std::tuple get_save_encoding_for_wav()

in torchaudio/csrc/sox/utils.cpp [203:284]

• 82 lines of code
• 24 McCabe index (conditional complexity)

std::tuple<sox_encoding_t, unsigned> get_save_encoding_for_wav(
    const std::string format,
    caffe2::TypeMeta dtype,
    const Encoding& encoding,
    const BitDepth& bits_per_sample) {
  switch (encoding) {
    case Encoding::NOT_PROVIDED:
      switch (bits_per_sample) {
        case BitDepth::NOT_PROVIDED:
          switch (dtype.toScalarType()) {
            case c10::ScalarType::Float:
              return std::make_tuple<>(SOX_ENCODING_FLOAT, 32);
            case c10::ScalarType::Int:
              return std::make_tuple<>(SOX_ENCODING_SIGN2, 32);
            case c10::ScalarType::Short:
              return std::make_tuple<>(SOX_ENCODING_SIGN2, 16);
            case c10::ScalarType::Byte:
              return std::make_tuple<>(SOX_ENCODING_UNSIGNED, 8);
            default:
              throw std::runtime_error("Internal Error: Unexpected dtype.");
          }
        case BitDepth::B8:
          return std::make_tuple<>(SOX_ENCODING_UNSIGNED, 8);
        default:
          return std::make_tuple<>(
              SOX_ENCODING_SIGN2, static_cast<unsigned>(bits_per_sample));
      }
    case Encoding::PCM_SIGNED:
      switch (bits_per_sample) {
        case BitDepth::NOT_PROVIDED:
          return std::make_tuple<>(SOX_ENCODING_SIGN2, 32);
        case BitDepth::B8:
          throw std::runtime_error(
              format + " does not support 8-bit signed PCM encoding.");
        default:
          return std::make_tuple<>(
              SOX_ENCODING_SIGN2, static_cast<unsigned>(bits_per_sample));
      }
    case Encoding::PCM_UNSIGNED:
      switch (bits_per_sample) {
        case BitDepth::NOT_PROVIDED:
        case BitDepth::B8:
          return std::make_tuple<>(SOX_ENCODING_UNSIGNED, 8);
        default:
          throw std::runtime_error(
              format + " only supports 8-bit for unsigned PCM encoding.");
      }
    case Encoding::PCM_FLOAT:
      switch (bits_per_sample) {
        case BitDepth::NOT_PROVIDED:
        case BitDepth::B32:
          return std::make_tuple<>(SOX_ENCODING_FLOAT, 32);
        case BitDepth::B64:
          return std::make_tuple<>(SOX_ENCODING_FLOAT, 64);
        default:
          throw std::runtime_error(
              format +
              " only supports 32-bit or 64-bit for floating-point PCM encoding.");
      }
    case Encoding::ULAW:
      switch (bits_per_sample) {
        case BitDepth::NOT_PROVIDED:
        case BitDepth::B8:
          return std::make_tuple<>(SOX_ENCODING_ULAW, 8);
        default:
          throw std::runtime_error(
              format + " only supports 8-bit for mu-law encoding.");
      }
    case Encoding::ALAW:
      switch (bits_per_sample) {
        case BitDepth::NOT_PROVIDED:
        case BitDepth::B8:
          return std::make_tuple<>(SOX_ENCODING_ALAW, 8);
        default:
          throw std::runtime_error(
              format + " only supports 8-bit for a-law encoding.");
      }
    default:
      throw std::runtime_error(
          format + " does not support encoding: " + to_string(encoding));
  }
}