Q
Give me an overview of the HDV
formats.
A
The HDV format includes the 720p and
1080i specifications. The 720p specification employs progressive scanning
with 720 vertical scanning lines (effective scanning lines). The 1080i
specification employs interlace scanning with 1,080 lines. |
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Q Isn't picture quality deterioration such as block noise
and errors usually a concern with MPEG-2?
A Since a
bit rate after compression of 25 Mbps has been achieved, the format allows
very good picture quality for recording and playback. |
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Q What companies support the HDV standard?
A
The HDV standard was established by
four companies: Canon Inc., Sharp Corporation, Sony Corporation, and the
Victor Company of Japan, Limited. Many companies including most of the
non-linear software manufacturers have expressed their support for the HDV
standard. For the latest list of companies that support this format visit
http://www.hdv-info.org
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Q What is the audio compression method for HDV?
A
The audio compression format is MPEG-1 Audio Layer
II. This format can compress and record a signal with a sampling frequency
of 48 kHz and quantization of 16 bits, at a bit rate of 384 Kbps |
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Q Why are there so many companies supporting HDV?
A This is because it is a based on the global DV standard,
and the same DV mechanisms can be used for HDV. Moreover, since it employs
the broadcast standard for image compression, MPEG-2, it is possible to
connect HDV devices with TVs and personal computers. |
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Q Which has better sound quality, HDV or DV?
A With DV's 16-bit 2-ch mode sound and HDV's audio
recording, DV has better quality sound for the parts where compression is
not carried out. However, since HDV uses a very high bit rate (384 Kbps) for
sound compression, the sound quality is almost on par with uncompressed
audio. |
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Q What kind of media is used for HDV?
A
Conventional DV tapes are used for recording in HDV. |
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Q Is the HDV sound quality comparable to a music CD?
A Since HDV
audio is compressed, theoretically it is inferior to CD sound quality.
However, as mentioned above, by securing a high bit rate after compression,
the sound quality is almost on par with that of a CD. |
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Q How long is the HDV recording time?
A It is the
same as DV recording time. Also, with the HDV 1080i specification, there is
no long- playing mode. |
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Q In the future, will the DV standard disappear and the HDV
standard become mainstream?
A Along
with the widespread adoption of HD broadcasting and HDTVs, it is expected
that the HDV standard will soon become the norm. However, DV is currently
the mainstream as far as price and the popularity of DV displays are
concerned. Nevertheless, there will soon be more models of HDV camcorders on
the market, and when the prices come down, HDV will likely replace DV as the
main standard. |
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Q How is it possible that the large HD video data quantity
of HDV can be recorded in the same running time as the DV standard on DV
tape?
A Recording
is possible in the same running time because MPEG-2 is used. MPEG-2 is a
compression system that can realize high resolution even at a low bit rate
by using information on differences between frames. |
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Q What is the difference between 1080i and 720p?
A The 720p
specification employs progressive scanning with 720 vertical scanning lines
(effective scanning lines), and the 1080i specification employs interlace
scanning with 1,080 lines. |
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Q What is the difference between HDV and DV? Which has
better picture quality? HDV and
DV have different image compression and tape recording methods. Since HDV
was developed in order to record and play back high resolution HDTV video,
HDV has higher resolution from the standpoint of the number of pixels. |
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Q Why are there two specifications (1080i and 720p) for the
HDV standard?
A
This is to enable the development of products that
meet different HD infrastructures around the world. |
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Q What is the HDV video compression method?
A HDV uses MPEG-2 compression, and the bit rate after
compression for the 1080i specification is 25 Mbps. |
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Q Which has better picture quality, HDV 1080i or HDV 720p?
A The picture quality depends on the specifications
of the product. Select the specification that best meets your needs. |
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Q Is it possible to record HDV and DV alternately on the
same DV tape?
A
It is possible under the standard, but it depends
on whether the manufactures will develop their products to allow mixed
recording on the same tape. |
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Q How does the HDV error correction method differ between
1080i and 720p?
