60p -> 24p conversion for ATSC
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
participants (5)
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RC -
Rich Felker -
rob -
rob pfile -
Steven Adeff