TBC Comparison

[hech54]

If you want to generate a legal signal you do need a TBC. No VTR will generate a 100% legal signal from an analogue tape unless it has some form of TBC.

What?

[magikarp99]

Studio vcrs like the old Panasonic AG-7xxx or JVC-BRxxxx are not ideal source decks for capturing tapes that were not recorded on similar studio vcrs. Just because they weigh 50 lbs and have a half dozen meter readouts, people easily assume they must be WAY better at playback than any mere consumer deck. But they often aren't. A JVC SR-VD400U or Mitsubishi HS-HD2000U will outperform an AG-7350 at concealing many types of tape defect. The AG-7350 can deliver a very clean, very precise signal from top-quality tapes, but isn't so hot playing tapes recorded on typical consumer vcrs or camcorders. The AG-7350 was also a bit of a diva, designed for studio use where it would be on a regular service/maintenance/alignment schedule. If yours hasn't been touched by a tech since 1998, it probably needs a tuneup to wring the best out of it.

Two points, the tapes I am transferring were produced in studios in similar equipment, these tapes were not produced on consumer devices. My AG-7350 has been serviced and maintained in accordance with the service manual and is in good working condition.

EDIT: re-reading this thread from the beginning, I just noticed you're one of those who have an aversion to any sort of processing. In that case, forget everything I said: processing is a necessary evil if you want to conceal or improve certain aspects of a tape. If you want absolute fidelity without a trace of visible processing, you will probably have to settle for the results you have now with your AG-7350 and Black Magic. You might be able to do some light touch-up with software filters, but any hardware assist will add visible "processing" effects (external "pro" TBCs being the worst offender by far, followed by hardware DNR). There is no practical way to "recover" the head-switching area aside from a couple prototype "software TBC" filters discussed in a thread by vaporeon800. That method may or may not work as you'd expect.

Post processing is always a trade off, I realise this. But there is often a good compromise, e.g. when removing hiss from audio recordings, removing all the hiss will leave horrible artefacts, but partial hiss removal will conceal the artefacts and make the signal clearer.

All I'm looking for is a full-frame TBC that doesn't screw with my lines or take my luma/chroma signals out of spec.

If you want to generate a legal signal you do need a TBC. No VTR will generate a 100% legal signal from an analogue tape unless it has some form of TBC.

What?

http://www.kramerus.com/academy/?keyword=TBC%28timeBaseCorrector%29
Analogue tape signals are rarely perfect for various reasons, e.g. tape stretch. These conditions cause the signal to fall out of spec, a signal that is not in spec is not legal. Some devices may accept signals which fall out of spec, mostly consumer devices. Professional equipment follows professional standards. Just because consumer equipment will make do with illegal signals doesn't make them legal.

Orsetto, I greatly appreciate your input on TBCs. There are a few points I don't agree on though.

any hardware assist will add visible "processing" effects (external "pro" TBCs being the worst offender by far

This is just plain wrong. Professional full-frame TBCs are most certainly not going to be the worst offender for degrading picture quality. Professional TBCs will strive to perform the function they were designed to do while having as little detrimental effect on the rest of the signal as possible. To indicate that they are worse at this than consumer units is just nonsense. I was very dubious about the TBC-1000 from the beginning to be honest.

I also don't believe I will achieve superior quality from combo DVD/VHS units.

I've never really been bothered about recovering head switching noise, but I have indicated that I would like to use a TBC that doesn't accentuate the problem. I also don't intend to use any hardware or software DNR.

[magikarp99]

[*]buy a pro brand full-frame TBC that likely wasn't designed with VHS in mind and hope that it can cope with the line timing (the one I have isn't as good as the DMR-ES15 despite having a mode specifically designed for VHS)

What professional TBC do you have?

[orsetto]

Two points, the tapes I am transferring were produced in studios in similar equipment, these tapes were not produced on consumer devices. My AG-7350 has been serviced and maintained in accordance with the service manual and is in good working condition.

Excellent: that means you have the best possible match of tapes to VCR. Unfortunately, that also means you've maxed out your hardware improvement options and can only go down from here. You've noted you do not want to see any processing artifacts: there are few to no hardware add-ons that will not visibly change your current results in ways that you don't like. As you've said, its a tradeoff, but if you don't like the trade involved its the same as if the option didn't exist. I understand this quite well, being non-plussed with many systems I've used myself.

All I'm looking for is a full-frame TBC that doesn't screw with my lines or take my luma/chroma signals out of spec.

And all we're trying to explain is that none of the currently available options is transparent to the degree you are hoping for. Professional provenance means absolutely nothing when VHS is the source. Exorbitant pricing means nothing for the same reason.

Orsetto, I greatly appreciate your input on TBCs. There are a few points I don't agree on though.

any hardware assist will add visible "processing" effects (external "pro" TBCs being the worst offender by far

This is just plain wrong. Professional full-frame TBCs are most certainly not going to be the worst offender for degrading picture quality. Professional TBCs will strive to perform the function they were designed to do while having as little detrimental effect on the rest of the signal as possible. To indicate that they are worse at this than consumer units is just nonsense. I was very dubious about the TBC-1000 from the beginning to be honest.

