PAL/NTSC Analog Video Problem - Page 1
Forum section: electronics / projects

author: dexters_lab
author_rank: Unknown
timestamp: October 16, 2017, 07:47:49 am
content: I just sent one of my quantel paintboxes to someone in the USA and they are having problems with the picture, i wonder if anyone out there with some analog video experience can offer any suggestions as the causethe paintbox is a PAL / 50hz system and worked just fine on my sony BVM monitor here in the UK before i shipped it, before we consider a some hardware fault caused by it's 7500 mile journey i want to know if it might be a PAL/NTSC/50hz/60hz problem or similarthere are a couple of pictures attached, there is only about the right hand half of the image being shown and part way down there is a wavey pattern horizontally. The signal is 4 wire, so separate R, G, B & Syncany thoughts from the collective?

author: oldway
author_rank: Super Contributor
timestamp: October 16, 2017, 08:04:40 am
content: You should have send your paintbox AND your Sony BVM monitor together, not only the paintbox.Problem is not only PAL/NTSC incompatibility (this give only color's problem), but also standarts are different....

author: Benta
author_rank: Super Contributor
timestamp: October 16, 2017, 08:13:50 am
content: If you're sending RGB, it's neither PAL nor NTSC (those terms only make sense with composite video).But I understand what you mean. Your box delivers 625-line/50-frame video, and the monitor only understands 525-line/60-frame. Not a lot you can do except try with a different monitor, preferable a multi-standard type.Correction: should read 625-line/25-frame and 525-line/30-frame

author: OzOnE
author_rank: Regular Contributor
timestamp: October 16, 2017, 08:18:56 am
content: Yep, the colour carrier is normally only affected when using Composite or S-Video.It won't usually be affected when using RGB or Component, unless the monitor is doing some other weird processing.(eg. Some of them can screw up the colour decoding if the sync is really bad too.)Time will tell with this I think. There's sure to be a capture card or other display that will confirm if the Paintbox is OK or not.Failing that, the guy will hopefully find an o'scope he can hook up, to see if the Csync from the PB is clean.EDIT: I know that many TVs in the UK / Europe started to add NTSC support in the late 90s, and even some VCRs, but I think it was far less common for TVs in the US to have PAL / multi-standard support?I'm sure some of the PVMs did, but even most of those were probably meant for NTSC only?

author: helius
author_rank: Super Contributor
timestamp: October 16, 2017, 08:26:20 am
content: Quote from: OzOnEThat's correct; of course with the takeover of LCD TVs I think multistandard became much more common.PVMs were made both with and without support. For example, the PVM-1342Q or many other comparable models would be capable of synchronizing to 50 fields/s RGB; the related PVM-1341 is only capable of 60 fields/s.

author: dexters_lab
author_rank: Unknown
timestamp: October 16, 2017, 08:27:29 am
content: Quote from: Benta on October 16, 2017, 08:13:50 amyea, sorry i wasn't meaning a pal/ntsc colour problem as it's RGB anywaywe don't know the model of the monitor yet, it's a sony BVM or PVM of some sorts so i just expected it would be compatible with both 625/525... if that is the issue then it's just a case of finding another monitor that can do both. I should know a bit more when the owner replies back.

author: dexters_lab
author_rank: Unknown
timestamp: October 16, 2017, 08:32:10 am
content: Quote from: helius on October 16, 2017, 08:26:20 amyes that's what i thought too

author: peteb2
author_rank: Regular Contributor
timestamp: October 16, 2017, 09:46:09 am
content: I am faintly stunned someone is still using 4:3 analog kit, speaking as studio and maintenance broadcast engineer of 35 +yrs. (Most places have ditched all such standards and HD-SDi prevails out of seriously high spec PCs and programs things like vizrt)!As to the images shown, it would be great to know the monitor model and whether the distortion part in the raster is locked or rolling it really does look like sync is "having issues"....My next thought is what model Paintbox and how many hours has it clocked plus has it been powered up much on USA 115Vac 60Hz mains much?Assuming your paintbox is second series (early '90s?) that is based on a generic general purpose PC of the era and using custom ancillary boards i would start to be concerned for the power supply performance in something so aged. It would probably have been wide Vac in even back then. We may also have some earth looping issues since we don't know if the installation location in the USA is using a grounded mains for the monitor and the Paintbox crate...Here's where someone needs to look at the actual R G B using some test colour bars as a reference with a waveform monitor or if that isn't possible at minimum an oscilloscope to see the condition of video signal and also the state of sync.Not knowing your specific PB is it possible someone has accessed the settings for the unit and chosen something it just cannot do?

