waveform.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <groove/groove.h>
#include <groove/encoder.h>
#include <pthread.h>
#include <png.h>
#include <limits.h>

static int version() {
    printf("2.0.0\n");
    return 0;
}

static int usage(const char *exe) {
    fprintf(stderr, "\
\n\
Usage:\n\
\n\
waveform [options] in\n\
(where `in` is a file path)\n\
\n\
Options:\n\
--scan                       duration scan (default off)\n\
\n\
WaveformJs Options:\n\
--wjs-width 800              width in samples\n\
--wjs-plain                  exclude metadata in output JSON (default off)\n\
\n");

    return 1;
}

static int double_ceil(double x) {
    int n = x;
    return (x == (double)n) ? n : n + 1;
}

int main(int argc, char * argv[]) {
    // arg parsing
    char *exe = argv[0];

    char *input_filename = NULL;
    char *waveformjs_output = NULL;

    int wjs_width = 800;
    int wjs_plain = 0;

    int scan = 0;

    int i;
    for (i = 1; i < argc; ++i) {
        char *arg = argv[i];
        if (arg[0] == '-' && arg[1] == '-') {
            arg += 2;
            if (strcmp(arg, "scan") == 0) {
                scan = 1;
            } else if (strcmp(arg, "wjs-plain") == 0) {
                wjs_plain = 1;
            } else if (strcmp(arg, "version") == 0) {
                return version();
            } else if (i + 1 >= argc) {
                // args that take 1 parameter
                return usage(exe);
            } else if (strcmp(arg, "wjs-width") == 0) {
                wjs_width = atoi(argv[++i]);
            } else {
                fprintf(stderr, "Unrecognized argument: %s\n", arg);
                return usage(exe);
            }
        } else if (!input_filename) {
            input_filename = arg;
        } else {
            fprintf(stderr, "Unexpected parameter: %s\n", arg);
            return usage(exe);
        }
    }

    if (!input_filename) {
        fprintf(stderr, "input file parameter required\n");
        return usage(exe);
    }

    // arg parsing done. let's begin.

    groove_init();
    atexit(groove_finish);

    struct GrooveFile *file = groove_file_open(input_filename);
    if (!file) {
        fprintf(stderr, "Error opening input file: %s\n", input_filename);
        return 1;
    }
    struct GroovePlaylist *playlist = groove_playlist_create();
    groove_playlist_set_fill_mode(playlist, GROOVE_ANY_SINK_FULL);

    struct GrooveSink *sink = groove_sink_create();
    sink->audio_format.sample_rate = 44100;
    sink->audio_format.channel_layout = GROOVE_CH_LAYOUT_MONO;
    sink->audio_format.sample_fmt = GROOVE_SAMPLE_FMT_S16;

    if (groove_sink_attach(sink, playlist) < 0) {
        fprintf(stderr, "error attaching sink\n");
        return 1;
    }

    struct GrooveBuffer *buffer;
    int frame_count;

    // scan the song for the exact correct frame count and duration
    float duration;
    if (scan) {
        struct GroovePlaylistItem *item = groove_playlist_insert(playlist, file, 1.0, 1.0, NULL);
        frame_count = 0;
        while (groove_sink_buffer_get(sink, &buffer, 1) == GROOVE_BUFFER_YES) {
            frame_count += buffer->frame_count;
            groove_buffer_unref(buffer);
        }
        groove_playlist_remove(playlist, item);
        duration = frame_count / 44100.0f;
    } else {
        duration = groove_file_duration(file);
        frame_count = double_ceil(duration * 44100.0);
    }

    // insert the item *after* creating the sinks to avoid race conditions
    groove_playlist_insert(playlist, file, 1.0, 1.0, NULL);

    FILE *waveformjs_f = NULL;
    int wjs_frames_per_pixel = 0;
    int16_t wjs_max_sample;
    int16_t wjs_min_sample;
    int wjs_frames_until_emit = 0;
    int wjs_emit_count;

    waveformjs_f = stdout;

    wjs_frames_per_pixel = frame_count / wjs_width;
    if (wjs_frames_per_pixel < 1)
        wjs_frames_per_pixel = 1;

    if (!wjs_plain) {
        fprintf(waveformjs_f, "{\"samples_per_pixel\":%d,\"sample_rate\":%d, \"bits\":%d, \"length\":%d, \"data\":",
                wjs_frames_per_pixel, 44100, 16, wjs_width);
    }

    fprintf(waveformjs_f, "[");

    wjs_max_sample = INT16_MIN;
    wjs_min_sample = INT16_MAX;
    wjs_frames_until_emit = wjs_frames_per_pixel;
    wjs_emit_count = 0;

    while (groove_sink_buffer_get(sink, &buffer, 1) == GROOVE_BUFFER_YES) {
        int i;
        for (i = 0; i < buffer->frame_count && wjs_emit_count < wjs_width;
                i += 1, wjs_frames_until_emit -= 1)
        {
            if (wjs_frames_until_emit == 0) {
                wjs_emit_count += 1;
                char *comma = (wjs_emit_count == wjs_width) ? "" : ",";
                int8_t max_8bit_sample = wjs_max_sample / (double) INT16_MAX * INT8_MAX;
                int8_t min_8bit_sample = wjs_min_sample / (double) INT16_MAX * INT8_MAX;
                //int8_t max_float_sample = wjs_max_sample / (double) INT16_MAX * 128;
                //int8_t min_float_sample = wjs_min_sample / (double) INT16_MAX * 128;
                fprintf(waveformjs_f, "%d,%d%s", min_8bit_sample, max_8bit_sample, comma);
                wjs_max_sample = INT16_MIN;
                wjs_min_sample = INT16_MAX;
                wjs_frames_until_emit = wjs_frames_per_pixel;
            }
            int16_t *data = (int16_t *) buffer->data[0];
            int16_t *sample = &data[i];
            //int16_t *right = &data[i + 1];
            if (*sample > wjs_max_sample) wjs_max_sample = *sample;
            //if (*right > wjs_max_sample) wjs_max_sample = *right;

            if (*sample < wjs_min_sample) wjs_min_sample = *sample;
            //if (*right < wjs_min_sample) wjs_min_sample = *right;
        }

        groove_buffer_unref(buffer);
    }

    if (wjs_emit_count < wjs_width) {
        // emit the last sample
        int8_t max_float_sample = wjs_max_sample / (double) INT16_MAX * 128;
        int8_t min_float_sample = wjs_min_sample / (double) INT16_MAX * 128;
        fprintf(waveformjs_f, "%d,%d", min_float_sample, max_float_sample);
    }

    fprintf(waveformjs_f, "]");

    if (!wjs_plain)
        fprintf(waveformjs_f, "}");

    fclose(waveformjs_f);


    groove_sink_detach(sink);
    groove_sink_destroy(sink);

    groove_playlist_clear(playlist);
    groove_file_close(file);
    groove_playlist_destroy(playlist);

    return 0;
}