You are taking the professional sphere at face value and assuming the same methods can be applied to VHS. Perfectly logical, and perfectly understandable. But many many of us have discovered it doesn't quite work like that. The performance of the pro gear does not scale to VHS effectively, and often makes matters worse. Large professional TBCs have a usable "transparency lifespan" with brevity approaching that of a fruitfly: after a year or two, they crap out unless rebuilt. There is a reason why every single AV forum thread on this topic, around the world, bar none, has recommended the DataVideo TBC-1000 or AVT-8710 variants since 2003: they are (or at least were) noticeably optimized for VHS compared to "pro" studio TBCs. Unfortunately, with the decline in factory quality control, they now suck as badly as a beat-up old Hotronic box, leaving zero alternative. I suppose you could try spending a couple thousand on a brand new studio TBC, theres a chance that might be dramatically more transparent. But no real guarantee, and forget buying a used one. I've had more I.Den, Prime Image, For A and Hotronics delivered to my house than pizzas. None was usable with VHS, all were worse than the DataVideo on a bad day. I would have had more luck plugging the cables into the pizza box.

There ARE some less-traveled options you could try to explore. The original DataVideo "consumer" model was the TBC-100, a PC card that was very well regarded eight years ago. Those who still use them swear they are significantly more transparent than the stand-alone TBC-1000 (which was a botched version). A number of people have created their own housing and power supply for their TBC-100, effectively making it a standalone unit. You might also look into the more modern, compact "Key West" line of pro TBCs. I have not been able to track one down at an affordable price, but friends in Europe/Australia have reported excellent results. I am sure there are others, but finding a model that is both transparent with VHS and costs less than $2000 may not be easy. The point we're all trying to make is don't jump to conclusions about "pro" TBCs: they aren't all they're cracked up to be, and they decay with frightening speed. They like BetaCam or Umatic or Type C but don't play well with VHS.

And of course you could try the "old DVD recorder or camcorder as pass thru TBC" trick mentioned many times here on VH. It can be surprising how well this sometimes works to massage VHS signals into something more smooth and stable. But the "transparency" bugaboo again raises its head: few of these units are transparent: the most effective ones (like Panasonic ES10) add a processed overlay that horrifies perfectionists. Cleaner units, like the old Toshiba DR and XS series, are transparent enough but also ineffective for a lot of tapes. The recent Funai/Magnavox units split the difference, but can require tricky compensation for color and contrast shifts.

I also don't believe I will achieve superior quality from combo DVD/VHS units.

This wasn't a reference to you personally: it was response/agreement to earlier posts suggesting the scope of useful hardware to make VHS encodes that look any better than a WalMart combo deck has dwindled rapidly the past couple years (i.e., worn-out specialty VCRs, dearth of repair techs, rotten TBC quality control, etc.). It is clear from your questions and hardware that you are working at a much higher level than WalMart.

[hech54]

If you want to generate a legal signal you do need a TBC. No VTR will generate a 100% legal signal from an analogue tape unless it has some form of TBC.

What?

http://www.kramerus.com/academy/?keyword=TBC%28timeBaseCorrector%29
Analogue tape signals are rarely perfect for various reasons, e.g. tape stretch. These conditions cause the signal to fall out of spec, a signal that is not in spec is not legal. Some devices may accept signals which fall out of spec, mostly consumer devices. Professional equipment follows professional standards. Just because consumer equipment will make do with illegal signals doesn't make them legal.

Another capturing thread descends into the deepest, darkest realms of absurdity.
Legal?......really?......LEGAL?
You read that somewhere did you?

[Steve(MS)]

magikarp99, not discounting any replies you got here but you may want to study digitalfaq.com as that
is where the professional hangs out.
From what I have read, you probably will need a TBC with your particular capture card(for vhs).

[Brad]

What professional TBC do you have?

DPS-470AV. It also horribly desaturates with VHS input (but is fine with DVD input).

[orsetto]

magikarp99, not discounting any replies you got here but you may want to study digitalfaq.com as that
is where the professional hangs out.
From what I have read, you probably will need a TBC with your particular capture card(for vhs).

Lets say for the sake of argument he does need a TBC, because his particular capture device benefits when connected to one. This still begs the question: what the hell TBC can he buy today that isn't gonna add its own problems to the mix? At the moment, there just isn't anything out there. Sending him over to DigitalFAQ will give him additional perspective, and perhaps a few more alternatives to look into. But LordSmurf himself usually recommends the AVT-8710, which is now crap on toast if bought new and a total coin toss on the used market. With the old pro rackmount TBCs out of the running for similar reasons (lack of transparent operation), choices are down to nothing unless he runs into a personal friend with a known-good TBC for sale that he can test before buying.

[2Bdecided]

If you're a perfectionist, you need a line TBC before anything else messes with the sync pulses. Otherwise you might as well use the worst capture device out there.

Why is this the case? My VCR can produce a very stable image from some tapes without a line TBC. Unless lines need to be resynchronised I would have thought using a line TBC would be a bad thing, as it is another step of lossy processing.

