examples/addon.node/addon.cpp

#include "napi.h"
#include "common.h"

#include "whisper.h"

#include <string>
#include <thread>
#include <vector>
#include <cmath>
#include <cstdint>

struct whisper_params {
    int32_t n_threads    = std::min(4, (int32_t) std::thread::hardware_concurrency());
    int32_t n_processors = 1;
    int32_t offset_t_ms  = 0;
    int32_t offset_n     = 0;
    int32_t duration_ms  = 0;
    int32_t max_context  = -1;
    int32_t max_len      = 0;
    int32_t best_of      = 5;
    int32_t beam_size    = -1;

    float word_thold    = 0.01f;
    float entropy_thold = 2.4f;
    float logprob_thold = -1.0f;

    bool speed_up       = false;
    bool translate      = false;
    bool diarize        = false;
    bool output_txt     = false;
    bool output_vtt     = false;
    bool output_srt     = false;
    bool output_wts     = false;
    bool output_csv     = false;
    bool print_special  = false;
    bool print_colors   = false;
    bool print_progress = false;
    bool no_timestamps  = false;
    bool use_gpu        = true;

    std::string language = "en";
    std::string prompt;
    std::string model    = "../../ggml-large.bin";

    std::vector<std::string> fname_inp = {};
    std::vector<std::string> fname_out = {};
};

struct whisper_print_user_data {
    const whisper_params * params;

    const std::vector<std::vector<float>> * pcmf32s;
};

//  500 -> 00:05.000
// 6000 -> 01:00.000
std::string to_timestamp(int64_t t, bool comma = false) {
    int64_t msec = t * 10;
    int64_t hr = msec / (1000 * 60 * 60);
    msec = msec - hr * (1000 * 60 * 60);
    int64_t min = msec / (1000 * 60);
    msec = msec - min * (1000 * 60);
    int64_t sec = msec / 1000;
    msec = msec - sec * 1000;

    char buf[32];
    snprintf(buf, sizeof(buf), "%02d:%02d:%02d%s%03d", (int) hr, (int) min, (int) sec, comma ? "," : ".", (int) msec);

    return std::string(buf);
}

int timestamp_to_sample(int64_t t, int n_samples) {
    return std::max(0, std::min((int) n_samples - 1, (int) ((t*WHISPER_SAMPLE_RATE)/100)));
}

void whisper_print_segment_callback(struct whisper_context * ctx, struct whisper_state * state, int n_new, void * user_data) {
    const auto & params  = *((whisper_print_user_data *) user_data)->params;
    const auto & pcmf32s = *((whisper_print_user_data *) user_data)->pcmf32s;

    const int n_segments = whisper_full_n_segments(ctx);

    std::string speaker = "";

    int64_t t0;
    int64_t t1;

    // print the last n_new segments
    const int s0 = n_segments - n_new;

    if (s0 == 0) {
        printf("\n");
    }

    for (int i = s0; i < n_segments; i++) {
        if (!params.no_timestamps || params.diarize) {
            t0 = whisper_full_get_segment_t0(ctx, i);
            t1 = whisper_full_get_segment_t1(ctx, i);
        }

        if (!params.no_timestamps) {
            printf("[%s --> %s]  ", to_timestamp(t0).c_str(), to_timestamp(t1).c_str());
        }

        if (params.diarize && pcmf32s.size() == 2) {
            const int64_t n_samples = pcmf32s[0].size();

            const int64_t is0 = timestamp_to_sample(t0, n_samples);
            const int64_t is1 = timestamp_to_sample(t1, n_samples);

            double energy0 = 0.0f;
            double energy1 = 0.0f;

            for (int64_t j = is0; j < is1; j++) {
                energy0 += fabs(pcmf32s[0][j]);
                energy1 += fabs(pcmf32s[1][j]);
            }

            if (energy0 > 1.1*energy1) {
                speaker = "(speaker 0)";
            } else if (energy1 > 1.1*energy0) {
                speaker = "(speaker 1)";
            } else {
                speaker = "(speaker ?)";
            }

