MuditaOS/module-audio/Audio/decoder/decoderWAV.cpp

/*
 *  @file decoderWAV.cpp
 *  @author Mateusz Piesta (mateusz.piesta@mudita.com)
 *  @date 06.04.19
 *  @brief 
 *  @copyright Copyright (C) 2019 mudita.com
 *  @details
 */

#include "decoderWAV.hpp"


namespace decoder {

    decoderWAV::decoderWAV(const char *fileName) :
            decoder(fileName),
            tag(std::make_unique<Tags>()) {

        if(fd == NULL){
            return;
        }

        if (vfs.fread(&waveHeader, 1, sizeof(waveHeader), fd) != sizeof(WAVE_FormatTypeDef)) {
            return;
        }

        tag->total_duration_s = (fileSize - sizeof(WAVE_FormatTypeDef)) / waveHeader.ByteRate;
        tag->duration_min = tag->total_duration_s / 60;
        tag->duration_hour = tag->duration_min / 60;
        tag->duration_sec = tag->total_duration_s % 60;
        tag->sample_rate = waveHeader.SampleRate;
        tag->num_channel = waveHeader.NbrChannels;

        sampleRate = waveHeader.SampleRate;
        bitsPerSample = waveHeader.BitPerSample;
        chanNumber = waveHeader.NbrChannels;
    }

    std::unique_ptr<Tags> decoderWAV::fetchTags() {

        tag->filePath.append(filePath);
        auto pos = filePath.rfind("/");
        if (pos == std::string::npos) {
            tag->title.append(filePath);
        } else {
            tag->title.append(&filePath[pos+1]);
        }

        return std::make_unique<Tags>(*tag);
    }

    uint32_t decoderWAV::decode(uint32_t samplesToRead, int16_t *pcmData) {
        uint32_t samples_read = 0;
        uint32_t samplesToReadChann = chanNumber == 1 ? samplesToRead / 2 : samplesToRead;

        // mono
        if (chanNumber == 1) {
            samples_read = vfs.fread(pcmData, sizeof(int16_t), samplesToReadChann, fd);
            if (samples_read == 0) {
                return samples_read;
            }

            // Internally mono recordings are converted to stereo by doubling samples.
            decoder::convertmono2stereo(pcmData, samplesToReadChann);
            samples_read *=2;
            samplesToReadChann *=2;
        }
            //stereo
        else {
            samples_read = vfs.fread(pcmData, sizeof(int16_t), samplesToReadChann, fd);
        }

        if (samples_read) {
            /* Calculate frame duration in seconds */
            position += (float) ((float) (samplesToReadChann / 2) / (float) (sampleRate));
        }

        return samples_read;
    }

    void decoderWAV::setPosition(float pos){

        vfs.fseek(fd,(fileSize*pos)+ sizeof(WAVE_FormatTypeDef),SEEK_SET);
        // Calculate new position
        position = (float) ((float) (vfs.ftell(fd)/sizeof(int16_t) / chanNumber) / (float) (sampleRate));

    }

}