I didn't say everyone needs a line TBC. I said a perfectionist does. Maybe your tapes really don't need a line TBC. However, I've seen plenty of tapes which, on the face of it, don't appear to need a line TBC - yet they still look better with one. The effect is more dramatic on a less forgiving capture devices. A perfectionist wouldn't dream of discounting this possibility without trying it. No perfectionist would miss the chance to see if they could do better.


I think you may be mistaken in using a "perfect" capture device to capture VHS. What matters is the end result. If some other combination of equipment gives a better result from VHS, then it's better for that job. The fact that you can capture a perfect source perfectly is irrelevant to the job in hand.

With the right TBC, you may well have the best set-up possible for your tapes. I couldn't possibly know.

Cheers,
David.

[magikarp99]

Another capturing thread descends into the deepest, darkest realms of absurdity.
Legal?......really?......LEGAL?
You read that somewhere did you?

Of course I read that somewhere, is there a problem with reading things? I'm not just accepting everything at face value. I hope you realise that when I say that a signal is legal, I mean that it is fully abiding of the specifications it is to adhere to. Legal of course, does not mean that it abiding by the legislation of some country. My signal must be legal so that my capture card doesn't drop the signal. If you don't have anything to contribute, please stop posting to this thread.

magikarp99, not discounting any replies you got here but you may want to study digitalfaq.com as that
is where the professional hangs out.
From what I have read, you probably will need a TBC with your particular capture card(for vhs).

Thanks for the input, but I already understand that I will need a TBC with my capture card.

I didn't say everyone needs a line TBC. I said a perfectionist does. Maybe your tapes really don't need a line TBC. However, I've seen plenty of tapes which, on the face of it, don't appear to need a line TBC - yet they still look better with one. The effect is more dramatic on a less forgiving capture devices. A perfectionist wouldn't dream of discounting this possibility without trying it. No perfectionist would miss the chance to see if they could do better.

Supposing that this is the case, what line TBC would I use? At the moment I am at a loss with full-frame TBCs, it seems to be the case that they all distort the signal in some manner. Adding another step in which this happens would degrade my signal further, and doesn't seem worthwhile on tapes that don't appear to need it. But if you know of a good line TBC, please do recommend one.

I think you may be mistaken in using a "perfect" capture device to capture VHS. What matters is the end result. If some other combination of equipment gives a better result from VHS, then it's better for that job. The fact that you can capture a perfect source perfectly is irrelevant to the job in hand.

When calibrating any device it is imperative that a perfect or reference source material is used. If I input reference colour bars into my capture card, and my capture does not get these correct then adjustments clearly need to be made. If I can't accurately replicate a source that I know as a standard, then how can I hope to accurately replicate any source? I understand what you are saying though, that VHS is an imperfect source and that many tapes were recorded on decks that were unaligned or required some mechanical or electrical adjustments. But these are all attempting to adhere to these standards, short of recalibrating my deck to suit each tape (which is a difficult task), calibrating to the standard is the best solution. If the video signal is clearly way off on a tape, e.g. there is a luma offset, then this can be corrected post capture.

You are taking the professional sphere at face value and assuming the same methods can be applied to VHS. Perfectly logical, and perfectly understandable. But many many of us have discovered it doesn't quite work like that. The performance of the pro gear does not scale to VHS effectively, and often makes matters worse. Large professional TBCs have a usable "transparency lifespan" with brevity approaching that of a fruitfly: after a year or two, they crap out unless rebuilt.

I greatly appreciate all your input. Assuming that a professional TBC is in perfect working order, why would it be unsuited to VHS?

You might also look into the more modern, compact "Key West" line of pro TBCs. I have not been able to track one down at an affordable price, but friends in Europe/Australia have reported excellent results.

I may be able to get one of these.

[2Bdecided]

Supposing that this is the case, what line TBC would I use?

Given your existing VCR seems a good fit for your tapes, I can only think of consumer devices you can loop the signal through. An ES10 or similar is the obvious choice. Should be apparent pretty quickly whether it's helping or hindering. I can hear lordsmurf choking on his coffee right now.

When calibrating any device it is imperative that a perfect or reference source material is used. If I input reference colour bars into my capture card, and my capture does not get these correct then adjustments clearly need to be made. If I can't accurately replicate a source that I know as a standard, then how can I hope to accurately replicate any source? I understand what you are saying though, that VHS is an imperfect source and that many tapes were recorded on decks that were unaligned or required some mechanical or electrical adjustments. But these are all attempting to adhere to these standards, short of recalibrating my deck to suit each tape (which is a difficult task), calibrating to the standard is the best solution. If the video signal is clearly way off on a tape, e.g. there is a luma offset, then this can be corrected post capture.

If you have VHS tapes with valid+relevant-to-the-source bars and tone on them, that's wonderful. Even so, you'd adjust the capture levels to match those, not nominally correct voltage levels. Without them, you just have to aim for correct levels and absolutely avoid clipping. If the levels clip, you can't correct them post capture.

