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HDV to Film: A Real-World Test
Making decisions and making discoveries on a tight-budgetfeature.
By John Jackman
In the world of professional video production, the HDV format has gone from
novelty to viability in record time. The rapid changes began over a year ago
when Sony introduced the HVR-FX1, and DVContributing Editor Adam Wilt
pronounced its compressed, MPEG-2 picture to be "better than it has any right
to be." The release of the Sony HVR-Z1U upped the professional-quality ante,
and HDV cameras from Canon, JVC, and Panasonic have streamed into the
market. With slick editing solutions available from all of the major players-
Apple, Avid, Canopus, CineForm, Lumiere HD, and others-the HDV format has
arrived in a big way.
Despite the sales success and broad acceptance of HDV, there is still an
information gap in terms of how well it really performs. Although a lot of HDV
units have been sold, a large number ofDVreaders are still on the fence about
whether to buy into the format or not.
So I decided to put the latest HDV techniques and technology to the test. I
produced a low-budget short from beginning to end in HDV, with the intent of
creating the best possible product in standard definition for DVD distribution,
HD for digital broadcast, and, because the promise of low-budget filmmaking is
driving the intense interest in HDV, I decided to take the piece all the way to a
35 mm film blowup.
The end result is here: An overview of the decisions and discoveries I made
while producing a real-world project in HDV, along with the reactions of some
seasoned DPs to the final film result. I found out a lot during the process-morethan can fit in the pages of the magazine. More details about the project are
available online at DV.com.
Early decisions: Camera, frame rate, and gamma
Armed with the script forWindsor Knot(a historical period drama about the
abdication of England's King Edward VIII that I've been wanting to shoot for
some time), I set out to choose a camera. At the time I was shooting (May
2005), I felt that there was only one viable camera for the project-the Sony
HVR-Z1U (Reviews, May '05 DV). The Z1 has several appealing features, the
most important of which are the abilities to use pro audio connections and
shoot in 1080i-50. Even though creating a 24 fps version for the film blowup
was critical, I found that creating true 24p was easier and more effective in my
tests starting with 50i than with 60i (more about this reasoning can be found
online at DV.com).
Search DV Search DV!
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I didn't consider Sony's CineFrame mode, which, though it creates a 24 fps
video file, has unaccept-able motion artifacts and image degradation (for more
about CineFrame, see Adam Wilt's analysis at www.adamwilt.com/
HDV/cineframe.html).
I experimented with the Z1U's CineGamma settings in an effort to achieve a
film-style gamma curve. The Z1U has two CineGamma settings, with
CineGamma 2 being more pronounced. I liked the look of CineGamma 2 and
decided to use that mode in shooting. On inexpensive cameras, these film-likegamma settings are accomplished not with the true S-curve that I would apply
in post, but rather by tilting the straight gamma curve to a more extreme
position Although this accomplishes almost the same thing as the gentle
S-curve, it's not quite the same. It doesn't supply the more gentle roll-off of
highlights and tends to crush dark grays to black sooner.
Click here to see a larger image
Video has a straight gamma curve. Film stocks often have a gamma curve
shaped like a shallow S. (right) Inexpensive cameras with "cine" gamma
adjustments usually simulate this by tipping the straight video gamma.
After testing color tweaks in the camera menus, I left most of the settings on
factory defaults. I turned the sharpness control down considerably, though not
to its lowest setting, which is a tweak I recommend for nearly all cameras if you
want a film-like finish. Reducing the artificial sharpening (technically known as
aperture correction) tones down harsh edges and avoids compression artifacts.
On location: Decisions and discoveries
I was dealing with a microbudget for this project (well under $3,000 for all
expenses and salaries), so I scheduled a single day of shooting on location.
The day came, we showed up with a truckload of equipment and people, and
Windsor Knotwas in production.
The decision to shoot in 50i necessitated a PAL-compatible monitoring solution.
I brought the JVC BYH13Y production monitor from my edit suite.
