in a single file named diar_infer_<domain>.yaml. Each .yaml file has a few different sections for the following modules: VAD, Speaker Embedding, Clustering and ASR.

In speaker diarization inference, the datasets provided in manifest format denote the data that you would like to perform speaker diarization on.

Diarizer Configurations#

An example diarizer Hydra configuration could look like:

diarizer:
  manifest_filepath: ???
  out_dir: ???
  oracle_vad: False # If True, uses RTTM files provided in manifest file to get speech activity (VAD) timestamps
  collar: 0.25 # Collar value for scoring
  ignore_overlap: True # Consider or ignore overlap segments while scoring

Under diarizer key, there are vad, speaker_embeddings, clustering and asr keys containing configurations for the inference of the corresponding modules.

Configurations for Voice Activity Detector#

Parameters for VAD model are provided as in the following Hydra config example.

vad:
  model_path: null # .nemo local model path or pretrained model name or none
  external_vad_manifest: null # This option is provided to use external vad and provide its speech activity labels for speaker embeddings extraction. Only one of model_path or external_vad_manifest should be set

  parameters: # Tuned parameters for CH109 (using the 11 multi-speaker sessions as dev set)
    window_length_in_sec: 0.15  # Window length in sec for VAD context input
    shift_length_in_sec: 0.01 # Shift length in sec for generate frame level VAD prediction
    smoothing: "median" # False or type of smoothing method (eg: median)
    overlap: 0.875 # Overlap ratio for overlapped mean/median smoothing filter
    onset: 0.4 # Onset threshold for detecting the beginning and end of a speech
    offset: 0.7 # Offset threshold for detecting the end of a speech
    pad_onset: 0.05 # Adding durations before each speech segment
    pad_offset: -0.1 # Adding durations after each speech segment
    min_duration_on: 0.2 # Threshold for short speech segment deletion
    min_duration_off: 0.2 # Threshold for small non_speech deletion
    filter_speech_first: True

Configurations for Speaker Embedding in Diarization#

Parameters for speaker embedding model are provided in the following Hydra config example. Note that multiscale parameters either accept list or single floating point number.

speaker_embeddings:
  model_path: ??? # .nemo local model path or pretrained model name (titanet_large, ecapa_tdnn or speakerverification_speakernet)
  parameters:
    window_length_in_sec: 1.5 # Window length(s) in sec (floating-point number). Either a number or a list. Ex) 1.5 or [1.5,1.25,1.0,0.75,0.5]
    shift_length_in_sec: 0.75 # Shift length(s) in sec (floating-point number). Either a number or a list. Ex) 0.75 or [0.75,0.625,0.5,0.375,0.25]
    multiscale_weights: null # Weight for each scale. should be null (for single scale) or a list matched with window/shift scale count. Ex) [1,1,1,1,1]
    save_embeddings: False # Save embeddings as pickle file for each audio input.

Configurations for Clustering in Diarization#

Parameters for clustering algorithm are provided in the following Hydra config example.

clustering:
  parameters:
    oracle_num_speakers: False # If True, use num of speakers value provided in the manifest file.
    max_num_speakers: 20 # Max number of speakers for each recording. If oracle_num_speakers is passed, this value is ignored.
    enhanced_count_thres: 80 # If the number of segments is lower than this number, enhanced speaker counting is activated.
    max_rp_threshold: 0.25 # Determines the range of p-value search: 0 < p <= max_rp_threshold.
    sparse_search_volume: 30 # The higher the number, the more values will be examined with more time.

Configurations for Diarization with ASR#

The following configuration needs to be appended under diarizer to run ASR with diarization to get a transcription with speaker labels.

asr:
  model_path: ??? # Provide NGC cloud ASR model name. stt_en_conformer_ctc_* models are recommended for diarization purposes.
  parameters:
    asr_based_vad: False # if True, speech segmentation for diarization is based on word-timestamps from ASR inference.
    asr_based_vad_threshold: 50 # threshold (multiple of 10ms) for ignoring the gap between two words when generating VAD timestamps using ASR based VAD.
    asr_batch_size: null # Batch size can be dependent on each ASR model. Default batch sizes are applied if set to null.
    lenient_overlap_WDER: True # If true, when a word falls into speaker-overlapped regions, consider the word as a correctly diarized word.
    decoder_delay_in_sec: null # Native decoder delay. null is recommended to use the default values for each ASR model.
    word_ts_anchor_offset: null # Offset to set a reference point from the start of the word. Recommended range of values is [-0.05  0.2].
    word_ts_anchor_pos: "start" # Select which part of the word timestamp we want to use. The options are: 'start', 'end', 'mid'.
    fix_word_ts_with_VAD: False # Fix the word timestamp using VAD output. You must provide a VAD model to use this feature.
    colored_text: False # If True, use colored text to distinguish speakers in the output transcript.
    print_time: True # If True, the start of the end time of each speaker turn is printed in the output transcript.
    break_lines: False # If True, the output transcript breaks the line to fix the line width (default is 90 chars)

  ctc_decoder_parameters: # Optional beam search decoder (pyctcdecode)
    pretrained_language_model: null # KenLM model file: .arpa model file or .bin binary file.
    beam_width: 32
    alpha: 0.5
    beta: 2.5

  realigning_lm_parameters: # Experimental feature
    arpa_language_model: null # Provide a KenLM language model in .arpa format.
    min_number_of_words: 3 # Min number of words for the left context.
    max_number_of_words: 10 # Max number of words for the right context.
    logprob_diff_threshold: 1.2  # The threshold for the difference between two log probability values from two hypotheses.