Blocky edges around VHS Captures - see screenshots

[li21]

Hi all

So i recently got a USB Kaisser Baas USB VHS to DVD kit which has a composite / svideo capture unit.

I used it to capture from VirtualDub, Ulead Video Studio and Cyberlink Power director..

I find when using max quality at 720x576 I always end up with captures with blocky edges.. despite decent detail and resolution

See below screen shot of a test capture I did
Seems no matter what settings and format (avi / mpeg2) I capture in, I get these artifacts / blocks along the edges ..
around ears, shoulders, arms etc..
Looks worse when you RIGHT click the pic below and open the photo in a new browser ..

Is there any way to avoid this or filter it out ?

I've tried using Handbrake to convert the raw capture to mp4 / mkv with block removal on max, detelecine on, de-comb on but it makes little difference..

The first cap is at 720x576 - Blocky edges

The 2nd cap is at 320x576 (according to the app, not 576x320) - better edges, worse overall resolution.. is it odd that lower res capture does not have these artifacts?




This is the Capture at

320x576

[loblolly364]

Those screenshots are much larger than 720 x 576 pixels in size. The reason you see the blocky edges is because Windows Media Player (which appears to be what you're using based on the player controls at the bottom) is upscaling the video from its original size to fill the player window (based, on your screenshots, it looks like you are running in full screen). The blocks are actually the pixels of the video magnified because of the upscaling. Try using Windows Media Player in the regular window mode, and right-click the video display and uncheck "Fit Video to Player on Resize" in the "Video Size" menu of the pop-up menu. (This applies to Windows Media Player 11, which I have because I'm on Windows Vista. You're evidently using Windows Media Player 12, so I don't know if these exact steps apply to your version.)

[li21]

Hi loblolly..

I've actually considered what you're saying..
To some degree it's true.. Bt I also think the edges are something else.. Not just pixelization..

For example when I capture at the lower res... Then blow up to full screen.. The edges are not as blocky as in the 720x576

Also when I look at the preview window when capturing, I can just make out the blocky edges... Which shouldn't really show up since the preview window is smaller than capture resolution?

Or am I expecting too much from an old VHS capture?
Hmm.. What I really want is just the same picture quality as VHS tape..

[sanlyn]

First, you have to learn to look at videos. You also need to learn to make frame captures, not screen captures. If you've been using VirtualDub, then you ought to be able to make a direct frame copy and save it in a photo app as .png (the best way) or very-low-compression jpg (the worst way). Also, PC displays are inherently progressive and do not automatically deinterlace the way your TV does it. You might want to try a different media player as well; WMP is one of the worst.

Another factor is the way most media players and most PC apps resize video -- which is not the way a better TV, a/v component, photo app, or media player would enlarge something, resulting in jaggies and serrated edges.

Half-frame capture from VHS produces soft-looki9ng video because the smaller capture size requires greater enlargement for the same display output size.

Some of those jaggies aren't really jaggies: they're enlarged dot crawl artifacts. Try posting a frame capture (unprocessed, un-enlarged, converted to .png -- you can do that in mspaint, among many other apps).

[themaster1]

You have to determine if it's like this in the video with a software or if it's a display problem, my 2 cents are on the latter, solution:
use ffdshow video filter as post processor and use a good resize algo like spline36

[li21]

thanks Sanlyn..
This is a frame capture I got our of VirtualDub..



Themaster1 - It looks like its the video steam no matter what software it is.. not a display problem..
I can see in the tiny preview window of each software I use to capture.. that the blocks around edges exist already..

But as I mentioned before they don't really show up in 352x576 capture res..

[davexnet]

Perhaps the bitrate on the full size capture is too low, and/or the interlacing artifacts are involved.

[sanlyn]

Nope. It's the capture device IMO. I also found some complaints posted elsewhere about the Kaisser unit. The frame capture you posted shows dot crawl and definite aliasing -- that's doesn't even include the rainbows, blotches, and other chroma noise (but most of the latter would come from the tape itself). If as you say you can see the edge effects in your preview windows during capture, it doesn't necessarily mean that aliasing is on the tape itself: what you see in preview is what your capture device is transmitting. If you don't clearly see these effects during normal tv playback, it's in your capture device or the way it records. The effect is most noticeable on high-contrast edges, which indicates dot crawl in concert with chroma upsampling erorr; you don't see it so clearly on inner detail such as the shirt pocket. You might also notice macroblocks and mottling in the shadow area on the lower right corner.