            //printf("is0 = %lld, is1 = %lld, energy0 = %f, energy1 = %f, %s\n", is0, is1, energy0, energy1, speaker.c_str());
        }

        // colorful print bug
        //
        const char * text = whisper_full_get_segment_text(ctx, i);
        printf("%s%s", speaker.c_str(), text);


        // with timestamps or speakers: each segment on new line
        if (!params.no_timestamps || params.diarize) {
            printf("\n");
        }

        fflush(stdout);
    }
}

int run(whisper_params &params, std::vector<std::vector<std::string>> &result) {
    if (params.fname_inp.empty()) {
        fprintf(stderr, "error: no input files specified\n");
        return 2;
    }

    if (params.language != "auto" && whisper_lang_id(params.language.c_str()) == -1) {
        fprintf(stderr, "error: unknown language '%s'\n", params.language.c_str());
        exit(0);
    }

    // whisper init

    struct whisper_context_params cparams;
    cparams.use_gpu = params.use_gpu;
    struct whisper_context * ctx = whisper_init_from_file_with_params(params.model.c_str(), cparams);

    if (ctx == nullptr) {
        fprintf(stderr, "error: failed to initialize whisper context\n");
        return 3;
    }

    for (int f = 0; f < (int) params.fname_inp.size(); ++f) {
        const auto fname_inp = params.fname_inp[f];
        const auto fname_out = f < (int)params.fname_out.size() && !params.fname_out[f].empty() ? params.fname_out[f] : params.fname_inp[f];

        std::vector<float> pcmf32; // mono-channel F32 PCM
        std::vector<std::vector<float>> pcmf32s; // stereo-channel F32 PCM

        if (!::read_wav(fname_inp, pcmf32, pcmf32s, params.diarize)) {
            fprintf(stderr, "error: failed to read WAV file '%s'\n", fname_inp.c_str());
            continue;
        }

        // print system information
        {
            fprintf(stderr, "\n");
            fprintf(stderr, "system_info: n_threads = %d / %d | %s\n",
                    params.n_threads*params.n_processors, std::thread::hardware_concurrency(), whisper_print_system_info());
        }

        // print some info about the processing
        {
            fprintf(stderr, "\n");
            if (!whisper_is_multilingual(ctx)) {
                if (params.language != "en" || params.translate) {
                    params.language = "en";
                    params.translate = false;
                    fprintf(stderr, "%s: WARNING: model is not multilingual, ignoring language and translation options\n", __func__);
                }
            }
            fprintf(stderr, "%s: processing '%s' (%d samples, %.1f sec), %d threads, %d processors, lang = %s, task = %s, timestamps = %d ...\n",
                    __func__, fname_inp.c_str(), int(pcmf32.size()), float(pcmf32.size())/WHISPER_SAMPLE_RATE,
                    params.n_threads, params.n_processors,
                    params.language.c_str(),
                    params.translate ? "translate" : "transcribe",
                    params.no_timestamps ? 0 : 1);

            fprintf(stderr, "\n");
        }

        // run the inference
        {
            whisper_full_params wparams = whisper_full_default_params(WHISPER_SAMPLING_GREEDY);

            wparams.strategy = params.beam_size > 1 ? WHISPER_SAMPLING_BEAM_SEARCH : WHISPER_SAMPLING_GREEDY;

            wparams.print_realtime   = false;
            wparams.print_progress   = params.print_progress;
            wparams.print_timestamps = !params.no_timestamps;
            wparams.print_special    = params.print_special;
            wparams.translate        = params.translate;
            wparams.language         = params.language.c_str();
            wparams.n_threads        = params.n_threads;
            wparams.n_max_text_ctx   = params.max_context >= 0 ? params.max_context : wparams.n_max_text_ctx;
            wparams.offset_ms        = params.offset_t_ms;
            wparams.duration_ms      = params.duration_ms;

            wparams.token_timestamps = params.output_wts || params.max_len > 0;
            wparams.thold_pt         = params.word_thold;
            wparams.entropy_thold    = params.entropy_thold;
            wparams.logprob_thold    = params.logprob_thold;
            wparams.max_len          = params.output_wts && params.max_len == 0 ? 60 : params.max_len;

            wparams.speed_up         = params.speed_up;

            wparams.greedy.best_of        = params.best_of;
            wparams.beam_search.beam_size = params.beam_size;

            wparams.initial_prompt   = params.prompt.c_str();

            whisper_print_user_data user_data = { &params, &pcmf32s };

