VHS Filters

[Tyler2000]

Are there any virtualdub or avisynth filters that can make this video look any better or should I use it as is?

This is from a vhs and I will be burning it on dvd.

[Megahurts]

The only filter in VirtualDub to help this video is Grayscale.

[SatStorm]

Virtualdub filters can't really help here: Try Flaxen VHS and then temporal smoother.

This mess needs a TBC and colour adjustment first...

[lordsmurf]

It needs to be played on a better VCR with a TBC. It's really too late for software to be of much good.

That's chroma noise.

Maybe try the chroma noise removal filter in Virtualdub.

[davideck]

Is this tape a second generation copy or beyond?
This looks like timebase errors accumulated over multiple generations without any TBC in between.
If so, I don't think a TBC will be much help at this point; it might even make things worse.

[Tyler2000]

Yes, this is a copy but I don't know how many generations. I don't have a TBC, but I played around with filters and I think this will work:



I reduced saturation to 60% then used temporal smoother (4). I didn't use the VHS filter because when I added it, it looked over-filtered to me.

[Barnabas]

Get a decent VCR. I suggest a JVC with Digipure. Those have a built-in TBC and Digital noise reduction. Make a HUGE different on poor tapes.

Check out "smurfs" site. He has some before and afer examples of one of the JVC vcr's that shows the improvement.

[davideck]

A TBC can only remove the timebase errors created by the last generation.
Once a copy is made without a TBC, the timebase errors become embedded in the picture content.
If that is what has happened here, a "better" or "decent" VCR will not help much, nor will a TBC.
It demonstrates the importance of always using a TBC when dubbing. While the TBC doesn't appear to do much at each dub operation, it prevents timebase errors from accumulating.

It's hard to tell from the still, but luminance looks very unstable too.
This image doesn't look noisy. It just looks very unstable.

[Tyler2000]

I created a dvd with this video and now it looks worse than it did before. When there is movement in the video, it kind of looks like a strobe light.

This what I did:
I put the VHS in a Sanyo VCR, output to a canon camcorder with analog pass-through into my PC with firewire connection. I captured the video with Pinnacle Studio 9 Plus.

Then I opend the DV Avi I captured into Virtualdub 1.5. I lowered saturation to 60% then used temporal smoother (4). I then saved video as an uncompressed RGB avi.

I loaded the RGB back into Studio 9, grabbed a frame for the menu, added a menu to the front with a title and a play button.

Then I created the DVD contents, but did not burn. I used the Best Video Quality setting which is 8000 Kbits/sec. I also used Dolby 2-channel audio.

I went into advanced settings and checked Constant BitRate. I also checked 'Always re-encode entire movie' and 'Enforce Strict DVD Compatiblity'.

After the DVD contents were created. I pasted the VIDEO_TS folder into Roxio Easy CD Creator and I also created an empty AUDIO_TS folder.

In CD Creator and I checked 'Copy to hard drive first' then I burned the video onto a DVD-R at 1x speed.

The video I burned is about 3 minutes long.

What caused the weird strobe effect? It almost looks like it is showing video frames out of order.

[lordsmurf]

Again, you should REALLY try to use the chroma reduction filter in VirtualDub.

[Tyler2000]

Ok, I don't see what chroma noise has to do with this problem, but I'll try it.

[Tyler2000]

Do you mean the chroma smoother(that came with virtualdub, I think) or the Chroma Noise Reduction by Gilles Mouchard?

What settings should I use?

[lordsmurf]

Ok, I don't see what chroma noise has to do with this problem, but I'll try it.

Chroma (UV) is where color information is stored. These red/blue/pink misty blobs on your video is chroma noise. Crosstalk between the "layers" of the video, resulting in this error.

You need to filter out this sort of issue. It is best to do it in hardware. But if you lack the hardware, and refuse to buy it, or if the file is already digital, try to use the Chrome Noise Reduction filter for VirtualDub.

