by Klaas Robers » Sun Feb 17, 2013 1:40 am
Because Albert,
Digital TV is encoded in a way that separate pictures are bidirectional interpolated between pictures that have been already and pictures that should come still. Of course this is not possible, so what you see is delayed by about a second from what happens now. When you switch over this delay must be waited before the show can start. And that is besides the fact that you have to wait about half a second before the first complete picture is assembled. So one and a half second. That is what we have to pay for the data compression, where about 6 to 10 TV-programs can be squeezed into one analogue TV channel, and with a better picture and sound quality.
Rewritable CDs and DVDs can only write information in a structure of emply blocks. The disc are sold without these blocks, so when you load a new disc and you want to write onto it, you have first to format it. Then all empty blocks are written. This is not needed for a write once disc.
When you load a written disc in the player, that player first has to read the "table of contents" of the disc. These discs can contain all kind of different information. That takes time, as this table of contents may be scattered over the disc and each part should be found prior to starting the program. Then some preliminary programming of the player might be read and done, so it takes quite some time before it starts.
You know?
When I was young and you switched on the radio, it took about half a minute to heat up the filaments of the thermionic valves (radio tubes). Only after that waiting time the music started.
Then came transistors, click... music.
But then we moved to computers and now you would be very happy if it started doing things for you half a minute after you switched it on.......