You don't need a TBC in 2023

[Alwyn]

So after buying an S-VHS player with TBC as directed here, I find this other thread with lordsmurf saying it should be turned off if you have an external TBC. Huh?

Normally, leave the the DVD Recorder/stabiliser out of workflow: SVHS VCR with inbuilt line TBC ON> Frame TBC > Digitiser.

If the tearing is so bad the VCR TBC can't correct it, turn VCR TBC Off > DVD Recorder > Frame TBC > Digitiser.

[Bwaak]

No, Playing back a VHS tape in a S-VHS machine has Absolutely nothing to do with the S-VHS mode, It has everything to do with how the luma and chroma (Y-C) signals get processed

Sure, but where have I claimed the opposite? The 60% improvement Marshalleq mentioned is recording in SVHS-ET mode, the improvement depends on how close the regular VHS tape to SVHS tape.

[dellsam34]

No, he was mentioning the improvement if a S-VHS machine with line TBC and S-Video out is used vs a low end composite machine with no line TBC (not the composite out of the same high end machine) encoded to DV, The acronym S-VHS here describing the type of a high tier machine not the S-VHS recording mode which where your confusion lies. Tapes have been already recorded in VHS, he can't go back in time and re-record them in S-VHS.

[Bwaak]

No, he was mentioning the improvement if a S-VHS machine with line TBC and S-Video out is used vs a low end composite machine with no line TBC (not the composite out of the same high end machine) encoded to DV, The acronym S-VHS here describing the type of a high tier machine not the S-VHS recording mode which where your confusion lies. Tapes have been already recorded in VHS, he can't go back in time and re-record them in S-VHS.

Where did he mention that SVHS/TBC configuration gives 60% improvement over VHS/no-TBC for playing back the same VHS tape?

And while we are at it, can you explain what do you mean by saying:

A frame TBC supposed to be transparent, it has no bearing on the visual quality

Any device inserted in the analog signal chain modifies the signal one way or another, usually in digital domain, which necessitates usage of A/D and D/A converters. The signal that comes out of any of these boxes is not the same as the input signal, which is the whole point of using them in the first place.

Unless you are suggesting to handle sync pulses digitally, while passing analog line signal through without digitizing, I guess this should be possible with line delay, PAL devices used something like this for color. I wonder whether such devices have been made for time base correction purposes. Then again, if a line a too long, it would not fit between sync pulses, so even in this case it would involve either duration or velocity manipulation, if only in analog domain, so will still will not be transparent.

[lollo]

Any device inserted in the analog signal chain modifies the signal one way or another, usually in digital domain, which necessitates usage of A/D and D/A converters.

Correct. But dellsam34 is using (among others) a BrightEye75 capture device, having internally a (frame)TBC. One of its advantage is that it avoids the usage of an external device with unnecessary conversions (but the penalty is not that big otherwise)

[Bwaak]

Any device inserted in the analog signal chain modifies the signal one way or another, usually in digital domain, which necessitates usage of A/D and D/A converters.

Correct. But dellsam34 is using (among others) a BrightEye75 capture device, having internally a (frame)TBC. One of its advantage is that it avoids the usage of an external device with unnecessary conversions (but the penalty is not that big otherwise)

Why are you mentioning external devices? Please, explain what is frame TBC, and how it avoiding "the usage of an external device with unnecessary conversions" prevents from conversions in the "frame TBC" itself? I agree that the penalty is not that big, but there is no full transparency, the signal is always being changed, unless there is another meaning for transparency.

BTW, this is why I laugh when someone brags about using a fancy 12-bit 4:4:4 digitizing card with an 8-bit 4:2:2 TBC inserted earlier in the chain.

[dellsam34]

To understand the full scope of the supposed 60% figure read posts #2 and #7.

You've been in the forum for quite some time and you should know by now what a frame TBC does, Yes it digitizes the signal and converts it back to analog but unless it is defective it should not change the visual properties of the image, just the frame timing. Off course converting any analog signal to digital or vise versa results in a slight loss due to dithering, But this is not the loss we are talking about here. Frame TBC's should be avoided whenever possible but sometimes they are necessary.

[Bwaak]

To understand the full scope of the supposed 60% figure read posts #2 and #7.

Post #2 is yours, post #7 is where he acknowledges post #2.

Further in the thread, he wrote:

But interestingly even on the S-VHS boxes they advertise a 60% quality improvement for standard VHS tapes. That sounds good doesn't it.