A
The main difference is the correction coding ratio,
and the mechanism for error correction over multiple tracks. |
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Q Can an HDV camcorder also record in DV?
This depends on the product specifications. |
|
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Canopus Apple
Lumiere
Sony Vegas
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Playback and editing |
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Q If I play a DV tape containing an HDV recording on a
regular DV camcorder rather than an HDV camcorder, and then output the
signal to a TV, will it still be HD output?
A Tapes with HDV recordings are only guaranteed for
playback on HDV camcorders. If you do try to do this anyway, either the
video and sound will not play back, or depending on the model, it will
determine that it is an HDV recording and warn you not to record over it. |
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Q Can I upload HDV data to my computer and edit it? Is it
possible to edit both the video and audio just like with DV data?
A This is possible if you have an HDV application
software on your computer. The type of editing will depend on your software. |
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Q Can tapes recorded with the 1080i specification be played
back on a 720p-specification camcorder? Or vice versa?
A It may not always be possible for a 720p camcorder
to play back a tape recorded in the 1080i specification, and vice versa.
Compatibility depends on the actual specifications of the product. |
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Q Can I upload HDV data to my computer and then save it on a
DVD disc?
A If your HDV application software allows you to
convert the data to SD, you can save it as a DVD video. Also, you can save
it on a DVD data disk, which is the same concept as data backup. However, in
this case it will not be compatible for use on a DVD player. |
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Q If I play an HDV recorded tape on an HDV camcorder, and
then connect it to a non-HD TV and output the signal, will it provide better
or worse picture quality than playing a DV recorded tape?
A This depends on the product specifications. |
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Q After uploading HDV data to my PC and editing it, can I
then write the data to a DV tape using the HDV or DV standard?
A Either is possible if your HDV application software
permits it. |
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Q If I connect an HDV camcorder to a TV for playback, which
terminal should I connect to for the best picture quality?
A i.LINK(IEEE1394) connection is recommended. |
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Q What are the necessary PC specs to allow for uploading and
editing of HDV data?
A Pentium 4 3.06 GHz or higher RAM: 256 MB or higher
(1 GB or more is recommended) HDD: UltraATA100 i.LINK terminal as standard
equipment Display: XGA or higher Video memory: 32 MB or higher Software:
Windows XP SP2 or higher * The above specifications are provided as a
guideline. Be sure to also check the specs required by the application
software. |
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Q Is it possible to store the data from a HDV recorded DV
tape on my PC hard drive? What format would the file be?
A This is possible using an HDV application software
on your PC. The file format will depend on your software. |
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Q How big is a HDV file when it is uploaded to a computer?
A If the data is uploaded in MPEG-2 format without
conversion, the file will be about the same size as a DV file of the same
running time. A ten minute video is about 2 GB. |
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Glossary |
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720p
The number "720" indicates the number of scanning lines, and
"p" indicates progressive scanning.
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Hi-Vision
This is the name of the HDTV service developed by Japan's
NHK. Digital HDTV is also called Digital Hi-Vision in Japan. |
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1080i
The number "1080" indicates the number of scanning lines,
and "i" indicates interlace scanning. |
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i.LINK
This is a standard for connecting computers to peripheral
equipment. The name i.LINK is a nickname for IEEE 1394 developed by Sony. It
allows up to 63 devices to be linked together, and has a maximum
transmission speed of 400 Mbps. It has the advantage of providing power
through the connection cable, as well as a hot plug (able to connect or
disconnect without cutting the power to the device). It is used to connect
with DV camcorders. In the DV standard i.LINK is called a DV terminal. |
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Aspect ratio
The aspect ratio is the ratio of the screen width to height.
