[MEncoder-users] interlaced/non-interlaced

[Andrew Berg]

 On 10/9/2010 11:11 AM, Toerless Eckert wrote:
> http://en.wikipedia.org/wiki/24p#24p_on_DVD
I see. I've only encountered a few DVDs with 24p material and all were
telecined to 60i, so I figured that was how all 24p material was handled
for DVD.
> All fields "should"represent a different point in time, but when
> TV stations or DVD players convert 24/25/30p to 50/60i, then this
> usually does not happen.
Now that I think about it some more, it may be possible to split a frame
into two fields without loss, but I'm not sure.
> > > Well, let's just assume original 25p -> 50i -> 25p and 30p -> 60i -> 30p.
> > > Those cases should be lossless.
> > Not if you maintain a constant resolution.
> > > Even 24p -> 60i -> 24p should be lossless.
> > I think so, but I'm not 100% sure.
> > > Thanks, but why would you use a high CRF == low bitrate for material
> > > with heavy artifacting ? SHhouldn't that lower bitrate just aggravate
> > > artifacts ?
> > The idea is that the original artifacts are going to be more obvious and
> > distracting than any introduced by raising the CRF value. You'll have a
> > lower bitrate and not notice the additional artifacting.
>
> Hmm.. then the additional artefacting shuold be 'nicer'than the
> usual mpeg blocking i know ;-)
It's not that they're nicer, but rather that they're unnoticeable. In
very clean material (e.g. a good Blu-ray source) they would stick out
(which is why I almost always use CRF=18 for Blu-ray), but in artifacted
material, they blend in and don't harm much of the remaining actual detail.
> Yeah, well, but the human (me) wants to outsource all the ongoing work
> to the DVR/software and not bother about the encoding for clips 
> individually ;-)
I rarely configure options on a clip-by-clip basis, but rather group
material by source quality. Using CRF makes it even easier since I don't
have to worry about what kind of material it is (I use a separate set of
encoding options for animation, but the CRF can remain constant).