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Post #137252

Author
Laserman
Parent topic
.: The X0 Project Discussion Thread :. (* unfinished project *)
Link to post in topic
https://originaltrilogy.com/post/id/137252/action/topic#137252
Date created
7-Sep-2005, 9:01 AM
Was that the Japanese or US definitive?

BTW, on black levels there are multiple ways to tackle it. I just re-read my previous explanation, and it isn't very clear.
The problem is American NTSC analogue devices, wether VHS, S-VHS, Hi 8 or Laserdisc, outputs black at 7.5 IRE.
i.e. the black output from them isn't at a voltage of Zero (unlike PAL and even Japanese NTSC) but is in fact 0.0536V (If it is correct, in the real world various players vary in their accuracy)
If you plug your laserdisc player into a video capture card that expects 0IRE then you might need to use a proc amp to set the analogue output to 0 IRE. If you don't do this, when you move from analog into digital, then your DVD's will look extremely washed out. You will get the same problem with most DV camcorders as well if you are getting your laserdisc to digital by plugging it into your camcorder.
You can get a reasonable proc amp here. http://www.signvideo.com/single_dual_proc-amp_video-processor.htm
Programs like Final Cut Pro have a 'virtual proc amp' built into the software.

Some capture cards can be set to expect an Input IRE of 7.5 for black, so set it if you need to.

I can post some waveforms from the scope of PAL vs NTSC colourbars, with and withour pedestal if anyone is interested, but basically just remember this.
If you get it wrong when you take an analogue source and make a US NTSC DVD, your blacks get raised twice by the time you see the picture on your telly, and the picture will not have *any* true blacks, will look washed out, will have a compressed range, and you will have to adjust your set away from what it *should* be just to get a decent black level.