live_pulseaudio.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 PulseAudio.

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

cmake --build build --target live_pulseaudio

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

gcc -o live_pulseaudio live_pulseaudio.c \
    $(pkg-config --libs --cflags pocketsphinx libpulse-simple)

/* Example of simple PocketSphinx speech segmentation.
 *
 * MIT license (c) 2022, see LICENSE for more information.
 *
 * Author: David Huggins-Daines <dhdaines@gmail.com>
 */
#include <pulse/simple.h>
#include <pulse/error.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[])
{
 
    pa_simple *s;
    pa_sample_spec ss;
    int 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 ((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");
 
    ss.format = PA_SAMPLE_S16NE;
    ss.channels = 1;
    ss.rate = ps_config_int(config, "samprate");
    if ((s = pa_simple_new(NULL, "live_pulseaudio", PA_STREAM_RECORD, NULL,
                           "live", &ss, NULL, NULL, &err)) == NULL)
        E_FATAL("Failed to connect to PulseAudio: %s\n",
                pa_strerror(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 (pa_simple_read(s, frame,
                           frame_size * sizeof(frame[0]), &err) < 0) {
            E_ERROR("Error in pa_simple_read: %s\n",
                    pa_strerror(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));
                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);
            if (!ps_endpointer_in_speech(ep)) {
                fprintf(stderr, "Speech end at %.2f\n",
                        ps_endpointer_speech_end(ep));
                ps_end_utt(decoder);
                if ((hyp = ps_get_hyp(decoder, NULL)) != NULL)
                    printf("%s\n", hyp);
            }
        }
    }
    pa_simple_free(s);
    free(frame);
    ps_endpointer_free(ep);
    ps_free(decoder);
    ps_config_free(config);
        
    return 0;
}