And this is what I replied to. These are different 60%:

Super VHS ET (Expansion Technology)*

A new innovation that puts higher quality within everybody's reach, this advanced function lets you record Super VHS signals on the more widely available VHS tapes**, so you can enjoy +60% better picture quality at the touch of a button.

* Only SP mode recording and playback is available for Super VHS ET.
** JVC's EHG (Extra High Grade) tapes recommended. There are some S-VHS VCR models by JVC and other manufacturers with which playback of an S-VHS ET recorded tape is not possible.

Regarding Frame TBC,

You've been in the forum for quite some time and you should know by now what a frame TBC does

Not really, because no one gave me the definition, and because this is not an industry-standard term, I could not find it online. I have my own conjecture of what it might be, but this is just an educated guess, I want to hear from the horse's mouth I can see a hint to what it does in you saying, "an external frame TBC helps them by providing them with a clean frame timing (a.k.a VBI, Vertical Blanking Intervals)."

Now, what do they call a device that restores V-Sync timing? What it might be? Bueller? Bueller?

Yes it digitizes the signal and converts it back to analog but unless it is defective it should not change the visual properties of the image, just the frame timing.

Are you saying that "frame TBC" restores V-Sync timing without effect on visible line signal whatsoever?

[lollo]

Why are you mentioning external devices?

Because few high-end capture cards have internal TBC and do not need an external device.

Have a look to dellsam34 YouTube channel workflow description at https://www.youtube.com/watch?v=FJRGUdOrrIw&t=993s : S-VHS Hi-Fi Stereo, Captured using: JVC HR-S7600AM (Line TBC/DNR On) -- BrightEye 75 Capture Device (Frame TBC/Sync On)

But he can explain better than me...

My workflow is similar, but I do not use the frame TBC because my tapes do not need it (and use a simple Hauppauge USB-Live 2)

Please, explain what is frame TBC

I won't enter in this game again

[Bwaak]

Please, explain what is frame TBC

I won't enter in this game again

So, you will continue using the term that you cannot explain, while yourself not using a device described with the term? One may wonder, does this strengthen comments like, "The folks at digitalfaq.com and videohelp.com have batshit crazy methods for capturing VHS."

[lollo]

"The folks at digitalfaq.com and videohelp.com have batshit crazy methods for capturing VHS."

Look at the results, instead of repeating comments from idiots.

[Marshalleq]

Only if used with a DVD recorder in passthrough, You miss read that post.

Excellent, thank you that is good news

[Marshalleq]

But as I understand it, the older eighties units used some kind of line based system and some of the newer ones used a different, maybe it was wave based system.

I did all my videoing in the 80s with a shoulder-carried full-size VHS recorder. No problems at all processing those tapes today with the standard VCR-ES15-(Frame TBC)-digitiser workflow.

Nice, yeah it was the go to thing back then. Some of ours are taken in Australia too - back then I was probably about 12 lol.

[Marshalleq]

So after buying an S-VHS player with TBC as directed here, I find this other thread with lordsmurf saying it should be turned off if you have an external TBC. Huh?

Normally, leave the the DVD Recorder/stabiliser out of workflow: SVHS VCR with inbuilt line TBC ON> Frame TBC > Digitiser.

If the tearing is so bad the VCR TBC can't correct it, turn VCR TBC Off > DVD Recorder > Frame TBC > Digitiser.

Thanks, I don't think mine is that bad - what I'm excited about is I feel like there might be one unreadable tape, which looked like some kind of alignment error, it all went black and white and such - so for this one I have some hope that we can get it back.

[Marshalleq]

@Bwaak I'm sorry that my thread has caused a disagreement, it's probably my fault for mixing topics quite a bit, largely due to my misunderstandings. I am also still searching for definitions of Frame TBC and TBC(ish) etc. I have however been watching videos and reading and starting to get a sense of it.

I'm not sure, but I think the TBC in the VCR, which I think is typically a line one - though I've heard later VCR's had a different type, might be sort of more head alignment related / tape sync type issues. The Frame one - which I think is external, I think covers dropouts and things that the VCR hasn't been able to fix. I've seen evidence that these external TBC's can replace lines in frames and even whole frames - something akin to a content aware fill in photoshop but based on it's memory of previous frames and perhaps future frames due to a buffer.

