[hello_hello]

Originally Posted by ogrgkyle

I will take a look at those SARs. I did not know 640x480 wasn't necessarily the correct scaling! I've always assumed that.

Are you saying using anamorphic pixels is closer to the MP4 container spec? Does this make any practical difference?

The mpeg4 PARs are the official PARs for standard definition Bluray. You can use whatever PARs you like, the mpeg4 PARs in the list are just the official anamorphic, standard definition PARs.

The whole thing's a bit of a mess and I only partly understand the history, but the original ITU spec was based on sampling analogue video and if you follow the spec it works out to roughly 704x480 or 702x576 for 4:3 (which was usually rounded to 704x576).
The mpeg4 PARs are the digital equivalent and result in almost exactly the same display aspect ratios as the ITU PARs but the numbers are simpler.

Contrary to all that though, the HDMI spec seems to say 4:3 and 16:9 are exactly 4:3 and 16:9, and most digital devices resize to exactly 4:3 or 16:9.
For reasons I don't understand (based on experience) pretty much all 4:3 DVDs follow the ITU/mpeg4 spec while the majority of 16:9 DVDs seem to use the generic PARs. What broadcasters may or may not do I have no idea.

Originally Posted by ogrgkyle

I'm a little confused. Aren't you still ending up with a display resolution of 640x480?

Yes but the MPEG4 PARs are based on (roughly) 704x480 being 4:3 and for the generic PARs 720x480 is 4:3. Therefore if you assume an mpeg4 PAR and resize the whole 720 width without cropping, you end up with something a little wider than 4:3. 656x480 would be an appropriate resizing if you don't crop.

Originally Posted by ogrgkyle

By the way, my "widescreen" DVD/MPEG recordings are not actually technically widescreen ratio, but letterboxed, so these unfortunately have even fewer useful pixels than the "fullscreen" recordings.

Not only that, but the one I looked at isn't 720x480, it's 352x480. The DVD spec doesn't support widescreen 352x480.
By the time it's cropped, you're down to 352x252 worth of picture.
I assume 352x480 should be exactly 4:3, so the pixels would be twice as wide as mpeg4 for 20/11, although I tried three encoding programs and StaxRip assumed 20/11 while Handbrake and MeGUI apparently assume 16/9 (8/9 x 2) which seems a bit unlikely to me.

Originally Posted by ogrgkyle

Any suggestions to get the best picture quality when encoding to x264? Thanks.

For your first sample I'd do something like this for cropping and resizing:

tfm().tdecimate()
crop(8, 2, -14, -2)
Spline36Resize(640,480)

but the picture quality is only just a tad shy of disastrous and while there's no doubt ways to improve it, it's not something I do often, so I'll wait to see if someone clever comes along to help there.