Converting a sound to a visual file and vice versa:

File formats of choice: WAV and PNG.

Understanding WAV file format:

struct WAVHeader {

  char riff_tag[4]; 
  uint32_t file_size;
  char wave_tag[4];
  char fmt_tag[4];
  uint32_t fmt_length;
  uint16_t audio_format;
  uint16_t num_channels;
  uint32_t sample_rate;
  uint32_t byte_rate;
  uint16_t block_align;
  uint16_t bits_per_sample;
  char data_tag[4];
  uint32_t data_length;

};