[intracube]

It looks like the video is being captured at half 720x576 (360x288), then scaled to 720x576 using nearest-neighbour interpolation.

It's a bit strange though. The 720x576 image is mostly half the resolution it should be - but there is some sub-2x2 pixel detail there...

[li21]

It's a bit strange though. The 720x576 image is mostly half the resolution it should be - but there is some sub-2x2 pixel detail there...

Im not sure exactly what that means.. how can I change so it is capturing full 720x576?

I have tried to change the settings in the "capture pin" to 720x576 but it makes little or no diffeence

what does make a difference is if i reduce Sharpness in the adjustments to 0..
reduced the jaggered-ness but seems to add some noise?

[sanlyn]

A basic rule of thumb is to not sharpen VHS during capture. You sharpen noise and cause residual tape noise to create artifacts that are very difficult to remove. If you are running active filters during capture, frames get dropped and skipping occurs. Glad you mentioned that you're trying to post-process during capture. No wonder.

[li21]

if any of you guys have time.. here is a 10mb sample of my capture work..
so here i've tried to capture at 720x576 (whether its really doing that or not as Intracube said..) and sharpening off

Is this the sort of quality you guys would get from standard VHS rip ?
Do the the edge look okay ?

Also whats with the sound ? its 256kbs but sounds like 96kpbs if you know what i mean ? has that low bitrate squelch where as the source VHS does not..

Here is the vid sample:
http://dl.dropbox.com/u/17078883/Captureh.mpg

[jagabo]

The video quality is pretty good for VHS capture. Though it does look like the card captured at a lower resolution and scaled it up. It's interlaced video (two half-pictures per frame, intended to be viewed separately), also normal for VHS caps (use a player that deinterlaces properly). The audio is probably from the low-fi mono linear audio track. If your deck has hi-fi audio capability make sure it's enabled. The tape may have been recorded with only a linear audio track so switching to hi-fi may not help. The audio is also distorted but it's not because it's captured too loud. It happened earlier. Does it sound just as crackly when watched on TV?

[themaster1]

Looks like it's been captured low rez 352x288 (which is the default size in most apps) , i'm not even sure you can record in full rez on win7 (hence why i use xp)
Tells us what os you use

[jagabo]

Looks like it's been captured low rez 352x288

It was capture at 352x576 at least, because there are clear interlace comb artifacts. But it does look like the horizontal axis was scaled up to 720 from a lower resolution.

[sanlyn]

The video quality is pretty good for VHS capture. Though it does look like the card captured at a lower resolution and scaled it up.

Agree on both counts. Sure looks like a resize to me. I can't say I've ever seen a capture do that. Every capture is a new experience anyway.

[jagabo]

The video quality is pretty good for VHS capture. Though it does look like the card captured at a lower resolution and scaled it up.

Agree on both counts. Sure looks like a resize to me. I can't say I've ever seen a capture do that.

Yes, most capture cards actually capture (internally, in the driver) at a higher resolution (often 1440) then filter and downscale to 720 before giving the frame to the capture program.

[sanlyn]

I wasn't aware of the resampling aspect, so thanks for that info. But those resizing effects are a new experience. I tried some antialias plugins but got only fair results. Some of that stairstepping looks pretty rugged.

[li21]

Thanks everyone for having a look at my samples

I'm actually using Windows 7!

Is there any reason my capture apps would say they are capturing at 720x576
Yet only really capture at 320x ???

I guess I'll give XP a try to see if it captures at full res, unless anyone has any suggestions

As for the audio.. The source played on tv does really have that echo/squelch the capture does..
It is a mono source however , played back on hifi VCR, captures in PCM stereo..
Maybe I should try capturing in mono next ?

The bad sound is only evident when played back over my home theatre speakers .. Can't tell on my laptop speakers

[sanlyn]

I'm not getting an audio squelch at my end....maybe I've been watching this clip too much!
It took a little effort, but some Avisynth plugins cleaned a bit and smoothed edges (with maa() and awarpsharp()). Not as much as I'd like, but the source clip was already soft. Was this video sample captured to lossless AVI or to MPEG? The latter was a hindrance. I'd hate to throw more filters at this puppy, but perhaps this effort can give a few ideas about possibilities. I fixed some rainbows, the black borders, and some horizontal bands and rips in frames 17-19, 76-77, 102, 178-179, 207-209, 236, 243-244, and the spots in frame 251. Unfortunately frames 170-174 have too much motion over 4 consecutive frames to fix the glitch there, and the blue bands in 254-255 or so wouldn't go away. Well, you can't have everything.


