Exporting MPEG2 Video Degradation Blurry Jittery Adobe Premiere

[ESP1138]

I couldn't find an answer and I hope I am not posting a duplicate question. My apologies.

I am uploading my VHS tapes to my PC for recording them on DVD later. I encountered a minor problem.

I created some files in AVI and MPEG and edited them with Premiere CS5. I exported this as an MPEG. They look fine. Later I decide I want to make further changes to this new file. I exported a new file one final time also in MPEG and during playback with Windows Media Player and K-Lite Media Player I notice the last file has some blurred/jittery shaking effect when a scene scrolls. This is especially noticeable during rolling credits.

Maybe I can clarify further with examples. I capture tape and label it File 1. I edit this file and export it as File 2. Later I edit File 2 and export it as File 3. File 2 looks fine. File 3 has a blurred look and I wonder if there is some degradation occurring. I didn't think digital files were supposed to lose quality.

I am working with MPEG2 and 4:3 NTSC DV High Quality, 720x480 29.97 fps, quality 4.0, lower MPEG, 224 kbps, 48 kHz.

Does anyone understand why this is happening and how to prevent it?

[babygdav]

https://www.youtube.com/watch?v=zfZFFLDPigs

Looks like 0:16?

Most likely you imported the video into your PC just fine - 29.97fps interlaced video.
Editing, somewhere, you either messed up the interlacing field order, or combined non-interlaced with interlaced video and messed things up more.
https://helpx.adobe.com/premiere-pro/using/interlacing-field-order.html

You'll need to maintain proper field order and interlacing all the way through from beginning to end, or you'll get junk.
Or, convert all the footage to progressive video, then edit using that.

Neither is "better", only ways to get around the interlaced video issue.

[LigH.de]

The worst you could do is scaling the height of an interlaced video without separating the fields.

[LMotlow]

I didn't think digital files were supposed to lose quality.

Brother, you are so misinformed. Big time.
Let's start with "uploading" VHS to your PC. Uploading ????

[ESP1138]

@babygdav: Yes. Good example.

Thank you everyone for trying to help me. I am still unsure what settings to change given that the capture was made with a different program (Ulead VideoStudio 11).

In the end I exported in a slightly different format MPEG2-DVD Progressive High Quality which has a De-interlaced setting. This did the trick and after exporting a final time the video file looks just fine. Again thanks to all for pointing me in the right direction.

[LMotlow]

Fortunately most of us have seen enough of these newb destruction projects to numb the initial impressions from reading them. But they still make me wince, after all these years.