HD TV, where the HD is for high definition tv (or high def tvs). This is perhaps the most significant revolution in broadcasting since TV changed to colour from black & white. HDTV uses widescreen digital flat panel tvs such as a Plasma televisions and LCD tvs where the screen resolution is at least 1280x720 pixels or HD Ready. There are 2 types of high def broadcasting, 720p/50 and 1080i/25.
HD Ready - What is it?
If a flat screen television carries the HD Ready label it will operate with a HD signal and will be able to show a HD picture. TVs that are specified to meet the necessities of the HD Ready logo must have a minimum screen resolution of (1280 pixels x 720 pixels) i.e. 720 vertical lines in 16:9 widescreen, where the signal received is either 720p/50 or 1080i/25 image formats and to be capable of accepting HD - the '50' or '25' is the amount of frames per second. They must also able to take HD inputs by either DVI or HDMI and on Component Inputs.
Every TV that has a screen resolution of-66 x 768 pixels and is HD Ready will make use of internal scalers to convert a 1080i signal down to the 768 lines; if it receives a 720p signal the internal circuits will upscale the image to 768 lines. The method of converting down or up is done by advanced software to fill the screen.
When a Full HD signal (1920 x 1080 pixels) is received by a HD Ready TV one to one pixel mapping is not viable due to insufficient pixels so the image has to be interpolated to the screen resolution.
What is 'HD ready 1080P' ?
If a plasma tv or lcd television has a 'HD ready 1080p' badge it has an adequate amount of pixels to show the full 1080p signal with pixel for pixel mapping with no interpolation. A 1080p flat screen lcd television or plasma tv is'20 x pixels 1080 pixels where the 1080 is the vertical resolution and the 'p' is for progressive scan. A HD Ready 1080p widescreen lcd television or plasma tv is the maximum screen resolution in the UK for high definition and thus the term 'full'. Any plasma television or lcd tv with this resolution can display 1080i and 1080p signals with no up or down scaling, and with one to one pixel mapping. Connectivity should be by either HDMI or DVI inputs. HD Ready 1080p full hd tv's must be able to display a 1080p/24 or 1080p/50 signal where the 24 and the 50 signify the quantity of frames per second.
If a flat panel 1080P TV receives a 720P picture the signal is 'oversampled' to fit the resolution of the 1080P widescreen Television. This is done using very complex algorithm sequences.
What is a Full HD Televisions ?
Older full HD flat panel tv's might not fulfill all 'HD Ready 1080P' requirements.
Interlaced Picture or Progressive Picture ?
An Interlaced Picture involves arranging the scan lines of one frame into two fields where one field contains the odd lines and a different field contains all of the even lines - so every field has half the resolution. The two fields of the frame are alternately displayed in sequence at a rate that is double the actual frame rate, this is known as Interlacing.
One of the advantages of Interlacing is that when footage is shot of a moving picture each of the fields of a frame are taken at separate times making motion that appears more fluid. Picture Interlacing is a procedure that was originally used to improve the image quality of a signal on CRT televisions without using extra signal bandwidth.
TVs in the UK have a PAL picture system that have a rate of 25 frames per second or 50 fields per second. An Interlaced signal utilizes half the bandwidth of a Progressive signal i.e. the progressive scanning process has to scan the picture 50 times per second whilst the interlaced scanning process operates at half of that speed.
Standard definition LCD tvs and Plasma tvs displays aren't able to operate on an interlaced mode for footage shot with a TV or video camera. Because LCD tv displays and Plasma tv displays do not have an electron scan to create an image they cannot benefit from interlacing. So internal processing in the flat panel tv creates a progressive scan image from the interlaced signal.
Progressive scan delivers benefits.
Each frame has all of the lines from the picture on a progressive scanned image instead of either the even or odd lines as with an interlaced image. Progressive scanning is a means of transmitting, storing and displaying the image.
The benefits of Progressive Scanning is that there is a better vertical resolution than on Interlaced images at the same frame rate without blurring, interlace artifacts, and reduced eye strain. It is also viable to scale to a higher resolution than it is with equivalent interlaced sources. Because interlaced signal sources have to be deinterlaced before scaling with noticeable combing artifacts, Progressive scanned full pictures give the best results when scaling.
