Interlaced vs Progressive Editing
Interlaced or Progressive editing?
You've looked at your sources, you've seen the
footage, you now have to ask yourself if you want to try removing the
interlacing before you start editing or are you going to just edit it
interlaced and deal with interlacing when it comes to distributing the
video on the Internet. There are different pros and cons for each, so
have a read through and decide for yourself.
All editing software is designed to edit interlaced footage.
It's already in a correct format specification (i.e. NTSC video @
29.97fps) and it means you can just edit the footage "as-is".
This is fine. You'll need to keep an eye on the field order,
but you should know the field order of your source now. The main caveat
with interlaced footage, in terms of editing,
is that whenever you slow it down, or move it around, or apply certain
effects, you need to deinterlace it. Deinterlacing can be good or bad
depending on the method and, unfortunately, the method used by one of
the most popular programs - Premiere - is pretty ugly. In fact, most
stock deinterlacing features in editing programs are pretty crap so,
during these parts, your video will look sub-standard. Also, if you
need to edit a still in photoshop or use a mouth section for lip-synch
you need to get sections that aren't interlaced otherwise things can
get really messy.
The secondary issue with interlaced footage arises when you
want to distribute your video for playback on a pc. Monitors are
progressive devices and interlacing looks ugly, so you need to remove
it somehow. The best way of removing interlacing from NTSC video is to recover
the original film frames using a process called Inverse Telecine or
IVTC. This works best when done before you edit - it is very
successfully IVTC after you have edited the source.
Some sources are already progressive, which is great. However,
the best way to get progressive footage from an interlaced source, as I
have mentioned, is by using
Inverse Telecine (IVTC). This will detect the pattern in which full
film frames have been converted to interlaced NTSC and try and reverse
it. With certain sources it can work very well. You can also have
progressive frames by deinterlacing as well. We will talk more about
the different methods later - right now you need to know what
difference it will make to your editing.
Progressive frames can be moved around, have effects done to
them and so on without having to worry about interlaced frames. It's
also very easy to take a still from any frame you like in order to edit
without worrying about the horizontal lines - this is great for
photoshop work, masking and all sorts of manual frame manipulation
One thing I will point out, however, is that running IVTC on
your footage will make it 23.976fps. If you are using Vegas video this
is not a problem... if you are using Adobe Premiere however, it is a
big problem Premiere cannot easily edit 23.976 fps and this is a very
annoying truth. It can edit in 23.98fps but this mode has all sorts of
synch issues and the final output is useless to everyone. Thankfully
you can change it to 24fps and premiere can edit
24fps fine so it's not all bad - it just requires a little more
preparation in advance.
23.976fps is no use for DV either as DV has to be 29.97fps (or
25fps for PAL DV).
Cons also like things, often, to be the standard 29.97fps interlaced
footage. Thankfully it's actually very easy to convert 23.976fps
29.97fps, so again it's not all bad (you can see how to do that later).
Mixing footage types:
If you are making an interlaced video, it is not a problem to mix in
progressive video and then export interlaced. You will not notice any
quality loss issues - progressive footage can have any field order and
will blend in perfectly. On a tv you wont even notice that they were
different. However, you should never add interlaced footage to a video
you are editing progressive, as the interlacing will stand out a mile
on a monitor.
So, if you know which way you are going to edit your footage, choose
your next option:
your footage Progressive
(removing interlacing) or skip straight to...
Aspect Ratios - PAR and DAR