We monitored composition, exposure, and color on SD via the down-converted
Y/C output of the camera. But we discovered that neither an SD monitor nor the
camera's viewfinder, nor its LCD screen were up to the job of representing
HDV's details-we ended up with slightly soft focus no matter what we used. To
deal with this issue, Sony provides a zoom function on the viewfinder, as well
as a peaking function, which flags high frequencies (such as in-focus sharp
edges) with an accent color (red, yellow, or white). This works well to visuallycue the camera operator when focus is right on. Unfortunately, peaking can't be
used at the same time as zebra display, so the cameraman had to keep
switching between the modes.
The HVR-Z1U also has a basic zebra display that defaults to 100 IRE. We set
the zebra at 90 IRE to avoid the "video look" of overexposure and clipped
whites. I think clipping in HDV is really nasty, even worse than in DV. So an
essential rule for shooting in HDV is don't overexpose!It's much better to be a
stop under rather than a stop over while shooting. If necessary, you can stretch
the contrast back out in post.
Postproduction: Quality control
If I was going to edit on a Mac with Final Cut Pro, my logical choice would have
been Lumiere HD, a plug-in that provides machine control and on-the-fly
transcoding to the editing codec of your choice. But my shop is PC based, so
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the strongest contender was CineForm's Aspect HD plug-in (Reviews, July '05
DV), which works in Adobe Premiere Pro 1.5.1.
Click here to see a larger image
Editing was done in Premiere Pro 1.5.1 in 1080-50i using CineForm Aspect
HD Codec.
Editing native in HDV with no quality loss is now touted by some NLE vendors,
but it was not an option forWindsor Knot. Because HDV's MPEG-2
compression retains only one frame (the I-frame) every half-second or so and
interpolates the others, native HDV editing must cope with a major challenge:
Even a simple cut, unless executed at an existing I-frame, causes massive
recompression and artifacting in the subsequent frames. I chose the CineForm
codec, which is wavelet based and doesn't interpolate frames, to avoid this
problem and gain some elbow room for the intense process of compositing and
color-correcting.
I used the Sony HVR-M10U (Reviews, Sept. '05 DV) as my VTR for capture
and recording. The editing system was built around a Windows XP CPU with a
3.2 GHz Intel Prescott HT processor, 2 GB of memory, and dual-200 GB SATA
drives set up in a RAID-0 configuration for video storage.
I upgraded to version 3.1 of Aspect HD. The 3.1 version enabled batch
capturing, and the process went smoothly. Immediately after each capture, the
software automatically transcoded the original MPEG-2 file into the Aspect HD
codec. This process was roughly equivalent to real time on the 3.2 GHz
machine, which means that, when you use this method, you need to budget for
about double the time needed to capture your footage.
Once capturing and transcoding was completed, managing files and editing the
HDV material worked just like in any other format. Editing with the Aspect HD
codec was a satisfying experience. The response was snappy, and CineForm's
real-time engine really worked and allowed me to play back more layers and
effects from the timeline than some higher-end hardware-based systems.
Just one thing was missing-live playback to a real monitor. This can't be done in
real time via 1394 with Aspect HD because the software must transcode back
to an MPEG transport stream for display. A couple of options enable playout to
a color-accurate video CRT. If your computer has a motherboard with the new
PCI-Express slots, the Nvidia Quadro FX 540 allows a dual-screen editing
setup plus built-in HD monitor output. My machine didn't have a PCI-Express
bus, so I used the Matrox Parhelia board, which allows a dual-screen setup
plus program output to an SD monitor. Although I prefer true HD monitoring, I
was able to check scene-to-scene color with this setup.
The color-correction tools in Aspect HD, while not high end, are comprehensive
enough to allow pretty decent manipulation of the color in shadows, midtones,
and highlights. I tried to stick with the Aspect HD real-time plug-ins to give them
a thorough test, and found that the combination of the two (Color Balance and
Color Corrector) generally allowed me to do what was necessary.
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Click here to see a larger image
The Aspect HD real-time color-correction tools provided enough control for
the basic scene-to-scene color correction.
Fix it in post
I ran into two problems from the initial shoot that normally would have prompted
a reshoot, but since that wasn't an option, I decided to fix them in post and test
the limits of special effects in the HDV format. Remember when I said an
essential rule for shooting in HDV was, "Don't overexpose"? Well, the first shot
we did was a rack focus with a brightly sunlit window that was completely blown
out. The second problem was a shot where the camera crossed the line,
meaning that the character in the shot seemed to be facing the wrong direction
when intercut with the other camera angles used in the scene. I decided to useAfter Effects to fix both these issues. I planned to motion-track a fix for the
blown-out window and use a greenscreen shot of one character facing the
correct direction to replace the other shot.
