Tips T0020
HDV, it’s Editing Hurdles & Snazzi*, the Complete
Solution To HD Editing
High
Definition Video
HDV is a "consumer high-definition video
format" proposed by a consortium of manufacturers,
the core of which is composed by JVC, Sony, Canon and
Sharp. These companies proposed the basic format specifications
in July of 2003, and the formal announcement of the
format came in a press release from the HDV consortium
on 30 September 2003. The first camera supporting HDV
format was introduced by JVC in June 2003, the JY-HD10U
(www.jvc.com/pro). In September of 2004 Sony's introduced
the HDR-FX1 HDV camcorder. This announcement was immediately
followed by HDV announcements from Adobe and leading
Editing equipment manufacturers- The HDV revolution
had officially begun!
In
fact, high definition video has been around for a number
of years. In America, you can buy high definition televisions,
and watch high definition video content on all the major
networks. Broadcasters are now buying HD equipment,
because they know that TV channels are demanding high
definition content. Meanwhile, for consumers, and anyone
else who wants to use HD but can't afford the tens of
thousands of dollars it costs for a professional camcorder,
there's HDV.
The
expression "HDV" is, fairly obviously, a combination
of "HD" and "DV"; and that's exactly
what HDV itself is: high definition video on a DV tape.
HDV uses MPEG-2 compression to achieve this feat - pure
genius on the part of the manufacturers because they've
managed to introduce an important new video format without
all the effort and expense of having to design a new
type of tape and the mechanical stuff to go with it.
Basically, HDV is a 19 megabit-per-second MPEG-2 transport
stream that records to existing stanard DV format digital
video cassettes, the most popular form factor of which
is the ini-DV shell. It is a fantastic new format. But,
to understand exactly how good it s, you need to understand
quite a lot about high definition television itself.
HDV is, in itself, just a way to achieve high definition
television. HD video isn't just a bit better; it's a
lot better than standard SD.
HDV Specs
As the basic idea behind HDV is to store high-def
MPEG-2 video on standard DV media (DV or Mini DV cassette
tape), and stream it across standard FireWire / IEEE
1394 interfaces.
The
HDV video format supports MPEG-2 compressed video (MP@H-14),
at two 16:9 resolutions:
- 720p (1280 x 720, progressive), at approximately 19
Mbps data rate
- 1080i (1440 x 1080, interlaced), at approximately
25 Mbps data rate
and
at both NTSC and PAL television rates (30 and 25 frames
per second):
- 720p at 60p, 30p, 50p, 25p
- 1080i at 60i, 50i
The HDV audio format supports MPEG1 Audio Layer II compression
at 48 kHz sample rate, with 16-bit samples, stereo (2-channel)
at 384 kbps data rate.
The HDV streaming data format over FireWire is a standard
MPEG-2-TS (Transport Stream) format. Unfortunately,
the MPEG transport stream format is typically used for
transmission and not data file storage, and therefore
cannot be processed directly by most video software
applications. The common MPEG computer file formats
are program streams (typically .MPG, with mixed video
and audio) and elementary streams (typically .M2V, with
just the video data). This is one of the issues limiting
software compatibility with the format.
Remember: the resolution of standard definition television
in the US is 720 by 480 pixels. The highest HD resolution
is an incredible 1920 by 1080 pixels. That's over two
megapixels, which means that it's well into the sort
of quality you can get from digital still cameras. Of
course it's nowhere near the tens of megapixels you
can get from high-end digital still cameras, but don't
forget that you get thirty of these pictures per second.
So the overall effect is simply stunning.
What Makes HDV Hard to Edit?
There are several factors that make HDV a difficult
format to edit. First of all the native HDV file is
an MPEG-2 Transport Stream. MPEG files use an "inter-frame"
style encoding. In order to encode an MPEG file data
is removed from various frames to reduce the overall
file size, but for playback/editing this file data must
be recalculated and decoded. During this decoding the
removed data can be reconstructed using data found in
nearby GOPs (Group of Pictures). This means if you drop
an MPEG clip into a timeline with the timeline cursor
on a frame and that frame is not entirely complete,
it needs to have the missing data filled in with data
from the surrounding pictures.
