720P
720p (1280×720); also called HD Ready) is a progressive HDTV signal format with 720 vertical lines and an aspect ratio (AR) of 16:9, normally known as widescreen HDTV (1.78:1).
The number 720 stands for the 720 horizontal scan lines of image display resolution (also known as 720 pixels of vertical resolution).[1]
The p stands for progressive scan, i.e. non-interlaced.
P的含義: progressive scan，逐行掃描的意思。
720p的視頻的分辨率為: 1280×720。
另外， 1080p 的分辨率是: 1920x1080。
YUV420采樣之后的數(shù)據(jù)大小
每個Y/U/V的采樣點用8bit來表示，即1Bytes.
- 720p
1280 * 720 * 8 *(1 + 1/4 + 1/4) / 8
= 1382400 Bytes
= 1350 KB
約= 1.318359375 M
大約是1.3M。
- 1080p
1920 * 1080 * 8 *(1 + 1/4 + 1/4) / 8
= 3110400 Bytes
= 3037.5 KB
約= 2.966308594 M
大約3M。
1080p 和 720p 一幀數(shù)據(jù)的比較
在同樣的抽樣格式(一般為4:2:0)的情況下:
(1920 * 1080) / (1280 * 720) = 2.25
可以看出1080p的一幀數(shù)據(jù)大小是720p的2.25倍。
