portapack-mayhem/firmware/baseband/audio_output.cpp

/*
 * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
 * Copyright (C) 2016 Furrtek
 * Copyright (C) 2024 Mark Thompson
 *
 * This file is part of PortaPack.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include "audio_output.hpp"

#include "portapack_shared_memory.hpp"

#include "audio_dma.hpp"

#include "message.hpp"

#include <cstdint>
#include <cstddef>
#include <array>

void AudioOutput::configure(const bool do_proc) {
    do_processing = do_proc;
}

void AudioOutput::configure(const iir_biquad_config_t& hpf_config, const iir_biquad_config_t& deemph_config, const float squelch_threshold) {
    hpf.configure(hpf_config);
    deemph.configure(deemph_config);
    squelch.set_threshold(squelch_threshold);
}

void AudioOutput::write_unprocessed(const buffer_s16_t& audio) {
    block_buffer_s16.feed(
        audio,
        [this](const buffer_s16_t& buffer) {
            audio_present = true;
            fill_audio_buffer(buffer, audio_present);
        });
}

void AudioOutput::write(const buffer_s16_t& audio) {
    std::array<float, 32> audio_f;
    for (size_t i = 0; i < audio.count; i++) {
        audio_f[i] = audio.p[i] * ki;
    }
    write(buffer_f32_t{audio_f.data(), audio.count, audio.sampling_rate});
}

void AudioOutput::write(const buffer_f32_t& audio) {
    block_buffer.feed(
        audio,
        [this](const buffer_f32_t& buffer) {
            this->on_block(buffer);
        });
}

void AudioOutput::on_block(const buffer_f32_t& audio) {
    if (do_processing) {
        const auto audio_present_now = squelch.execute(audio);

        hpf.execute_in_place(audio);
        deemph.execute_in_place(audio);

        audio_present_history = (audio_present_history << 1) | (audio_present_now ? 1 : 0);
        audio_present = (audio_present_history != 0);

        if (!audio_present) {
            for (size_t i = 0; i < audio.count; i++) {
                audio.p[i] = 0;
            }
        }
    } else
        audio_present = true;

    fill_audio_buffer(audio, audio_present);
}

bool AudioOutput::is_squelched() {
    return !audio_present;
}

void AudioOutput::fill_audio_buffer(const buffer_s16_t& audio, const bool send_to_fifo) {
    auto audio_buffer = audio::dma::tx_empty_buffer();
    for (size_t i = 0; i < audio_buffer.count; i++) {
        audio_buffer.p[i].left = audio_buffer.p[i].right = audio.p[i];
    }
    if (stream && send_to_fifo) {
        stream->write(audio.p, audio_buffer.count * sizeof(int16_t));
    }

    feed_audio_stats(audio);
}

void AudioOutput::fill_audio_buffer(const buffer_f32_t& audio, const bool send_to_fifo) {
    std::array<int16_t, 32> audio_int;

    auto audio_buffer = audio::dma::tx_empty_buffer();
    for (size_t i = 0; i < audio_buffer.count; i++) {
        const int32_t sample_int = audio.p[i] * k;
        const int32_t sample_saturated = __SSAT(sample_int, 16);
        audio_buffer.p[i].left = audio_buffer.p[i].right = sample_saturated;
        audio_int[i] = sample_saturated;
    }
    if (stream && send_to_fifo) {
        stream->write(audio_int.data(), audio_buffer.count * sizeof(audio_int[0]));
    }

    feed_audio_stats(audio);
}

void AudioOutput::feed_audio_stats(const buffer_s16_t& audio) {
    audio_stats.feed(
        audio,
        [](const AudioStatistics& statistics) {
            const AudioStatisticsMessage audio_stats_message{statistics};
            shared_memory.application_queue.push(audio_stats_message);
        });
}

void AudioOutput::feed_audio_stats(const buffer_f32_t& audio) {
    audio_stats.feed(
        audio,
        [](const AudioStatistics& statistics) {
            const AudioStatisticsMessage audio_stats_message{statistics};
            shared_memory.application_queue.push(audio_stats_message);
        });
}