[MEncoder-users] compression: 1080i versus 720p

[Jarred Nicholls]

On Wed, Dec 23, 2009 at 11:54 PM, RC <cooleyr at gmail.com> wrote:

> On Wed, 23 Dec 2009 06:45:04 -0600
> Andrew Berg <bahamutzero8825 at gmail.com> wrote:
>
> > The comment
> > > When you deinterlace the 1080i video, you're reducing it to 30fps.
> > states that deinterlacing reduces the frame rate, which directly
> > affects how much raw video data there is. There is no mention of
> > compressibility here. Deinterlacing does not reduce the frame rate,
> > therefore the statement is false.
>
> Well, if I take 60 fps material, delete half the frames, and then
> duplicate each frame to end up with 60 fps material, would you say the
> frame-rate was halved, or not?  Explain.
>
>
I think he's saying that though it's 60 fields per second, that they are
being played back (viewed) at 30 frames per second (perception) when it is
interlaced...and deinterlacing the fields turns the 60 fields into 30 full
frames and still is played back at 30 frames per second.  At least such is
the case with any software video player such as Mplayer.  So in other words,
the video has just as many perceivable frames per second (the same speed if
you will) whether it's 60Hz interlaced or 30fps deinterlaced.  So...one
could treat Andrew's statement as such.

It's like we are having two separate conversations in this thread with
regards to deinterlacing - one about frame rate and one about field
data/compression :-)

Jarred


> --
> Ha. I'm the idiot.
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