CodecAACFAAD.h

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#pragma once
 
// #include "Stream.h"
#include "AudioTools/AudioCodecs/AudioCodecsBase.h"
#include "faad.h"
 
#ifndef FAAD_INPUT_BUFFER_SIZE
#define FAAD_INPUT_BUFFER_SIZE 1024*2
#endif
 
// to prevent Decoding error: Maximum number of bitstream elements exceeded
#ifndef FAAD_UNDERFLOW_LIMIT
#define FAAD_UNDERFLOW_LIMIT 500
#endif
 
 
namespace audio_tools {
 
class AACDecoderFAAD : public AudioDecoder {
 public:
  AACDecoderFAAD() {
    info.channels = 2;
    info.sample_rate = 44100;
    info.bits_per_sample = 16;
  };
 
  ~AACDecoderFAAD() { end(); }
 
  const char *mime() override { return "audio/aac"; }
 
  bool begin() {
    TRACED();
 
    unsigned long cap = NeAACDecGetCapabilities();
    // Check if decoder has the needed capabilities
 
    if (!cap & FIXED_POINT_CAP) {
      LOGE("Fixed Point");
      return false;
    }
 
    // Open the library
    hAac = NeAACDecOpen();
 
    // // Get the current config
    conf = NeAACDecGetCurrentConfiguration(hAac);
 
    // // If needed change some of the values in conf
    conf->outputFormat = FAAD_FMT_16BIT;
    //conf->defObjectType = LC;
    conf->defSampleRate = info.sample_rate;
    conf->downMatrix = true; // 5.1 channel downmatrixed to 2 channel
    conf->useOldADTSFormat = false;
    conf->dontUpSampleImplicitSBR = false;
 
    // Set the new configuration
    if (!NeAACDecSetConfiguration(hAac, conf)) {
      LOGE("NeAACDecSetConfiguration");
      return false;
    }
 
    // setup input buffer
    if (input_buffer.size() != buffer_size_input){
      input_buffer.resize(buffer_size_input);
    }
    is_init = false;
    return true;
  }
 
  virtual void end() {
    TRACED();
    flush();
    if (hAac != nullptr) {
      NeAACDecClose(hAac);
      hAac = nullptr;
    }
  }
 
  size_t write(const uint8_t *data, size_t len) {
    // Write supplied data to input buffer
    size_t result = input_buffer.writeArray((uint8_t *)data, len);
    // Decode from input buffer
    decode(underflow_limit);
 
    return result;
  }
 
  void flush() {
    decode(0);
  }
 
  void setInputBufferSize(int len){
    buffer_size_input = len;
  }
 
  void setUnderflowLimit(int len){
    underflow_limit = len;
  }
 
  virtual operator bool() { return hAac != nullptr; }
 
 protected:
  int buffer_size_input = FAAD_INPUT_BUFFER_SIZE;
  int underflow_limit = FAAD_UNDERFLOW_LIMIT;
  NeAACDecHandle hAac = nullptr;
  NeAACDecConfigurationPtr conf;
  SingleBuffer<uint8_t> input_buffer{0};
  bool is_init = false;
 
  void init(uint8_t *data, size_t len) {
    TRACEI();
    // Initialise the library using one of the initialization functions
    unsigned long samplerate = info.sample_rate;
    unsigned char channels = info.channels;
 
    if (NeAACDecInit(hAac, data, len, &samplerate, &channels)==-1) {
      LOGE("NeAACDecInit");
    }
    info.sample_rate = samplerate;
    info.channels = channels;
    is_init = true;
  }
 
  void decode(int minBufferSize) {
    TRACED();
    NeAACDecFrameInfo hInfo;
 
    // decode until we do not conume any bytes
    while (input_buffer.available()>minBufferSize) {
      int eff_len = input_buffer.available();
 
      if (!is_init) {
        init(input_buffer.data(), eff_len);
      }
 
      uint8_t *sample_buffer=(uint8_t *)NeAACDecDecode(hAac, &hInfo, input_buffer.address(), eff_len);
 
      LOGD("bytesconsumed: %d of %d", (int)hInfo.bytesconsumed, (int)eff_len);
      if (hInfo.error != 0) {
        LOGW("Decoding error: %s", NeAACDecGetErrorMessage(hInfo.error));
      } 
      
      if (hInfo.bytesconsumed == 0 ) {
        break;
      }
 
      LOGD("Decoded %lu samples", hInfo.samples);
      LOGD("  bytesconsumed: %lu", hInfo.bytesconsumed);
      LOGD("  channels: %d", hInfo.channels);
      LOGD("  samplerate: %lu", hInfo.samplerate);
      LOGD("  sbr: %u", hInfo.sbr);
      LOGD("  object_type: %u", hInfo.object_type);
      LOGD("  header_type: %u", hInfo.header_type);
      LOGD("  num_front_channels: %u", hInfo.num_front_channels);
      LOGD("  num_side_channels: %u", hInfo.num_side_channels);
      LOGD("  num_back_channels: %u", hInfo.num_back_channels);
      LOGD("  num_lfe_channels: %u", hInfo.num_lfe_channels);
      LOGD("  ps: %u", hInfo.ps);
 
      // removed consumed data
      input_buffer.clearArray(hInfo.bytesconsumed);
 
      // check for changes in config
      AudioInfo tmp{(sample_rate_t)hInfo.samplerate, hInfo.channels, 16};
      if (tmp != info) {
        setAudioInfo(tmp);
      }
 
      int bytes = hInfo.samples * sizeof(int16_t);
      size_t len = p_print->write(sample_buffer, bytes);
      if (len != bytes) {
        TRACEE();
      }
    }
  }
};
 
}  // namespace audio_tools