            // this callback is called on each new segment
            if (!wparams.print_realtime) {
                wparams.new_segment_callback           = whisper_print_segment_callback;
                wparams.new_segment_callback_user_data = &user_data;
            }

            // example for abort mechanism
            // in this example, we do not abort the processing, but we could if the flag is set to true
            // the callback is called before every encoder run - if it returns false, the processing is aborted
            {
                static bool is_aborted = false; // NOTE: this should be atomic to avoid data race

                wparams.encoder_begin_callback = [](struct whisper_context * /*ctx*/, struct whisper_state * /*state*/, void * user_data) {
                    bool is_aborted = *(bool*)user_data;
                    return !is_aborted;
                };
                wparams.encoder_begin_callback_user_data = &is_aborted;
            }

            if (whisper_full_parallel(ctx, wparams, pcmf32.data(), pcmf32.size(), params.n_processors) != 0) {
                fprintf(stderr, "failed to process audio\n");
                return 10;
            }
        }
    }

    const int n_segments = whisper_full_n_segments(ctx);
    result.resize(n_segments);
    for (int i = 0; i < n_segments; ++i) {
        const char * text = whisper_full_get_segment_text(ctx, i);
        const int64_t t0 = whisper_full_get_segment_t0(ctx, i);
        const int64_t t1 = whisper_full_get_segment_t1(ctx, i);

        result[i].emplace_back(to_timestamp(t0, true));
        result[i].emplace_back(to_timestamp(t1, true));
        result[i].emplace_back(text);
    }

    whisper_print_timings(ctx);
    whisper_free(ctx);

    return 0;
}

class Worker : public Napi::AsyncWorker {
 public:
  Worker(Napi::Function& callback, whisper_params params)
      : Napi::AsyncWorker(callback), params(params) {}

  void Execute() override {
    run(params, result);
  }

  void OnOK() override {
    Napi::HandleScope scope(Env());
    Napi::Object res = Napi::Array::New(Env(), result.size());
    for (uint64_t i = 0; i < result.size(); ++i) {
      Napi::Object tmp = Napi::Array::New(Env(), 3);
      for (uint64_t j = 0; j < 3; ++j) {
        tmp[j] = Napi::String::New(Env(), result[i][j]);
      }
      res[i] = tmp;
    }
    Callback().Call({Env().Null(), res});
  }

 private:
  whisper_params params;
  std::vector<std::vector<std::string>> result;
};



Napi::Value whisper(const Napi::CallbackInfo& info) {
  Napi::Env env = info.Env();
  if (info.Length() <= 0 || !info[0].IsObject()) {
    Napi::TypeError::New(env, "object expected").ThrowAsJavaScriptException();
  }
  whisper_params params;

  Napi::Object whisper_params = info[0].As<Napi::Object>();
  std::string language = whisper_params.Get("language").As<Napi::String>();
  std::string model = whisper_params.Get("model").As<Napi::String>();
  std::string input = whisper_params.Get("fname_inp").As<Napi::String>();
  bool use_gpu = whisper_params.Get("use_gpu").As<Napi::Boolean>();

  params.language = language;
  params.model = model;
  params.fname_inp.emplace_back(input);
  params.use_gpu = use_gpu;

  Napi::Function callback = info[1].As<Napi::Function>();
  Worker* worker = new Worker(callback, params);
  worker->Queue();
  return env.Undefined();
}


Napi::Object Init(Napi::Env env, Napi::Object exports) {
  exports.Set(
      Napi::String::New(env, "whisper"),
      Napi::Function::New(env, whisper)
  );
  return exports;
}

NODE_API_MODULE(whisper, Init);