[davideck]

These red/blue/pink misty blobs on your video is chroma noise. Crosstalk between the "layers" of the video, resulting in this error. You need to filter out this sort of issue. It is best to do it in hardware.

"Layers" of the video? What's that?
This is not noise or crosstalk. It's a clean chroma subcarrier of incorrect phase.
These are timebase errors. This is what a TBC prevents when used properly.
What kind of hardware are you suggesting will "filter" out an embedded chroma phase error?

[lordsmurf]

These red/blue/pink misty blobs on your video is chroma noise. Crosstalk between the "layers" of the video, resulting in this error. You need to filter out this sort of issue. It is best to do it in hardware.

"Layers" of the video? What's that?
This is not noise or crosstalk. It's a clean chroma subcarrier of incorrect phase.
These are timebase errors. This is what a TBC prevents when used properly.
What kind of hardware are you suggesting will "filter" out an embedded chroma phase error?

Trying to explain video in non-tech terms. You have a "leaking" effect from chroma/luma being mixed together (the "layers" I'm referring to, YUV), and there is indeed some crosstalk happening. Separating it back out with s-video will help, as will using DNR/TBC.

This is chroma noise. A TBC will not necessarily help it. I could ram this video through any number of TBCs and it'd still look the same. But something aimed at filtering out chroma noise will, like the high end JVC S-VHS units equipped with the DNR/TBC system.

It's best to do it in hardware, but software can help to a degree. Again, the vdub filter is a solid filter, I've used it a number of times in the past, when needed. Just be careful with it, as you can easily overuse or underuse the filter

[davideck]

You have a "leaking" effect from chroma/luma being mixed together (the "layers" I'm referring to, YUV), and there is indeed some crosstalk happening

OK, so you are suggesting that there is crosstalk among the Y, U, and V "components". I disagree. While it is possible for detailed luminance at or near the chroma subcarrier frequency to "leak" through a chroma bandpass filter and appear as bands of color, that level of detail does not exist in this image.

This is chroma noise.

If your concept of chroma noise includes chroma phase (hue) errors, then we agree. The definition of chroma noise that I am familiar with refers to amplitude errors of the chroma subcarrier or the U and V components themselves; noisy areas of the picture will appear "snowy". For composite or S-Video sources, Chroma hue errors are due to timebase instability, not amplitude noise.

It needs to be played on a better VCR with a TBC.
...
A TBC will not necessarily help it. I could ram this video through any number of TBCs and it'd still look the same.

These two statements are contradictory...

[lordsmurf]

It needs to be played on a better VCR with a TBC.
...
A TBC will not necessarily help it. I could ram this video through any number of TBCs and it'd still look the same.

These two statements are contradictory...

Not at all.

A plan TBC does almost nothing for "cleaning the picture". We've been over this before. It's not there to clean the picture, it's there to clean the signal. WHile it can clean the picture, it's usually minimal, often completely unnoticeable.

A VCR that has a TBC, specifically the JVC line, has more than the TBC. These little gadgets in the VCR are meant to clean the picture. It does not do much in the way of cleaning the signal.

[davideck]

A plan TBC does almost nothing for "cleaning the picture".

That is absolutely incorrect.
This image is a classic example of what happens when a "plain" TBC is NOT used to keep the picture "clean" during dubbing.

I agree that during each dub operation its "cleaning" effect appears to be "often completely unnoticeable". Nevertheless, its useage is critical in order to prevent these "minimal" timebase errors from accumulating across multiple generations and embedding timebase (hue) errors into the picture content.

Please read this; http://www.questronix.com.au/info/info_tbc.htm

A VCR that has a TBC, specifically the JVC line, has more than the TBC. These little gadgets in the VCR are meant to clean the picture.

The JVC DNR will reduce chroma AMPLITUDE noise by temporal filtering.
It will NOT remove embedded timebase (hue) errors. The pink region on the man's forehead is not amplitude noise; its a timebase error.

A VCR that has a TBC ... does not do much in the way of cleaning the signal.