I am still learning, but getting there, very exciting.

[Alwyn]

@Bwaak I'm sorry that my thread has caused a disagreement

Don't apologise to Bwaak. Despite dozens of posts on this subject, he still bangs on and on about it. This has been going on for months and He/she really is getting tiresome. Instead of hijacking other people's threads, he should just create his own "What is a TBC?".

[Bwaak]

Have a look to dellsam34 YouTube channel workflow description at https://www.youtube.com/watch?v=FJRGUdOrrIw&t=993s : S-VHS Hi-Fi Stereo, Captured using: JVC HR-S7600AM (Line TBC/DNR On) -- BrightEye 75 Capture Device (Frame TBC/Sync On)

"The folks at digitalfaq.com and videohelp.com have batshit crazy methods for capturing VHS."

Look at the results, instead of repeating comments from idiots.

The question is about methods not results. Say, you recommend someone to use frame TBC, they will google for "frame TBC" and will return back to this forum, because this term is used almost nowhere else. BrightEye 75 does not contain "Frame TBC" in its user manual, but it does say,

A TBC/Frame Sync is a standard feature and allows the BrightEye to work with any type of video input.

So, the functionality that you call "Frame TBC" is called "Frame Synchronizer" everywhere else, and as dellsam34 correctly noted above, it provides "a clean frame timing (a.k.a VBI, Vertical Blanking Intervals)". Frame Synchronizer box does not have to include TBC, just like a TBC does not have to include a Frame Synchronizer. It is just when the box has a whole frame buffer, it is possible to do so much more: replacing lines or whole frames, sync frames with other video or with sync signal, proc amp, other digital manipulations. Boxes that have a full frame buffer can do a myriad of things.

So, please, stop the insanity with "Line TBC" and "Frame TBC". The former is just a normal TBC, the main task of which is lining up H-Sync. The latter is a Frame Synchronizer, which lines up V-Sync. Normally, Frame Synchronizer is used to sync two or more videos, but it also can be used to recover V-Sync pulses using clock built into the synchroniser. If every frame has the required number of lines, then Frame Synchronizer is not needed, because equal intervals between H-Sync pulses will ensure equal intervals between V-Sync pulses. But if the frames get damaged and some lines are lost, then Frame Synchronizer ensures that the picture does not roll or break up completely. Some converter boxes like Black Magic, apparently require consistent V-Sync. Other boxes are more resilient.

[Bwaak]

@Bwaak I'm sorry that my thread has caused a disagreement

Don't apologise to Bwaak. Despite dozens of posts on this subject, he still bangs on and on about it. This has been going on for months and He/she really is getting tiresome. Instead of hijacking other people's threads, he should just create his own "What is a TBC?".

Maybe I should, thanks for the tip. I just get wound up every time I see people use these "terms"

[lordsmurf]

standard VCR-ES15-(Frame TBC)-digitiser workflow.

^ Just quoting, not responding to Alwyn here.

ES10/15 type DVD recorders lack frame sync TBC, having only frame sync. The frames are not properly timed on non-TBC frame sync. The errors are simply baked in as mistimed (drop/dupe/blend) to maintain audio sync. ES10/15 type recorders are praised for a strong (though crippled) line TBC, not for any sort of frame corrections. DVD recorders are not TBCs, and do not replace TBCs.

- Frame TBCS (mostly) cleans the signal.
- Line TBCs (mostly) clean the image.
- You need both.

The "mostly" is because both bleed into correcting some of the other. Certain sources, with certain issues (or lack thereof), with certain capture cards -- during a full moon, while standing on one leg -- can skate by with minimal signal loss issues on non-TBC frame sync. If you can do this, congrats, you're the exception, sort of. Not the rule. That assuming you've not simply missed the errors, which happens often.

It's often best to (at minimum) chase a line TBC (ES10/15 or VCR) with frame TBC from certain other devices. If not an ideal model, then a weaker budget unit.

Frame TBC's should be avoided whenever possible but sometimes they are necessary.

I would not state that. Frame TBCs are almost always needed, because the signal on VHS tape is controlled chaos.

To illustrate this, I sent somebody a crass definition today:
- Consumer analog (VHS, Hi8, etc) is like the random girl/guy you met at the bar, and decided to take home for the night. Dirty, unknown.
- Line TBCs are like condoms, you only hope it works correctly.
- Having both line and frame TBC is like using both condom and pill/IUD/etc. Near-zero chance of something bad happening (STDs, crotch goblins).

