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Old 8th March 2013, 11:15   #17949  |  Link
DragonQ
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Join Date: Mar 2007
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Quote:
Originally Posted by Toku View Post
I'm not very knowledgeable in the subject of what is a 'true' interlaced file (I know the basics of what Interlaced means though)
It just means there is motion between each field. If a file is 25 fps interlaced, that means there are 50 points in time that are captured (half a frame each).

Quote:
Originally Posted by Toku View Post
all I know is that an experienced encoder would not push for a 1080p encode of an Anime of which the source was mastered in an interlaced Format, (720p is usually regarded as the max in these kinds of situations, depending on the situation a lower resolution would suffice. E.g a dvd). As always there are a few exceptions.) and this has happened quite often.
Personally I would encode 1080i/25 to 1080p/50 if I was forced to deliver a progressive file. It's the only way to not throw away temporal or spatial information. The best method is to just leave the file untouched but obviously this results in a larger file, plus a lot of people don't have their media players set up correctly for interlaced content.

Quote:
Originally Posted by Toku View Post
If these are not true examples of interlaced content then the fact that these were mastered in an interlaced format probably points to a different reason to not out a 1080p release rather than it actually being interlaced.
As someone else pointed out above, if the original master is 1080i then there's a few possibilities:

- It's actually 1080p/25 in a 1080i/25 "wrapper" (no motion between fields in the same frame). This is very common because neither BD nor DVD supports 25p natively. "Inverse telecine" is required.
- The material is 1080p/25 but there are some 1080i/25 graphics or something.
- The material is actually 1080i/25, which means it must've come from a 1080p/50 source (why would you only draw every other line for animation?), which has no standard delivery format yet.

Since most animation is 12,24 or 25 fps, the last option is surely the rarest. It's easy to spot though - play the source file using hardware deinterlacing (IVTC off) and step between frames. If there is a difference between each frame, it's 1080i/25. If there is only a difference between every other frame, it's 1080p/25. If there's a more complicated motion pattern then something weird is going on, like frame rate conversion, field blending from or pulldown.
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