It sounds like you may be working with professional recordings, in which case you can hope someone aimed for correct levels. Consumer camcorders (analogue ones, digital ones, HD ones) intentionally record levels that are too high.

Cheers,
David.

[Brad]

Assuming that a professional TBC is in perfect working order, why would it be unsuited to VHS?

Pros don't deal often with VHS in production of course, and it requires additional engineering to handle the more extreme timing variations. The default mode of the DPS-470AV leaves a bent picture with VHS sources. The Extreme Head Switch mode mostly corrects this but the top of the image is still bent, while I have three DVD recorders now that straighten the signal just fine.

Similar to how your Intensity Pro can't capture low def video signals (240p video game systems) while consumer TVs have never had a problem with them, and some $10 capture sticks accept them without issue.

[SixFiftyThree]

Some points I want to bring up for the OP:

1. A line TBC provides the most significant improvement for your footage. All VHS is unstable in this regard and should be corrected - and isn't something that can be done in post. As happy as you are with your BMI, it does not include any correction of this nature. As you've already been advised, passthrough using certain DVD recorder models is the recommended solution today, and will also provide frame sync for further stabilisation.

2. Wherever you heard it or read it, you have misunderstood the topic of ''legal" and its relation to TBCs. Tape instability does not make a video illegal, unless we are specifically referring to 'legal' video levels as used in broadcasting. Traditionally, all standalone TBCs included proc amps that would be set to ensure that levels did not breach spec. Other quality factors are irrelevant in this context.

3. I think you have the wrong approach to this conversion - though it is a common mistake. Basically, no "perfect" conversion is really possible, and neither should it be desired. Line timing, levels, colour, noise etc. all need attention. Thus, do not get obsessed about retaining fidelity because VHS is a) never right to begin with and b) demands editing for final output.

4. It is simply too difficult to perfectly calibrate a tape during capture - just ensure that your levels aren't clipping across the board, and adjust the rest in post. Trying to do otherwise will send you mad because VHS always fluctuates. There are some good DVD recorders, and other devices, that do a nice job of stabilising levels, but for the highest quality you'll have to adjust them yourself.

5. As a general rule, avoid seeking out pro or expensive hardware - very often you'll find that it's the affordable, somewhat obscure devices that do the best job. Sometimes they just need a workaround of some sort. And if it doesn't work out, or breaks down, at least you didn't pay much and it's more easily replaceable.

You have already run into a problem with choosing the BMI for capture - it expects a broadcast quality signal for which a full frame TBC is required. A much cheaper but good USB TV stick eg. ATI-600 makes no such demands. Pair that with an equally cheap DMR-ES10 or similar and you're well on your way to quality captures. Kind of puts things in perspective doesn't it?

6. Always remember you are capturing a crappy consumer format - never intended for pro use. Choose your methods appropriately.

Anyway, you have received advice here from some of VH's most knowledgeable members on this topic. Orsetto in particular is unrivalled in his knowledge of hardware. I would definitely follow their advice.

[magikarp99]

Pros don't deal often with VHS in production of course, and it requires additional engineering to handle the more extreme timing variations. The default mode of the DPS-470AV leaves a bent picture with VHS sources. The Extreme Head Switch mode mostly corrects this but the top of the image is still bent, while I have three DVD recorders now that straighten the signal just fine.

You give an example of a tape that is clearly in bad condition, giving a bent picture. These kinds of issues are not present in any of my tapes. Does the DPS-470AV still perform poorly with good tapes? I'm not looking to recover dying tapes, just to restore the sync pulse in good ones.

Some points I want to bring up for the OP:

1. A line TBC provides the most significant improvement for your footage. All VHS is unstable in this regard and should be corrected - and isn't something that can be done in post. As happy as you are with your BMI, it does not include any correction of this nature. As you've already been advised, passthrough using certain DVD recorder models is the recommended solution today, and will also provide frame sync for further stabilisation.

So even with a stable image, where lines are correctly aligned, a line TBC will provide benefit? How exactly? I don't doubt it, but I would like to know what feature of line TBCs I am missing.

2. Wherever you heard it or read it, you have misunderstood the topic of ''legal" and its relation to TBCs. Tape instability does not make a video illegal, unless we are specifically referring to 'legal' video levels as used in broadcasting. Traditionally, all standalone TBCs included proc amps that would be set to ensure that levels did not breach spec. Other quality factors are irrelevant in this context.

A legal video signal is synchronised to the appropriate rate for PAL or NTSC. A full-frame TBC is required when this rate falls out of sync. Or is this wrong?

3. I think you have the wrong approach to this conversion - though it is a common mistake. Basically, no "perfect" conversion is really possible, and neither should it be desired. Line timing, levels, colour, noise etc. all need attention. Thus, do not get obsessed about retaining fidelity because VHS is a) never right to begin with and b) demands editing for final output.

I have never stated that I am aiming for a perfect conversion, all attempts are best effort. I am paying attention to levels, noise, etc. as you say. But as has been said many times before, it is important to get your signal as good as possible before capturing. Garbage in, garbage out.