[Attachment 14881 - Click to enlarge]

Another learning experience . . .

[intracube]

li21; the video in post #12 shows much less noticeable blockiness/aliasing compared to the still in post #6. What did you do differently?

[sanlyn]

The video in post #12 still has jaggies, crosshatching, dot crawl, split and broken lines, and other resize artifacts. li21 stated that sharpening was disabled during capture. Except when using high-end playback and capture gear, VHS should never be sharpened during capture.

[lordsmurf]

You can sharpen VHS before capture, but only with proper hardware.

The video I'm seeing here appears deinterlaced. Hence the jaggies.

The capture device is simply garbage. End of story.

[sanlyn]

Proper hardware, yes. That's the problem here. Long way from proper.
Although it might not be possible in the O.P.'s case (money, time, whatever), I'd advise to really try to get a better capture setup.

The video I'm seeing here appears deinterlaced. Hence the jaggies.

According to the O.P., video is straight from VHS to capture device to (apparently) Kaisser Baas or somebody's not-so-good MPEG2 encoder. Yes, I know: one of the 50 ways it should not be done. Alas, that's what most people want to do.

[jagabo]

It may just be improper setup of the software. The posted MPG file is interlaced video. It was not deinterlaced.

[sanlyn]

if any of you guys have time.. here is a 10mb sample of my capture work..
so here i've tried to capture at 720x576 (whether its really doing that or not as Intracube said..) and sharpening off

Is this the sort of quality you guys would get from standard VHS rip ?
Do the the edge look okay ?

Thank you for the sample. It helped to answer many questions, although you didn't relate how this mpg was made, precisely. I spent some time with it and posted a newer mpg earlier.

I don't think there is a "standard" VHS rip. BTW this isn't a rip: it's a capture. People use all kinds of stuff for VHS->DVD work. The "standard" usually advocated here is to use as good a player as you can find, a quality capture device whether new or used (the older analog cards are the best for VHS capture IMO, if you can find one). Capture to real-time lossless AVI with huffyuv or Lagarith compression, post-process to repair and clean the usual analog problems that make digital encoders go haywire, then encode to a DVD standard with a creditable encoder (there are free ones and some cheapies that are actually used in full-time shops), then author to disc with (also free and even cheap) decent authoring apps. Even some top-rated DVD burning software is free.

Re: the edges...No, actually, they don't look good. Looks better than the earlier samples but, really, I think the capture device and the encoder didn't do justice to the 8000-plus bitrate. The video's noise is a dead giveaway that it's VHS that hasn't been cleaned much, which doesn't help the encoder. I think you could get much better results without great difficulty, but you need a better capture card.

[intracube]

The video in post #12 still has jaggies, crosshatching, dot crawl, split and broken lines, and other resize artifacts.

But nowhere near as bad as in post #6:

- right; mplayer output with resizing disabled
(the floating image viewer on this forum resizes the image, so open it in a new tab to see 1:1)

Sharpening wouldn't explain the difference. The output from mplayer still isn't correct - there's still some sub-optimal resizing going on somewhere.

[sanlyn]

Amazing how different devices do different things to the same colors from the same tape (right-hand image is more yellow). The image on the left is oversharpened, making the artifacts look worse. The right image is "nowhere near as bad", but it's pretty bad. Most of those edge artifacts shouldn't be there. Something somewhere is haywire, as those jaggies and split line-edges are extremely uniform over the entire image.

[intracube]

Amazing how different devices do different things to the same colors from the same tape (right-hand image is more yellow). The image on the left is oversharpened, making the artifacts look worse. The right image is "nowhere near as bad", but it's pretty bad. Most of those edge artifacts shouldn't be there. Something somewhere is haywire, as those jaggies and split line-edges are extremely uniform over the entire image.

The colour differences might be attributed to colourspace issues - Rec.609 vs Rec.701
EDIT: that, or my recent colour management adjustments have had unforeseen consequences...

I disagree that the image on the left is blocky as a result of oversharpening. Or if it is, it's a terrible sharpening algorithm.

As I said earlier, my cap still has aliasing issues. These look a bit like bad 'weighting' (not sure what the correct word is here) for the resampling/rescaling filter. I'm attempting to reduce this. Will post results shortly.

[intracube]

left is 500% zoom of mplayer output, right has 1.2 horizontal blur applied in GIMP.

after some sharpening:

*sharpening wasn't interlace aware, so ignore any issues relating to that...