On Wednesday 16 July 2003 22:50, Vidiot wrote: >Billy responded: >> One annoyance with DV for NTSC is that it's 4:1:1 and converting >> from 4:1:1 to the 4:2:0 you need for MPEG-1/2 is a pain to do >> well. Still, that sort of annoyance is best left to those seeking >> ultra-correctness. > >Not had a problem so far. Unfortunately at this point it has all > been done under Windbloze. But, a friend has been playing with > Linux tools and as far as I know, hasn't had a problem either. > >>> BTW, before going to VCD and/or DVD, the NTSC setup level needs >>> to be removed. So whatever tool you use, make sure that it can >>> remove NTSC setup, as the MPEG-1/2 standard does not use it and >>> leaving it in will cause problems. >> >> What are you talking about here? The Y'CbCr specs for MPEG-1/2 >> are the same as for DV. Please clarify. > >Please read what I wrote. I said that the "NTSC setup" needs to be > removed. Most consumer, and even pro-sumer, devices will not remove > NTSC setup when fed an analog signal for conversion to DV. The > setup is left intact in the DV data. My DVCAM decks are like that. > No switch to tell it to remove, or add, setup. It records what > you feed it. > >MB Speaking as a broadcast engineer, let me be the first to proclaim that the subject of setup, eg the artificial raising of the black level in the std signal, is both required by the FCC, and set at 7.5 IRE on a peak white=about 0.717 volts=100 IRE, thereby wasting nearly 10% of the luminance range available to be actually modulated and transmitted by an NTSC transmitter, and it is also probably the single most abused knob on the average framestore's built in processing amplifier. The lack of the average operators basic understanding of what it is, and a near genetic incapability of reading the waveform monitors we engineers put in just so they can check it, leads to what I'll just say is some pretty wild settings. This was originally done way back up the logs in about 1946 as a way to make sure the superblack sync pulses stayed superblack and invisible. However, if we could forget the occasional pre 1970 tv thats still out there, we could now turn it down to 0 IRE and superglue the flippin knob in place. However, I'm equally sure that if we were to do that, the friendly candy company would walk in the door tomorrow with a list of setup violations at $20,000 each. So we're stuck with it, at least till hell freezes over or ntsc transmissions are shut down forever. Personally, at the present rate of conversion, I'm betting on hell freezing over first... -- Cheers, Gene AMD K6-III@500mhz 320M Athlon1600XP@1400mhz 512M 99.26% setiathome rank, not too shabby for a WV hillbilly Yahoo.com attornies please note, additions to this message by Gene Heskett are: Copyright 2003 by Maurice Eugene Heskett, all rights reserved.
