OK I think I got it, anyone let me know if I'm wrong in my thinking.
US devices (VCRs, DVD players, Tivos, STBs, DVRs etc.) via SD outputs, output a signal that is +7.5 IRE for blacks. US displays (via SD inputs) are calibrated for black at a input of +7.5 IRE(unlike the rest of the world that uses 0 IRE for black). US devices output a 0 IRE from HD outputs(component, HDMI or DVI) if so equipped. In this case our displays are calibrated for black at 0 IRE(the international standard).
A standard US DVDR via it's SD inputs(basically all DVDRs have) drops it's +7.5 IRE input to 0 IRE(DVD standard) for blacks. Upon playback the DVDR(or any US DVD player) must add +7.5 IRE to SD outputs to retain correct blacks.
US Panasonic DVDRs (other than the old HS2 with the so called black level bug
) have a setting(called DARKER) for SD line inputs to subtract 7.5 IRE(knowing US SD devices output a +7.5 IRE), this retains compatibility with the DVD standard of 0 IRE. Upon playback the DVDR adds 7.5 IRE(for SD outputs) to be compatible with our +7.5 IRE displays.International
DVDRs(like my Panasonic) have no such IRE settings and only go off the international standard of 0 IRE in, 0 IRE out for ALL inputs/outputs.
Using a Panasonic international
DVDR in the US runs into a problem for recording(and playing via it's SD outputs), that is it's expecting line inputs to be a 0 IRE. The problem is, US devices output a +7.5 IRE. DVDs recorded in such a manner will be overly bright when played back from the DVDRs HD outputs(HDMI or Component) because again US displays are looking for a 0 IRE output and not a +7.5 IRE. If played from the DVDRs SD outputs the DVDs will be fine, not because the DVDR is adding +7.5 to the output but rather the DVD was recorded +7.5(not DVD spec). These recorded DVDs played back on a US DVD player will be +7.5 IRE too bright from it's HD outputs and a terrible +15 IRE from it's SD outputs(because the US player adds +7.5 IRE to a DVD that is already +7.5 IRE hot).
I see no ideal way to correct this because if I install a -7.5 IRE attenuating device on my international
DVDRs line input I'll get proper spec DVDs(that will play worldwide on any NTSC DVD player) but they will look too dark coming from the DVDRs SD outputs. I guess this is the best scenario because I don't want all my recorded DVDs to be out of spec by +7.5 IRE making them incompatible with basically all US DVD players from any
output. I'll probably only use HD outputs of my DVDR anyway.
Agree, disagree? boy this whole +/- 7.5 IRE thing can sure get complicated, all because the US didn't want to stick with a worldwide
Don't get me started on ATSC
edit:moderator Ken H, I hope this thread is OK in the Technical forum. I tried to get answers in the DVD Recorders forum(on a thread specific to my DVDR) but had no bits. I thought since this was more of a technical question(and involved more devices than just DVDRs) it might be OK in the Technical forum, besides we seem to get more international
members in this forum. If not you could certainly move it to the DVDR forum. This
was my original post in the DVDR forum. In the end I think I'll put a link in that thread to this one since I'm getting important information here.