author: dexters_lab
author_rank: Unknown
timestamp: October 16, 2017, 10:15:17 am
content: Quote from: peteb2 on October 16, 2017, 09:46:09 amsome of us like old techit's being used in a studio where people can come and be creative using old and modified video equipment for video art projects. The owner also has things like Farlight CVIs and NewTek VideoToasters in there as well so the paintbox fits in quiet well.Quotei have asked the owner these exact questions, i am waiting to hear backQuoteit's an early v-series, this as far as i know it's first trip to USA and hence running on 115v. The PSU is switchable though, i tested it on 115v before it was sent.Quotethe second generation paintboxes (the v-series) didn't use a PC, it's all running around a motorola 68k and custom ASICs. It wasn't until the 2000s quantel switched to using PCs and windowsi'll ask about the mains ground setupQuotei need to find out what equipment he has like this, hopefully he'll have something he can use.Quotei don't think so, it's literally been unpacked from shipping and turned on

author: stj
author_rank: Super Contributor
timestamp: October 16, 2017, 02:12:00 pm
content: you really need to find the make/model of his tv/monitor and what input on it he is using.

author: Scrts
author_rank: Frequent Contributor
timestamp: October 16, 2017, 03:17:11 pm
content: Quote from: Benta on October 16, 2017, 08:13:50 amSeems like you are right - the TV does not understand the frame size and rate. Even if it would cope with a slower frame rate, it doesn't digest the frame size.

author: BrianHG
author_rank: Super Contributor
timestamp: October 16, 2017, 06:09:57 pm
content: Is your user of the paint-box using it's external sync input. If I remember, the paint-box can receive a sync to lock onto your studio's master reference for use in a studio mixing console environment, like many pros who use the Video Toaster who may use a master sync reference generator for all their gear. The photo you are giving us looks like the external sync locking input is loosing lock part way down the screen.I've seen this once on an old high end Amiga NTSC genlock where the source sync was the wrong amplitude. Funny that the cheaper crummy genlocks had no problem with the locking, but the pro-gear was really tight on studio specs.Note1: if he was feeding a pal sync into a RGB+Sync monitor, the vertical may go out of whack, but, the horizontal shouldn't go all swiggly.Note2: if he is feeding the Amiga Video Toaster and the paintbox unit's output sync isn't perfectly timed, even though it is set to NTSC, the Toaster will loose horizontal lock exactly as you see. In this case, you do need to feed the paintbox a reference NTSC sync to ensure it's internal clock is dead on. (Assuming the paintbox's internal video clock generator is a PLL oscillator which may have too large a drift factor when not receiving an external sync. (It is not that the output of the paint-box is swiggling, it's that it is just too slow or too fast for the crystal PLL tuned clock in the VideoToaster to hold onto and the result is what you see coming out of the Video Toaster)). I've seen this before feeding a Video Toaster with a color bar generator who's video source was slightly off due to the wrong loading capacitors on the reference 27MHz crystal. (Yes, it was my design of a color bar generator...)

author: dexters_lab
author_rank: Unknown
timestamp: October 17, 2017, 06:56:25 am
content: well we finally pinned it down to no sync from the paintboxthey re-seated all the cards, connections and it's working perfectly now so it looks like it was just a bad connectionthank you everyone for your ideas!

author: Benta
author_rank: Super Contributor
timestamp: October 17, 2017, 09:31:13 am
content: Very good!Thanks for coming back with the solution, a lot of people forget that.

author: BrianHG
author_rank: Super Contributor
timestamp: October 17, 2017, 09:13:03 pm
content: Damn, no sync on the sync signal and the monitor was attempting a Sync-on-Green, without one being there, but still a picture. I should have recognized that type of visual artifact/problem since the horizontal alignment messed up with the contents in the picture and I've seen it before on my studio RGB VGA screens which had separate RGB H&V BNC connectors and this is what you got if the H&V weren't plugged in...