Click here to see a larger image
To correct and over-exposed window a new exterior was motion-tracked in
After Effects. Luma Key and Matte Choker filters were used to make the
original clipped window transparent.
The Aspect HD footage imported correctly into After Effects, though it was
necessary to manually create a 1.33 anamorphic aspect ratio preset for the
footage to display properly. To correct the overexposed window, I prepared and
blurred a graphic of exterior foliage to seem out of focus. I placed it behind the
video footage (below it on the composition line). I applied the luminance keyer
with the matte choker to make the offending window transparent, and the new
exterior was motion tracked to match the foreground. Because the shot wasn't
designed to be tracked, it required some extensive hand-tweaking to get themotion just right, along with the look of the rack focus. The end result works
well, however, and doesn't call attention to itself.
A
Click here to see a larger image
B
Click here to see a larger image
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(a) The original footage with clipped exterior; (b) the finished effect is less
distracting.
The greenscreen shot was an interesting test of how far you can push this
highly compressed 4:2:0 format in the special-effects realm. We had high-res
still photos of every corner of the opulent living room set, and I simply used a
portion of one of those as the background plate. We shot the character (StanleyBaldwin) delivering his line in front of a green fabric backdrop with similar
lighting to the live shoot.
Click here to see a larger image
I created a greenscreen composite using the Color Range keyer in After
Effects. I used the matte Choker filter to smooth the jagged edges of the
matte and choke (contract) it to eliminate green edges.
In post, I tested several keyers, including Ultimatte AdvantEdge and Zmatte,
but got the best results on our footage with the Color Range Keyer and Matte
Choker in After Effects. The After Effects matte choker has improved in the last
few upgrades, and now can smooth out the jagged edges of low color sampling
schemes (such as DV 4:1:1 or HDV 4:2:0) effectively. Considerable choking
was necessary to achieve a clean edge. This worked nicely with Stanley
Baldwin, whose 1936-era slicked-back hair provided a fairly defined edge to
work with. On a subject with wisps of escaping hair or similar fine lines, those
details would have been lost.
I also needed to blur the edge of the matte considerably to match the other
hard edges in the natural picture. The initial matte had a crisp, well-defined
edge that looked artificial-too sharp-when composited into the HDV picture.
This is true to a lesser degree in less-compressed HD formats as well, but
mainly showed the limits of the Z1U lens. The HDV format can hold edges that
are much sharper than the standard lens can transmit.
Deinterlacing and conversion
Shooting in 50i was a decision I made in the beginning to preserve video quality
through to the end. Prepping the final sequence for DVD and film output
required a two-step process: First, I had to deinterlace the footage (from 50i to
25p), and then change the frame rate from 25p to 24p. (After I wrapped up
postproduction on Windsor Knot, a new version of Aspect HD was released that
would have made it a one-step process; see the "An Even Better Workflow"
sidebar.)
There are numerous techniques for deinterlacing footage, some of which are
terrible (field duplica-tion), others of which are a little better (field blending
methods), but the goal is to get good results without sacrificing vertical
resolution. After all, what's the point of shooting in a high-definition format if you
just go and toss away half the vertical detail in post?
The approach I used forWindsor Knotwas a "smart" deinterlace in After
Effects, which involves identifying those areas of a picture that have motion
between the fields and those that don't, and selectively applying field blending
only to the areas that have interfield motion. Another good option for smart
deinterlacing is DV Filmmaker from DV Film in Austin, TX (www.dvfilm.com).
DV Filmmaker is available for both Windows and Mac, and has a batch mode
that can process individual capture files. For all of the details on what
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constitutes a "smart" deinterlace, along with detailed instructions for setting it
up in After Effects, go to DV.com.
Once the material was deinterlaced into a 25p AVI movie, conversion to 24p
was done on a frame-to-frame basis by interpreting it as 24 fps in After Effects.
To stay in sync, the audio was slowed down 4 percent in Sound Forge
separately. The resulting 1440 x 1080 24p AVI file was ready for output to film.
