Here's few random comments from someone who has used Cinelerra for numerous DVD projects over
the past few years.
Firstly, I'm not sure why there's an emphasis on deinterlacing in the context of making a DVD.
While deinterlacing will make the clips and the resulting video look better when played back
on a non-interlaced monitor (which usually means on a computer via software which does not do
decent realtime software deinterlacing) it will actually make the resulting DVD look *worse*
when played back on a normal interlaced TV. The only exception to this is if the field order
gets changed between the raw video and the final DVD MPEG2 stream - then the DVD will look
absolutely terrible. One could fill a book with the details of field order, interlacing, when
to use it, how to get it right, etc etc - it's a complex subject which only gets worse in NTSC
land. The upshot though is that you only want to deinterlace material which will be viewed on
a computer; for DVDs destined for a normal TV you want to preserve interlacing (and field
order).
As to cinelerra being a memory hog, I can confirm that this is the case. However, the extent
that this was encountered by the author is not consistent with my experience. Admittedly I
use the HV (Heroine Virtual) cinelerra, not the CV version seemingly used by the author, so
perhaps there are memory issues in the CV version which are not in the HV version. Even so, I
can confidently say that in 5+ years of using cinelerra for projects up to 6 hours long with
individual clips lasting 90 minutes I have never once had Cinelerra HV cause the OOM killer to
act. This is on a very lowly 866 MHz Pentium3 with only 512 MB of RAM and minimal use of swap
(in the past it's been even slower with less RAM).
Cinelerra does have a propensity to crash for no apparent reason though. "Save often" is
definitely good advice. It's interface is also somewhat unusual and takes some getting used
to. Once you know how to drive it you can do incredible things, but the learning curve is
unnecessarily steep which is unfortunate. In this day and age there are certainly more
intuitive GUI interface concepts/nomenclatures for achieving the same things.
This is certainly not to bash cinelerra. I think the authors (both HV and CV) have done an
incredible job on getting this complex tool to the point where it's at today. It's a tool
which does allow me to complete the projects I'm working on to a standard I simply couldn't do
with any of the other FOSS NLEs in existance today and for this I am very grateful. Having
said that, the developers behind the CV version are aware of the need to work on stability and
the GUI (there has been recent discussings about this on the CV mailing list). As stated in
the article though it does seem that the developer pool is rather thin and as a result any
significant work on cinelerra-cv (and the HV version for that matter) does take an inordinate
length of time.
I should also note that I use cinelerra only for the video portion of my projects. For the
audio side of things (which invariably involves multitrack sources and mixdown) I utilise
ardour.
As a parting comment, I agree totally with the general conclusions reached in this article -
we have some promising FOSS video tools but they all need varying amounts of work before they
are ready for the masses. They can be used now to do "real work", but only if one is willing
to put up with the often considerable rough edges.
Posted Jan 24, 2008 11:24 UTC (Thu) by tialaramex (subscriber, #21167)
[Link]
In principle, the parent comment is correct about interlacing, but it's not apparent to me
that it's necessarily desirable now in 2008
A "normal" interlaced TV was the only thing in people's homes in the 1990s when DVD was
introduced. However most of the material people are actually watching on DVD, that is, movies
and high budget TV productions was shot on film (or a film-like digital process), and so no
true interlaced source exists. As a result what's actually on the DVD is essentially 24 fps
progressive scan, and the interlacing is created during playback.
[ It's possible to use the same telecine process an analog TV channel uses to broadcast a
movie, and then record the interlaced result on DVD, and in a few famous cases this has
actually been done to movies you've heard of, e.g. some releases of The Princess Bride, but
it's acknowledged that this is the Wrong Thing™ ]
In another decade, with CRTs gone from most people's homes, interlaced video may be solely a
legacy format. At that point approaches your choice for old home videos, where the source
material really is interlaced will be between relying on a realtime de-interlacing filter in
your DVD playback hardware or television, and doing it once with high quality software as our
Grumpy Editor elected to.
interlaced video
Posted Jan 24, 2008 23:41 UTC (Thu) by jwoithe (subscriber, #10521)
[Link]
I agree that the move away from "traditional" TV devices, video interfaces and delivery
methods in favour of non-interlaced and computer-based options is slowly making interlaced
video a legacy format. I also suspect that the speed at which interlaced formats become
deprecated will be different in almost every country.
Having said that, a vast majority of people I provide video to are still running AV equipment
which relies on standard PAL interconnects - and that means interlaced video. For such
people, providing a deinterlaced 25 fps program (25p) will result in an obvious drop in
quality compared to 25i (and is in fact a lossy operation if starting with 25i source
material). Obviously everyone's situation is different, but in this case 25i is a format
which provides the best result for everyone: those with 25i equipment get the best result they
can hope for, and those with gear capable of 50p will still get an acceptable picture due to
deinterlacers in their players/tvs (which aren't all that bad even now). Note that
distributing with 50p isn't really an option yet since few people have players capable of
dealing with this format (DVD doesn't).
While the above refers (obviously) to PAL land, similar statements apply to NTSC.
It should also be noted that in our editor's case (as in mine), the source material was almost
certainly interlaced, so his deinterlacing operation from 30i to 30p was in fact lossy.
This whole area is a minefield and looks set to remain that way for some time to come.
Ideally interlacing would just go away, but there's a huge installed base of interlaced
equipment which guarantees that this will be a long drawn out process. Until that process
completes one has to be aware of all the issues and make a call based on their particular
circumstances.
interlaced video
Posted Jan 25, 2008 7:21 UTC (Fri) by njs (guest, #40338)
[Link]
Almost all current HD broadcasts are interlaced too ("1080i"), and will be for some time :-(.
AFAIU the reason they do this is that for most shows it's actually considered superior to the
equivalent progressive format ("720p"), because at a given bit-rate, interlaced video gives
better spatial resolution at the cost of some temporal resolution. Maybe. Something like
that.
Looking forward to ubiquitous 1080p, myself. (At last, something to use those terabyte drives
for!)