Strange blurring effect during TMPG encoding

[filmjax]

Is there any acceptable DVD resolution between 352x240 and 352x480? I get some weird blurring on occasion when I use 352x480 on my VHS conversions. But 352x240 makes live events like sports and talk shows look like film instead of video.

[bugster]

If you want to remain DVD compliant, then no.

https://www.videohelp.com/dvd

The blurring may be due to resizing, or are you capturing at those resolutions?

[andkiich]

Well, the difference between the 2 is that one is interlaces(480) and the other is not(240).

Could it be that the blurring is due to some option or setting in the interlaced file that is not correct? Possibly field order or motion search precision?

[filmjax]

The blurring is hard to explain... its as if there are two portions of the screen where there is a smear... two lines of blur, left to right.

-----------------------------------------


blurblurblurblurblurblurblurblurblur




blurblurblurblurblurblurblurblurblur


-----------------------------------------

For example, I am backing up old Late Night with David Letterman episodes. You can plainly see the blur when the Top Ten List graphics are full screen. Also, when credits scroll up, you can see the words scroll through the "blur zones".

I'm capturing in DV-AVI, 720x480.

[wulf109]

It would seem unlikely your 352x240 are non-interlaced. That would be true if you converted them to VCD. Download Bitrate Viewer and run one of the 352x240 mpg's thru it. It will tell wether the file is interlaced or non-intelaced(progressive).

[filmjax]

This is what Bitrate says about my 352x480 file:

Num. of picture read: 31
Stream type: MPEG-2 MP@ML VBR
Resolution: 352*480
Aspect ratio: 4:3 Generic
Framerate: 29.97
Nom. bitrate: 8000000 Bit/Sec
VBV buffer size: 112
Constrained param. flag: No
Chroma format: 4:2:0
DCT precision: 10
Pic. structure: Frame
Field topfirst: No
DCT type: Field
Quantscale: Nonlinear
Scan type: Alternate
Frame type: Interlaced

and then my 352x240 file:

Num. of picture read: 31
Stream type: MPEG-2 MP@ML VBR
Resolution: 352*240
Aspect ratio: 4:3 Generic
Framerate: 29.97
Nom. bitrate: 8000000 Bit/Sec
VBV buffer size: 112
Constrained param. flag: No
Chroma format: 4:2:0
DCT precision: 10
Pic. structure: Frame
Field topfirst: No
DCT type: Frame
Quantscale: Nonlinear
Scan type: ZigZag
Frame type: Progressive

[bugster]

Ok, so its nothing to do with resizing like I first suggested, it is to do with interlacing. Your 352*480 captures are bottom field first (Field topfirst: No, from bitrate viewer). Try reversing the field order, I think VHS should be top field first.

[filmjax]

I changed it to top field in TMPG and did a sample encode, and while changing it makes it look slightly better (picture quality wise), the playback is jerky and otherwise unwatchable.

[bugster]

I changed it to top field in TMPG and did a sample encode, and while changing it makes it look slightly better (picture quality wise), the playback is jerky and otherwise unwatchable.

If you are viewing this on a PC, make sure you use a proper software DVD player that will de-interlace on the fly. I know PowerDvd does this, WinDvd probably does too, tho not sure. WMP does not. As your PC monitor is a progressive display, this is essential for proper playback.

[filmjax]

All of this is based on my viewings on a television, after burning the mpg file to DVD. You can see it on a PC monitor as well, but I am also seeing it on the final DVD product.

[bugster]

Could it be the field order setting in your capture process that is incorrect?

BTW, what is your capture process.

[filmjax]

I capture with DVIO to type 2 AVI. My capture device is the Canopus ADVC-100.

This link (http://www.daily-reviews.com/Clipboard01.jpg) is my best attempt to demonstrate what I'm talking about. It is much more noticable on a TV screen than it is here, but you can still see it. Look on the line where it says "5. Never Be Seen In Public" and you can tell its blurry, moreso than the lines underneath it.

You cannot see this blur in the AVI file (at least I can't), so it would seem to be a problem during the encoding process?

[bugster]

Ok, so your avi is DV-avi, in which case it is Bottom field first. (I assumed analog capture as you were talking about capturing from VHS).

What happens when you encode at full D1 res (720 * 480) as that is the resolution you are capturing at. Also, which encoder are you using and what resize method.

[filmjax]

If I try and encode to full D1, the picture is much too pixelated, almost like watching things through a digital honeycomb.

I use TMPGEnc to encode my AVIs to MPG.

[bugster]

If I try and encode to full D1, the picture is much too pixelated, almost like watching things through a digital honeycomb.

I use TMPGEnc to encode my AVIs to MPG.

That is because the bitrate is too low. You could use a higher bitrate, I would reccomend not going below an average of 4000Kbits at this res but of course you are limiting the playing time. Make sure you use compressed audio such as mp2 (if your player supports it) or Ac3. LPCM just wastes too much space IMHO.

I am tending to go back towards resizing being the problem here. going from 720 to 352 is not an exact multiple so there will be some esimating going on. You could try doing the resize in virtualdub using the built-in resize filter. Select bicubic resize at the best quality (1.0) then frameserve to Tmpgenc. This will be slower than just using Tmpgenc but may solve your problem.

[filmjax]

That seemed to do the trick!

Now, is there any way to capture directly to 352x480 instead of this extra step? Keep in mind my capture device is the Canopus ADVC-100.

[bugster]

That seemed to do the trick!

Now, is there any way to capture directly to 352x480 instead of this extra step? Keep in mind my capture device is the Canopus ADVC-100.

In that case, no. DV-avi is fixed resolution, nothing you can do about it. Some capture apps will resize and re-encode 'on the fly' but you need a fast PC and quality will almost certainly suffer.

[filmjax]

So there's no way I can capture in half D1 AVI? Damn.