For DVD output, the file was scaled in After Effects down to 720 x 480 with 3:2
pulldown applied. The end result-viewed on a 720p projector- looked very film
like. Surround-sound encoding was provided by the SurCode for Dolby Digital5.1 Encoder plug-in.
If you'd like to see Windsor Knot, you can learn more about the short and get a
DVD copy online at www.windsorknot.org.
Film blowup discoveries
The most intriguing test of the HDV format was the final stage-the output to 35
mm film. I sent identical 2-minute 24p CineForm HD codec files to DV Film in
Texas and Heavy Light Digital in New York. The file included a test shot with
high color and detail, and the greenscreen composite shot from the finished
short, as well as interior and exterior shots from the piece. Both labs printed the
file to Fuji 8522 negative stock and printed to Fuji print stock.
Because HDV-to-35 mm is still fairly new territory, I used two different labs to
discover what, if any, differences would show up in the final print. The results
point out the importance of running a test before choosing a lab.
We screened the test prints at the School of Filmmaking, North Carolina School
of the Arts, in a full-size theater. A panel of experienced film DPs was in
attendance, including Arledge Armenaki (Dennis the Menace, The Howling V),
Richard Clabaugh (Children of the Corn IV, Plato's Run, The Prophecy II), and
D. A. Oldis (Non-Abductees Anonymous). Armenaki and Clabaugh had both
taken part in a similar screening of DV-originated footage blown up to 35 mm a
couple of years ago.
The first print from DV Film was a bit disappointing. The DPs complained about
low black density (blacks looked dark gray instead of black), graininess,
pixelization, color blocking, and low saturation. The resolution of fine detail in
the test shot was lacking.
The print from Heavy Light Digital was much better. The print had good black
density, yet still had visible detail in dark areas. The color was better, and the
resolution was much sharper. Wide shots of the manor house exterior showed
detail in individual stones.
DV Film asked for another shot at the footage. The second print was better and
had higher overall detail. The blacks were denser-too dense, in fact, with a
subsequent loss of detail, and the color was artificially intense.
We watched the samples twice, pausing in between to talk about them.
Afterward, I asked the group to sum up their reactions to the best example, and
to HDV as a low-budget filmmaking format. Overall, they agreed that the HDV
blowup was substantially better than DV-originated blow-ups we had seen
previously, though the sample HDV clearly remains a step below true HD in
effective resolution. They thought it was likely that the inexpensive lenses used
on the lower-priced prosumer units contributed to the softer image when
compared with footage from a Panasonic VariCam or Sony FDW-900H; those
cameras are used with lenses that cost many times more than the total price of
the Z1U.
After some discussion, Armenaki and Clabaugh agreed that the blowup from
Heavy Light looked very much like a blowup from 16 mm. They felt that
origination on Super 16 would look somewhat sharper, but the parallel to 16
mm was strong. Armenaki went so far as to say that if he had been told it was a
blowup from 16 mm before screening the footage, he might not have noticed
the subtle cues that the footage had originated as video. All agreed that the
result was watchable, and that an average audience wouldn't notice the
differences if the other aspects of story and filmmaking craft were right.
It was interesting that none of the DPs noticed the greenscreen composite shot
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until I pointed it out. D. A. Oldis was impressed that the composite was so clean
when originating from a 4:2:0 format.
Budget considerations
Then came the difficult question: At what budget level should a filmmaker
consider HDV? This produced several answers and discussion about local
low-budget projects being shot on film. Armenaki and Clabaugh finally
suggested a feature project under $200,000. Both felt if they had higherbudgets, they would opt for renting a higher-end HD camera or shooting on
Super 16.
To answer this question, of course, requires a judgment call. There are many
other factors that would enter into a producer's decision to use HDV for a film
with potential for theatrical release. Many types of documentaries would be
better if they were acquired on video because it's more economical, allowing for
many hours of lengthy subject interviews. While a DP might want the higher
resolution and exposure latitude of a VariCam or CineAlta on a $500,000
project, the producer and director might opt to pay for higher quality talent in
front of the lens-or hire a larger number of high-quality actors. The producer
might even prefer to actually pay actors who otherwise would be working on
deferral (fat chance!).