The differences between 720p/50 and 1080i/25 formats
When a 1080i/25 (1,920 pixels x 1080 pixels resolution) signal displays a still picture the horizontal resolution is marginally better than the 720p/50 (1,280 pixels x 720 pixels resolution) image. When an image moves on an interlaced signal the subjective line resolution is reduced due to line twitter since the two fields that make up the frames are slightly different. Depending on the bandwidth availability broadcasters are at present using either 720p/50 or 1080i/25.
Smoother movement is produced with 720p progressive scanned images, above all on slow-motion, compared to 1080i interlaced pictures. Better still images are produced with interlaced 1080i signals. By means of good quality built in processing a 1080i signal will appear superior on a 1080 television compared to a 720p source. The one you should choose, will depend on the type of images being predominantly displayed, either static or moving, and your preferences.
It is easier to convert a progressive signal (i.e. 1080p/50) into an interlaced format, such as 1080i/25, than it is to convert an interlaced format into a progressive format.
What is 1080p/24 ?
For the reason that the films that are shown in cinemas are created at 24 frames per second a signal is in its purest form at this frame rate. Films are available on Blu ray disc at 24 frames per second with the intention of giving the ultimate picture quality when displayed on widescreen full high definition TVs. When a full hd tv receives a 1080p/24 signal it creates supplementary middle frames, which are inserted between the original ones to raise the frame rate to 48 or 72 frames per second giving more fluid motion.
HDTV Sources
HDTV broadcasts are presently at 720p/50 or 1080i/25 and are available on SKY Digital HD, Freesat, BT Vision, and Virgin media Cable. All of these require a HD Ready TV. Currently Full HD 1080P signals are only accessible on Blu-Ray Disc, Playstation 3 and by download films on the web. The Xbox 360 games machine operates at 720p.
The conclusion
High definition television produces an enhanced subjective picture quality that makes the argument for HD compelling. If you have possession of, or intend to own, a Playstation 3, a Blu ray player, or download full HD films from the internet then a Full HD 1080p television is the best choice. If not a HD Ready television will be appropriate. Whilst these recommendations deal with today's available options they don't allow for the likelihood of future broadcasts in Full 1080p HD. If you want to be totally sure that you protect your purchase against this scenario then buy a Full 1080p HD flat panel television. - 32388
HD Ready - What is it?
If a flat screen television carries the HD Ready label it will operate with a HD signal and will be able to show a HD picture. TVs that are specified to meet the necessities of the HD Ready logo must have a minimum screen resolution of (1280 pixels x 720 pixels) i.e. 720 vertical lines in 16:9 widescreen, where the signal received is either 720p/50 or 1080i/25 image formats and to be capable of accepting HD - the '50' or '25' is the amount of frames per second. They must also able to take HD inputs by either DVI or HDMI and on Component Inputs.
Every TV that has a screen resolution of-66 x 768 pixels and is HD Ready will make use of internal scalers to convert a 1080i signal down to the 768 lines; if it receives a 720p signal the internal circuits will upscale the image to 768 lines. The method of converting down or up is done by advanced software to fill the screen.
When a Full HD signal (1920 x 1080 pixels) is received by a HD Ready TV one to one pixel mapping is not viable due to insufficient pixels so the image has to be interpolated to the screen resolution.
What is 'HD ready 1080P' ?
If a plasma tv or lcd television has a 'HD ready 1080p' badge it has an adequate amount of pixels to show the full 1080p signal with pixel for pixel mapping with no interpolation. A 1080p flat screen lcd television or plasma tv is'20 x pixels 1080 pixels where the 1080 is the vertical resolution and the 'p' is for progressive scan. A HD Ready 1080p widescreen lcd television or plasma tv is the maximum screen resolution in the UK for high definition and thus the term 'full'. Any plasma television or lcd tv with this resolution can display 1080i and 1080p signals with no up or down scaling, and with one to one pixel mapping. Connectivity should be by either HDMI or DVI inputs. HD Ready 1080p full hd tv's must be able to display a 1080p/24 or 1080p/50 signal where the 24 and the 50 signify the quantity of frames per second.
If a flat panel 1080P TV receives a 720P picture the signal is 'oversampled' to fit the resolution of the 1080P widescreen Television. This is done using very complex algorithm sequences.
