Convert FFMPEG Waveform Back to audio
FFmpeg can't do this.

Even theoretically, the method seems unsound (no pun intended). Audios are typically sampled at 40K+ Hz per second. Max image dimension in ffmpeg is 65K. So even at that size, one can barely represent 1.5 seconds of audio at full sampling resolution. Once you go lower and rely on interpolation, your output quality will start to degrade, as your reconstruction gets coarser.