Conclusions
My overall reaction to this trial project was real excitement about the potential of
the HDV format.I'll be even more excited when the manufacturers stop
squabbling and get HD DVD or Blu-Ray players shipping, so there is a viable
HD distribution and playback method. Editing was a far better experience than I
expected, and the end result was more filmic than I expected.
As people who have attended one of my workshops know, I pay a lot of
attention to compression artifacting. One of the very interesting discoveries I
made was that the MPEG-2 artifacting in most scenes seemed very similar to
film grain- very different from the obvious mosquito noise artifacting of DCT
compression in DV footage. Although the pseudofilm grain was more
pronounced than I prefer, it wasn't unpleasant or intrusive, and wasn't more
noticeable than the grain on some film stocks.
In retrospect, I would probably opt to use the less-aggressive CineGamma 1
setting on the Z1U or to change the gamma in post.
The format wasn't as delicate as I predicted, contrary to early fears about
dropouts. I ran initial tests using ordinary pro DV tape rather than Sony's more
expensive HDV tape, and saw no noticeable dropouts. Of course, for a more
extensive project, I'd probably want to use the HDV tape just to have the extra
bit of insurance against dropouts.
I'll probably buy one of the HDV cameras soon, but before I make my decision,
I want to undertake a similar test all the way to 35 mm film blowup. And I plan
on reporting the discoveries I make along the way, so stay tuned.
An Even Better Workflow: Converting 50i to 24p
After I completed post for Windsor Knot, CineForm released Aspect
HD 3.3 with some extra features-one of which is an on-the-fly frame
rate conversion to 24 fps. I tested this option by capturing some of m
original 50i footage and converting each clip to 24 fps (okay, really
48i) during the Aspect transcoding. Audio for each clip was slowed 4
percent during the transcode. The test clips were then batch-
deinterlaced in DV Filmmaker, and the clips edited on a 24p timeline.
The results were clean and the workflow was much better than the
somewhat cumbersome and multistage process I used on Windsor
Knot.
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I strongly recommend this workflow for PC users who want to end up
with a 24p product. I was less pleased with the results of Aspect 3.3'
direct conversion of CineFrame'd footage to 24p. Because of the
nature of CineFrame, the resulting frames lost about a third of their
vertical resolution. It's an easier work-flow, but at a price. Using the
50i-to-24p workflow instead with an interlaced camera like the Sony
Z1U will extract the highest quality possible from the format, with a
motion blur very similar to film.
Mac users still must under-take a more laborious conversion from 50
to 24p because Lumiere HD doesn't appear to have a similar frame
rate conversion utility. It's easy enough to simply reset the frame rate
of the clip, but the audio will still need resampling for the highest
quality finished product. DV Filmmaker for Mac can be used to
deinterlace, or you can use a plug-in like Magic Bullet.
HDV to Film: A Real-World Test (Bonus Tracks)
Now that you've read through the main article, here are some extra details and
information about the HDV-to-film process that just didn't fit into available space
for the feature.
Bonus Track 1: Reality Check
So, you're going to do a pizza-budget indie film with your pals in HDV, and
dream of doing a 35mm film blowup for distribution. That's great, and exactly
why I tested the production process with Windsor Knot. However, let's be
realistic. A quality digital blowup from HDV of a feature-length film is going to
run anywhere from $40,000 - $60,000 to start with. And then there's
distribution, without which only friends and relatives will see your film. In my
workshops on digital filmmaking, I make a pretty big deal about raining on this
parade -- because I've seen too many people hock everything and end up
bankrupt. Did you know that less than five per cent (that's 5%, or 1/20th) of
fully funded, completed feature films are picked up for theatrical distribution?
The percentage of films in the dreaming stage that will find distribution is
infinitesimal.
Dont let this stop you from pursuing your dream movie. However, I
recommend that most filmmakers plan for a film blowup -- but don't even think
of actually doing one until distribution is on the immediate horizon.
Bonus Track 2: Anatomy of An HDV Stream
HDV is a format agreed on by a consortium of manufacturers including Canon,
Sharp, Sony, and JVC. Panasonic is noticeably absent from the consortium
and appears to have no interest developing HDV products.
The format has been defined as a constant data rate, highly compressed
long-GOP MPEG2 stream that can be recorded on stock DV cassette tapes.