What is a Full HD Televisions ?
Older full HD flat panel tv's might not fulfill all 'HD Ready 1080P' requirements.
Interlaced Picture or Progressive Picture ?
An Interlaced Picture involves arranging the scan lines of one frame into two fields where one field contains the odd lines and a different field contains all of the even lines - so every field has half the resolution. The two fields of the frame are alternately displayed in sequence at a rate that is double the actual frame rate, this is known as Interlacing.
One of the advantages of Interlacing is that when footage is shot of a moving picture each of the fields of a frame are taken at separate times making motion that appears more fluid. Picture Interlacing is a procedure that was originally used to improve the image quality of a signal on CRT televisions without using extra signal bandwidth.
TVs in the UK have a PAL picture system that have a rate of 25 frames per second or 50 fields per second. An Interlaced signal utilizes half the bandwidth of a Progressive signal i.e. the progressive scanning process has to scan the picture 50 times per second whilst the interlaced scanning process operates at half of that speed.
Standard definition LCD tvs and Plasma tvs displays aren't able to operate on an interlaced mode for footage shot with a TV or video camera. Because LCD tv displays and Plasma tv displays do not have an electron scan to create an image they cannot benefit from interlacing. So internal processing in the flat panel tv creates a progressive scan image from the interlaced signal.
Progressive scan delivers benefits.
Each frame has all of the lines from the picture on a progressive scanned image instead of either the even or odd lines as with an interlaced image. Progressive scanning is a means of transmitting, storing and displaying the image.
The benefits of Progressive Scanning is that there is a better vertical resolution than on Interlaced images at the same frame rate without blurring, interlace artifacts, and reduced eye strain. It is also viable to scale to a higher resolution than it is with equivalent interlaced sources. Because interlaced signal sources have to be deinterlaced before scaling with noticeable combing artifacts, Progressive scanned full pictures give the best results when scaling.
The differences between 720p/50 and 1080i/25 formats
When a 1080i/25 (1,920 pixels x 1080 pixels resolution) signal displays a still picture the horizontal resolution is marginally better than the 720p/50 (1,280 pixels x 720 pixels resolution) image. When an image moves on an interlaced signal the subjective line resolution is reduced due to line twitter since the two fields that make up the frames are slightly different. Depending on the bandwidth availability broadcasters are at present using either 720p/50 or 1080i/25.
Smoother movement is produced with 720p progressive scanned images, above all on slow-motion, compared to 1080i interlaced pictures. Better still images are produced with interlaced 1080i signals. By means of good quality built in processing a 1080i signal will appear superior on a 1080 television compared to a 720p source. The one you should choose, will depend on the type of images being predominantly displayed, either static or moving, and your preferences.
It is easier to convert a progressive signal (i.e. 1080p/50) into an interlaced format, such as 1080i/25, than it is to convert an interlaced format into a progressive format.
What is 1080p/24 ?
For the reason that the films that are shown in cinemas are created at 24 frames per second a signal is in its purest form at this frame rate. Films are available on Blu ray disc at 24 frames per second with the intention of giving the ultimate picture quality when displayed on widescreen full high definition TVs. When a full hd tv receives a 1080p/24 signal it creates supplementary middle frames, which are inserted between the original ones to raise the frame rate to 48 or 72 frames per second giving more fluid motion.
HDTV Sources
HDTV broadcasts are presently at 720p/50 or 1080i/25 and are available on SKY Digital HD, Freesat, BT Vision, and Virgin media Cable. All of these require a HD Ready TV. Currently Full HD 1080P signals are only accessible on Blu-Ray Disc, Playstation 3 and by download films on the web. The Xbox 360 games machine operates at 720p.
The conclusion
High definition television produces an enhanced subjective picture quality that makes the argument for HD compelling. If you have possession of, or intend to own, a Playstation 3, a Blu ray player, or download full HD films from the internet then a Full HD 1080p television is the best choice. If not a HD Ready television will be appropriate. Whilst these recommendations deal with today's available options they don't allow for the likelihood of future broadcasts in Full 1080p HD. If you want to be totally sure that you protect your purchase against this scenario then buy a Full 1080p HD flat panel television. - 32388
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