4. It is simply too difficult to perfectly calibrate a tape during capture - just ensure that your levels aren't clipping across the board, and adjust the rest in post. Trying to do otherwise will send you mad because VHS always fluctuates. There are some good DVD recorders, and other devices, that do a nice job of stabilising levels, but for the highest quality you'll have to adjust them yourself.

My VTR is correctly calibrated and levels from the majority of my tapes do not clip on output. Playback of an alignment tape also verifies that my levels are in spec. Running it through the TBC-1000 alters the levels, I guess one of the main issues it has is that it has no proc amp functionality.

5. As a general rule, avoid seeking out pro or expensive hardware - very often you'll find that it's the affordable, somewhat obscure devices that do the best job. Sometimes they just need a workaround of some sort. And if it doesn't work out, or breaks down, at least you didn't pay much and it's more easily replaceable.

I disagree, consumer hardware designed for VHS is never going to be better than professional hardware designed for VHS. It may not be a format that was adopted in industry, but equipment exists. It seems the issue as has been indicated by others is that such equipment requires frequent servicing. Perhaps consumer units designed to stabilise decaying supermarket tapes are better adjusted for those situations, but they certainly aren't designed with accuracy in mind.

You have already run into a problem with choosing the BMI for capture - it expects a broadcast quality signal for which a full frame TBC is required. A much cheaper but good USB TV stick eg. ATI-600 makes no such demands. Pair that with an equally cheap DMR-ES10 or similar and you're well on your way to quality captures. Kind of puts things in perspective doesn't it?

I knew exactly what the BMI was going to be like before I bought it, and have run into no problems due to its use. I would be greatly surprised to find that a unit like the ATI produces better results.

6. Always remember you are capturing a crappy consumer format - never intended for pro use. Choose your methods appropriately.

So? Are you saying that because it is a bad format, it doesn't matter if we degrade the signal? What is your point here?

Anyway, you have received advice here from some of VH's most knowledgeable members on this topic. Orsetto in particular is unrivalled in his knowledge of hardware. I would definitely follow their advice.

I am very grateful for it. There has been some excellent input from orsetto, vaporeon800, sanlyn and 2Bdecided. I really appreciate it.

[magikarp99]

Given your existing VCR seems a good fit for your tapes, I can only think of consumer devices you can loop the signal through. An ES10 or similar is the obvious choice. Should be apparent pretty quickly whether it's helping or hindering. I can hear lordsmurf choking on his coffee right now.

I will look into this, thanks.

If you have VHS tapes with valid+relevant-to-the-source bars and tone on them, that's wonderful. Even so, you'd adjust the capture levels to match those, not nominally correct voltage levels. Without them, you just have to aim for correct levels and absolutely avoid clipping. If the levels clip, you can't correct them post capture.

It sounds like you may be working with professional recordings, in which case you can hope someone aimed for correct levels. Consumer camcorders (analogue ones, digital ones, HD ones) intentionally record levels that are too high.

This is my exact issue, the TBC-1000 is causing my levels to clip, whereas if I skip the TBC-1000 then my levels are correct.

[jagabo]

You give an example of a tape that is clearly in bad condition, giving a bent picture. These kinds of issues are not present in any of my tapes.

Every VHS recording has line jitter and every VHS player produces more line jitter. Your BMIP can't fix that, only a line TBC can.

https://forum.videohelp.com/threads/319420-Who-uses-a-DVD-recorder-as-a-line-TBC-and-wh...=1#post1983288
https://forum.videohelp.com/threads/305506-Hauppauge-HD-PVR-USB-questions?p=1876983&vie...=1#post1876983

Even if you don't care about seeing that jitter, if you are encoding with MPEG 2, AVC, or similar, it eats up bitrate. It can easily require twice as much bitrate to encode a jittery video vs a non-jittery video.

[hech54]

Another capturing thread descends into the deepest, darkest realms of absurdity.
Legal?......really?......LEGAL?
You read that somewhere did you?

Of course I read that somewhere, is there a problem with reading things? I'm not just accepting everything at face value. I hope you realise that when I say that a signal is legal, I mean that it is fully abiding of the specifications it is to adhere to. Legal of course, does not mean that it abiding by the legislation of some country. My signal must be legal so that my capture card doesn't drop the signal. If you don't have anything to contribute, please stop posting to this thread.

NTSC tape captured with a PAL VCR(Panasonic NV-HD620...SCART to S-Video cable) as PAL60 captured with modified WinTV software and a Hauppauge PVR-350 capture card.....no TBC of any kind.
It sounds to me like you ARE accepting(at face value) that any good VHS capture requires a TBC of some sort....hence the title of this thread. Does this look "legal" to you? (30MB)
https://mega.co.nz/#!BdRWjYgC!w0IWDjcp0nW9JQuxc9kwWQA1PQdox9Dl3oRxkQM-18Q

Complete name : G:\commercial.mpg
Format : MPEG-PS
File size : 30.1 MiB
Duration : 29s 730ms
Overall bit rate : 8 495 Kbps