The overall datarate is about 19Mbps for 720p and 25Mbps for 1080i. The
color sampling is 4:2:0, similar to that of DVDs and unlike the 4:1:1 used in
NTSC DV. A 48kHz, 16 bit stereo audio stream is compressed with MPEG1
and is incorporated in the HDV transport stream. The resulting file can be
captured via IEEE1394 interface just like DV footage.
The MPEG2 compression used for HDV includes an IBP structure, including
both Predicted and Bidirectional frames. While this approach dramatically
reduces the bitrate for a given quality, it also means that editing is quite
challenging. The entire GOP, or Group of Pictures, must be decoded and held
in memory on the fly. When working a transition or multiple layers, the
computer may have to decode and hold as many as fifteen or twenty
decompressed frames in memory. The Sony Z1U uses a 15-frame GOP while
the JVC HD100 uses a shorter, 6-frame GOP.
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Click here to see a larger image
An illustration of the MPEG-2 format, with its IBP encoding structure. Only
the I-frames have all the information necessary to recreate the captured
image. The P and B frames have less information, and the correct cadence of
the I, P, B frames is required to play the footage correctly.
Heres a short glossary of MPEG2 and HDV terms:
GOP: Group of Pictures.
Short GOP: a Group of Pictures containing only an I frame.
Long GOP: a Group of Pictures containing more than one frame, whether IP,
IPPP, or IBP. A Long GOP may contain up to 18 frames in NTSC.
I-frame: Intra-frame, a frame containing all information necessary for the
codec to reconstruct the complete image. Each GOP starts with an I-frame,
which serves as a starting reference point for the following frames and which
allows random access points within a video stream.
B-frame: Bi-directional frame, a frame created by forwards and backwards
referencing of the P-frames and I-frames. Contains only predictive data about
changes from I and P frames, not enough data to make up an entire picture by
itself.
P-frame: Predicted frame, a frame created by using motion vectors to predict
the differences between it and the closest previous I-frame or P-frame.
P-frames, like B-frames, contain only predictive data.
Other Editing Options
ForWindsor Knot, I used Cineform's Aspect HD to transform my original
MPEG-2 HDV footage to an I-frame-only codec I felt would give me better
results in editorial. Cineform's products are PC based, and so they are a
natural choice for a Windows shop running Adobe Premiere Pro. But what ifyou're running a Mac with Final Cut Pro? FCP is now able to edit HDV footage
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natively, but if you want to use an I-frame-only solution similar to the one I used,
your primary choice for FCP is Lumire HD, an excellent plugin that provides
machine control, capture and automatic transcoding to the codec of your
choice. Frederic Haubrich of Lumire recommends editing in the
uncompressed 8 Bit Quicktime codec for highest quality, although his tests with
the new lossless Sheer Video codecs from BitJazz have been very promising.
Other options are out there, of course. Turnkey solutions like such as the
Matrox Axio and Canopus Edius NX for HDV are ready to go,. Software and
software packages like Sony Vegas and Avid (formerly Pinnacle) and Pinnacle
Liquid Edition can all handle HDVfootage can handle HDV, as can Avid's other
Windows-based NLEs (software or turnkey)..
Bonus Track 3: Demythologizing Deinterlacing
Deinterlacing techniques are a favorite topic of self-declared "experts" in web
forums, but unfortunately there's lots more smoke and verbiage in those
threads than actual illumination. So let's demythologize the subject here.
The basic deinterlacing provided on the timeline in most NLE packages is
simply field duplication. One of the fields (perhaps the even field) is thrown
away and the "kept" field (in this case, the odd field) is duplicated. In this
approach, lines 1 and 2 are duplicates, line 6 is a duplicate of line 5, etc. This
approach is quick-and-dirty and produces the least satisfactory result, since the
vertical resolution is instantly halved.
A slightly better result can be obtained with a technique sometimes called
"instant sex" (honest, I'm not making this up!) which is the deinterlacing version
of a color enhancement technique from a decade back. The video track is
duplicated and laid over itself on an NLEs timeline. The bottom track is
deinterlaced using the odd field. The top track is deinterlaced using the even
field, and then the opacity of the top track set to 50%. Various techniques
touted online call for different variations of boosted chroma, a touch of gaussian
blur, or some other combination of effects. The result is what is known as field
blending. It is an improvement over field duplication because it doesn't have
the jagged edges of the first method, but it still reduces vertical resolution byhalf.