Conventional TVs have an aspect ratio of 4:3, while HDTV has a wider ratio
of 16:9. |
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ATSC
This stands for "Advanced Television Systems Committee," a
committee composed of private companies that make digital TV policies in the
US. ATSC is also used to indicate the digital TV broadcast format set by the
same committee. There are standards for both terrestrial and cable TV
broadcasting.
MPEG-2 is the video standard, and Dolby AC-3 is the audio
standard. |
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I nterlace scanning
Interlace scanning is a method that can produce two images
in a single scan, by scanning every other line. For example, if there are
480 scanning lines, only the oddnumbered lines are scanned for the first
image (1, 3, 5, ... 479), and all the even-numbered lines are then scanned
for the next image (2, 4, 6, ... 480). Interlace scanning has the advantage
of displaying smooth movement. However, the disadvantage is that strictly
speaking the resolution for each image is lower.
Interlace scanning is mainly used for TV broadcasts. The
reason for this is that if the image continuity is high and interlace
scanning can provide smoother movement as mentioned previously, while the
frequency range is limited, it is adopted since the reduced resolution is
not very noticeable. |
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Blu-ray Disc
This is the optical disk developed by Sony, Panasonic, and
Phillips. On a disk the size of a regular DVD, 27 GB of data or six times
the data of a DVD can be stored. Using this technology for recording, it is
possible to maintain the quality of HDTV content.
Compression
A generic term for any technology that enables data to take up less space.
Compression can be applied to data files, images, audio, or video.
Lossless compression is used for software, text files, or any
application where all the original bits must be retained when a file is
decompressed. Lossy compression is most often used for digital audio,
video, or images, where some of the original data can be sacrificed to
reduce large file sizes. Lossy compression degrades the quality of the
original data somewhat. But the smaller file size makes the data much easier
to store and faster to transmit.
Composite Video
A type of video signal in which all the necessary video information is
combined into one signal. This is the type of signal used for broadcast TV
in the United States. Most computer monitors use RGB video, in which the
red, blue, and green signals are sent separately to produce a sharper image |
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ISDB
This stands for "Integrated Services Digital Broadcasting",
which is an HDTV broadcasting system based on a digital format developed by
the NHK Science & Technical Research Laboratories (NHK STRL) in Japan. It
includes terrestrial and satellite transmission standards, and the main
types are ISDB-T for terrestrial digital, ISDB-S for satellite digital, and
ISDB-C for cable digital broadcasting.
For all of these standards MPEG-2 is used as the video
coding, while MPEG-2 Advanced Audio Codec (AAC) is used for the audio
coding. It has the advantage of allowing the use of common receivers
regardless of the transmission format, as it is offered together with
services such as EPG and data broadcasting. |
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Component terminals
These terminals transmit each of the three video chrominance
difference signals: Y (luminance signal), R-Y (signal of red signal minus
luminance), and B-Y (signal of blue signal minus luminance), through
separate cables. Since three cables are used, the terminals are also divided
into three. |
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MPEG-2
MPEG means "Moving Picture Expert Group", and is the name of
the organization that developed the standard for recording video and audio
as digital data. It also indicates the video and audio digitalization
standard created by the same organization. MPEG-2 is one of the standards
developed by this organization, and is used in various fields including DVDs
and digital broadcasting. |
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Digital cable television
This is broadcasting through digitized cable signals. The
digital cable TV standard includes ISDB and DVB. |
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MUSE
This stands for "Multiple Sub-Nyquist-Sampling Encoding",
which is an HDTV broadcasting system based on an analog format developed by
the NHK Science & Technical Research Laboratories (NHK STRL) in Japan. This
format was a precursor to today's HDTV system. |
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Digital satellite broadcasting
This indicates digital broadcasting from man-made satellites
orbiting the earth. The digital satellite broadcasting standards include
ISDB and DVB. |
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NTSC
This is the SDTV broadcasting format established by the
"National Television Systems Committee" in the US. It uses interlace
scanning with 525 scanning lines and a frame frequency of 30 Hz. |
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D terminal
This is a terminal that can transmit the three chrominance
difference signals that make up the video signal: Y (luminance signal), R-Y
(signal of red signal minus luminance signal), and B-Y (signal of blue
signal minus luminance signal), in one cable. Its name comes from the fact
that the shape of the terminal looks like the letter "D." The types of
terminals include the D1 terminal for 480i, the D2 terminal for 480p and
480i, the D3 terminal for 1080i, 480p, and 480i, and the D4 terminal for
720p, 1080i, 480p, and 480i. In order to transmit the HDTV video signal, the
devices at both ends need to have D3 or D4 terminals. |
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Number of effective scanning lines
This is the number of scanning lines that actually produce
the image on the screen. |
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PAL
PAL is an abbreviation for "Phase Alternation by Line",
which is an SDTV broadcasting format developed in the former West Germany.
