T_T
看来1.1版还来不及出，就要出1.2版了……谢谢TCT66大大的指导
Intra-frames tuning这一整页的设置，在我看来似乎没什么很大的用处。
我在写的时候也考虑到
I-frame closer than...(frames):1
...are reduced by(%):20%
这个选项的问题了。
在DOOM9的解释中，这项设置的解释是“In our example, I-frames th
an are closer than 1 frame (so there won't be any), would be reduced by 20%.”
但是谁都知道，这种连续出现IF情况是不大可能出现的。所以，我觉得这一整页的设置都大可保留默认值，不必去留意。
至于GMC，我记得TCT66的文章里面提到过GMC的兼容性问题？如果兼容性不好，迟些再用也可以。
还有，TCT66有一个词拼写错了，应该是PSNR，而不是PNSR^^
我在XVID.ORG看到了一段话，顺便贴到这里来。
· What exactly are all those neat features (GMC, Quarter-pel, Adaptative quantization) that the development version of Xvid has and that you keep talking so excitedly about? Just how good they are, and how do they work to help the encoder improve image qual
Explaining the details of this would last too long. As a short answer:
MPEG-4 is very effective in compression, because it reuses data from one image to generate the next one (still images of a video are only 1/25 of a second or even less apart from each other, in almost all cases they look very similar).
There a diferent ways how to detect which part of the picture can be reused, and QPel = "Quarterpel Motion Compensation" and GMC = "Global Motion Compensation" are two advanced ways of doing this. Normally you only use "Halfpel Motion Compensation", so the resolution is higher with Quarterpel.
A different step in compression is to divide some coefficients by a number to gives them smaller values (and hopefully zero). This is called "Quantization". Normally, every 16x16 block in the image is divided by the same value, but with "adaptive quantization", for every block a different value can be chose.
This _can_ lead to better quality, when e.g. important parts like faces are compressed less, and less importants part (background) are compressed stronger, but it's still experimental.
