Going back on a conversion

[carlmart]

Here's the thing.

Back in the days when we did not have a real SD to HD conversion, I converted some SD videos, originally from DVD resolution, to 720p or 1080p using Vidcoder.

The main advantage was manipulations of those videos, particularly for subtitles, because there was no "real resolution gain".

Now several programs have been released, supposedly IA controlled, like Topaz Video Enhance AI and some others that are even better, that analyze each frame and process the image in a very effective way.

I did process a whole documentary I had shot in DV and converted to mkv, and the results were magnificent. Contrary to the Vidcoder processing, where you could not find any differences between the SD and the fake-HD frames, this time you can see visible improvements.

Now my question: how do I do to go back from a "fake-HD" video onto its original format, so I can reprocess it with Topaz?

[davexnet]

Now my question: how do I do to go back from a "fake-HD" video onto its original format, so I can reprocess it with Topaz?

You start with the original SD videos

[carlmart]

I wouldn't have made that question if I had them.

[davexnet]

I wouldn't have made that question if I had them.

It'll be an interesting experiment since you already incurred a quality loss with your
"Fake HD"
What did you have in mind? Is it necessary to resize it back down?
If it is, perhaps use a lossless codec

[carlmart]

If there was quality loss when making HD "versions" of the SD files, it was not visible on a side by side, zoomed view of same SD and HD file

[jagabo]

Downscale your videos back to SD and upscale from there. Filters like DeLanczosResizeMT() or DeBucubicResizeMT() in AviSynth (from the ReSampleMT package) would probably work best.

[carlmart]

Some filters were used, like those mentioned, on the Vidcoder when I made the conversion to mkv, some to 720p.

As I intend to upscale to 1080p, not 4K, starting from 720p mkv would be fine. What I was thinking to do with the 1080p files was to turn off most of the filters in Vidcoder and descale them to 720p too.

I completely forgot how to process things with Avisynth, which I had refined very much in my DVD SD days.

If anyone knows Vidcoder, it would be great what settings would be recommended to use to go from 1080 to 720p just adjusting the size and nothing else.