Capture drops colour to black/white only?
 

Hi, I'm using Philips VR1000 (JVC clone) with line and frame tbc, with pinnacle usb card from LS.

I've noticed in two recent captures that within the first 10 mins there is a single section of the captured file where the colour drops to leave only black and white section.

I can't recall but these may have been the first captures of the day/session after power up. Do these devices need a "warm up" period or anything? I can go back and capture the same sections of the tape without issue on a subsequent run.

Would this be VCR, card or TBC issue?

It's annoying if I don't have confidence that captures are accurate. Is there an avisynth script I can run to verify captures haven't black and white sections in them to avoid a painstaking manual check?

-- merged --

I tried to reproduce this morning, took TBC out of the loop and sure enough on the first capture there was issue within minutes of capture freezing, and also the drop to black/white. I've tried changing s-video cables which was fine for the subsequent capture but not sure if that is just masking the real issue.

You can check it with a CRT and the regular VCR you use for rewinding tapes.

I don't watch the capture continuously so was keen to find a post-capture validation method.

During my test captures today I did watch on an old CRT screen and the colour was fine on it, but the preview window in VDub was only black/white. Either cables or the capture card I assume.

The capture card is the least likely thing. I had something similar happen and I jumped to conclusions. Is it doing the same thing in composite?

Loss of chroma is
- usually wires
- often VCR, damaged I/O
- only TBC if bad unit, usually bad model (black AVT-8710, bad-cap TBC-1000, etc)
- rarely capture card, unless known-bad card (Blackmagic, various HD cards, Easycaps, etc)

I heavily suspect wires, or the input/output on the VCR.

It may be tired caps. When they're on the borderline of failure, an increase in temperature can sometimes give them enough of a boost to work in the circuit for a while but it wont last. They need to be replaced.

99%+ unlikely on the exact TBC he has. :wink2:

Thanks all, will try with a different s-video cable from the VCR out and see how it goes. It definitely isn't TBC as its the same behaviour with TBC out of the loop.

VCR was from VCRShop and probably only done about 20 tapes so I'd be hoping for no issues there.

I didnt specify the device, just that caps could be an issue.

I just assumed you meant the TBC, as VCRs don't really have caps, nor do capture cards. I mean, yes "they do", but also not really. While caps is a common problem among certain items, it's not all items. I think "bad caps" is sometimes thrown around like a bogeyman, being mentioned too early in a troubleshoot conversation these days.

Sort of like cleaning VCR heads without much regard for the actual more-likely problem.

In this specific case, I strongly suspect that Traderbam has damaged the output block on the VCR, caused by using a bad cable (or cables, plural). This is why I hate fat-header "name brand" (Monster/etc) type cables. The fancy cable damages gear, because it fits too tight. The "shielding" is too thick, to the point of being ridiculous. You're usually better off with cheap Amazon cables vs. the overpriced "name brand" cables.

Or, hopefully, this is just bad cables.

VCRShop does a decent job at VCR repair, but he does have a volume that can let some bad units slip by. I don't think he does burn-in testing like I do. But unlike your average random/eBay seller, he does at least stand behind his work, good work ethic, and will re-repair those bad decks, contact him. An exact situation like this, assuming my diagnosis is correct on the output block, the error could be a preexisting condition (but isn't necessarily the case).

Update:

I've been doing more diagnostics over the last few days. Here's a summary of the issues...

Loss of chroma - this has occurred on 2 VCRs using different s-video cables and different tapes.

Video freezing during capture - I've rebuilt capture machine and reinstalled drivers. Issue seems to have gone. It may have been down to some legacy policy blocking the proper installation and using something from Windows update.

On a number of tapes I've noticed a bizarre issue where there is flickering immediately after a scene change in the captured video. On my test tape I noticed this on approximately 60% of scene changes.

Here's the summary of the diagnostics for this issue:
- VCR - same issue on both VR1000 and NV-HS860
- DSPC ON/OFF - no difference
- S-video cables - no difference with different cables
- TBC PSU - no difference with different PSU
- Capture card - no difference between USB-Live2 and USB-710
- TV preview via SCART - issue not present
- Composite - no difference from using S-video

- TBC - the only scenario where the issue was removed was my taking the frame TBC out of the loop. With the TBC in line, the issue persisted across both s-video and composite port usage.

This is a really odd one. It seems that the TBC cannot handle whatever is going on. I have noticed this on a few tapes although majority seem to be fine.

Short samples attached.

In the 2nd clip, the color is blown out. I've seen this happen on some tapes, then when I get another copy of the same tape, the problem is gone. So it's possible that what you have is a badly recorded tape that nobody noticed when it was played back on a CRT.

. Then it sounds like the TBC is the problem...

To be honest that particular clip is on a segment that does look overblown but everything else is fine. This was a tape made by a local production company and sold widely, not a 2nd gen tv recording etc. The tape is totally fine when I take the TBC out of the loop.

@LordSmurf - any suggestions on how to troubleshoot the TBC element in more detail please?

Confirm TBC:
- Soft = off
- PAL = set value, not auto

The unfortunate byproduct of correcting timing is sometimes other values/aspects of the tape are harmed. That's because those values/aspects are intertwined with bad timing. This is, for example, why VCR line TBCs have trouble handling tearing. This is the exact reason why I have multiple VCRs and TBCs, to make sure I can handle 99.9%+ of all tapes near-perfectly.

I'm not yet convinced this is truly what's happening here, but it would be possible for he above reason.

Confirmed.

-- merged --

Update on the chroma loss issue - this does seem to be related to the capture card.

I have tried with 2 different VCRs, have taken the TBC out of loop, have tried another capture card which is fine, have tried on several capture machines, have tried different s-video cables, different tapes.

It's a reproduceable issue almost all the time on the first capture of the day when the equipment is recently switched on. I tried leaving VCR powered on for several hours but keeping capture computer and card off until ready to capture. The chroma loss usually happens around 10-20mins into the first capture. Subsequent captures are usually ok.

It doesn't fill me with confidence and suspect that the card won't last long. Any suggestions on anything else to test?

-- merged --

@LordSmurf anything further to suggest on troubleshooting these devices please?

I see two issues here The loss of chroma and the flickering. I think you should tackle them one at a time and always isolate the equipement, Don't troubleshoot with a series of equipment attached and assume one is faulty, Start with a TV first, then switch to the capture workflow with only VCR and capture card, then start adding devices one at a time until the problem appears.

On the topic of flickering, I have had that happen before with a Panasonic ES15 in the chain, what follows is a quick flash of white. (Perhaps the AGC gets screwed. resulting in a quick flash) I have had this sort of flickering problem when I had a Kramer FC-400 TBC, but outside of including a Panasonic ES15 along side it, hasn't happened since I switched to a Cypress CDM 640 TBC.

Yes, the chroma loss issue is the one to focus on. I've already done all the isolation I can and all routes seem to point to the capture card being the problem.

Confirm all VirtualDub settings with screencaps.

In main settings, DirectX OFF.

In capture mode, main window, lower right, 25fps, 48.kHz
Capture > Timing
Video > Capture filter, pin, Set custom format, Compression

I'm betting you'll see this issue with another capture card.
I think it's signal, maybe VirtualDub settings. You can always try VirtualDub2, or AmaRecTV, but odds are the same thing will happen.

Capture cards insist on compliant signals, PAL TVs allow "other" signals, so the "use TV first" test can give false results. Just be cognizant of that fact.