随着硬盘空间越来越小，最近想试试h265。发现其编码速度是很慢的，用auto2pass明显不现实。所以想到，h265的crf。
通过网上的资料可知，h264的默认值为23，压制出来的体积已经不小。而且画质中上等品质吧。
似乎有资料说h265的默认值28，就相当于h264的crf23。这种压制出来体积会小很多。又是默认值。
想请教一下诸位大神，h265 crf28，是否可视为一个理想的编码方式。
也就是说，压制出来，品质中上等，体积又很小，充分发挥了h265低码率的优势。

1080P动画，压制速度，不到1倍速，也就是比影片的播放时长还要慢一些。

可以，但我不这么认为

x265默认的crf28不推荐日常使用。如果需要极低码率的使用场景，建议用av1。

对画面质量没有要求的话可以考虑，否则……
（Srsly？crf28压出来东西能看？）

我个人压a片最多接受1080p下crf26，再大画面细节就丢很多了，还不如看在线的

我用cqp比crf效果好。同等vmaf得分，文件小20%

h265，刚尝到了点甜头。
crf28一口气压了好几部超清动画。体积确实惊人，720p静态画面多的动画，一集50M左右。
1080p静态多的动画，一集90多M。打戏和特效多的集，也不过250M左右。
体积小巧，用小米3增强版盒子试了试，还是对付不了h265，解码速度跟不上，音画错位。

crf20以上我个人不太接受得了

你这不是已经压了不少了么 你自己看着能接受就好了
不过如果能再想想将来升级了更好的设备是否还依旧能接受这勉强能看的画质 那就更好了

外网找到一些关于x265压制动画片参数的讨论
大致总结如下：
1、采用10bit编码
2、bframe=6-8，较高的b帧
3、关闭sao，或limit-sao
4、心理视觉模型？psy-rd=1
5、边缘、纹理控制 aq-mode=3
6、去块deblock=-1,-1
FYI
或者，简化直接crf=28，加上tune=animation
自动调入参数：psy-rd=0.4:aq-strength=0.4:deblock=1,1:bframes=(preset+2).
aq-strength=0.4远低于常规数值1，纹理大量抹平，码率降低显著。
=================原文如下=============原文如下======================
How to preserve dark lines when re-encoding anime to x265?
Summary for x265 Encode Settings
Set preset=slow. Then choose 1 following to override the default parameters. These are my recommended settings, feel free to tune them.
1．1Setting to rule them all: crf=19-20,
Code:limit-sao:bframes=8:psy-rd=1:aq-mode=3
2．Flat, slow anime (slice of life, everything is well lit): crf=19-20,
Code:bframes=8:psy-rd=1:aq-mode=3:aq-strength=0.8:deblock=1,1
3．Some dark scene, some battle scene (shonen, historical, etc.): crf=18-19 (motion + fancy FX),
Code:limit-sao:bframes=8:psy-rd=1.5:psy-rdoq=2:aq-mode=3
4．Movie-tier dark scene, complex grain/detail: crf=16-18,
Code:no-sao:bframes=8:psy-rd=1.5:psy-rdoq=4:aq-mode=3
5．I have infinite storage, a supercomputer, and I want details: preset=veryslow, crf=14,
Code:no-sao:no-strong-intra-smoothing:bframes=8:psy-rd=2:psy-rdoq=5:aq-mode=3:deblock=-1,-1:ref=6
Here an excerpt from a Reddit poster:
· Use the 10-bit encoder. Not the 8-bit nor the 12-bit.
· Optimally, use the slow preset. Veryslow preset is a luxury reserved for very powerful systems and high crf (22+) encodes.
· aq-mode=3! This sets dark scene aq bias, which is really helpful for anime, as this is where most of the artifacts and banding will be.
· Don't use tune animation. The appended options are: psy-rd=0.4:aq-strength=0.4:deblock=1,1:bframes=(preset+2). These are optimized for cartoon-style animation, anything more complex than slice of life is going to suffer, especially with newer BD releases utilizing dynamic grain to prevent banding.
For "Anime" anime, I recommend
psy-rd1 to 2 (more complex/action packed/detailed anime = higher value needed, also increases bitrate),
aq-strength 0.6 to 1 (more complex/detailed = need higher value, don't go beyond 1 as you may introduce ringing artifacts. You will mostly use 0.8-1. Also raises bitrate.),
deblock -1:-1 to 1:1 (depends on source, leave on 0:0 if you don't know what to use)
and bframes 4 to 8 (I highly recommend 6, 8 if possible. Encode penalty is only ~5% going from 4 to 8).
Additionally, if your source has grain, psy-rdoq should be raised from the default 1 to 3-5 depending on source
(note: only combine higher rdoq with crf<18 and no-sao, or you'll end up with grain "blocks" instead of grain "grain").
· Use limit-sao for crf 17-19. Use no-sao for crf<18 if there are fine grain present. Else leave on default.
· Use no-strong-intra-smoothing only for crf<16. This helps preserve fine details. High crf will result in blocking due to lack of smoothing on 32x32 blocks.

显示dpi 300以上，crf28也很清晰，
dpi300-200，crf28就看起来不那么清晰
dpi200以下，更容易察觉到块、涂抹

只不过是6“屏横流的时代，nhd crf 28 h264 完全够用。

最近压制又试了试CRF23。1080p 一集24分钟时长的动画，大概还是150m-260m这种体积。
这样看来，即使是CRF18，体积也还是很小。估计也就300-400M左右。
看来之前，我设置crf28是大了点，没有必要那么大。