whisper.cpp/examples/stream/stream.cpp

// Real-time speech recognition of input from a microphone
//
// A very quick-n-dirty implementation serving mainly as a proof of concept.

#include "whisper.h"

#include <SDL.h>
#include <SDL_audio.h>

#include <cassert>
#include <cstdio>
#include <string>
#include <thread>
#include <vector>
#include <fstream>

//  500 -> 00:05.000
// 6000 -> 01:00.000
std::string to_timestamp(int64_t t) {
    int64_t sec = t/100;
    int64_t msec = t - sec*100;
    int64_t min = sec/60;
    sec = sec - min*60;

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

    return std::string(buf);
}

// command-line parameters
struct whisper_params {
    int32_t n_threads  = std::min(4, (int32_t) std::thread::hardware_concurrency());
    int32_t step_ms    = 3000;
    int32_t length_ms  = 10000;
    int32_t capture_id = -1;
    int32_t max_tokens = 32;
    int32_t audio_ctx  = 0;

    bool speed_up      = false;
    bool translate     = false;
    bool no_context    = true;
    bool print_special = false;
    bool no_timestamps = true;

    std::string language  = "en";
    std::string model     = "models/ggml-base.en.bin";
    std::string fname_out = "";
};

void whisper_print_usage(int argc, char ** argv, const whisper_params & params);

bool whisper_params_parse(int argc, char ** argv, whisper_params & params) {
    for (int i = 1; i < argc; i++) {
        std::string arg = argv[i];

        if (arg == "-h" || arg == "--help") {
            whisper_print_usage(argc, argv, params);
            exit(0);
        }
        else if (arg == "-t"   || arg == "--threads")       { params.n_threads     = std::stoi(argv[++i]); }
        else if (                 arg == "--step")          { params.step_ms       = std::stoi(argv[++i]); }
        else if (                 arg == "--length")        { params.length_ms     = std::stoi(argv[++i]); }
        else if (arg == "-c"   || arg == "--capture")       { params.capture_id    = std::stoi(argv[++i]); }
        else if (arg == "-mt"  || arg == "--max-tokens")    { params.max_tokens    = std::stoi(argv[++i]); }
        else if (arg == "-ac"  || arg == "--audio-ctx")     { params.audio_ctx     = std::stoi(argv[++i]); }
        else if (arg == "-su"  || arg == "--speed-up")      { params.speed_up      = true; }
        else if (arg == "-tr"  || arg == "--translate")     { params.translate     = true; }
        else if (arg == "-kc"  || arg == "--keep-context")  { params.no_context    = false; }
        else if (arg == "-ps"  || arg == "--print-special") { params.print_special = true; }
        else if (arg == "-l"   || arg == "--language")      { params.language      = argv[++i]; }
        else if (arg == "-m"   || arg == "--model")         { params.model         = argv[++i]; }
        else if (arg == "-f"   || arg == "--file")          { params.fname_out     = argv[++i]; }
        else {
            fprintf(stderr, "error: unknown argument: %s\n", arg.c_str());
            whisper_print_usage(argc, argv, params);
            exit(0);
        }
    }

    return true;
}

void whisper_print_usage(int argc, char ** argv, const whisper_params & params) {
    fprintf(stderr, "\n");
    fprintf(stderr, "usage: %s [options]\n", argv[0]);
    fprintf(stderr, "\n");
    fprintf(stderr, "options:\n");
    fprintf(stderr, "  -h,       --help          [default] show this help message and exit\n");
    fprintf(stderr, "  -t N,     --threads N     [%-7d] number of threads to use during computation\n", params.n_threads);
    fprintf(stderr, "            --step N        [%-7d] audio step size in milliseconds\n",             params.step_ms);
    fprintf(stderr, "            --length N      [%-7d] audio length in milliseconds\n",                params.length_ms);
    fprintf(stderr, "  -c ID,    --capture ID    [%-7d] capture device ID\n",                           params.capture_id);
    fprintf(stderr, "  -mt N,    --max-tokens N  [%-7d] maximum number of tokens per audio chunk\n",    params.max_tokens);
    fprintf(stderr, "  -ac N,    --audio-ctx N   [%-7d] audio context size (0 - all)\n",                params.audio_ctx);
    fprintf(stderr, "  -su,      --speed-up      [%-7s] speed up audio by x2 (reduced accuracy)\n",     params.speed_up ? "true" : "false");
    fprintf(stderr, "  -tr,      --translate     [%-7s] translate from source language to english\n",   params.translate ? "true" : "false");
    fprintf(stderr, "  -kc,      --keep-context  [%-7s] keep context between audio chunks\n",           params.no_context ? "false" : "true");
    fprintf(stderr, "  -ps,      --print-special [%-7s] print special tokens\n",                        params.print_special ? "true" : "false");
    fprintf(stderr, "  -l LANG,  --language LANG [%-7s] spoken language\n",                             params.language.c_str());
    fprintf(stderr, "  -m FNAME, --model FNAME   [%-7s] model path\n",                                  params.model.c_str());
    fprintf(stderr, "  -f FNAME, --file FNAME    [%-7s] text output file name\n",                       params.fname_out.c_str());
    fprintf(stderr, "\n");
}

