whisper.cpp/examples/addon.node/addon.cpp

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

#include "napi.h"

#define DR_WAV_IMPLEMENTATION
#include "dr_wav.h"

#include "whisper.h"

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;

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

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

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, 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 * ctx = whisper_init_from_file(params.model.c_str());

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

    // initial prompt
    std::vector<whisper_token> prompt_tokens;

    if (!params.prompt.empty()) {
        prompt_tokens.resize(1024);
        prompt_tokens.resize(whisper_tokenize(ctx, params.prompt.c_str(), prompt_tokens.data(), prompt_tokens.size()));

        fprintf(stderr, "\n");
        fprintf(stderr, "initial prompt: '%s'\n", params.prompt.c_str());
        fprintf(stderr, "initial tokens: [ ");
        for (int i = 0; i < (int) prompt_tokens.size(); ++i) {
            fprintf(stderr, "%d ", prompt_tokens[i]);
        }
        fprintf(stderr, "]\n");
    }

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

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

        // WAV input
        {
            drwav wav;
            std::vector<uint8_t> wav_data; // used for pipe input from stdin

            if (fname_inp == "-") {
                {
                    uint8_t buf[1024];
                    while (true)
                    {
                        const size_t n = fread(buf, 1, sizeof(buf), stdin);
                        if (n == 0) {
                            break;
                        }
                        wav_data.insert(wav_data.end(), buf, buf + n);
                    }
                }

                if (drwav_init_memory(&wav, wav_data.data(), wav_data.size(), nullptr) == false) {
                    fprintf(stderr, "error: failed to open WAV file from stdin\n");
                    return 4;
                }

                fprintf(stderr, "%s: read %zu bytes from stdin\n", __func__, wav_data.size());
            }
            else if (drwav_init_file(&wav, fname_inp.c_str(), nullptr) == false) {
                fprintf(stderr, "error: failed to open '%s' as WAV file\n", fname_inp.c_str());
                return 5;
            }

           if (wav.channels != 1 && wav.channels != 2) {
               fprintf(stderr, "error: WAV file '%s' must be mono or stereo\n", fname_inp.c_str());
               return 6;
           }

           if (params.diarize && wav.channels != 2 && params.no_timestamps == false) {
               fprintf(stderr, "error: WAV file '%s' must be stereo for diarization and timestamps have to be enabled\n", fname_inp.c_str());
               return 6;
           }

           if (wav.sampleRate != WHISPER_SAMPLE_RATE) {
               fprintf(stderr, "error: WAV file '%s' must be %i kHz\n", fname_inp.c_str(), WHISPER_SAMPLE_RATE/1000);
               return 8;
           }

           if (wav.bitsPerSample != 16) {
               fprintf(stderr, "error: WAV file '%s' must be 16-bit\n", fname_inp.c_str());
               return 9;
           }

            const uint64_t n = wav_data.empty() ? wav.totalPCMFrameCount : wav_data.size()/(wav.channels*wav.bitsPerSample/8);

            std::vector<int16_t> pcm16;
            pcm16.resize(n*wav.channels);
            drwav_read_pcm_frames_s16(&wav, n, pcm16.data());
            drwav_uninit(&wav);

            // convert to mono, float
            pcmf32.resize(n);
            if (wav.channels == 1) {
                for (uint64_t i = 0; i < n; i++) {
                    pcmf32[i] = float(pcm16[i])/32768.0f;
                }
            } else {
                for (uint64_t i = 0; i < n; i++) {
                    pcmf32[i] = float(pcm16[2*i] + pcm16[2*i + 1])/65536.0f;
                }
            }

            if (params.diarize) {
                // convert to stereo, float
                pcmf32s.resize(2);

                pcmf32s[0].resize(n);
                pcmf32s[1].resize(n);
                for (uint64_t i = 0; i < n; i++) {
                    pcmf32s[0][i] = float(pcm16[2*i])/32768.0f;
                    pcmf32s[1][i] = float(pcm16[2*i + 1])/32768.0f;
                }
            }
        }

        // 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.prompt_tokens     = prompt_tokens.empty() ? nullptr : prompt_tokens.data();
            wparams.prompt_n_tokens   = prompt_tokens.empty() ? 0       : prompt_tokens.size();

            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*/, 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;
}

Napi::Object 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;
    std::vector<std::vector<std::string>> result;

    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>();

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

    // run model
    run(params, result);

    fprintf(stderr, "RESULT:\n");
    for (auto sentence:result) {
        fprintf(stderr, "t0: %s, t1: %s, content: %s \n",
                sentence[0].c_str(), sentence[1].c_str(), sentence[2].c_str());
    }

    Napi::Object res = Napi::Array::New(env, result.size());
    for (u_int32_t i = 0; i < result.size(); ++i) {
        Napi::Object tmp = Napi::Array::New(env, 3);
        for (u_int32_t j = 0; j < 3; ++j) {
            tmp[j] = Napi::String::New(env, result[i][j]);
        }
        res[i] = tmp;
    }

    return res;
}


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);