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Digital Cinema Concepts
Digital Cinema Concepts: Interlacing problems
When someone watches interlaced video on a progressive monitor with poor deinterlacing, they can see "combing" in movement between two fields of one frame.
Interlaced video is designed to be captured, stored, transmitted, and displayed in the same interlaced format. Because each interlaced video frame is two fields captured at different moments in time, interlaced video frames can exhibit motion artifacts known as interlacing effects, or combing, if recorded objects move fast enough to be in different positions when each individual field is captured. These artifacts may be more visible when interlaced video is displayed at a slower speed than it was captured, or in still frames.
1080 vertical lines per frame
Some cameras and broadcast systems that use 1080 vertical lines per frame do not actually use the full 1920 pixels of a nominal 1080i picture for image capture and encoding. Common subsampling ratios include 3/4 (resulting in 1440x1080i frame resolution) and 1/2 (resulting in 960x1080i frame resolution). Where used, the lower horizontal resolution is scaled to capture and/or display a full-sized picture. Using half horizontal resolution and only one field of each frame (possibly with added anti-alias filtering or progressive capture) results in the format known as qHD, which has frame resolution 960x540 and 30 or 25 frames per second.
Due to the chosen 16x16 pixel size for a compressed video packet known as a macroblock as used in ITU H.261 to H.264 video standards, a 1080 line video must be encoded as 1088 lines and cropped to 1080 by the de-compressor. The 720 line video format divides perfectly by 16 and therefore doesn't need the eight wasted lines.Digital Cinema Concepts review
Digital Cinema Concepts HD979: 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.
Higher contrast ratio
There are ways to achieve a higher contrast ratio. As you have likely noticed, commercial and high end movie theaters are always dark, including black walls and ceilings. Movie theaters and high end installations go through all this trouble because projectors look their best when there is no light in the room. In high end installations this even includes stray light reflected off of the projection screen. Stray and ambient light will reduce the contrast of the image and work to make the blacks appear more grey, essentially washing out the image. A projector does not projector black, black is the absence of light. Any light falling on the screen from a source other than the projector will raise the absolute black level and reduce the contrast. Ideally, a home theater should have little to no ambient light present. However, most people do not want to darken the walls of their home theater or multipurpose rooms just to achieve ideal theater conditions. The other option is to purchase a high-contrast gray screen which will improve black levels and the contrast ratio of the projector image. For the best possible image, proceed with any steps necessary to eliminate ambient light and reflective surfaces on the walls and ceiling. Digital Cinema Concepts HD979 for sale
Digital Cinema Concepts review: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.
When someone watches interlaced video on a progressive monitor with poor deinterlacing, they can see "combing" in movement between two fields of one frame.
Interlaced video is designed to be captured, stored, transmitted, and displayed in the same interlaced format. Because each interlaced video frame is two fields captured at different moments in time, interlaced video frames can exhibit motion artifacts known as interlacing effects, or combing, if recorded objects move fast enough to be in different positions when each individual field is captured. These artifacts may be more visible when interlaced video is displayed at a slower speed than it was captured, or in still frames.
1080 vertical lines per frame
Some cameras and broadcast systems that use 1080 vertical lines per frame do not actually use the full 1920 pixels of a nominal 1080i picture for image capture and encoding. Common subsampling ratios include 3/4 (resulting in 1440x1080i frame resolution) and 1/2 (resulting in 960x1080i frame resolution). Where used, the lower horizontal resolution is scaled to capture and/or display a full-sized picture. Using half horizontal resolution and only one field of each frame (possibly with added anti-alias filtering or progressive capture) results in the format known as qHD, which has frame resolution 960x540 and 30 or 25 frames per second.
Due to the chosen 16x16 pixel size for a compressed video packet known as a macroblock as used in ITU H.261 to H.264 video standards, a 1080 line video must be encoded as 1088 lines and cropped to 1080 by the de-compressor. The 720 line video format divides perfectly by 16 and therefore doesn't need the eight wasted lines.Digital Cinema Concepts review
Digital Cinema Concepts HD979: 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 sell
Higher contrast ratio
There are ways to achieve a higher contrast ratio. As you have likely noticed, commercial and high end movie theaters are always dark, including black walls and ceilings. Movie theaters and high end installations go through all this trouble because projectors look their best when there is no light in the room. In high end installations this even includes stray light reflected off of the projection screen. Stray and ambient light will reduce the contrast of the image and work to make the blacks appear more grey, essentially washing out the image. A projector does not projector black, black is the absence of light. Any light falling on the screen from a source other than the projector will raise the absolute black level and reduce the contrast. Ideally, a home theater should have little to no ambient light present. However, most people do not want to darken the walls of their home theater or multipurpose rooms just to achieve ideal theater conditions. The other option is to purchase a high-contrast gray screen which will improve black levels and the contrast ratio of the projector image. For the best possible image, proceed with any steps necessary to eliminate ambient light and reflective surfaces on the walls and ceiling. Digital Cinema Concepts HD979 for sale
Digital Cinema Concepts review: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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