//
// SDL Audio capture
//

SDL_AudioDeviceID g_dev_id_in = 0;

bool audio_sdl_init(const int capture_id) {
    if (g_dev_id_in) {
        fprintf(stderr, "%s: already initialized\n", __func__);
        return false;
    }

    SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);

    if (SDL_Init(SDL_INIT_AUDIO) < 0) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
        return (1);
    }

    SDL_SetHintWithPriority(SDL_HINT_AUDIO_RESAMPLING_MODE, "medium", SDL_HINT_OVERRIDE);

    {
        int nDevices = SDL_GetNumAudioDevices(SDL_TRUE);
        fprintf(stderr, "%s: found %d capture devices:\n", __func__, nDevices);
        for (int i = 0; i < nDevices; i++) {
            fprintf(stderr, "%s:    - Capture device #%d: '%s'\n", __func__, i, SDL_GetAudioDeviceName(i, SDL_TRUE));
        }
    }

    SDL_AudioSpec capture_spec_requested;
    SDL_AudioSpec capture_spec_obtained;

    SDL_zero(capture_spec_requested);
    SDL_zero(capture_spec_obtained);

    capture_spec_requested.freq     = WHISPER_SAMPLE_RATE;
    capture_spec_requested.format   = AUDIO_F32;
    capture_spec_requested.channels = 1;
    capture_spec_requested.samples  = 1024;

    if (capture_id >= 0) {
        fprintf(stderr, "%s: attempt to open capture device %d : '%s' ...\n", __func__, capture_id, SDL_GetAudioDeviceName(capture_id, SDL_TRUE));
        g_dev_id_in = SDL_OpenAudioDevice(SDL_GetAudioDeviceName(capture_id, SDL_TRUE), SDL_TRUE, &capture_spec_requested, &capture_spec_obtained, 0);
    } else {
        fprintf(stderr, "%s: attempt to open default capture device ...\n", __func__);
        g_dev_id_in = SDL_OpenAudioDevice(nullptr, SDL_TRUE, &capture_spec_requested, &capture_spec_obtained, 0);
    }
    if (!g_dev_id_in) {
        fprintf(stderr, "%s: couldn't open an audio device for capture: %s!\n", __func__, SDL_GetError());
        g_dev_id_in = 0;
    } else {
        fprintf(stderr, "%s: obtained spec for input device (SDL Id = %d):\n", __func__, g_dev_id_in);
        fprintf(stderr, "%s:     - sample rate:       %d\n", __func__, capture_spec_obtained.freq);
        fprintf(stderr, "%s:     - format:            %d (required: %d)\n", __func__, capture_spec_obtained.format, capture_spec_requested.format);
        fprintf(stderr, "%s:     - channels:          %d (required: %d)\n", __func__, capture_spec_obtained.channels, capture_spec_requested.channels);
        fprintf(stderr, "%s:     - samples per frame: %d\n", __func__, capture_spec_obtained.samples);
    }

    return true;
}

///////////////////////////

int main(int argc, char ** argv) {
    whisper_params params;

    if (whisper_params_parse(argc, argv, params) == false) {
        return 1;
    }

    // init audio

    if (!audio_sdl_init(params.capture_id)) {
        fprintf(stderr, "%s: audio_sdl_init() failed!\n", __func__);
        return 1;
    }

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

    // whisper init

    struct whisper_context * ctx = whisper_init(params.model.c_str());

    const int n_samples = (params.step_ms/1000.0)*WHISPER_SAMPLE_RATE;
    const int n_samples_len = (params.length_ms/1000.0)*WHISPER_SAMPLE_RATE;
    const int n_samples_30s = 30*WHISPER_SAMPLE_RATE;
    const int n_samples_keep = 0.2*WHISPER_SAMPLE_RATE;

    std::vector<float> pcmf32(n_samples_30s, 0.0f);
    std::vector<float> pcmf32_old;

    std::vector<whisper_token> prompt_tokens;
    const int n_new_line = params.length_ms / params.step_ms - 1;

    // 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 %d samples (step = %.1f sec / len = %.1f sec), %d threads, lang = %s, task = %s, timestamps = %d ...\n",
                __func__,
                n_samples,
                float(n_samples)/WHISPER_SAMPLE_RATE,
                float(n_samples_len)/WHISPER_SAMPLE_RATE,
                params.n_threads,
                params.language.c_str(),
                params.translate ? "translate" : "transcribe",
                params.no_timestamps ? 0 : 1);

        fprintf(stderr, "%s: n_new_line = %d\n", __func__, n_new_line);
        fprintf(stderr, "\n");
    }

    SDL_PauseAudioDevice(g_dev_id_in, 0);

    int n_iter = 0;
    bool is_running = true;

    std::ofstream fout;
    if (params.fname_out.length() > 0) {
        fout.open(params.fname_out);
        if (!fout.is_open()) {
            fprintf(stderr, "%s: failed to open output file '%s'!\n", __func__, params.fname_out.c_str());
            return 1;
        }
    }

    printf("[Start speaking]");
    fflush(stdout);