This process requires a lot of extra CPU effort, even
for a single frame, and lowers overall realtime performance.
This is further complicated when filters, layers, transitions,
and titles are added. Imagine processing a color correction
and/or a PiP (Picture and Picture) in addition to the
overhead added to decode the MPEG. Now you are not only
asking your editing software to figure out the color
correction and/or PiP at that very frame, but it also
may need to decode the frame by retrieving information
from the surround pictures as well. This extra decoding
and dependency on other frames makes native HDV very
difficult to edit.
Compare this method to "intra-frame" style
compression used by the DV format. "Intra-frame
compression" means that all the data required to
decode the frame is located within the same frame. "Intra-frame"
style compression makes the file significantly easier
to decode for playback and editing because the CPU does
not have to look in multiple places for a single frame's
data.
The second factor that makes HDV very hard to edit is
preview to an external monitor. Many people who edit
SD video understand that editing with a broadcast monitor
is a necessity to be able to view the true results of
what they are editing. Without an external monitor it
is impossible to accurately tell how colors and details
will appear upon final output. HDV presents a new problem
for external output however. In NTSC, for example, an
SD monitor uses 720 x 480i and a HD monitor uses 1920
x 1080i of resolution.
Snazzi*, the Complete Solution to HD Editing
If HDV is using 1440 x 1080i resolution, how
is one supposed to get full-resolution output to an
external monitor? Snazzi* & SnaZio* combined with
Snazzi* Premiere Pro Studio HDV package answers this
key question.
System
Recommendations for HDV editing production
Before we recommend any specific NLE for HDV,
we need to understand that all this extra resolution
requires VERY powerful computers to process. For 720p
productions you will be able to get by with a single
processor system, but for 1080i resolution you will
need to get dual processors.
Software
Application
•
Snazzi* Premiere Pro (AVIO Edition)
o Bundled with full version of Premiere Pro
1.5 + HDV plug-in 1.5 + Audition 1.5 + Encore DVD 1.5If
HDV is using 1440 x 1080i resolution, how is one supposed
to get full-resolution output to an external
•
Aspect HD
System Recommendations for HDV editing production
Before we recommend any specific NLE for HDV,
we need to understand that all this extra resolution
requires VERY powerful computers to process. For 720p
productions you will be able to get by with a single
processor system, but for 1080i resolution you will
need to get dual processors.
Aspect
HD v3.0 Features
• Supports all existing editing modes
and features of Adobe Premiere Pro 1.5, including Adobe's
new "HDV plug-in"
• Supported HDV resolutions: 480p60, 576p50, 720p30,
1080i50, 1080i60.
• IEEE-1394 Source Input Format: - MPEG2 MP@HL
Transport Stream (HDV format)
• File Input Format: - Any file compatible for
import into Adobe Premiere Pro 1.5
• Editing file format: CineForm Visually Perfect™
CFHD. YUV 4:2:2 . AVI wrapper for compatibility with
other Windows AVI applications.
• Includes HDLink, CineForm's HDV I/O application
and MPEG conversion utility
• CFHD Compressed File Sizes: Variable based on
scene complexity.
1080i60 HDV files compress to typically 9MB - 14MB per
second, approximately 40 GB/hour.
720p30 HDV files compress to typically 7.5MB/sec, approximately
30GB/hour
• Multiple video quality range settings during
capture
• Multiple resolutions supported simultaneously
on timeline
• Simultaneous real-time effects on multiple layers
of HD video:
- Keyframeable color adjustment
- Over 40 parameter-controllable transitions
- Slow-motion and frame hold
- Static and moving titles and video overlays
- Pan/Scan/Rotate/Zoom (PSRZ). For standard definition
output, PSRZ allow real-time zooms and camera rotations
to be added in post- production without any loss of
pixel resolution.
