Irregularities in the number of revolutions of the VLP also give rise to irregularities in the reconstruction of the signal. This meant that extreme precision was required in the design of the VLP player. In order to reproduce a smooth film picture, hundreds of thousands of pixels have to be reproduced every second. The VLP therefore rotates 25 times a second so that every second approximately 15 metres of pit track can be read. This represents a speed in excess of 50 kilometres per hour.
Extreme precision is required.
When we played the first video disc we saw nothing but snow. That was a bit silly really. In our haste we had forgotten to calculate how much light we needed in order to be able to follow the pit track. We had simply used a powerful Philips incandescent lamp. That was cheap.