Video
ID : 224 (0xE0)
Format : MPEG Video
Format version : Version 2
Format profile : Main@Main
Format settings, BVOP : Yes
Format settings, Matrix : Default
Duration : 29s 730ms
Bit rate mode : Variable
Bit rate : 8 500 Kbps
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate : 29.970 fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First
Bits/(Pixel*Frame) : 0.821
Stream size : 28.8 MiB (96%)

Audio
ID : 192 (0xC0)
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 2
Duration : 29s 712ms
Bit rate mode : Constant
Bit rate : 192 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Video delay : -33ms
Stream size : 696 KiB (2%)

[magikarp99]

NTSC tape captured with a PAL VCR(Panasonic NV-HD620...SCART to S-Video cable) as PAL60 captured with modified WinTV software and a Hauppauge PVR-350 capture card.....no TBC of any kind.
It sounds to me like you ARE accepting(at face value) that any good VHS capture requires a TBC of some sort....hence the title of this thread. Does this look "legal" to you? (30MB)
https://mega.co.nz/#!BdRWjYgC!w0IWDjcp0nW9JQuxc9kwWQA1PQdox9Dl3oRxkQM-18Q

Your PVR-350 essentially has a TBC built into it. The Blackmagic does not.

A quote from the Blackmagic forums: http://forum.blackmagicdesign.com/viewtopic.php?f=10&t=168

With VHS tapes, you may look into renting or acquiring a TBC to compensate for the imperfections in the older medium. Else if the signal may drop if it falls out of spec and you'll experience black frames within your recordings. TBC's are relatively inexpensive to rent and come in a variety of options depending on what your needs are.

[SixFiftyThree]

Judging from some of what you have said, you are more the exception than the rule. If the tapes and deck are indeed up to the quality you say they are, consider yourself lucky. It's a pretty rare circumstance.

There's really not much to say that hasn't been already. You may think otherwise, but I assure you line correction will improve your footage and, as Jagabo pointed out, your final encode. At the very least, the DVD recorder passthrough option will also provide frame sync which is what you are after. It should do so with more transparency than the Datavideo, which seems to have some QC issues these days.

Some other things to address -

A legal video signal is synchronised to the appropriate rate for PAL or NTSC. A full-frame TBC is required when this rate falls out of sync. Or is this wrong?

To my knowledge, a 'legal' signal simply refers to legal video levels AKA broadcast-safe levels. It is still a requirement for all digital video, be it SD or HD and any frame rate. I don't know it to be synonymous with analog specs, but yes, TBCs were needed to ensure stabilised signals in analog broadcasting.

it is important to get your signal as good as possible before capturing. Garbage in, garbage out.

Indeed, but there's only so much you can - or rather, should do. S/w provides better options for the majority of restoration these days. The only things you really need to do are, again, provide line correction, ideally frame sync, and ensure levels aren't clipping across the tape. What they all have in common is that they cannot be performed post capture - everything else you can do at your leisure.

By avoiding the use of h/w proc amps, detailers etc. you also get to avoid the degradation caused by multiple A/D conversions. As long as you're not capturing to a highly compressed format like DVD-spec MPEG2, noise is also a non-issue that can be much better resolved in software. Particularly if you're capturing losslessly.

I disagree, consumer hardware designed for VHS is never going to be better than professional hardware designed for VHS.

Not true. Pro hardware is neither designed nor suited for typical consumer tapes - but again you may be the exception here. For 9/10 people I advise stay the hell away from anything pro. If you search the threads for pro decks and the like here, you will see the kind of shitty experiences people have with them.

I would be greatly surprised to find that a unit like the ATI produces better results.

Are you saying that because it is a bad format, it doesn't matter if we degrade the signal? What is your point here?

I'm putting these quotes together because they have the same answer.

Long answer -
Which is you use the tools appropriate for the job. VHS is the lowest of consumer analog formats, and its entire bandwidth can be easily captured by cheap consumer devices - no need for even the quite affordable BMI, which is a) better suited for broadcast analog formats and b) actually designed for HD, with analog functionality as an afterthought.

Simply put, as long as you're capturing to either a lossless or high bitrate intermediate, and your capture device is playing nice with your tapes eg. not AGCing the hell out of them or dropping frames, you won't be doing much if any degrading. Most of the hard work you'll face in s/w, and by the time you get to encoding, the videos will likely look very different to what they were - and better for it.

Short answer -
Yes, the ATI-600 is better suited for VHS capture as it does not demand a precise signal. Quality should be about on par despite lacking chroma resolution, since VHS has barely any to begin with. At final encoding stage, you won't tell the difference.

[hech54]

NTSC tape captured with a PAL VCR(Panasonic NV-HD620...SCART to S-Video cable) as PAL60 captured with modified WinTV software and a Hauppauge PVR-350 capture card.....no TBC of any kind.
It sounds to me like you ARE accepting(at face value) that any good VHS capture requires a TBC of some sort....hence the title of this thread. Does this look "legal" to you? (30MB)
https://mega.co.nz/#!BdRWjYgC!w0IWDjcp0nW9JQuxc9kwWQA1PQdox9Dl3oRxkQM-18Q

Your PVR-350 essentially has a TBC built into it.

