live_portaudio.c

Speech recognition with live audio input and endpointing.

Speech recognition with live audio input and endpointing.This file shows how to use PocketSphinx with microphone input using PortAudio (v19 and above).

To compile it, assuming you have built the library as in these directions, you can run:

cmake --build build --target live_portaudio

Alternately, if PocketSphinx is installed system-wide, you can run:

gcc -o live_portaudio live_portaudio.c \
    $(pkg-config --libs --cflags pocketsphinx portaudio-2.0)

/* Example of simple PocketSphinx speech segmentation.
 *
 * MIT license (c) 2022, see LICENSE for more information.
 *
 * Author: David Huggins-Daines <dhdaines@gmail.com>
 */
#include <portaudio.h>
#include <pocketsphinx.h>
#include <signal.h>
 
static int global_done = 0;
static void
catch_sig(int signum)
{
    (void)signum;
    global_done = 1;
}
 
int
main(int argc, char *argv[])
{
 
    PaStream *stream;
    PaError err;
    ps_decoder_t *decoder;
    ps_config_t *config;
    ps_endpointer_t *ep;
    short *frame;
    size_t frame_size;
 
    (void)argc; (void)argv;
 
    config = ps_config_init(NULL);
    ps_default_search_args(config);
 
    if ((err = Pa_Initialize()) != paNoError)
        E_FATAL("Failed to initialize PortAudio: %s\n",
                Pa_GetErrorText(err));
    if ((decoder = ps_init(config)) == NULL)
        E_FATAL("PocketSphinx decoder init failed\n");
    if ((ep = ps_endpointer_init(0, 0.0, 0, 0, 0)) == NULL)
        E_FATAL("PocketSphinx endpointer init failed\n");
    frame_size = ps_endpointer_frame_size(ep);
    if ((frame = malloc(frame_size * sizeof(frame[0]))) == NULL)
        E_FATAL_SYSTEM("Failed to allocate frame");
    if ((err = Pa_OpenDefaultStream(&stream, 1, 0, paInt16,
                                    ps_config_int(config, "samprate"),
                                    frame_size, NULL, NULL)) != paNoError)
        E_FATAL("Failed to open PortAudio stream: %s\n",
                Pa_GetErrorText(err));
    if ((err = Pa_StartStream(stream)) != paNoError)
        E_FATAL("Failed to start PortAudio stream: %s\n",
                Pa_GetErrorText(err));
    if (signal(SIGINT, catch_sig) == SIG_ERR)
        E_FATAL_SYSTEM("Failed to set SIGINT handler");
    while (!global_done) {
        const int16 *speech;
        int prev_in_speech = ps_endpointer_in_speech(ep);
        if ((err = Pa_ReadStream(stream, frame, frame_size)) != paNoError) {
            E_ERROR("Error in PortAudio read: %s\n",
                Pa_GetErrorText(err));
            break;
        }
        speech = ps_endpointer_process(ep, frame);
        if (speech != NULL) {
            const char *hyp;
            if (!prev_in_speech) {
                fprintf(stderr, "Speech start at %.2f\n",
                        ps_endpointer_speech_start(ep));
        fflush(stderr); /* For broken MSYS2 terminal */
                ps_start_utt(decoder);
            }
            if (ps_process_raw(decoder, speech, frame_size, FALSE, FALSE) < 0)
                E_FATAL("ps_process_raw() failed\n");
            if ((hyp = ps_get_hyp(decoder, NULL)) != NULL) {
                fprintf(stderr, "PARTIAL RESULT: %s\n", hyp);
        fflush(stderr);
        }
            if (!ps_endpointer_in_speech(ep)) {
                fprintf(stderr, "Speech end at %.2f\n",
                        ps_endpointer_speech_end(ep));
        fflush(stderr);
                ps_end_utt(decoder);
                if ((hyp = ps_get_hyp(decoder, NULL)) != NULL) {
            printf("%s\n", hyp);
            fflush(stdout);
        }
            }
        }
    }
    if ((err = Pa_StopStream(stream)) != paNoError)
        E_FATAL("Failed to stop PortAudio stream: %s\n",
                Pa_GetErrorText(err));
    if ((err = Pa_Terminate()) != paNoError)
        E_FATAL("Failed to terminate PortAudio: %s\n",
                Pa_GetErrorText(err));
    free(frame);
    ps_endpointer_free(ep);
    ps_free(decoder);
    ps_config_free(config);
        
    return 0;
}