So, please, stop the insanity with "Line TBC" and "Frame TBC". The former is just a normal TBC, the main task of which is lining up H-Sync. The latter is a Frame Synchronizer, which lines up V-Sync. Normally, Frame Synchronizer is used to sync two or more videos, .

That explanation has errors, gaps of missing info. An obvious error is confusing a frame sync with a genlock.

- There are multiple types of TBC.
- And there is a big different between mere frame sync and frame sync TBC.

[Marshalleq]

In terms of checking how well your ADVC-100 is handling tape wiggles, the best material is a steady shot of something with black-and-white vertical-running lines (bright lamp posts against a dark background, large letters "I" and "T", etc.).

Just a basic screenshot - there were a few places where I could clearly see things are not straight. I've only done this one video through the ADVC-100 so far, but in a few places there are very clearly non straight vertical lines. Once I actually get a TBC and have my new S-VHS player arrive, I'll be able to do some better testing. I'd also add that this is the absolute newest of the VHS tapes I have, taken around 1998 or perhaps 1999 on a much newer recorder. I assume therefore others may be worse.

So I think this absolutely confirms that the ADVC-100 does not have any kind of TBC - even though I know others have said that clearly, these rumours do still persist!

[dellsam34]

Further in the thread, he wrote:

But interestingly even on the S-VHS boxes they advertise a 60% quality improvement for standard VHS tapes.

That sounds good doesn't it.

Unless he means "S-VHS machines advertise 60% of quality improvement for standard VHS tapes playback", And that's how I took it since we are talking about capturing not recording to tapes which is the complete opposite process. Though playback alone does not account for that much improvement but a significant one. if you consider S-VHS machines have better electronic circuits, better mechanism, better signal processing in terms of timing, DNR, Y-C separation, Dynamic range.

Frame TBC and frame synchronizer have different functions, frame TBC always precedes frame sync. In a conventional capture workflow say of a VCR -> frame TBC -> USB stick -> Capture software (PC). The frame TBC insures the VBI signal is clean, if not it corrects it or replaces it so the capture card can lock on the signal, The frame synchronization is handled by the software, it makes sure the incoming stream from the capture card will have the right frame rate and synced to the audio, if not it will drop or add frames to get a perfect synchronization, The better the VCR and tapes the less work the frame TBC and frame sync have to do.

Here is where good capture cards shine, they can lock on timing signals within an analog video signal straight from the VCR without frame TBC as long as the VCR and tape are good.

Analog to SDI converters use the same approach except it's all processed in an FPGA environment, The video ADC and audio ADC feed the processing stage where proc amp, frame TBC, frame sync and Y-C processing are all done in the digital domain, then a complete processed and timed digital signal is then sent via SDI socket to a desktop equipped with a SDI port or via an adapter if a laptop is used.

[Bwaak]

Unless he means "S-VHS machines advertise 60% of quality improvement for standard VHS tapes playback"

He did not mean anything, he read it on the box. I told you above what this means.

The frame synchronization is handled by the software, it makes sure the incoming stream from the capture card will have the right frame rate and synced to the audio, if not it will drop or add frames to get a perfect synchronization, The better the VCR and tapes the less work the frame TBC and frame sync have to do.

Attached is a block diagram of the device that you use. Notice, that TBC and Frame Synchronizer are parts of the video chain, while the audio is mixed in later, in the embedder. How does this block diagram agree with your definition of frame synchronization?

Here the full description from the manual. Have you read it?

As shown in the functional block diagram below, analog video is converted at 14 bits of resolution and digitally decoded to YCrCb components (601). The signal is then time base corrected and frame synchronized to the reference input. Proc amp adjustments are provided for the converted video.

The audio is converted to digital and then passes through the built-in 2-channel mixer with shuffle and level control.

The video and audio signals are joined in the embedder. This embedded signal passes through a serializer to an SDI output on the rear of the unit.

[dellsam34]

You are aware that a block diagram and an electronic circuit schematic are two different things, While the diagram simplifies the outlook of an electronic circuit for an average person to understand, the electronic circuits and Soc chips work differently, There are thousands of communication channels inside an FPGA or a processing chip, inputs and outputs are driven by lines of feedback. If it's that simple, explain to me what does a Mixer/Shuffler does? and how does the embedder know that an audio packet correspond to a certain frame since there is no relationship between those parts according to your interpretation?