Absolutely untrue.

[L-Train]

Hi magikarp,

I recently picked up a Blackmagic Intensity Pro to capture a few VHS tapes, and soon after I also picked up a Panasonic ES10 DVD recorder once I discovered most of my tapes needed a TBC. The ES10 is connected to the Intensity Pro via component cables. The S-VHS deck I'm using is a JVC HR-S9600U. A few observations about this setup:

- The Intensity Pro cannot lock onto the JVC's menu screens (it shows up as a black screen), inserting the ES10 as a passthrough fixes the issue as well as any dropped frames I was getting when capturing VHS from the S9600 directly
- To me, the ES10's line TBC is subjectively almost as good as the JVC's internal line TBC, if not indistinguishable from it
- There are no MPEG compression artifacts when using the ES10 as a passthrough, and when the ES10's "Line In NR" setting is set to "off" I can't detect any smearing or loss of visual quality
- Connecting a Pioneer DV-343 DVD player to the ES10 as a passthrough via s-video, I compared a capture of the Digital Video Essentials NTSC DVD to a digital rip of the same disc, and found that:
1) The ES10 scaler isn't the greatest as it has minor horizontal scaling artifacts that are detectable via test patterns, but it is not visible when capturing VHS
2) The ES10 has very good color accuracy when comparing the raw YUV values via Avisynth's ColorYUV(analyze=true) function

If you want me to test anything with this setup for you, please let me know.

[Brad]

Pros don't deal often with VHS in production of course, and it requires additional engineering to handle the more extreme timing variations. The default mode of the DPS-470AV leaves a bent picture with VHS sources. The Extreme Head Switch mode mostly corrects this but the top of the image is still bent, while I have three DVD recorders now that straighten the signal just fine.

You give an example of a tape that is clearly in bad condition, giving a bent picture.

Alright then, if you know more about my tapes than I do then I guess there's nothing more to say.

[jmac698]

hech54:
>Absolutely untrue.

Capture cards do have a virtual line-tbc function.
"Ultralock technology that locks to an incoming analog video signal. Ultralock is able to recognize unstable video signals caused by VCR headswitches..." - Connexant Fusion 878 Video Decoder http://www.conexant.com/supportdocs/techdocs/Technical%20Documents/PBR-200097-001_CX25834.pdf

I say virtual because they don't output a stable analog signal again, they just sync it digitally for the purpose of capture.

There's no reason why you couldn't just program a capture card to fully act like a TBC. Some of the chips allow nearly unrestricted raw digitization, and you could write a program to do the TBC. I have such a board, and a Linux driver to dump raw video frames. I even have programs to interpret raw data, and do that special PAL decoding they used on Dr. Who, which removes most color cross-talk. So the pieces are all there. My only problem is getting an older version of Linux to run on my computer

Legal Values
The luma and colors levels get added into a composite signal, and bad levels can cause that signal to have excessive voltage, which would lead to distortion in the RF amplifier, and cause interference from the TV station. That was originally. Now we have x.v.color, and modern devices can accept 0-255 values (but don't do that in this case)

A solution to the TBC causing hot levels, is to use yet another gadget called a proc amp. Really, you could even put together a cable with a variable resistor

I should also note that some cards/drivers will happily record levels all the way up to 255 (compared to the "legal" 235), and you *can* turn that down post-processing with no loss. There is a slight difference, due to non-linearity in the ADC (I've measured some to be "bowed" in the middle range).

I'd do a simple test with hot values and read the YUV values in AvsP to see if it passes >235.

[Steve(MS)]

This still begs the question: what the hell TBC can he buy today that isn't gonna add its own problems to the mix? At the moment, there just isn't anything out there. Sending him over to DigitalFAQ will give him additional perspective, and perhaps a few more alternatives to look into. But LordSmurf himself usually recommends the AVT-8710, which is now crap on toast if bought new and a total coin toss on the used market. With the old pro rackmount TBCs out of the running for similar reasons (lack of transparent operation), choices are down to nothing unless he runs into a personal friend with a known-good TBC for sale that he can test before buying.

I dunno yet why would anyone wait till 2014 then buy a BMI to transfer vhs, not knowing that particular card needs bigtime TBC because it doesn't like the chaotic signal from vhs?

Yet there are many that will still spend mucho $$ on vhs transfers...which is incredible in itself (not including many hours of learning how to do the transfers).

[hech54]

hech54:
>Absolutely untrue.

Capture cards do have a virtual line-tbc function.
"Ultralock technology that locks to an incoming analog video signal. Ultralock is able to recognize unstable video signals caused by VCR headswitches..." - Connexant Fusion 878 Video Decoder http://www.conexant.com/supportdocs/techdocs/Technical%20Documents/PBR-200097-001_CX25834.pdf

UltraLock simply meant that no matter what the screen was doing....capture would not stop. It recorded whatever came across....even a blank, black screen. That was an often-asked question "back in the day".
My Philips VR-1100 has TBC and selectable noise reduction. The TBC is an on/off button. It is an on/off button because I can, and have turned it off because it did more harm than good on several VHS captures with both my PVR-350 and my USB Live2 devices.
Oh I have noticed improvements with Philips/JVC rudimentary TBC turned on....especially with text on the screen you can see an improvement, but then 98% of my captures are old VHS concert videos and music videos.
The moral of the story is that TBCs have on/off buttons/switches for a reason. They are not the 1000% "cure-er of all things video"....and not a must-have item.
Beauty is in the eye of the beholder, and a fool and his money are soon parted.

