576p

576p is the shorthand name for a video display resolution. The p stands for progressive scan, i.e. non-interlaced, the 576 for a vertical resolution of 576 pixels, usually with a horizontal resolution of 720 or 704 pixels. The frame rate can be given explicitly after the letter.[1]

576p25

576p25 has a frame rate of 25 frames per second, and thus uses the same bandwidth and carries the same amount of pixel data as 576i; as such, 576p25 is considered to be standard definition. It can be used on analog PAL or SECAM systems, where it may be transported as a 576i signal with both interlaced fields corresponding to a unique frame. PALplus supports it via a "movie" mode signal flag. It can also be transported by both major digital television formats, ATSC and DVB, and on DVD.

576p50

With doubled temporal resolution, 576p50 is considered enhanced-definition television (EDTV), regardless of the image being scaled the same way as an interlaced frame. In some countries, such as Australia, the 576p resolution standard is technically considered high-definition and was in use by the Special Broadcasting Service (SBS TV) (16:9 the format has aspect ratio 1.468), eventually replaced by 720p for its high-definition subchannel; SBS later changed to using 1080i. The Seven Network initially used 576p for its high-definition subchannel, but now uses 1080i instead.

The frames are doubled (from a 25 frame source) on broadcast (to avoid flicker) for display devices that lack any kind of frame doubling ability. Widescreen 16:9 material has only the width scaled down to fit 720 pixels instead of an unscaled 1024 width. SMPTE 344M defines a 576p50 standard with twice the data rate of BT.601, using 704 × 576 active pixels with 16 x 576 horizontal blanking pixels.

See also

Television

References

  1. ↑ afterdawn.com - 576p
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