This is also incorrect.
The JVC TBC DOES eliminate timebase errors and reinsert a clean sync/burst interval, just like any other TBC. In fact, it does it much better than most. The only thing it doesn't do is provide a continuous sync/burst signal throughout dropout and/or blank tape regions.

[lordsmurf]

Well, my years of experience in doing this says otherwise. Your theory and documents may toss out a lot of technobabble, but the application of the tools simply shows otherwise.

A TBC is not made to clean the picture. Period.
It's there to clean the signal.

A JVC high-end S-VHS unit with a TBC and DNR filter is made to clean the picture. Period.
It's not there to clean the signal.

Cleaning the signal and cleaning the picture are independent concepts, much like resolution and aspect ratio are independent topics (another topic that people commonly have difficulty understanding).

My advice on this exact problem would be a better VCR, namely the high end JVC S-VHS line.

If a better VCR in not an option, use the Chroma Noise Reduction filter in VirtualDub. Just be very careful with it, as you can cause chroma ghosting if overused, or it does nothing if underused. This filter is temporal, but only on the chroma axis, not on the luma. It samples out "foreign" noise, and it works because chroma noise is usually not an error with a static location (chaos, random ... like analog is).

[davideck]

OK lordsmurf, I'll stop here.

For months now, I have tried my best to explain some basic TBC theory to you. At this point, I'll just assume that you're not interested.

I am not just making this stuff up. I've been trying to help.

If clinging to your "non-tech" explanations and vocabulary serves a purpose for you, then that's fine.

Let me be the one to suggest that we agree to disagree so that we can stop wasting time.

[lordsmurf]

I think the problem is you approach from a backwards basis. A TBC will prevent errors from happening, but once they exist, they exist. Prevention is not the same as cleaning. Once the error is on the video, you have to clean it out with filters, the TBC isn't going to help.

Designing or programming hardware is software is not the same as using it. In fact, very often programmers and hardware designers have a skewed understanding of the field/hobby. Panasonic, ATI and Intervideo come to mind.

Agreeing to disagree is fine by me.

[Tyler2000]

So anyway......

I used the chroma reduction filter, setting everything to 80%. I burned the dvd and overall the picture looks good enough, but I'm still seeing the problem I mentioned earlier.

Whenever there is a lot of motion in the dvd, it becomes kind of jerky or flashy like it is showing frames of the video before they are suppose to be shown.

So I tried creating a dvd-compatible mpeg2 file and the problem shows up then, too.

The problem must be with the mpeg2 encoding. But I tried loading it in mpeg virtualdub and the problem went away.

Any ideas why this is happening?


By the way, I'm not going to buy a better vcr with a tbc because this is probably the last time I'm going to be converting a vhs to dvd. If someone asks me to convert their tapes for them I'll just suggest they buy those standalone converters.

[Leighgion]

I'm not directly familiar with the software you're using (I'm a Mac user) but I've some experience with mpeg2 encoding in general. It seems possible that what you're seeing is frame rate or interlacing problem. You could check to make sure your mpeg encoder is configured for the right frame rate and for interlaced input of the appropriate field dominance?

[SatStorm]

That sounds like a strange field distortion...

Wrong field order maybe?

[Tyler2000]

I used the reverse field dominance filter by Donald Graft and that fixed it. I read that it makes the audio out of sync, but it is hard to tell if it did. Is there a set amount of milliseconds that I can offset the audio with that would fix the small sync issue with this filter?

[SatStorm]

Well, you can always use audio "interleaving" on Virtualdub

[Tyler2000]

Yeah, that's what I meant. I think the filter says it cuts off the first field of the video, how many millseconds should I delay the audio by?

[junkmalle]

Yeah, that's what I meant. I think the filter says it cuts off the first field of the video, how many millseconds should I delay the audio by?

You can reverse the field order by shifting the image up or down by 1 scanline. No audio issues that way.

[Tyler2000]

Ok, nevermind.