[FFmpeg-user] "interlace"

Edward Park kumowoon1025 at gmail.com
Sun Sep 6 23:16:36 EEST 2020


> In the case of "interlace":
> "It's interlaced video" -- video in which the lines alternate (i.e. are interlaced) between two (or theoretically, more) fields (e.g. odd-even-odd-even...). That employs the past participle of the verb, "interlace", as an adjective to modify "video".
> H.262 refers to "interlace video" when referring to hard telecine. But "interlace video" is a bit of a mutt. "Interlace" is clearly being used as an adjective, yet "interlace" is not a participle (past or present) -- "interlaced" is the past participle and "interlacing" is the present participle. What it would have to be is a verbal adjective (i.e. a verb used as an adjective). I may be wrong, but I don't think there exists such a thing as a verbal adjective.
That's more or less what a participle is.

> A hard telecined video residing on a disc is clearly not interlaced. It is clearly deinterlaced (i.e. stored in fields). Since it is deinterlaced, it can be fed directly to a scanning TV (i.e. CRT) provided it is of the proper frame rate, or it can be interlaced -- a verb -- by a decoder as part of the decoding step.

Is it? Hard telecine is like telecining film and then recording it on a VCR, isn't it? And you don't need to deinterlace interlaced video to display it on an interlaced scanning TV. I think the confusion is when you deinterlace interlaced video, it is still interlaced video (or at least I think of it that way).

Ted Park

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