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A High Definition Primer
High definition production has become increasingly more prevalent since we switched from
analog to digital broadcast television. However, HD is often an improperly understood
format, which is why we decided to provide this outline of what it is and how it works. If
you have ever seen a movie or television show in widescreen, then the look of HD is not
unfamiliar to you. The methodology behind it however, may be completely alien.
High Definition Versus Standard Definition
The most outwardly visible difference between the two formats are their aspect ratios, a
term that refers to the mathematical expression of a frame's width divided by its height. So-
called "regular" video, (or NTSC - the proper term for analog standard definition) is
represented by a 4:3 aspect ratio. HD has a 16:9 ratio or wide-screen image. And of
course, when viewed on a quality HD television, high definition has an image that is six
times sharper than a standard definition image. Good quality high definition on a large
screen can look stunning.
Why It Looks The Way It Looks
The highest resolution or picture quality in HD provides 1920×1080 progressively scanned
images. 1920×1080 refers to the lines of pixels in a frame (NTSC is 720×480). Progressive
scan means that these lines of pixels are being displayed in an ordered full frame
sequence to make up each frame of video. There are thirty frames that make up one
second of video in either HD or NTSC. 1080P is only used in Blue Ray and is not broadcast.
1080i and 720P are the current HD broadcast standards in the U.S.
Progressive Versus Interlace Scanning
Virtually every new flat panel video display today is progressive. LCD, DLP, LED and plasma
screens for both television and computers are progressively scanned. When television was
first invented however, interlace scanning was necessary because the cathode ray tube or
CRT monitor could not produce a full screen of video thirty times every second. The
phosphors in the CRT would lose their "glow" too quickly and thus create a lagging and
uneven brightness in the picture. The tube could not draw the image from the left to the
right in a progressive mode fast enough to keep the image on the entire screen to produce
a smooth, full motion television signal. The fix at the time was to create two fields of half
the total resolution each. Each field made up one frame of video or, when combined, a
whole useable picture. Each field had 262.5 lines for NTSC and worked in an odd and even
mode. The cathode ray tube would draw the odd field first, starting at the upper left with
lines 1,3, 5, 7 etc, then scan the even lines 2, 4, 6, 8 etc. Persistence of vision helped make
this TV trick work just as it does with film. Two fields for every one frame, 60 fields a
second or restated as 30 frames per second, tricks the eye into smooth motion. With the
advent of better CRT materials and eventually, with the introduction of LCD, DLP, plasma
and now LED technologies, progressively scanned video is now available. The progressive
images are smoother, resolution is greater and all without various artifacts associated with
interlaced images.
720P Versus 1080i
Both high definition 720P and 1080i images have advantages and disadvantages but both
produce very high quality pictures. Some think of 1080/60i as having higher resolution than
720/60P, but the reality is that the vertical resolution of a 1080/60i image is 540 lines per
field. By doubling the fields each second, 540 lines become 1080 lines when combined or
interlaced, hence the "i" in 1080i. The advantage of 1080i is higher perceived resolution.
Meanwhile, 720P offers a more efficient broadcast signal. All 720P frame rates are
progressively scanned making for a smaller bandwidth when used in broadcast
applications. 1080 however is available in both progressive or interlace, the latter 60i
signal is used in broadcast applications. 1080P is only used in movies recorded on Blue Ray
discs. Some satellite networks are beginning to offer movies broadcast in 1080P as well.
Broadcast networks use both 1080i and 720P for different reasons. NBC, CBS, PBS use
1080i for it’s high resolution while ABC, Fox, ESPN use 720p for it’s signal efficiency. One
signal type is not necessarily better than the other. Both produce very high quality images,
just in different ways.
HD Formats Versus Frame Rates
When it comes to HD standards, keep in mind there is no standard. When discussing
network and cable channel television, there are two high definition resolutions that are
currently broadcast, 720P (the P stands for progressive scan) and 1080i (the i stands for
interlace scan). Within those resolutions, there are multiple frame rates. Even if a network
broadcasts at 1080i, video field acquisition can still be made at 1080/24p or 30p. The
reason to shoot with a 24p frame rate is for a more ‘film like’ look. The motion captured is
similar to how a film camera captures images – one full frame at a time, 24 or 30 frames
per second. However, in video, fast pans and quick motion may have a stuttering effect.