    // main audio loop
    while (is_running) {
        // handle Ctrl + C
        {
            SDL_Event event;
            while (SDL_PollEvent(&event)) {
                switch (event.type) {
                    case SDL_QUIT:
                        {
                            is_running = false;
                        } break;
                    default:
                        break;
                }
            }

            if (!is_running) {
                break;
            }
        }

        if (!is_running) {
            break;
        }

        // process new audio
        if (n_iter > 0 && SDL_GetQueuedAudioSize(g_dev_id_in) > 2*n_samples*sizeof(float)) {
            fprintf(stderr, "\n\n%s: WARNING: cannot process audio fast enough, dropping audio ...\n\n", __func__);
            SDL_ClearQueuedAudio(g_dev_id_in);
        }

        while (SDL_GetQueuedAudioSize(g_dev_id_in) < n_samples*sizeof(float)) {
            SDL_Delay(1);
        }

        const int n_samples_new = SDL_GetQueuedAudioSize(g_dev_id_in)/sizeof(float);

        // take one second from previous iteration
        //const int n_samples_take = std::min((int) pcmf32_old.size(), std::max(0, n_samples_30s/30 - n_samples_new));

        // take up to params.length_ms audio from previous iteration
        const int n_samples_take = std::min((int) pcmf32_old.size(), std::max(0, n_samples_keep + n_samples_len - n_samples_new));

        //printf("processing: take = %d, new = %d, old = %d\n", n_samples_take, n_samples_new, (int) pcmf32_old.size());

        pcmf32.resize(n_samples_new + n_samples_take);

        for (int i = 0; i < n_samples_take; i++) {
            pcmf32[i] = pcmf32_old[pcmf32_old.size() - n_samples_take + i];
        }

        SDL_DequeueAudio(g_dev_id_in, pcmf32.data() + n_samples_take, n_samples_new*sizeof(float));

        pcmf32_old = pcmf32;

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

            wparams.print_progress   = false;
            wparams.print_special    = params.print_special;
            wparams.print_realtime   = false;
            wparams.print_timestamps = !params.no_timestamps;
            wparams.translate        = params.translate;
            wparams.no_context       = true;
            wparams.single_segment   = true;
            wparams.max_tokens       = params.max_tokens;
            wparams.language         = params.language.c_str();
            wparams.n_threads        = params.n_threads;

            wparams.audio_ctx        = params.audio_ctx;
            wparams.speed_up         = params.speed_up;

            wparams.prompt_tokens    = params.no_context ? nullptr : prompt_tokens.data();
            wparams.prompt_n_tokens  = params.no_context ? 0       : prompt_tokens.size();

            if (whisper_full(ctx, wparams, pcmf32.data(), pcmf32.size()) != 0) {
                fprintf(stderr, "%s: failed to process audio\n", argv[0]);
                return 6;
            }

            // print result;
            {
                printf("\33[2K\r");

                // print long empty line to clear the previous line
                printf("%s", std::string(100, ' ').c_str());

                printf("\33[2K\r");

                const int n_segments = whisper_full_n_segments(ctx);
                for (int i = 0; i < n_segments; ++i) {
                    const char * text = whisper_full_get_segment_text(ctx, i);

                    if (params.no_timestamps) {
                        printf("%s", text);
                        fflush(stdout);

                        if (params.fname_out.length() > 0) {
                            fout << text;
                        }
                    } else {
                        const int64_t t0 = whisper_full_get_segment_t0(ctx, i);
                        const int64_t t1 = whisper_full_get_segment_t1(ctx, i);

                        printf ("[%s --> %s]  %s\n", to_timestamp(t0).c_str(), to_timestamp(t1).c_str(), text);

                        if (params.fname_out.length() > 0) {
                            fout << "[" << to_timestamp(t0) << " --> " << to_timestamp(t1) << "]  " << text << std::endl;
                        }
                    }
                }

                if (params.fname_out.length() > 0) {
                    fout << std::endl;
                }
            }

            ++n_iter;

            if ((n_iter % n_new_line) == 0) {
                printf("\n");

                // keep part of the audio for next iteration to try to mitigate word boundary issues
                pcmf32_old = std::vector<float>(pcmf32.end() - n_samples_keep, pcmf32.end());

                // Add tokens of the last full length segment as the prompt
                if (!params.no_context) {
                    prompt_tokens.clear();

                    const int n_segments = whisper_full_n_segments(ctx);
                    for (int i = 0; i < n_segments; ++i) {
                        const int token_count = whisper_full_n_tokens(ctx, i);
                        for (int j = 0; j < token_count; ++j) {
                            prompt_tokens.push_back(whisper_full_get_token_id(ctx, i, j));
                        }
                    }
                }
            }
        }
    }

    whisper_print_timings(ctx);
    whisper_free(ctx);

    return 0;
}