I know you like to argue and try to make a point for the sake of making a point but trust I have no desire in all of that, I just like to come here to help people if I could, If not I stay away from the topic.

[lollo]

The question is about methods not results.

The (original) question, was how to obtain quality capture in post #1: "How much good is it going to do me if the tapes are of fairly decent quality?"

I indicate the method to achieve good results in post #4: "Even for tape in pristine quality you need a S-VHS player with TBC/N.R. to get the best out of them. And you may also need an external frame TBC if the conditions of the tapes are not that good."

That's all that was needed.

And then you started your silly and useless crusade about the words. As usual...

[Eric-jan]

Unless he means "S-VHS machines advertise 60% of quality improvement for standard VHS tapes playback"

He did not mean anything, he read it on the box. I told you above what this means.

The frame synchronization is handled by the software, it makes sure the incoming stream from the capture card will have the right frame rate and synced to the audio, if not it will drop or add frames to get a perfect synchronization, The better the VCR and tapes the less work the frame TBC and frame sync have to do.

Attached is a block diagram of the device that you use. Notice, that TBC and Frame Synchronizer are parts of the video chain, while the audio is mixed in later, in the embedder. How does this block diagram agree with your definition of frame synchronization?

Here the full description from the manual. Have you read it?

As shown in the functional block diagram below, analog video is converted at 14 bits of resolution and digitally decoded to YCrCb components (601). The signal is then time base corrected and frame synchronized to the reference input. Proc amp adjustments are provided for the converted video.

The audio is converted to digital and then passes through the built-in 2-channel mixer with shuffle and level control.

The video and audio signals are joined in the embedder. This embedded signal passes through a serializer to an SDI output on the rear of the unit.

the TBC in the block diagram, does it's work without anything on the (BNC) reference input ?

[Bwaak]

The question is about methods not results.

The (original) question, was how to obtain quality capture in post #1: "How much good is it going to do me if the tapes are of fairly decent quality?"

I indicate the method to achieve good results in post #4: "Even for tape in pristine quality you need a S-VHS player with TBC/N.R. to get the best out of them. And you may also need an external frame TBC if the conditions of the tapes are not that good."

That's all that was needed.

That would be all that was needed if you could explain what frame TBC was Since you have declined the explanation, this simple task turns into a quest akin to "Go I Know Not Whither and Fetch I Know Not What".

[lollo]

Go I Know Not Whither and Fetch I Know Not What"

Do what I say and you’ll get good results (lollo’s novel, 2023)

[dellsam34]

the TBC in the block diagram, does it's work without anything on the (BNC) reference input ?

The external reference is for studio environment where multiple sources are used at the same time, If no reference input it switches to its internal clock.

[Bwaak]

I know you like to argue and try to make a point for the sake of making a point but trust I have no desire in all of that, I just like to come here to help people if I could, If not I stay away from the topic.

I am not arguing to make a point for the sake of making a point. I expect people who use certain tools and recommend similar, as they think, tools to solve similar problems to understand their functionality and use standard terminology so that one could research similar tools on their own.

This is from BrightEye 75 user manual, again.

Frame Sync

A Frame Synchronizer is used to synchronize the timing of a video signal to coincide with a timing reference (usually a color black signal that is distributed throughout a facility). The synchronizer accomplishes this by writing the incoming video into a frame buffer memory under the timing direction of the sync information contained in that video. Simultaneously the memory is being read back by a timing system that is genlocked to a house reference. As a result, the timing or alignment of the video frame can be adjusted so that the scan of the upper left corner of the image is happening simultaneously on all sources. This is a requirement for both analog and digital systems in order to perform video effects or switch glitch-free in a router.

So, please stop perpetuating a non-standard definition of frame synchronizer if you come here to help people.

BrightEye 75 is not a mythical "frame TBC", it is a combination of TBC + frame synchronizer.

Go I Know Not Whither and Fetch I Know Not What"

Do what I say and you’ll get good results (lollo’s novel, 2023)

This only works if someone uses exactly the same equipment as yours. But you said that you do not use "frame TBC" and you cannot define "frame TBC". So, your advice is impossible to follow.

[Alwyn]

I expect people who use certain tools and recommend similar, as they think, tools to solve similar problems to understand their functionality and use standard terminology so that one could research similar tools on their own.

Seriously?