Cayin SMP-PRO4 Посібник з відтворення - Сторінка 2

Переглянути онлайн або завантажити pdf Посібник з відтворення для Медіаплеєр Cayin SMP-PRO4. Cayin SMP-PRO4 12 сторінок. Smp series

CAYIN SMP Player Video Playback Guide

1. About Digital Video

Video, also called motion picture, comprises a series of still images displayed in rapid

succession at a constant rate. As digital video is getting popular nowadays, it has become a new

and crucial technology to compress and store digital video files into digital media.

Digital video has the following attributes:



Number of frames per second (frame/sec, or fps):

Also called frame rate, this is the number of still images that are displayed per second.

Generally, a higher frame rate will bring smoother and better video quality while

increasing a multimedia player's loading. For example, the PAL standard delivers 25fps,

while the NTSC standard delivers 29.97 (usually implement as 30fps). Early movies before

the digital age were usually filmed at 24fps or lower.



Resolution (pixels):

Digital video usually uses pixels as the resolution unit. The frame size consists of the

width (W) and height (H) of the pixels (for example, 1280(W) x 720(H)). Other

abbreviations are also used, such as 720p (meaning the resolution is 1280 x 720) or 1080i

(meaning 1920 x 1080) to represent resolution.

The "p" represents progress scan, which means all pixels will be refreshed when playing

each frame. On the other hand, "i" represents interlaced scan, which means it will record

the image in alternating sets of lines – the odd‐numbered lines are scanned, and then the

even‐numbered lines are scanned, then the odd‐numbered lines are scanned again, and

so on. These lines will be refreshed by turns in order to present the motion effects.

For this reason, sometimes the rapid moving area in interlaced video will show some

jagged lines. To solve this issue, multimedia players can use a de‐interlacing algorithm to

smooth those jagged lines. Usually, playing interlaced video will cause a slower loading

process than when playing a progress one, but a de‐interlacing algorithm will help

increase the process loading for a media player.



Compression method (Codec):

The data size of digital still images is usually very huge. For example, the data size for 10

minutes of 720p (30fps) uncompressed video can be calculated as follows:

1280*720*3(bytes per pixels)*30 (fps)*600 (sec.) = 46.35 (Giga bytes)

That means your gigantic 500GB hard drive will soon run out of space from just 100

minutes of uncompressed video files. In response to the demand for digital video storage,

video compression technology nowadays plays a crucial role. Video compression methods

have been developed for a long time. From early lossless compression to the MPEG family

and its variants, new technology is continually developing to enhance the compression

efficiency. However, at the same time, this makes it a more complicated job for media