JVC ProHD GY-HD251, ProHD GY-HD251E Specifications
Compact High Definition Camcorder
For Studio & ENG Applications
Live Uncompressed 720p & 1080i
GY-HD251
Defining the future of
professional video
with ProHD
With the introduction of JVC’s ProHD, the promise of digital
technology has finally been fulfilled. Surprisingly affordable,
impressively professional, and remarkably compact, ProHD
embraces the HDV format to deliver a complete high-definition
solution that has been designed to meet the needs of today’s
most demanding professionals, while retaining the ability to
adapt to future requirements.
Since the launch of D9 in 1996 and Professional DV in 1999, JVC
has continued to develop and diversify its digital video offerings
in response to the rapidly changing environment of visual
communications and production. The evolution of JVC’s range
of digital cameras and recorders continues with the introduction
of advanced features and varied storage options, including fullsize DV tape and hard disk drives.
Now with the production and delivery of video content starting
to shift to high definition, JVC has combined its expertise in
camera, encoding and storage technologies to create an
affordable HD solution. JVC’s ProHD system,
adopting the HDV format, utilises widely available
non-proprietary technologies such as MPEG-2
compression, DV recording media
and conventional hard disk drives.
Based on input from leading end users,
JVC has developed a system with
the most sought-after professional features
and performance. Noteworthy ProHD features
include full HD progressive
scanning, real 24p,
and a dual recording
system using tape
& HDD. As ProHD
evolves, it will include
solid state recording
media. Designed and
built for professionals,
ProHD is the fulfillment
of the digital promise,
offering true high definition
performance in a compact,
affordable system.
The latest addition to the ProHD
system is the GY-HD251, a compact
studio-capable shoulder camcorder
featuring full-frame 50p recording
for smooth, continuous images.
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ProHD — JVC’s Affordable
HD Solution
1. HDV Full Progressive Scanning (720p)
Leading industry professionals told us that they wanted a fullframe progressive scanning system that would shoot and
record the highest quality continuous moving images. ProHD
uses the 720/50p progressive HDV format and produces crisp,
native HD images which perfectly match today’s digital
displays and which can be converted easily, without
degradation, to interlaced scanning pictures.
2. Time Code
As a professional system, ProHD products include the facility
to record and display timecode. Convenient menu operation
makes it easy to preset time code at the beginning of a tape.
Simply select REC RUN or re-generation mode. User bits are
also available.
3. Highly efficient video compression
To provide the highest quality HD recording, JVC uses the
broadcast industry standard MPEG-2 Main Profile at H-14.
Offering far greater efficiency than frame-bound systems,
ProHD records at data rates at or above commercial broadcast
rates. Recent advancements in non-linear editing have made it
possible to edit ProHD on virtually all popular non-linear
systems. Direct digital transfers via IEEE 1394 ensure the
quality is maintained throughout the transfer process.
4. Dual recording system
Designed to utilise both DV tape and hard disk drives, ProHD
offers the ultimate in media versatility, maximising productivity
with efficient, economical editing and low-cost archiving. Now
you can safely archive the original tape cassette and then plug
the hard disk straight into your NLE. Editing can start right
away — no need to make dubs or to transfer data.
5. Real 24p
With ProHD, the dream of creating HD video with the essence
of film has at last been realised. By capturing and recording at
the film frame rate of 24fps, and offering extensive user
configurable settings such as exposure, gamma and detail,
ProHD becomes an important tool for creative expression. For
the ultimate form of display on the cinema screen, 24 frame
progressive recordings can be transferred easily to 16 mm or
35 mm film.
GY-HD251
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Advantages of ProHD
1. HDV format
HDV is a video format
designed to enable the
recording of high definition
MPEG-2 video on standard
DV media (DV or MiniDV
cassette tape). The HDV
format was defined by four companies: Canon Inc., Sharp
Corporation, Sony Corporation, and Victor Company of Japan
Limited (JVC). The specification of the HDV format incorporates
two versions, one progressive (720p) and the other interlaced
(1080i). HDV uses the same track pitch and tape speed as the
DV format, and therefore the recording times are the same
length as the DV format.
2. HD Progressive (720p/50) format for high
quality moving pictures and digital stills
Progressive scanning
JVC’s ProHD products use the same
progressive scanning system used in highend HDTV cameras. Because the
GY-HD251 uses a full-frame (50p)
progressive scanning system, it has the
unique ability to capture and store full
frames of image information. An added
bonus of progressive scanning is that it is
a very simple process to convert a
progressive image to interlaced, but not
vice versa. When progressive recordings
are paused or played in slow motion, each
individual frame contains the full detail of
the original image — excellent for viewing
and analysing motion. Stills and prints
captured from HD progressive video look
far better than from interlaced video. In any
case, today’s flat panel television displays and fixed matrix
projectors, such as D-ILA, DLP and LCD, are all native
progressive scanning systems. This means that JVC’s
progressive HDV recordings can be displayed without
imperfection, because they do not need to pass through the
degenerative process of de-interlacing, prior to being
displayed.
HDV and DV compatibility
The HDV format uses the same recording track pitch (10 µm)
as Professional DV, meaning that ProHD also offers track pitch
compatibility with the DV format and the same recording time.
This remarkable HD recording capability was achieved by
developing a new high-power MPEG codec system capable of
maintaining high-definition picture quality, whilst compressing
the data to 19.7 Mbps bit rate. With its superior resolution and
advanced processing, ProHD delivers top performance in both
its native 16:9 HD mode and in the SD mode.
Progressive HDV-compatible support
To maximise picture quality and performance from input to
output, JVC employs the HDV 720 progressive system.
Progressive HDV’s resolution of 1280 x 720 is the same as the
native resolution of most HD display devices in use today
(LCD, plasma, DLP, D-ILA). HDV 720p is thus natively
compatible in terms of both resolution and scanning system
with the vast majority of today’s HD displays.
3. Real 24p
24p Progressive Full HD images are ideal for cinematographic
applications. From shooting to editing and distribution, an HD
system can be established for film-like productions. Unlike 24p
images in standard definition, when real 24p HD video is
down-converted to SD, the result is truly film-like DVDs. The
camcorder itself, with its video lens removed and replaced by a
film lens converter system, such as the Mini 35 from P & S
Technik, effectively becomes a digital film camera.
The GY-HD251, fitted with
Mini 35 film adapter from P &
S Technik, becomes a digital
film camera.
4.JVC’s dual recording system
The optional JVC Hard Disk Recorder DR-HD100 creates a
dual recording system of tape and hard disk. This system is
already utilised by Professional DV users the world over. The
many advantages inherent in JVC’s dual recording system of
tape & hard disk drive are well appreciated. It was only natural
that JVC’s range of ProHD models would include a Hard Disk
Drive recorder and one that can operate equally in DV and
HDV modes. The dual recording system provides fast and
efficient HDD-based editing and cost-effective archiving, using
low-cost tapes. Thanks to the newly developed MPEG-2
encoding IC, high-quality pictures can be recorded on readily
available compact DV cassettes, so running costs are minimal.
As no special equipment or exclusive media are required, the
operating costs of the total system can be kept low. The
DR-HD100 is mounted at the rear of the camcorder, utilising an
optional bracket which is provided by the leading battery
systems manufacturers.
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