Motion will not looks as smooth as captured at 60i (60 interlaced fields or 30 frames per
second). This is true for 720/24P or 1080/24P. 30P is a little smoother but does not look as
much like film as video shot at 24P. Each project type and production style will dictate the
field acquisition format, no matter what the mastering format requirement is.
HD and the Web
More and more, the web is readying itself for HD content. Video hosting sites like U-Tube
and Vimeo are starting to test HD channels capable of handling the codec
(compression/decompression) involved. Currently, high definition with it’s greater amount
of information, makes it difficult to download and view the larger files that HD creates.
Eventually, the speed of the Internet will catch up and the compression technology used in
creating files will improve in order to broadcast true HD signals on the web.
A Note of Caution
Recording in high definition does not necessarily mean you will always produce better
quality video images. Now that the HD format is widely available to the public, consumer
cameras that use the format are being released with ever lower price tags. However,
cheaper cameras do not always deliver the stunning image you might expect. If you view a
high definition broadcast signal on a good quality television, you will quickly see that there
is a big difference in HD images regarding quality. Lower quality high definition can be as
bad as viewing a standard definition signal. How can that be?
Prosumer Versus Broadcast HD Cameras
Some programs are shot with lower quality “prosumer HD” cameras. A prosumer
("professional consumer" hybrid) camera will not deliver the same quality image that an
expensive broadcast camera will. These prosumer cameras, while more than ideal for
recording personal events and home video use, do not compare in quality and functionality
to professional or broadcast grade equipment. This is a good example of you get what you
pay for.
For example, one of the first compromises in prosumer cameras is their ability to reproduce
a true high definition signal. Most prosumer cameras record less information or a highly
compressed HD signal. Professional cameras record true high definition at higher bit rates
for the best quality resolution.
Many prosumer HD cameras do not have the option to change lenses, something that can
greatly effect the quality of a production. The ability to use different lenses specifically
designed for HD production, such as telephoto and wide-angle zooms, will allow your
project to tell a deeper, more engaging visual story. Restricting oneself to a narrow field of
view will in turn, restrict the impact a video can have. Broadcast HD lenses usually cost
more than an entire prosumer HD camera with a fixed lens. Such is the quality of their
optics.
Something else non-professional HD cameras lack is exposure latitude, meaning they do
not capture and handle contrast as well as their professional counterparts. Correct
exposure and the ability to handle highlights and contrast is essential to reproducing high
quality video images. Color reproduction can also be effected by using a prosumer type
camera. Professional cameras have larger and higher quality image sensors that provide
much more accurate color reproduction. In addition, broadcast cameras have the ability to
modify or adjust the look of the image in a menu function much more readily than a
prosumer camera. These adjustments can fine tune the image to provide stunning, life-like
results.
Before choosing any video format, be sure to call us to help determine what might be best
suited for your individual production. We carry a variety of cameras for every budget. For
more information about high definition, visit our HD vs. SD link.
Qualities of a ‘Film Look’
Many times productions strive for a film look as opposed to the normal broadcast
news/sports look that video cameras typically produce. The film look involves various
factors, including the use of large source lighting, a frame rate of 24 per second similar to
film cameras, cinematic blocking between camera and talent, adjusting the camera’s
gamma settings and post-production color enhancement, lens or post-production diffusion,
reduced electronic detail, shooting with shallower depth of fields at wider lens f stops or
using a 35mm Cine adapter with 35mm lenses to achieve selective focus. Additionally,
increased camera movement with a dolly, jib, or Steadicam unit contributes to a more
cinematic look. In post production, the use of cuts as opposed to dissolves and effected
transitions add to the film look. And of course, the wide screen aspect ratio of high
definition enhance the feeling of film. All these factors contribute to help make the look of
film when shot on video.
