[MPlayer-users] 60p -> 24p conversion for ATSC

[rob pfile]

some time ago i posted about this topic, and Rich Felker was kind 
enough to reply. he mentioned that there was a hack using vf_tinterlace 
to do frame decimation of 24p material that's had frames duplicated for 
broadcast as 60p ATSC. i wasnt able to find any mention of this 
anywhere in the archives, so if someone out there can describe this 
hack, i'd be interested in hearing about it.

i ask because i have had some success with vf_decimate, but in low 
motion scenes vf_decimate starts discarding the wrong frames. the 
problem seems to be that the duplicated frames have of course been 
re-encoded for transmission, so even though they are clearly duplicates 
to the human eye, to mencoder the duplicate frames actually can be 
quite different, thus sneaking through vf_decimate and then being 
'randomly' discarded by the output fps constraint of 24000/1001.

i have considered hacking on vf_decimate a bit to try to lock onto the 
3/2 pattern, but i havent gotten there yet.

i'm surprised there isnt more discussion of this... which could mean 
that i just don't know what i'm doing (very likely of course :). i've 
noticed that TV shows available from different sources around the 'net 
have what appears to be rock-solid 60p->24p conversion, but invariably 
these shows have been encoded with nandub or virtual dub or whatever on 
windows. surely there must be a surefire way to accomplish this with 
mencoder?

thanks,

rob