«Մասնակից:GrigorGB/Ավազարկղ11»–ի խմբագրումների տարբերություն
Content deleted Content added
Տող 212.
Existing video transmission systems of both analogue and digital formats already introduce known quantifiable delays. Existing [[Digital Video Broadcasting|DVB]] TV channels that [[simulcast]] by both terrestrial and satellite transmissions experience the same 0.25-second delay difference between the two services with no detrimental effect, and it goes unnoticed by viewers.
==Արագության պահանջները==
[[File:Figure2a.jpg|thumb|400px|Bandwidth capacity for simultaneously two HDTV streams, two SD streams, additional to HSD and voice]]
Թվային տեսագրությունը թվային պատկերների հաջորդականություն է, որոնք պատկերի էլեմենտրներից կամ պիքսելներից: Յուրաքանչյուր պիքսել ունի երկու արժեք. [[luminance]] and [[chrominance]].
Digital video is a combination of sequence of digital images, and they are made up of [[pixel]]s or picture elements. Each pixel has two values, which are [[luminance]] and [[chrominance]]. Luminance is representing intensity of the pixel; chrominance represents the colour of the pixel. Three bytes would be used to represent the colour of the high quality image for a true colour technique. A sequence of images is creating the digital video, in that case, images are called as frames.▼
▲
Movies use 24 frames per second; however, the rate of the frames can change according to territories' electrical systems so that there are different kinds of frame rates, for instance, North America is using approximately 30 frames per second where the Europe television frame rate is 25 frames per second. Each digital video has dimensions width and height; when referred to analogue television, the dimension for SDTV is 720×480 pixels, on the other hand, numerous HDTV requires 1920×1080 pixels. Moreover, whilst for SDTV, two bytes (16 bits) is enough to create the colour depth, HDTV requires three bytes (24 bits) to create the colour depth.
| |||