satdump/src-core/modules/demod/module_demod_base.cpp

#include "module_demod_base.h"
#include "logger.h"
#include "imgui/imgui.h"
#include "core/config.h"

namespace demod
{
    BaseDemodModule::BaseDemodModule(std::string input_file, std::string output_file_hint, nlohmann::json parameters) : ProcessingModule(input_file, output_file_hint, parameters),
                                                                                                                        constellation(100.0f / 127.0f, 100.0f / 127.0f, demod_constellation_size)
    {
        // Parameters parsing
        if (parameters.count("samplerate") > 0)
            d_samplerate = parameters["samplerate"].get<long>();
        else
            throw std::runtime_error("Samplerate parameter must be present!");

        if (parameters.count("buffer_size") > 0)
            d_buffer_size = parameters["buffer_size"].get<long>();
        else
            d_buffer_size = std::min<int>(dsp::STREAM_BUFFER_SIZE, std::max<int>(8192 + 1, d_samplerate / 200));

        if (parameters.count("symbolrate") > 0)
            d_symbolrate = parameters["symbolrate"].get<long>();

        if (parameters.count("agc_rate") > 0)
            d_agc_rate = parameters["agc_rate"].get<float>();

        if (parameters.count("dc_block") > 0)
            d_dc_block = parameters["dc_block"].get<bool>();

        if (parameters.count("freq_shift") > 0)
            d_frequency_shift = parameters["freq_shift"].get<long>();

        if (parameters.count("iq_swap") > 0)
            d_iq_swap = parameters["iq_swap"].get<bool>();

        snr = 0;
        peak_snr = 0;

        showWaterfall = satdump::config::main_cfg["user_interface"]["show_waterfall_demod_fft"]["value"].get<bool>();
    }

    void BaseDemodModule::initb(bool resample_here)
    {
        float input_sps = (float)d_samplerate / (float)d_symbolrate; // Compute input SPS
        resample = input_sps > MAX_SPS || input_sps < MIN_SPS;       // If SPS is out of allowed range, we resample

        int range = pow(10, (std::to_string(int(d_symbolrate)).size() - 1)); // Avoid complex resampling

        final_samplerate = d_samplerate;

        if (d_parameters.count("custom_samplerate") > 0)
            final_samplerate = d_parameters["custom_samplerate"].get<long>();
        else if (MAX_SPS == MIN_SPS)
            final_samplerate = d_symbolrate * MAX_SPS;
        else if (input_sps > MAX_SPS)
            final_samplerate = resample ? (round(d_symbolrate / range) * range) * MAX_SPS : d_samplerate; // Get the final samplerate we'll be working with
        else if (input_sps < MIN_SPS)
            final_samplerate = resample ? d_symbolrate * MIN_SPS : d_samplerate; // Get the final samplerate we'll be working with

        float decimation_factor = d_samplerate / final_samplerate; // Decimation factor to rescale our input buffer

        if (resample)
            d_buffer_size *= ceil(decimation_factor);
        if (d_buffer_size > 8192 * 20)
            d_buffer_size = 8192 * 20;

        final_sps = final_samplerate / (float)d_symbolrate;

        logger->debug("Input SPS : %f", input_sps);
        logger->debug("Resample : " + std::to_string(resample));
        logger->debug("Samplerate : %f", final_samplerate);
        logger->debug("Dec factor : %f", decimation_factor);
        logger->debug("Final SPS : %f", final_sps);

        if (final_sps < 1.0)
            throw std::runtime_exception("SPS is invalid. Must be above 1!");

        // Init DSP Blocks
        if (input_data_type == DATA_FILE)
            file_source = std::make_shared<dsp::FileSourceBlock>(d_input_file, dsp::basebandTypeFromString(d_parameters["baseband_format"]), d_buffer_size, d_iq_swap);

        if (d_dc_block)
            dc_blocker = std::make_shared<dsp::CorrectIQBlock<complex_t>>(input_data_type == DATA_DSP_STREAM ? input_stream : file_source->output_stream);

        // Cleanup things a bit
        std::shared_ptr<dsp::stream<complex_t>> input_data = d_dc_block ? dc_blocker->output_stream : (input_data_type == DATA_DSP_STREAM ? input_stream : file_source->output_stream);

        if (d_frequency_shift != 0)
            freq_shift = std::make_shared<dsp::FreqShiftBlock>(input_data, d_samplerate, d_frequency_shift);

        std::shared_ptr<dsp::stream<complex_t>> input_data_final = d_frequency_shift != 0 ? freq_shift->output_stream : input_data;

        if (input_data_type == DATA_FILE)
        {
            fft_splitter = std::make_shared<dsp::SplitterBlock>(input_data_final);
            fft_splitter->add_output("fft");
            fft_splitter->set_enabled("fft", show_fft);

            fft_proc = std::make_shared<dsp::FFTPanBlock>(fft_splitter->get_output("fft"));
            fft_proc->set_fft_settings(8192, final_samplerate, 120);
            fft_proc->avg_rate = 0.02;
            fft_plot = std::make_shared<widgets::FFTPlot>(fft_proc->output_stream->writeBuf, 8192, -10, 20, 10);
            waterfall_plot = std::make_shared<widgets::WaterfallPlot>(8192, 500);
            waterfall_plot->set_rate(120, 10);
            fft_proc->on_fft = [this](float *v)
            { waterfall_plot->push_fft(v); };
        }

        std::shared_ptr<dsp::stream<complex_t>> input_data_final_fft = input_data_type == DATA_FILE ? fft_splitter->output_stream : input_data_final;

