PAL DVD resize

[beav]

For a 4:3 PAL DVD with a width of 720 and height of 576, Do I have to downscale to a width of 720 and a height of 540? Or is it best to leave it the same as the original? I'm encoding a dvd onto my computer for personal use through an avisynth script.

[Baldrick]

You can leave it as the original. Just set the display aspect ratio to 4:3.

[Lowlander]

To be able to store and watch a DVD video on a computer you do not have to encode anything.

I suggest you have a look at MakeMKV, which can very easily create MKV files from DVDs without encoding, .i.e. without touching video or audio quality. Resulting files may be large though.

[beav]

Yes, but personally I like to filter and add subtitles to my dvds. So I re-encode using 10-bit H.264 through avisynth and MeGUI. Deiterlacing must be perfect for me as well.

[beav]

Thank-you Baldrick.

[hello_hello]

I finished encoding a bunch of old PAL 4:3 DVDs recently, for the second time, after encoding them all once and then having second thoughts about the aspect ratio. I suspect most 4:3 DVDs use ITU resizing, which means the correct aspect ratio is slightly wider than 4:3.

One rule of thumb seems to relate to the size of any black bars down the sides of the picture. If it's around 16 pixels or more then the DVD most likely uses ITU resizing. If pretty much the whole 720 pixel width is picture area, it's more likely to use straight 4:3 resizing. There's no hard and fast rule though, but for 4:3 that seems to be a good guide to use. 16:9 DVDs seem to be a different beast and in my opinion generally use straight 16:9 resizing.

Anyway, if you're converting a PAL 4:3 DVD to square pixels, you might want to try 738x540 instead, although the difference isn't huge. Personally I always resize DVDs to square pixels when encoding rather than keeping the original resolution due to a couple of TVs with built in media players (and a Bluray player) which don't understand aspect ratios in MKVs, but I guess if you're encoding using the 10 bit version of x264, hardware playback probably isn't an issue.

Actually if you wanted to keep the full resolution (assuming no cropping) then technically 768x576 (or 786x576) would be a better option, although I find most of the time with 4:3 DVDs you can go down to 640x480 (or 656x480) without seeing any loss of detail.

Given you mentioned perfect de-interlacing, I thought I'd mention QTGMC in case you haven't discovered it yet. It's way slower, but way closer to being perfect than any of MeGUI's native de-interlacers, however as using it restricts CPU usage to around 50% when encoding a DVD with my PC, I run two encodes at a time to make up for it.
And in case you haven't discovered the joy of de-interlacing to full frame rate (50fps) yet..... once you see the different it makes to how smooth motion is when compared to 25fps.... you'll probably never go back. Have you tried Yadid (with Bob) as an MeGUI de-interlacing option? It does a pretty good job of de-interlacing to full frame rate but QTGMC is better.