08-13-2007, 06:56 PM
Nota Interesante sobre material grabado nativo 1080p24fps
Availability
1080i film-based content can become true 1080p/24
The following examples refer to content that is encoded in progressive-scan form during recording or transmission—what would be considered "native" progressive signals. However, where 24 fps film-based material is concerned, a 1080i encoded/transmitted stream can become a true "1080p" signal during playback by deinterlacing to re-combine the split field pairs into progressive film-scanned frames. Regarding 24 fps film-source material presented in conventional 1080i60 form, the deinterlacing process that achieves this goal is usually referred to as "3:2 pulldown reversal" [also known as "inverse telecine"]. The importance of this is that, where film-based content is concerned, all 1080-interlaced signals are potentially 1080p signals given the proper deinterlacing. As long as no additional image-degradation steps were applied during signal mastering (such as excessive vertical-pass filtering), the image from a properly deinterlaced film-source 1080i signal and a native-encoded 1080p signal will look approximately the same. It should be noted that Blu-ray Disc and HD DVD sources are 1080p with no vertical filtering, therefore, 1080i output from players can be perfectly reconstructed to 1080p with 3:2 pulldown reversal.
As more and more processors and displays come to market able to apply 3:2 pulldown reversal to film-based 1080i60 signals, the amount of available "1080p" content for viewing expands (encompassing film-based 1080i60 feeds from broadcast HD, cable, and satellite).
Ability of the eye to see 1080p
A person's ability to distinguish small details is described by visual acuity. When individual pixels are barely resolvable, increased resolution brings no benefit for the viewer, unless the viewing distance can be shortened. For normal television viewing distances, in order to see a benefit from 1080p content a display must be bigger than usual or the viewing distance needs to be closer than usual. The ability of the eye to resolve 1080p content depends on the amount of contrast in the picture. For optimum viewing of resolution you need to sit back three times the viewing height [8] [9]. For example at nine feet (2,75 m) away you need at least a 46 inch (115 cm) display to see a benefit from 1080p or for optimum viewing of the resolution you need a 70 inch (175 cm) display.
Availability
1080i film-based content can become true 1080p/24
The following examples refer to content that is encoded in progressive-scan form during recording or transmission—what would be considered "native" progressive signals. However, where 24 fps film-based material is concerned, a 1080i encoded/transmitted stream can become a true "1080p" signal during playback by deinterlacing to re-combine the split field pairs into progressive film-scanned frames. Regarding 24 fps film-source material presented in conventional 1080i60 form, the deinterlacing process that achieves this goal is usually referred to as "3:2 pulldown reversal" [also known as "inverse telecine"]. The importance of this is that, where film-based content is concerned, all 1080-interlaced signals are potentially 1080p signals given the proper deinterlacing. As long as no additional image-degradation steps were applied during signal mastering (such as excessive vertical-pass filtering), the image from a properly deinterlaced film-source 1080i signal and a native-encoded 1080p signal will look approximately the same. It should be noted that Blu-ray Disc and HD DVD sources are 1080p with no vertical filtering, therefore, 1080i output from players can be perfectly reconstructed to 1080p with 3:2 pulldown reversal.
As more and more processors and displays come to market able to apply 3:2 pulldown reversal to film-based 1080i60 signals, the amount of available "1080p" content for viewing expands (encompassing film-based 1080i60 feeds from broadcast HD, cable, and satellite).
Ability of the eye to see 1080p
A person's ability to distinguish small details is described by visual acuity. When individual pixels are barely resolvable, increased resolution brings no benefit for the viewer, unless the viewing distance can be shortened. For normal television viewing distances, in order to see a benefit from 1080p content a display must be bigger than usual or the viewing distance needs to be closer than usual. The ability of the eye to resolve 1080p content depends on the amount of contrast in the picture. For optimum viewing of resolution you need to sit back three times the viewing height [8] [9]. For example at nine feet (2,75 m) away you need at least a 46 inch (115 cm) display to see a benefit from 1080p or for optimum viewing of the resolution you need a 70 inch (175 cm) display.