[Brad]

Really, you could even put together a cable with a variable resistor

I was wondering about that. I once passed a composite signal from one VCR to the outputs of another one, successfully bringing down the levels.

[jmac698]

Yep it works to a point, if you turn it down too much, the sync signals are too weak to pick up. I saw very little difference actually, because the tv I was watching it on seemed to auto normalize the levels.

[SixFiftyThree]

The moral of the story is that TBCs have on/off buttons/switches for a reason. They are not the 1000% "cure-er of all things video"....and not a must-have item.

They can have their quirks, true. Or in the case of JVC TBC, the linked DNR may not be appealing. But in my experience it almost always helps, and so is best left on unless it specifically causes problems. For those looking to improve their footage, it may not be the curer of all things video but it's the easiest correction they can do.

For those happy without, well that's fine. But this is the restoration forum...

Beauty is in the eye of the beholder, and a fool and his money are soon parted.

Yet ironically, a DVD recorder with line TBC is far less expensive than your Philips JVC clone - which is expensive precisely because of its TBC. If you're rarely using that feature, you may as well have just chosen a different, more affordable VCR.

[magikarp99]

There's no reason why you couldn't just program a capture card to fully act like a TBC. Some of the chips allow nearly unrestricted raw digitization, and you could write a program to do the TBC. I have such a board, and a Linux driver to dump raw video frames. I even have programs to interpret raw data, and do that special PAL decoding they used on Dr. Who, which removes most color cross-talk. So the pieces are all there. My only problem is getting an older version of Linux to run on my computer

Have you tried running the older version in a VM, and using PCI or USB passthrough to give control over your capture device?

A solution to the TBC causing hot levels, is to use yet another gadget called a proc amp. Really, you could even put together a cable with a variable resistor

I think this may be the best solution, as it sounds like I may just run into the same problems with other TBCs.

I should also note that some cards/drivers will happily record levels all the way up to 255 (compared to the "legal" 235), and you *can* turn that down post-processing with no loss. There is a slight difference, due to non-linearity in the ADC (I've measured some to be "bowed" in the middle range).

The BMI is one of these cards that will capture up to 255, but the Datavideo pushes the luma signal just beyond even that.

I dunno yet why would anyone wait till 2014 then buy a BMI to transfer vhs, not knowing that particular card needs bigtime TBC because it doesn't like the chaotic signal from vhs?

Yet there are many that will still spend mucho $$ on vhs transfers...which is incredible in itself (not including many hours of learning how to do the transfers).

As was mentioned previously when someone brought this up, I have not waited until 2014 to do this, but have only recently acquired these tapes. I knew the BMI would need a TBC, I just didn't realise TBCs were so inconsistent, the TBC-1000 had received a lot of praise. Besides, I didn't buy the BMI to just capture VHS. As to why people spend time and money on this, this can be a learning experience and a hobby.

Pros don't deal often with VHS in production of course, and it requires additional engineering to handle the more extreme timing variations. The default mode of the DPS-470AV leaves a bent picture with VHS sources. The Extreme Head Switch mode mostly corrects this but the top of the image is still bent, while I have three DVD recorders now that straighten the signal just fine.

You give an example of a tape that is clearly in bad condition, giving a bent picture.

Alright then, if you know more about my tapes than I do then I guess there's nothing more to say.

Sorry if I misinterpreted what you said, at first read it sounded like the DPS-470AV was causing the bending in the image, but then you went on to say that you "have three DVD recorders now that straighten the signal just fine", indicating the image was bent before the DPS-470AV and required fixing. Was I wrong?

[2Bdecided]

A solution to the TBC causing hot levels, is to use yet another gadget called a proc amp. Really, you could even put together a cable with a variable resistor

I know you put a smiley, but really, don't do that. It reduces the level of the video signal and the sync signals in tandem. Many capture devices will AGC the signal relative to the level of the sync signal it finds. Adding a resistor will have zero effect with such capture devices - they'll just boost it again.


btw, I think black magic may be being a bit disingenuous about what constitutes a legal signal. What they mean is that their device expects a near-perfect signal in one of a very few specific formats, and cannot cope with any timing irregularities for format differences.

Consider this: the use of genlocking when switching between video sources introduced far worse timing irregularities into real ("legal!") broadcast video throughout the all-analogue broadcast era. ITU-R BT.470-6 (the international standard for 50Hz video) flags some already fairly wide tolerances as not applying during Genlock. In the UK, the number of lines in a field was allowed to vary by +/-3 during genlocking (I am not making this up - I read this in the IBA rulebook) and TVs were simply expected to cope with this.

I bet your BMI card won't.

Cheers,
David.