        // Init resampler if required
        if (resample && resample_here)
            resampler = std::make_shared<dsp::SmartResamplerBlock<complex_t>>(input_data_final_fft, final_samplerate, d_samplerate);

        // AGC
        agc = std::make_shared<dsp::AGCBlock<complex_t>>((resample && resample_here) ? resampler->output_stream : input_data_final_fft, d_agc_rate, 1.0f, 1.0f, 65536);
    }

    std::vector<ModuleDataType> BaseDemodModule::getInputTypes()
    {
        return {DATA_FILE, DATA_DSP_STREAM};
    }

    std::vector<ModuleDataType> BaseDemodModule::getOutputTypes()
    {
        return {DATA_FILE, DATA_STREAM};
    }

    BaseDemodModule::~BaseDemodModule()
    {
    }

    void BaseDemodModule::start()
    {
        // Start
        if (input_data_type == DATA_FILE)
            file_source->start();
        if (d_dc_block)
            dc_blocker->start();
        if (d_frequency_shift != 0)
            freq_shift->start();
        if (input_data_type == DATA_FILE)
            fft_splitter->start();
        if (input_data_type == DATA_FILE)
            fft_proc->start();
        if (resample)
            resampler->start();
        agc->start();
    }

    void BaseDemodModule::stop()
    {
        // Stop
        if (input_data_type == DATA_FILE)
            file_source->stop();
        if (d_dc_block)
            dc_blocker->stop();
        if (d_frequency_shift != 0)
            freq_shift->stop();
        if (input_data_type == DATA_FILE)
            fft_splitter->stop();
        if (input_data_type == DATA_FILE)
            fft_proc->stop();
        if (resample)
            resampler->stop();
        agc->stop();
    }

    void BaseDemodModule::drawUI(bool window)
    {
        ImGui::Begin(name.c_str(), NULL, window ? 0 : NOWINDOW_FLAGS);

        ImGui::BeginGroup();
        constellation.draw(); // Constellation
        ImGui::EndGroup();

        ImGui::SameLine();

        ImGui::BeginGroup();
        {
            // Show SNR information
            ImGui::Button("Signal", {200 * ui_scale, 20 * ui_scale});
            if (show_freq)
            {
                ImGui::Text("Freq : ");
                ImGui::SameLine();
                ImGui::TextColored(IMCOLOR_SYNCING, "%.0f Hz", display_freq);
            }
            snr_plot.draw(snr, peak_snr);
            if (!streamingInput)
                if (ImGui::Checkbox("Show FFT", &show_fft))
                    fft_splitter->set_enabled("fft", show_fft);
        }
        ImGui::EndGroup();

        if (!streamingInput)
            ImGui::ProgressBar((double)progress / (double)filesize, ImVec2(ImGui::GetWindowWidth() - 10, 20 * ui_scale));

        drawStopButton();

        ImGui::End();

        drawFFT();
    }

    void BaseDemodModule::drawFFT()
    {
        if (show_fft && !streamingInput)
        {
            ImGui::SetNextWindowSize({400 * (float)ui_scale, (float)(showWaterfall ? 400 : 200) * (float)ui_scale});
            if (ImGui::Begin("Baseband FFT", NULL, ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoResize))
            {
                fft_plot->draw({float(ImGui::GetWindowSize().x - 0), float(ImGui::GetWindowSize().y - 40 * ui_scale) * float(showWaterfall ? 0.5 : 1.0)});

                // Find "actual" left edge of FFT, before frequency shift.
                // Inset by 10% (819), then account for > 100% freq shifts via modulo
                int pos = (abs((float)d_frequency_shift / (float)d_samplerate) * (float)8192) + 819;
                pos %= 8192;

                // Compute min and max of the middle 80% of original baseband
                float min = 1000;
                float max = -1000;
                for (int i = 0; i < 6554; i++) // 8192 * 80% = 6554
                {
                    if (fft_proc->output_stream->writeBuf[pos] < min)
                        min = fft_proc->output_stream->writeBuf[pos];
                    if (fft_proc->output_stream->writeBuf[pos] > max)
                        max = fft_proc->output_stream->writeBuf[pos];
                    pos++;
                    if (pos >= 8192)
                        pos = 0;
                }

                waterfall_plot->scale_min = fft_plot->scale_min = fft_plot->scale_min * 0.99 + min * 0.01;
                waterfall_plot->scale_max = fft_plot->scale_max = fft_plot->scale_max * 0.99 + max * 0.01;

                if (showWaterfall)
                    waterfall_plot->draw({ImGui::GetWindowSize().x - 0, (float)(ImGui::GetWindowSize().y - 45 * ui_scale) / 2});
            }

            ImGui::End();
        }
    }

    void BaseDemodModule::drawStopButton()
    {
        if (input_data_type != DATA_FILE)
            return;

        if (ImGui::IsWindowHovered(ImGuiHoveredFlags_AllowWhenBlockedByActiveItem))
        {
            ImGui::SetCursorPos({ImGui::GetCursorPos().x + ImGui::GetWindowWidth() - 55 * ui_scale,
                                 ImGui::GetCursorPos().y - 25 * ui_scale});
            ImGui::PushStyleColor(ImGuiCol_Button, ImVec4(255, 0, 0, 255));
            if (ImGui::Button("Abort##demodstop"))
                demod_should_stop = true;
            ImGui::PopStyleColor();
            if (ImGui::IsItemHovered())
                ImGui::SetTooltip("This Abort button will simulate the \ndemodulation being finished. \nProcessing will carry on!");
        }
    }

    std::vector<std::string> BaseDemodModule::getParameters()
    {
        return {"samplerate", "symbolrate", "agc_rate", "iq_swap", "buffer_size", "dc_block", "baseband_format"};
    }
}