sherpa-ncnn/dotnet-examples/decode-file/DecodeFile.cs

// Copyright (c)  2023  Xiaomi Corporation (authors: Fangjun Kuang)
using System;

class DecodeFile {
  public static void Main(String[] args) {
    String usage = @"
      ./DecodeFile.exe \
         /path/to/tokens.txt \
         /path/to/encoder.ncnn.param \
         /path/to/encoder.ncnn.bin \
         /path/to/decoder.ncnn.param \
         /path/to/decoder.ncnn.bin \
         /path/to/joiner.ncnn.param \
         /path/to/joiner.ncnn.bin \
         /path/to/foo.wav [<num_threads> [decode_method]]

      num_threads: Default to 2
      decoding_method: greedy_search (default), or modified_beam_search

      Please refer to
      https://k2-fsa.github.io/sherpa/ncnn/pretrained_models/index.html
      for a list of pre-trained models to download.
      ";
    if (args.Length < 8 || args.Length > 10) {
      Console.WriteLine(usage);
      return;
    }

    String waveFilename = args[7];
    SherpaNcnn.WaveReader waveReader = new SherpaNcnn.WaveReader(waveFilename);

    SherpaNcnn.OnlineRecognizerConfig config = new SherpaNcnn.OnlineRecognizerConfig();
    config.FeatConfig.SampleRate =  16000;
    config.FeatConfig.FeatureDim =  80;
    config.ModelConfig.Tokens = args[0];
    config.ModelConfig.EncoderParam = args[1];
    config.ModelConfig.EncoderBin = args[2];

    config.ModelConfig.DecoderParam = args[3];
    config.ModelConfig.DecoderBin = args[4];

    config.ModelConfig.JoinerParam = args[5];
    config.ModelConfig.JoinerBin = args[6];

    config.ModelConfig.UseVulkanCompute = 0;
    config.ModelConfig.NumThreads = 1;
    if (args.Length >= 9) {
      config.ModelConfig.NumThreads = Int32.Parse(args[8]);
      if (config.ModelConfig.NumThreads > 1) {
        Console.WriteLine($"Use num_threads: {config.ModelConfig.NumThreads}");
      }
    }

    config.DecoderConfig.DecodingMethod = "greedy_search";
    if (args.Length == 10 && args[9] != "greedy_search") {
      Console.WriteLine($"Use decoding_method {args[9]}");
      config.DecoderConfig.DecodingMethod = args[9];
    }

    config.DecoderConfig.NumActivePaths = 4;

    SherpaNcnn.OnlineRecognizer recognizer = new SherpaNcnn.OnlineRecognizer(config);

    SherpaNcnn.OnlineStream stream =  recognizer.CreateStream();
    stream.AcceptWaveform(waveReader.SampleRate, waveReader.Samples);

    float[] tailPadding = new float[(int)(waveReader.SampleRate * 0.3)];
    stream.AcceptWaveform(waveReader.SampleRate, tailPadding);

    stream.InputFinished();

    while(recognizer.IsReady(stream)) {
      recognizer.Decode(stream);
    }

    SherpaNcnn.OnlineRecognizerResult result = recognizer.GetResult(stream);
    Console.WriteLine(result.Text);
  }
}