timescale.c

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/*
 * © Stuart Longland VK4MSL
 * SPDX-License-Identifier: MIT
 */
 
#include <assert.h>
#include <libsstvenc/timescale.h>
#include <math.h>
 
uint64_t sstvenc_ts_unit_scale(uint8_t unit) {
        switch (unit) {
        case SSTVENC_TS_UNIT_SECONDS:
                return 1;
        case SSTVENC_TS_UNIT_MILLISECONDS:
                return 1000;
        case SSTVENC_TS_UNIT_MICROSECONDS:
                return 1000000;
        case SSTVENC_TS_UNIT_NANOSECONDS:
                return 1000000000;
        default:
                /* Not supported */
                assert(0);
        }
}
 
uint32_t sstvenc_ts_clamp_samples(uint64_t samples) {
        if (samples > UINT32_MAX) {
                return SSTVENC_TS_INFINITE;
        } else {
                return samples;
        }
}
 
uint32_t sstvenc_ts_unit_to_samples(double time, uint32_t sample_rate,
                                    uint8_t unit) {
        if (time == INFINITY) {
                return SSTVENC_TS_INFINITE;
        } else {
                return sstvenc_ts_clamp_samples(
                    ((uint64_t)((time * sample_rate) + 0.5))
                    / sstvenc_ts_unit_scale(unit));
        }
}
 
double sstvenc_ts_samples_to_unit(uint32_t samples, uint32_t sample_rate,
                                  uint8_t unit) {
        if (samples == SSTVENC_TS_INFINITE) {
                return INFINITY;
        } else {
                uint64_t n = samples * sstvenc_ts_unit_scale(unit);
                return ((double)n) / ((double)sample_rate);
        }
}