请教一下sar的定义

[tinkle]

其实关于sar看到过很多讲述和讨论的文章，但是由于各方意思都不统一所以自己也昏了，比如说首先sar是什么的缩写呢，关于这一点就有看到2种说法，一个是Storage Aspect Ratio，一个是Sample Aspect Ratio，有的说SAR=PAR，有的又不是……平时自己做一些压制都在电脑上放，对sar没设置过，所以对sar不熟悉，基本概念没搞清，求科普

[xiao7]

SAR（Sample Aspect Ratio）采样横纵比 ------对像素做采样的时候进行变形 保证DAR正确
DAR（Display Aspect Ratio）显示横纵比 ------你最后看到的比例 例如16：9 /4：3这类
PAR（Pixel Aspect Ratio）象素横纵比 ------分辨率比例 例如 720x480 1280x720

DAR = PAR*SAR

[tinkle]

SAR（Sample Aspect Ratio）采样横纵比 ------对像素做采样的时候进行变形 保证DAR正确
DAR（Display Aspect Ratio）显示横纵比 ------你最后看到的比例 例如16：9 /4：3这类
PAR（Pixel Aspect Ratio）象素横纵比 ------分辨率比例 例如 720x480 1280x720

DAR = PAR*SAR

嗯，这个也是看到的解释一种，另外我前面提到的Storage Aspect Ratio不知道是不是和什么搞混了，某软件里面可以设置sar，鼠标放在上面他给出的解释就是Storage Aspect Ratio，说是storage frame的长宽比，不过不知道啥叫storage frame。
另外在维基百科查的关于sar的解释：

This article primarily addresses the aspect ratio of images as displayed, which is more formally referred to as the Display Aspect Ratio (DAR). In digital images, there is a distinction with the Storage Aspect Ratio (SAR), which is the ratio of pixel dimensions. If an image is displayed with square pixels, then these ratios agree; if not, then non-square, "rectangular" pixels are used, and these ratios disagree. The aspect ratio of the pixels themselves is known as the Pixel Aspect Ratio (PAR) – for square pixels this is 1:1 – and these are related by the identity:

SAR × PAR = DAR.

Rearranging (solving for PAR) yields:

PAR = DAR/SAR.

For example, a 640 × 480 VGA image has a SAR of 640/480 = 4:3, and if displayed on a 4:3 display (DAR = 4:3) has square pixels, hence a PAR of 1:1. By contrast, a 720 × 576 D-1 PAL image has a SAR of 720/576 = 5:4, but is displayed on a 4:3 display (DAR = 4:3), so by this formula it would have a PAR of (4:3)/(5:4) = 16:15.

貌似和你说的sar、par刚好相反

[mawen1250]

一般情况下SAR（Sample Aspect Ratio）和PAR（Pixel Aspect Ratio）是一样的，只不过前者强调采样过程中每个像素的AR，后者强调视频中每个像素的AR。