It uses interlace scanning with 625 scanning lines and a phase frequency of
25 Hz. |
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DVB
This stands for "Digital Video Broadcasting", and is the
digital TV broadcast format developed by the DVB project established jointly
by European manufacturers. It includes standards for terrestrial, satellite
and other forms of transmission, and the main standards include DVB-T for
terrestrial digital, DVB-S for satellite digital, and DVB-C for cable
digital broadcasting. MPEG-2 is used as the standard for video coding, and
MPEG-2 Layer I and II are used for the audio coding standard. DVB is not
just for HDTV, but also provides a lot of services that use the data
reduction benefits of digitalization to create multiple channels. |
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Progressive scanning
Progressive scanning is a display method where lines are
scanned in order from the first to the last, and one image is produced with
one scan. It is also called non-interlace scanning. For example, if there
are 480 scanning lines, the lines are scanned in order from the first to the
480th line. The advantage of progressive scanning is that a picture without
flickering can be achieved. |
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DV standard
This is the standard for videocassette recorders, which can
record images and sound in the digital format on special compact tapes. It
has the advantages of good quality through recording in the digital format,
and high compatibility with computers. |
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RCA pin
This is the connector used for composite video / audio, and
component terminals. It was developed by RCA in the US. |
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Field
A field indicates one image under the interlace system. With
interlace scanning, one image is one field, that is to say, there are two
fields in one frame. |
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Resolution
Resolution indicates the level of the picture quality. When
the resolution is high, then the picture clarity is also high. |
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Field frequency
Field frequency indicates the number of fields produced in
one second. |
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S canning
Scanning involves the movement of light points to produce TV
images. TV pictures are produced by the movement of points of light, which
create afterimages. The points of light move from the left to the right side
of the screen's top row, and then repeat this movement in the next row from
left to right. Once the right side of the bottom row is reached, one image
has been completed. |
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Frame
A frame is an image unit where all the scanning lines are
scanned. Since one image is produced with one scan under progressive
scanning, one frame equals one image. However, with interlace scanning, one
frame equals two images, as two images are produced with a single scan. |
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Scanning lines
This is the line created by the points of light moving from
left to right across the TV screen. The larger the number of scanning lines,
the sharper the picture. |
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Frame frequency
Frame frequency is the number of frames produced in one
second. |
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SDTV
SDTV stands for "Standard-definition Television", indicating
the usual TV picture quality before the development of HDTV. It is a TV
broadcasting standard with an aspect ratio of 4:3. |
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HDTV
HDTV stands for "High-definition Television", which is a new
TV technology that provides more realistic images than conventional
televisions. In order to increase the feeling of realism, a high level of
resolution needed for larger screen TVs has been achieved, along with the
adoption of a 16:9 aspect ratio. Furthermore, HDTV is a next-generation
television broadcast standard that is a complete departure from the existing
broadcast formats of NTSC, PAL, and SECAM. |
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SECAM
This is the SDTV broadcasting format developed in France
called Sequential Couleur A Memoire (Sequential Color with Memory). It uses
interlace scanning with 625 scanning lines and a frame frequency of 25 Hz. |
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HDTV standard for studio production
This is the standard for studio production to allow easy
international exchange of HDTV content. It establishes standards for the
HDTV video signal including the number of scanning lines. All the HDTV
broadcasting formats follow the studio standard so that video content can be
easily exchanged from one region to another, even though the broadcasting
formats differ. |
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S terminal
This is a terminal that can separate the video signal into
luminance and color signals before transmitting them.
