Resize width only

[agisthos]

I have come across some home DVD that was stored with half width, ie 352x576 and displays (DAR) at 704x576.

So my question is, using Avisynth, if doing a 2x resize on width only, what is the optimum resize filter/tool to use? Spline? Lanczos?

[hello_hello]

If you want to resize to square pixel dimensions, try CropResize in my signature, along with your preferred resizing method. You can crop the width or height, but ResizeWO mode will ensure only the width is resized. I'd probably use Spline36, which is the CropResize default.

The first two zeros would normally be the output width and height (ignored in ResizeWO mode) while the next four zeros would be any cropping required. Info=true just shows you what the script is doing.

CropResize(0,0, 0,0,0,0, ResizeWO=true, InDAR=704.0/576.0, Resizer="Spline36", Info=true)

The above assumes 704x576 is the correct DAR. If it's supposed to be 4:3, try InDAR=4.0/3.0 or InDAR=15.0/11.0 instead.
If you only want to double the width though, there's no advantage to using CropResize.

There's also the Resize8 script in my signature. It corrects the slight chroma shift caused by Avisynth's resizers, and it can use any of Avisynth's resizing methods. It also includes ringing repair.

Resize8(704,576, Kernel="Spline36", Show=true)

Or CropResize can resize using Resize8.

CropResize(0,0, 0,0,0,0, ResizeWO=true, InDAR=4.0/3.0, Resizer="Resize8", RStr=""" Kernel="Spline36" """, Info=true)

[agisthos]

Thanks this is very helpful!

[hello_hello]

You're welcome. I've edited my previous post to add some info on Resize8 too, in case you missed it.

And I just realised the CropResize version in my signature doesn't include the RStr argument. You can still resize with Resize8 though. The default for upscaling is Lanczos4. The new CropResize version has the RStr argument, but I probably won't finish checking it until later today. I'll update the CropResize thread with the new version when it's done, but in the mean time (it should be fine)......

CropResize 2021-10-11.avsi

[ProWo]

You will have no benefit doing a recode, only quality loss.

[jagabo]

I have come across some home DVD that was stored with half width, ie 352x576 and displays (DAR) at 704x576.

DVDs only come in 4:3 or 16:9 DAR, not 11:9 DAR (704:576). In your case the square pixel equivalent of 4:3 DAR would be 768x576.

[Cornucopia]

@jagabo, sounds like agisthos had a 1/2 D1-encoded DVD. It still appropriately displays with 4:3 DAR, am guessing the "704 x 576" bit was in assuming it would need to be resized (because why? wrong?) and then re-encoded to a full D1, but not realizing that is a legit variation to DVD using a double-wide PAR from 704, and also not knowing it would be best (for quality) left as-is. If, OTOH, it DOESN'T display with a 4:3 DAR, then it was flagged wrong when encoded and/or authored. That could be changed separately. Need more feedback to tell.

Scott

[jagabo]

MPEG 2 video cannot even be flagged for 11:9 DAR. By the spec the only possible values for the flag are 4:3, 16:9, 2.11:1 DAR and 1:1 SAR (AKA PAR). Of those only 4:3 and 16:9 DAR are valid for DVD. If the OP is using some DVD authoring software that doesn't accept half D1 he will have to resize to 704x576 and set the DAR to 4:3.

Regarding "what is the optimum resize filter": There is no "best" for all videos. It depends on the source. You want to avoid resizers that sharpen (splineXX, Lanczos, etc.) if the source is already sharp. Doing so will produce oversharpening halos and aliased edges. In a case like that a less sharp resizer will look better. Another option is something like nnedi3_rpow2() which will keep sharp edges while minimizing oversharpening halos and aliasing.

[agisthos]

I do not care about DVD authoring so that is not an issue.

So far all my VHS capture or DVD rip has been 720x576. This one was surprisingly 352, so I presumed its an already cropped (704) half width.
All 720 wide content I just set the 4:3 flag to display at 768, but in this case thought it would be best to resize it back to 704 than let the media player handle it.

All the original VHS-C mini tapes were destroyed in a shed fire 15 years ago !!

[agisthos]

And DVD rot is real.

I have 7 numbered VHS tapes transferred to 7 DVD's sometime in the 00's.

Of those 7 discs only 2 was I able to extract the MKV. The rest all fail with massive amount of read errors.

Luckily the 7 original tapes were not thrown out. Shame about the original mini tapes though...

[jagabo]

All 720 wide content I just set the 4:3 flag to display at 768, but in this case thought it would be best to resize it back to 704 than let the media player handle it.

If you're media player can display 720x576 as 4:3 DAR it can also display 352x576 as 4:3 DAR. You will gain nothing by increasing the video to 704x576. You will get three rounds of potential quality reduction: the resize from 352x576 to 704x576, the re-encoding (assuming you use a lossy codec), and the media player's final resize to your screen size (typically 1440x1080). Whereas, if you leave the file as it is you only get one round of quality reduction -- the media players scaling to the screen size (1440x1080).