You will find here links for a modification of Dscaler5 that offers a first level of Film Detection and 3:2 Pulldown. This version has been optimized for 1080i film content and should not be used for anything else.
You are welcome to give me your feedbacks, there is still a big margin for optimizations.
Film detection is not an easy process and its efficiency depends on many factors such as the decoder, video card, quality of the compression. If a decoder can not properly detect if a content is a film, it will assume it is a video and try to deinterlace it, which means most of the time "blend" the two fields or discard half the fields and basically reduce the resolution from 1080 lines to 540 lines.
As far as I can tell most of the mpeg2 decoders available (except some hardware based decoders) do not do a very good job at identifying films. There are rumours the 81.84 nvidia Forceware drivers are supposed to offer much better 3:2 Pulldown.
If the new option "inverse telecine" is enabled in Dscaler and you are watching telecined content you have got now quite a high chance to watch it in its true high definition that is at last in 1080p and no longer in crappy 540p. The decoder will try to detect as well if some video content is detected between two movies portions (for instance commercials), the decoder will try to ignore it and then resync after.
It has quite a low CPU overhead and since Dscaler is software based decoder it can be used with ffdshow.
Access Source + Binaries + Guide through this page:http://www.geocities.com/kzeuhkzeuh/index.htm
Many thanks to the authors of Dscaler Michel Lespinasse, Aaron Holtzman, Gabest and John Adcock that have created this awesome decoder with great picture quality.
Thanks to FMalibu for his "blind IVTC" modification which gave me the inspiration for the full IVTC algorithm.
Please note that this version is not official and is not supported by the original Dscaler authors. I hope they won't mind me releasing it.
Edit: Fixed Link