x265 - CRF and quantizers

[shazzla]

Hi all !

Sorry for the n00b question,but im a n00b.

Well,the question is:

Is any correlation between quantizers (0-69) and CRF encoding?
Because when i change it(quantizers),the final encoded movies lenght are the same?!

[johns0]

They just set the encoding bitrate and size according to the video content,has nothing to do with the length of videos.

[shazzla]

So,if i change the quantizers to 1-30 and make a CRF 18 encode,then the resulting file will be bigger than 1-69/CRF18 ?!
Hope you understand me.

[poisondeathray]

Is any correlation between quantizers (0-69) and CRF encoding?
Because when i change it(quantizers),the final encoded movies lenght are the same?!

So,if i change the quantizers to 1-30 and make a CRF 18 encode,then the resulting file will be bigger than 1-69/CRF18 ?!
Hope you understand me.

Which "quantizer" ? Did you mean --qp , or did you mean --qpmin, --qpmax ? --qp is mutually exclusive with --crf (you cannot use both)

If you meant --qpmin, --qpmax, the default is 0 and 69 ; that means no limit

If you set --qpmin 0 and --qpmax 30, the filesize could theoretically be slightly larger, because higher quantizers beyond 30 are not allowed.

But at CRF18, the average quantizer range will rarely (if at all) go past 30 anyways, so it will probably not make any difference

You can do short test it to find out for yourself

[shazzla]

Ohh. Everythings clear now.
Thank you very much!