• 24p editing workflow. If exporting to M2T, automatic
pull-down conversion from 24p to 60i is provided.
• Hyper-threaded encoder for faster ingest on
dual-CPU (Xeon or Opteron) PC
• Dual-monitor support for dedicated timeline
monitoring (optional): Most nVidia, ATI, and Matrox
graphics cards with either dual-head monitor connectors
or an NTSC s-video output are compatible. For dual-head
graphics cards, the second display should be configured
to use the overlay channel
• After Effects 6.5 importer/exporter components.
• Output Formats supported by Premiere natively
or through plug-ins, including:
- HD: Windows Media Video 9 (WMV9); MPEG2 MP@HL, MPEG2-TS
MP@HL (HDV),
- SD: MPEG2, DVD (anamorphic and letterboxed), Analog
VHS (External video output card required)
Supported
HDV camcorders
- Sony
HDR-FX1
- Sony
HVR-Z1
- JVC
JY-HD10U HD and HD?GR-HD1
- JVC
HM-DH30000U DVHS Dec
HDV in Practice
Imagine you're a wedding videographer. You've
decided to go with HDV and have a 1080i HDV camcorder
and a Snazzi* Studio HDV editing package. You shoot
your video and edit just as if it were standard definition
DV. The only difference for you is that, when you were
shooting, you probably spent more time looking at details,
because HDV shows up everything. Now you have to figure
out how to prepare the video for distribution to the
wedding guests.
The first decision is easy. You've got to make a DVD.
That's because standard definition video isn't going
to disappear overnight, and it's what most people will
be expecting, anyway. Don't think that just because
you're delivering a standard definition DVD, you're
throwing away all the benefits of shooting in HDV. The
chances are that your DVD will look better than the
ones you used to make from footage sourced in DV. That's
because Snazzi* Premiere Pro Studio HDV can convert
directly from HDV to DVD format, and because the additional
visual information in HDV footage actually helps the
DVD type MPEG compressor make a better picture. So,
standard definition customers will benefit from your
choice to use HDV.
You'll
also want to produce high definition versions. Don't
forget that people often look at wedding videos five,
ten or more years after they were made. So you need
to make a version that's going to be viewable for the
foreseeable future. That's difficult because we don't
know what's going to happen in the future.
So what you can do for the time being is:
- Make
a Windows Media file for viewing on computers and
– probably – future high definition video
players, and
-
store the material as HDV video on tape – or
store the files themselves on removable storage media.
Remember
that Snazzi* will be able to deal with virtually any
new HD distribution formats – so you're always
going to be able to convert your material at a later
date.
Now let's suppose that you're a corporate videomaker.
Again, for the time being, you're probably going to
have to produce DVDs from your HDV material. Your clients
will appreciate the different “look” to
your material. They'll also like the way your graphics
and charts look clearer because all graphics processing
is done by Snazzi* in high definition resolution –
even if you're only working with standard definition.
And if you have to incorporate archive footage, or use
material in standard definition, Snazzi* will let you
mix multiple formats on the timeline, in real-time;
upscaling video to HD if necessary.
If
your work is to be shown in the company's atrium, they've
probably got an MPEG-2 HD server, which will want an
MPEG-2 transport stream. This is something you can easily
output with Snazzi*. They might even want a version
for their web site. You've already got the tools to
do this, and the quality will still look better than
the DV-sourced equivalent.
FINALLY....
You don't have to upgrade to HDV. Standard
Definition is going to be with us for a long time yet.
But HDV editing systems are here, now, and so are the
cameras. So, when you upgrade your editing system, buy
one that can do HDV. A Snazzi* editing system will work
superbly with your old footage, and it'll be ready for
you when you want to make High Definition masterpieces,
that will still look fantastic in ten years and beyond.
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