1946 Why 405 lines?

[Geordie McBoyne]

Was A.C.Cossor Ltd present at these discussions? Very important firm which was not just a user of bits. Was a manufacturer of TV and radio receivers, valves and CRTs and test instruments. Scientific glassware.
The firm suggested the adoption of a 525 line TV system for post-war Britain.

Geordie McBoyne.

[peter scott]

Cossors aren't specifically mentioned in the witnesses but I haven't been able to trace all the names in the Radio Industry Council group. Perhaps MacQueen, Williams or Browne may have been a Cossor representative?

Peter

[ppppenguin]

Not sure how much it really weighed on the decision but the government wanted to telelvise the victory parade in 1946. It was enough of a struggle to get the TV service going at all just after WW2, let alone on a new standard, in time for the parade. I'm not claiming this is a good reason for retaining 405, just a possible one.

Looking at the push to imporved standards, 405/50 was a good choice before WW2. Possible to implement at the time with enough headroom for later improvements. Looking at 525/60 in the USA this really did stand the test of time. Conversely French 819/50 turned out to be a step too far. A brave attempt but ultimately not really a success. Modern HD at 720p has about the same number of active lines, though not interlaced.

[Richard_FM]

The 819 system needed a lot of bandwith, which meant some clever squeezing to fit it into the French bands I & III.

The Belgian version was a little more manageable but they dropped it when they started a colour service.

[ppppenguin]

The Belgian version of 819 was a horrible bodge to put 819 lines into a channel that was only wide enough for 625. The result was a horizontal definition that was even less than 625 in the same channel width.

[Mike Watterson]

Yes, the Belgian system was madness. However a Belgian company became a leader in Multistandard TVs as many Belgians wanted TV from different countries (Netherlands, France and Germany).

Just to clarify, I think UK restarting TV in 1946 was largely political, but the choice of 405 lines was inevitable at the time due to what actually existed and to suit both existing viewers that still had sets, the BBC and EMI. It was too soon by about 2 years for 625 and the 525 was new replacing the earlier US TV system and would have needed modification to cameras, time base generators and USA set designs due to 110V 60 Hz vs 240V 50Hz.

So really in 1946 or 1947 the pre-war 405 lines was the only solution. It might have been a different decision if the start up was 1948 or 1949. Most of Europe delayed and went for 625 rather than restarting with the 400+ line pre war systems.

South Africa for political reasons was one of the last countries in the world able to have TV, to do it. They also had a terrific political row about Digital TV. Sensible standards worldwide for Digital and especially HDTV was a terrible lost opportunity to have a better frame rate and better cinema compatibility. Wide Screen on Analogue and then on SD Digital TV were both greedy stupid decisions.
The consumer suffers the most. Even to-day some Cinema releases are not on BD and only on NTSC DVDs. There are two sorts of NTSC DVDs, proper "From film" use progressive and 3:2 pull down is done by the player, with a progressive player and HDMI, Component or VGA "HD" you have no pull-down artefacts. Other NTSC DVDs are stored in interlace, which is nasty if they are from a telecine source, though at least most HDTVs can do inverse telecine. Older SD Analogue TVs obviously can't! Also The USA region 1 DVDs are essentially 480 lines compared to 576 lines for the 625 line other region DVDs. Hence you can see why one so called USA Broadcast HD format is 480p and the 720p popular for transmission, whereas in Europe the 1080i is more popular than 720p, because for much content there isn't as much quality difference between 576i content and 720p as there is between 480i with 3:2 pull down on cinema /film content and 720p.

Now we have the stupidity of 4K at 24 fps, 30 fps and 25 fps instead of 1920 x 1080 @ 72 fps or 96 fps. You'd want to be sitting about 2m or less from at least a 65" screen with good eyesight for 4K to make sense. An increased frame rate in progressive only makes far more sense than more resolution. The Interlace is evil to convert or upsample. It only ever made sense in the analogue environment as a free way to do 2:1 bandwidth compression, because we are less sensitive to resolution with busy moving pictures and you get twice as much on a static image with a slow phosphor.

The French 819 seems mad and the Belgian decision to have 819 in a smaller channel totally crazy.