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HDV standard
This is the videocassette recorder standard that can record
and play back HD (aspect ratio of 16:9) video and audio using widely
available DV tapes. Since it employs the MPEG-2 compression system, it can
record in the same running time as the DV standard, despite the higher
resolution involved. HDV includes the 1080i specification using 1,080
effective scanning lines (interlace), and the 720p specification with 720
lines (progressive). |
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Terrestrial digital broadcasting
This is digital broadcasting from TV towers built on the
ground. The terrestrial digital broadcasting standards include ISDB, DVB,
and ATSC. |
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HDV Specifications
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Under the HDV standard, there are two types of HD recording
systems. The first is the 720p specification featuring 720 effective
scanning lines (progressive scanning) and 1,280 horizontal pixels. The other
system is the 1080i specification with 1,080 effective scanning lines and
1,440 horizontal pixels. Therefore, the necessary high-resolution recording
and playback system has been established for the true HD age. |
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HDV (1080i specification) |
HDV (720p specification) |
DV |
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Media |
DV tape |
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Video signal |
1080/50i and 1080/60i |
720/25p, 720/50p,720/30p, and 720/60p |
576/50i (PAL) and 480/60i (NTSC) |
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Number of pixels |
1440 x 1080 |
1280 x 720 |
720 x 576 (PAL) and 720 x 480 (NTSC) |
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Aspect ratio |
16:9 |
4:3 (16:9) |
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Compression (video) |
MPEG-2 Video (Profile & level: MP@H-14) |
DV |
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Sampling frequency for luminance |
55.6875 MHz |
74.25 MHz |
13.5 MHz |
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Sampling format |
4:2:0 |
4:2:0 (PAL) / 4:1:1 (NTSC) |
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Quantization |
8 bit |
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Bit rate after compression (video) |
25 Mbps |
19 Mbps |
25 Mbps |
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Compression (audio) |
MPEG-1 Audio Layer II |
48 kHz / 44.1 kHz (2-ch mode) 32 kHz (4-ch mode) |
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Sampling frequency |
48 kHz |
48 kHz / 44.1 kHz (2-ch mode) 32 kHz (4-ch mode) |
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Quantization |
16 bit |
6 bit (2-ch mode), 12 bit non-linear (4-ch mode) |
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Bit rate after compression (audio) |
384 kbps |
1.5 Mbps |
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Audio mode |
Stereo (2-ch) |
Stereo (2-ch) / Stereo x 2 (4-ch) |
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Data format |
MPEG-2 system |
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Stream type |
Packetized elementary stream |
Transport stream |
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Stream interface |
IEEE 1394 (MPEG-2-TS) |
IEEE 1394 (DV) |
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Aspect ratio : Width and height ratio of the picture
Sampling frequency :
The unit for measuring the number of times a data sample can be output in a
second, when
converting analog signals to digital data.
Sampling format :
This indicates the frequency ratio allotted to three chrominance difference
signals: Y (luminance signal),
R-Y (signal of red signal minus luminance signal), and B-Y (signal of blue
signal minus luminance signal),
when converting analog video to digital data.
Quantization : This indicates what level value to express
the data sample with (16 bit is expressed with 216 = 65,536 level)
Bit rate : This means the amount of data used in one second
(1 Mbps means 1 megabit of data is used in one second)
Data format : This is the standard used when recording video
and audio as digital data.
Stream type : This is the system for combining video and
audio data into a single set of data in the MPEG-2 system.
Stream interface : Data transmission standard
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