High definition production has become increasingly more prevalent since we switched from
analog to digital broadcast television. However, HD is often an improperly understood
format, which is why we decided to provide this outline of what it is and how it works. If
you have ever seen a movie or television show in widescreen, then the look of HD is not
unfamiliar to you. The methodology behind it however, may be completely alien.
High Definition Versus Standard Definition
The most outwardly visible difference between the two formats are their aspect ratios, a
term that refers to the mathematical expression of a frame's width divided by its height. So-
called "regular" video, (or NTSC - the proper term for analog standard definition) is
represented by a 4:3 aspect ratio. HD has a 16:9 ratio or wide-screen image. And of
course, when viewed on a quality HD television, high definition has an image that is six
times sharper than a standard definition image. Good quality high definition on a large
screen can look stunning.
Why It Looks The Way It Looks
The highest resolution or picture quality in HD provides 1920×1080 progressively scanned
images. 1920×1080 refers to the lines of pixels in a frame (NTSC is 720×480). Progressive
scan means that these lines of pixels are being displayed in an ordered full frame
sequence to make up each frame of video. There are thirty frames that make up one
second of video in either HD or NTSC. 1080P is only used in Blue Ray and is not broadcast.
1080i and 720P are the current HD broadcast standards in the U.S.
Progressive Versus Interlace Scanning
Virtually every new flat panel video display today is progressive. LCD, DLP, LED and plasma
screens for both television and computers are progressively scanned. When television was
first invented however, interlace scanning was necessary because the cathode ray tube or
CRT monitor could not produce a full screen of video thirty times every second. The
phosphors in the CRT would lose their "glow" too quickly and thus create a lagging and
uneven brightness in the picture. The tube could not draw the image from the left to the
right in a progressive mode fast enough to keep the image on the entire screen to produce
a smooth, full motion television signal. The fix at the time was to create two fields of half
the total resolution each. Each field made up one frame of video or, when combined, a
whole useable picture. Each field had 262.5 lines for NTSC and worked in an odd and even
mode. The cathode ray tube would draw the odd field first, starting at the upper left with
lines 1,3, 5, 7 etc, then scan the even lines 2, 4, 6, 8 etc. Persistence of vision helped make
this TV trick work just as it does with film. Two fields for every one frame, 60 fields a
second or restated as 30 frames per second, tricks the eye into smooth motion. With the
advent of better CRT materials and eventually, with the introduction of LCD, DLP, plasma
and now LED technologies, progressively scanned video is now available. The progressive
images are smoother, resolution is greater and all without various artifacts associated with
interlaced images.
720P Versus 1080i
Both high definition 720P and 1080i images have advantages and disadvantages but both
produce very high quality pictures. Some think of 1080/60i as having higher resolution than
720/60P, but the reality is that the vertical resolution of a 1080/60i image is 540 lines per
field. By doubling the fields each second, 540 lines become 1080 lines when combined or
interlaced, hence the "i" in 1080i. The advantage of 1080i is higher perceived resolution.
Meanwhile, 720P offers a more efficient broadcast signal. All 720P frame rates are
progressively scanned making for a smaller bandwidth when used in broadcast
applications. 1080 however is available in both progressive or interlace, the latter 60i
signal is used in broadcast applications. 1080P is only used in movies recorded on Blue Ray
discs. Some satellite networks are beginning to offer movies broadcast in 1080P as well.
Broadcast networks use both 1080i and 720P for different reasons. NBC, CBS, PBS use
1080i for it’s high resolution while ABC, Fox, ESPN use 720p for it’s signal efficiency. One
signal type is not necessarily better than the other. Both produce very high quality images,
just in different ways.
HD Formats Versus Frame Rates
When it comes to HD standards, keep in mind there is no standard. When discussing
network and cable channel television, there are two high definition resolutions that are
currently broadcast, 720P (the P stands for progressive scan) and 1080i (the i stands for
interlace scan). Within those resolutions, there are multiple frame rates. Even if a network
broadcasts at 1080i, video field acquisition can still be made at 1080/24p or 30p. The
reason to shoot with a 24p frame rate is for a more ‘film like’ look. The motion captured is
similar to how a film camera captures images – one full frame at a time, 24 or 30 frames
per second. However, in video, fast pans and quick motion may have a stuttering effect.
