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Digital Cinema Concepts
Digital Cinema Concepts HD979 for sale: Over-the-air broadcasts
In the United States, 1080p over-the-air broadcasts still do not exist as of November 2014; all major networks use either 720p60 or 1080i60 encoded with MPEG-2. However, satellite services (e.g., DirecTV, XstreamHD and Dish Network) utilize the 1080p/24-30 format with MPEG-4 AVC/H.264 encoding for pay-per-view movies that are downloaded in advance via satellite or on-demand via broadband. At this time, no pay service channel such as USA, HDNET, etc. nor premium movie channel such as HBO, etc., stream their services live to their distributors (MVPD) in this format because many MVPDs, especially DBS and cable, do not have sufficient bandwidth to provide the format streaming live to their subscribers without negatively impacting their current services. In addition is the high "cost" of using more bandwidth for one 1080p/24 channel than that necessary for a 1080i or even a 720p channel and for only those relatively few subscribers who have HDTV devices that can display 1080p/24 being an efficient use of their limited bandwidth.
Benefits of interlacing
One of the most important factors in analog television is signal bandwidth, measured in megahertz. The greater the bandwidth, the more expensive and complex the entire production and broadcasting chain. This includes cameras, storage systems, broadcast systems�and reception systems: terrestrial, cable, satellite, Internet, and end-user displays (TVs computer monitors).
For a fixed bandwidth, interlace provides a video signal with twice the display refresh rate for a given line count (versus progressive scan video at a similar frame rate�for instance 1080i at 60 half-frames per second, vs. 1080p at 30 full frames per second). The higher refresh rate improves the appearance of objects motion, because it updates their position on the display more often, and when objects are stationary, human vision combines information from multiple similar half-frames to produce the same perceived resolution as progressive full frames. This technique is only useful though, if source material is available in higher refresh rates. Cinema movies are typically recorded at 24fps, and don't benefit from interlacing.Digital Cinema Concepts
Digital Cinema Concepts sell: The field rate of 1080i
The field rate of 1080i is typically 60 Hz (i.e., 60 fields per second) for countries that use or used System M as analog broadcast television system (such as United States, Canada, Japan, and most of Latin America), or 50 Hz for regions that traditionally used television systems with 50 fields/sec rate (such as in Europe, Australia, much of Asia, Africa, and part of Latin America). Both field rates can be carried by major digital television broadcast formats such as ATSC, DVB, and ISDB-T International.
The frame rate can be implied by the context, while the field rate is generally specified after the letter i, such as "1080i60". In this case 1080i60 refers to 60 fields per second. The European Broadcasting Union (EBU) prefers to use the resolution and frame rate (not field rate) separated by a slash, as in 1080i/30 and 1080i/25, likewise 480i/30 and 576i/25. Resolutions of 1080i60 or 1080i50 often refers to 1080i/30 or 1080i/25 in EBU notation.
Static contrast
Static contrast ratio is the luminosity ratio comparing the brightest and darkest color the system is capable of producing simultaneously at any instant of time, while dynamic contrast ratio is the luminosity ratio comparing the brightest and darkest color the system is capable of producing over time (while the picture is moving). Moving from a system that displays a static motionless image to a system that displays a dynamic, changing picture slightly complicates the definition of the contrast ratio, due to the need to take into account the extra temporal dimension to the measuring process. Digital Cinema Concepts review
Digital Cinema Concepts HD979 for sale:The ANSI contrast
The ANSI contrast - the measurement is done with a checker board patterned test image where the black and white luminosity values are measured simultaneously. This is a more realistic measure of system capability, but includes the potential of including the effects of the room into the measurement, if the test is not performed in a room that is close to ideal.
It is useful to note that the full on/full off method effectively measures the dynamic contrast ratio of a display, while the ANSI contrast measures the static contrast ratio.
In the United States, 1080p over-the-air broadcasts still do not exist as of November 2014; all major networks use either 720p60 or 1080i60 encoded with MPEG-2. However, satellite services (e.g., DirecTV, XstreamHD and Dish Network) utilize the 1080p/24-30 format with MPEG-4 AVC/H.264 encoding for pay-per-view movies that are downloaded in advance via satellite or on-demand via broadband. At this time, no pay service channel such as USA, HDNET, etc. nor premium movie channel such as HBO, etc., stream their services live to their distributors (MVPD) in this format because many MVPDs, especially DBS and cable, do not have sufficient bandwidth to provide the format streaming live to their subscribers without negatively impacting their current services. In addition is the high "cost" of using more bandwidth for one 1080p/24 channel than that necessary for a 1080i or even a 720p channel and for only those relatively few subscribers who have HDTV devices that can display 1080p/24 being an efficient use of their limited bandwidth.
Benefits of interlacing
One of the most important factors in analog television is signal bandwidth, measured in megahertz. The greater the bandwidth, the more expensive and complex the entire production and broadcasting chain. This includes cameras, storage systems, broadcast systems�and reception systems: terrestrial, cable, satellite, Internet, and end-user displays (TVs computer monitors).
For a fixed bandwidth, interlace provides a video signal with twice the display refresh rate for a given line count (versus progressive scan video at a similar frame rate�for instance 1080i at 60 half-frames per second, vs. 1080p at 30 full frames per second). The higher refresh rate improves the appearance of objects motion, because it updates their position on the display more often, and when objects are stationary, human vision combines information from multiple similar half-frames to produce the same perceived resolution as progressive full frames. This technique is only useful though, if source material is available in higher refresh rates. Cinema movies are typically recorded at 24fps, and don't benefit from interlacing.Digital Cinema Concepts
Digital Cinema Concepts sell: The field rate of 1080i
The field rate of 1080i is typically 60 Hz (i.e., 60 fields per second) for countries that use or used System M as analog broadcast television system (such as United States, Canada, Japan, and most of Latin America), or 50 Hz for regions that traditionally used television systems with 50 fields/sec rate (such as in Europe, Australia, much of Asia, Africa, and part of Latin America). Both field rates can be carried by major digital television broadcast formats such as ATSC, DVB, and ISDB-T International.
The frame rate can be implied by the context, while the field rate is generally specified after the letter i, such as "1080i60". In this case 1080i60 refers to 60 fields per second. The European Broadcasting Union (EBU) prefers to use the resolution and frame rate (not field rate) separated by a slash, as in 1080i/30 and 1080i/25, likewise 480i/30 and 576i/25. Resolutions of 1080i60 or 1080i50 often refers to 1080i/30 or 1080i/25 in EBU notation.
Digital Cinema Concepts HD979
Static contrast
Static contrast ratio is the luminosity ratio comparing the brightest and darkest color the system is capable of producing simultaneously at any instant of time, while dynamic contrast ratio is the luminosity ratio comparing the brightest and darkest color the system is capable of producing over time (while the picture is moving). Moving from a system that displays a static motionless image to a system that displays a dynamic, changing picture slightly complicates the definition of the contrast ratio, due to the need to take into account the extra temporal dimension to the measuring process. Digital Cinema Concepts review
Digital Cinema Concepts HD979 for sale:The ANSI contrast
The ANSI contrast - the measurement is done with a checker board patterned test image where the black and white luminosity values are measured simultaneously. This is a more realistic measure of system capability, but includes the potential of including the effects of the room into the measurement, if the test is not performed in a room that is close to ideal.
It is useful to note that the full on/full off method effectively measures the dynamic contrast ratio of a display, while the ANSI contrast measures the static contrast ratio.
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