[1] Attempts at developing Phonovision were undertaken in the late 1920s in London by its inventor, Scottish television pioneer John Logie Baird.
[4] Unlike Baird's other experiments (including stereoscopy, colour and infra-red night-vision), there is no evidence of him having demonstrated playback of pictures, though he did play back the sound of the vision signal to audiences.
[6][7] From 1982, Donald F. McLean undertook a forensic-level investigation that identified a total of five different disc recordings dated 1927-28 that closely aligned with the principles of Baird's Phonovision patents.
[8] In addition, study of the distortions in the recordings led to a new understanding of the mechanical problems Baird had encountered explaining why these discs were never good enough for picture playback.
In April 1933, an early television enthusiast used a Silvatone home sound recording outfit that indented a signal-modulated groove into a bare aluminium disc thereby capturing the video signal from a BBC 30-line 12.5 frames per second live broadcast.