Motion will not looks as smooth as captured at 60i (60 interlaced fields or 30 frames per
second). This is true for 720/24P or 1080/24P. 30P is a little smoother but does not look as
much like film as video shot at 24P. Each project type and production style will dictate the
field acquisition format, no matter what the mastering format requirement is.
HD and the Web
More and more, the web is readying itself for HD content. Video hosting sites like U-Tube
and Vimeo are starting to test HD channels capable of handling the codec
(compression/decompression) involved. Currently, high definition with it’s greater amount
of information, makes it difficult to download and view the larger files that HD creates.
Eventually, the speed of the Internet will catch up and the compression technology used in
creating files will improve in order to broadcast true HD signals on the web.
A Note of Caution
Recording in high definition does not necessarily mean you will always produce better
quality video images. Now that the HD format is widely available to the public, consumer
cameras that use the format are being released with ever lower price tags. However,
cheaper cameras do not always deliver the stunning image you might expect. If you view a
high definition broadcast signal on a good quality television, you will quickly see that there
is a big difference in HD images regarding quality. Lower quality high definition can be as
bad as viewing a standard definition signal. How can that be?
Prosumer Versus Broadcast HD Cameras
Some programs are shot with lower quality “prosumer HD” cameras. A prosumer
("professional consumer" hybrid) camera will not deliver the same quality image that an
expensive broadcast camera will. These prosumer cameras, while more than ideal for
recording personal events and home video use, do not compare in quality and functionality
to professional or broadcast grade equipment. This is a good example of you get what you
pay for.
For example, one of the first compromises in prosumer cameras is their ability to reproduce
a true high definition signal. Most prosumer cameras record less information or a highly
compressed HD signal. Professional cameras record true high definition at higher bit rates
for the best quality resolution.
Many prosumer HD cameras do not have the option to change lenses, something that can
greatly effect the quality of a production. The ability to use different lenses specifically
designed for HD production, such as telephoto and wide-angle zooms, will allow your
project to tell a deeper, more engaging visual story. Restricting oneself to a narrow field of
view will in turn, restrict the impact a video can have. Broadcast HD lenses usually cost
more than an entire prosumer HD camera with a fixed lens. Such is the quality of their
optics.
Something else non-professional HD cameras lack is exposure latitude, meaning they do
not capture and handle contrast as well as their professional counterparts. Correct
exposure and the ability to handle highlights and contrast is essential to reproducing high
quality video images. Color reproduction can also be effected by using a prosumer type
camera. Professional cameras have larger and higher quality image sensors that provide
much more accurate color reproduction. In addition, broadcast cameras have the ability to
modify or adjust the look of the image in a menu function much more readily than a
prosumer camera. These adjustments can fine tune the image to provide stunning, life-like
results.
Before choosing any video format, be sure to call us to help determine what might be best
suited for your individual production. We carry a variety of cameras for every budget. For
more information about high definition, visit our HD vs. SD link.
Qualities of a ‘Film Look’
Many times productions strive for a film look as opposed to the normal broadcast
news/sports look that video cameras typically produce. The film look involves various
factors, including the use of large source lighting, a frame rate of 24 per second similar to
film cameras, cinematic blocking between camera and talent, adjusting the camera’s
gamma settings and post-production color enhancement, lens or post-production diffusion,
reduced electronic detail, shooting with shallower depth of fields at wider lens f stops or
using a 35mm Cine adapter with 35mm lenses to achieve selective focus. Additionally,
increased camera movement with a dolly, jib, or Steadicam unit contributes to a more
cinematic look. In post production, the use of cuts as opposed to dissolves and effected
transitions add to the film look. And of course, the wide screen aspect ratio of high
definition enhance the feeling of film. All these factors contribute to help make the look of
film when shot on video.
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