No, no this isn't about breaking DCRM!
I've had a number of minor annoyance and posted a few of them but they were just annoyances and as no one else seemed to think them significant I haven't pushed them.
But just now they have all come together and I believe I have the answer but I'd sure appreciate some input from a few experts as this is a significant issue.
In a nutshell it seems all to easy to end up with levels outside the broadcast legal range. For example the Generated Media black will give a black level below 0 IRE when converted to analogue. This is a real no no as far as I know. If the black level falls below 0 then sync circuits may see this as a sync pulse and have a real dummy spit.
I've been having this happen a lot. I have a cheap but new TV that I use as a monitor. I output from VV through my D8 camera to the monitor and to record to VHS. I put 30 secs of black at the start of the time line, if there's a cut straight to a bright scene when that goes to the monitor, total sync loss. If I PTT with VVs black leader before the black on the TL, total sync loss at that point also.
Run the Broadcast Legal filter on the video bus and all these problems disappear. Look at the historgram after the filter and the blacks have been pulled up from zero.
So OK I've solved my problem why am i posting this. Well firstly to see if anyone else thinks I've really found the correct answer. Secondly because and I've said this before. Send a tape out for broadcast with levels below zero or too high and if the broadcaster cares about what they put to air they're going to reject it and that's a real bummer.
This isn't an issue for DV as far as I can see, it doesn't have sync pulses per se and as far as I can see should run from 0 to 255 in each channel else its just wasting resolution. However a tape that's going out for broadcast or being printed to an analogue format would seem to need to be legalised.
I'd always assumed I could blindly ignore all this technical stuff, the gear should convert the zero black level of DV to a legal black level when it's converted to composite video. I seem to have been a little too ignorant on this point. I kind of hope I'm wrong else it's just one more thing to worry about.
By the way I'm working in PAL, NTSC with +7.5 setup maybe a different story.
I've had a number of minor annoyance and posted a few of them but they were just annoyances and as no one else seemed to think them significant I haven't pushed them.
But just now they have all come together and I believe I have the answer but I'd sure appreciate some input from a few experts as this is a significant issue.
In a nutshell it seems all to easy to end up with levels outside the broadcast legal range. For example the Generated Media black will give a black level below 0 IRE when converted to analogue. This is a real no no as far as I know. If the black level falls below 0 then sync circuits may see this as a sync pulse and have a real dummy spit.
I've been having this happen a lot. I have a cheap but new TV that I use as a monitor. I output from VV through my D8 camera to the monitor and to record to VHS. I put 30 secs of black at the start of the time line, if there's a cut straight to a bright scene when that goes to the monitor, total sync loss. If I PTT with VVs black leader before the black on the TL, total sync loss at that point also.
Run the Broadcast Legal filter on the video bus and all these problems disappear. Look at the historgram after the filter and the blacks have been pulled up from zero.
So OK I've solved my problem why am i posting this. Well firstly to see if anyone else thinks I've really found the correct answer. Secondly because and I've said this before. Send a tape out for broadcast with levels below zero or too high and if the broadcaster cares about what they put to air they're going to reject it and that's a real bummer.
This isn't an issue for DV as far as I can see, it doesn't have sync pulses per se and as far as I can see should run from 0 to 255 in each channel else its just wasting resolution. However a tape that's going out for broadcast or being printed to an analogue format would seem to need to be legalised.
I'd always assumed I could blindly ignore all this technical stuff, the gear should convert the zero black level of DV to a legal black level when it's converted to composite video. I seem to have been a little too ignorant on this point. I kind of hope I'm wrong else it's just one more thing to worry about.
By the way I'm working in PAL, NTSC with +7.5 setup maybe a different story.