The best deinterlacing (which some have called a "smart" deinterlace) involves
identifying areas of the picture that contain motion between the fields, and
creating a mask so that only those areas are affected. Inside that mask, the
fields are blended (resulting in convincing motion blur) but areas where there is
no motion are left unchanged -- and hence retain their full vertical resolution.
This method can be achieved in After Effects (as described in the article), but is
also used by DV Filmmaker and Magic Bullet for the 30P mode.
The method I used in the actual post for Windsor Knot was a "smart"
deinterlace in After Effects. After the final edit was completed, the entire file
was exported as an AVI and then brought into AE. There are two excellent
methods of field blend deinterlacing in AE, depending on the effect you want.
The first results in a sharper picture with less motion blur, the second results in
slightly more blur for objects in motion. In both, areas of the picture that do not
move between fields are unaffected and remain at full resolution.
Method 1: In the File menu, select Interpret Footage, and in the resulting
dialog box, select the proper field order.. In the case of HDV footage, choose
Upper Field First in the Separate Fields pulldown menu. Then check the
Motion Detect box immediately below the Separate Fields pulldown, and click
OK. Then, from the Effect menu, choose Video and apply the Reduce Interlace
Flicker filter to the entire program. Set the Softness slider to 0.7-0.9. Do not
exceed 1.0.
Method 2: In the Interpret Footage dialog, set Separate Fields to Off. The
Motion Detect box will be disabled. Then, apply the Video/Reduce Interlace
Flicker filter to the entire program. Set the Softness slider to 0.7-0.9. Do notexceed 1.0.
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Both of these methods work quite well; the second does begin to affect
non-motion pixels if Softness values of 1.0 or above are used. It does give
stronger apparent motion blur, however, and that was desirable for the look of
Windsor Knot, so I used method #2.
As mentioned in the article, aAnother good option for "smart" deinterlacing is
DV Filmmaker from DV Film in Austin, Texas www.dvfilm.com, and is available
. DV Filmmaker is available for both Windows and Mac., and has abatch mode
that can process individual capture files.
Bonus track 4: What about the CineFrame mode?
The Sony HVR-Z1U has a "CineFrame" mode which the manufacturer claims
creates a film-like motion. While the mode has some fans, most aficionados of
the film look decry the mode. CineFrame mode takes the interlaced video
and applies a 3:2 pulldown to it; indeed, this is similar to the manner in which
24 FPS film is transferred to video. However, since the Sony's CCDs operate
only in interlaced mode, the motion blur is the same as 60i, not like 24p at all.
And since the faked pulldown is achieved by tossing away fields periodically,
the resulting motion is jerky and irregular. The motion artifact shows up most
dramatically on camera motion that is usually avoided in 24p camera work; but
the irregular jerkiness is evident enough to make me avoid the mode. Inaddition, when CineFrame mode footage is deinterlaced to create true 24p, the
result has lower vertical resolution. In his tests, Adam Wilt also identified an
artifact that would show up occasionally where a field would be pulling color
samples from a previous field, resulting in an odd color flash in some scene
transitions.
Bonus track 5: What About 60i to 24p?
While there are some amazingly good methods of creating 24p footage out of
60i, they are very complex and involve sophisticated motion interpolation.
Examples would be the Snell & Wilcox Alchemist standards converter or the
Twixtor plugin. Any software that does not use motion interpolation (such as
Magic Bullet or CineLook) will accomplish the conversion by "throwing away" a
field periodically to make the frame conversion math work. The result is often
an irregular jerky motion that would not occur in real film, and which can be
quite distracting. This is why shooting in PAL 50i has always been preferred for
24p conversion, since the frame rate is so close that a frame-to-frame
conversion can be done without losing any fields or frames in the process.
The Rev. John Jackman has been shooting video for over 25 years. He was
one of the early cheerleaders of the DV format, but was pretty pessimistic about
HDV when it was first announced. You can hear him eating his words at The
Craft of Lighting forum atDV.com.
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