Thoughts on standards conversion

[Terry]

Frame rate conversion was still optical until 1968 when the BBC devised the first frame rate converter in time for the 1968 Mexico Olympics.

Wasn't this a full field converter, Jeffrey? I can certainly remember an interim solution for 525-line colour conversion which couldn't handle 525 - 625 line conversion bit did manage the frame rate bit.

As a result the converted picture was only 525-lines with a black band top and bottom. To compensate, the line rate conversion added a blanking period at the start and end of each line.

This was the only way of showing 525-line NTSC colour programmes when the UK colour service first started in 1967 because (we were told) that optical conversion didn't work for colour.

The full field converter was definitely in use long before the October 1968 Olympics because I remember setting up a new colour set in a customer's house while the funeral of Bobby Kennedy the previous June was being shown. I have a lasting memory of a long shot of the motorcade from behind travelling along a straight road. As the camera was some way above ground, all the rear lights could be clearly seen: one row on the left hand side of the cars, as usual, the other row travelling up the field on the other side of the fence bordering the road!

I was amazed that a camera with such obviously mis-registered tubes was allowed to be used for such an event!

The first digital converter was the IBA's DICE from 1971. This is well described in IBA Tech Review book 8. This may be available online. I have all 24 volumes both in print and as PDFs but they are huge, 28-40MB each.

38.2MB: You can download it here.