[HELP] "Real" PAL<>NTSC framerate conversion with speed changing?

[DannyHicks]

For the US market. 23.976 (progressive) -> 29.97 (progressive + pulldown) is what telecine is for.
Starting with telecined content some morons use a deinterlacer to convert from 29.97 (progressive + pulldown) to 29.97 progressive when they should have used an inverse telecine method to convert from 29.97 (progressive + pulldown) to 23.976 (progressive). Or the original content might have been a mix of progressive, interlaced and telecined content,... This is where things can get more and more complicated.

You got two solutions (without spending hours of analyzing the content):
a. keep all frames and to a speed change from 29.97 to 25, downside of this is that the pitch adjustment to the audio might be more noticeable due to the greater change.
b. reencode the content and throw out unneeded frames (by using Filtering->Avisynth->Restore->sRestore or Filtering->Vapoursynth->Other->Retstore->sRestore).
Upside of this is that lots of unneeded frames will be removed. Downside is this will require a video reencode which always includes a quality loss (unless lossless encoding is used which would let the file size explode).

-> there are other/better methods which require a lot of knowledge and understanding of the two formats, but the above two are probably the best you can do without having to spend lots of time.

O my god.. 

I've been googling a bit for methods to "inverse telecine progressive and pulldown to progressive" but no luck. It indeed seems pretty very complicated. What a shame. I expected it would just be a matter of converting 29.97 to 23.976 by removing the duplicated frames (automatically).

It's hard to go with one of the simpler solutions you suggested. I mean, I'm very alert to small details like the speed difference between 23.97 fps and 25 fps. It kinda triggers me, and I'm pretty sure solution "a" would make the series unwatchable to me. And yea, the quality loss that comes with solution "b" isn't that nice either.

Are you sure there isn't another way without having to spend hours? :#