More than 1 pass and preset question

[lutinor]

Hi all,

i don't know when it's useful to make a more than 1 pass encode...when is it especially useful?

What about preset ? Is there a big difference in term of quality about slow/slower/very slow?

Thx in adv,

Max.

[mp3dom]

For 1 pass you mean CRF or a true first pass?
In the second case, the quality of the second pass will give you higher quality even if you do a slow-firstpass (at least this is what I've seen directly on my test sources)

[lutinor]

For 1 pass you mean CRF or a true first pass?
In the second case, the quality of the second pass will give you higher quality even if you do a slow-firstpass (at least this is what I've seen directly on my test sources)

This option : --pass 1 (second line is --pass 2)

Btw, i mean, what is more important , more than 1 pass or slower preset ?

[LoRd_MuldeR]

If you do a 2-Pass encode, you should use the very same preset for both passes. x264 will automatically use faster settings in the first pass, regardless of the preset.

Also, whether you do a 2-Pass "target bitrate" (target file size) or a 1-Pass CRF "target quality" encode should depend on what your goal is...

(If you need to hit a specific file size and you want to achieve the best possible quality for that file size, then use 2-Pass mode. Otherwise use 1-Pass CRF mode)

[mp3dom]

That 1 pass is not good as a final output. If you need to encode in a short time, change the preset but do 2 pass or do a CRF (which take the time of 1 pass but output a higher quality. The drawback is that the final size can't be calculated)

[lutinor]

Basically 2 pass and --slow/slower preset is a good way in term of speed/quality ratio ?

[LoRd_MuldeR]

Basically 2 pass and --slow/slower preset is a good way in term of speed/quality ratio ?

Again: 2-Pass (aka "target bitrate") mode is for a different purpose than 1-Pass CRF (aka "target quality") mode.

First of all, you have to find out what your goal is. Once you have done that (and have selected the appropriate encoding mode), then choose the slowest preset that you can afford!

And, as said before, if you go for 2-Pass mode, then x264 will use faster settings in the first pass anyway, regardless of what preset you select...

(Note: 1-Pass ABR generally is worse than a full 2-Pass encode. So if you need to hit a target bitrate/filesize, then 2-Pass is highly recommended. 1-Pass CRF is perfectly fine though)

[lutinor]

Again: 2-Pass (aka "target bitrate") mode is for a different purpose than 1-Pass CRF (aka "target quality") mode.

First of all, you have to find out what your goal is. Once you have done that (and have selected the appropriate encoding mode), then choose the slowest preset that you can afford!

And, as said before, if you go for 2-Pass mode, then x264 will use faster settings in the first pass anyway, regardless of what preset you select...

(Note: 1-Pass ABR generally is worse than a full 2-Pass encode. So if you need to hit a target bitrate/filesize, then 2-Pass is highly recommended. 1-Pass CRF is perfectly fine though)

thanks a lot for your help :thanks:

[vrpatilisl]

hi now am confused though question seems foolish please give the answer,

If i want best quality DVD rip to mkv, size is not matter then which is best crf of 2 pass . but if same quality i getting with more compression then which is better in compression as well quality.i want transparent dvd rips size is not a matter.

[LoRd_MuldeR]

If i want best quality DVD rip to mkv, size is not matter then which is best crf of 2 pass . but if same quality i getting with more compression then which is better in compression as well quality.i want transparent dvd rips size is not a matter.

The difference in quality between a 1-Pass CRF encode and a 2-Pass encode of the same file size (i.e. same average bitrate) is negligible! So the major difference is that with CRF mode you can't know the final file size beforehand, while with 2-Pass mode you set the target average bitrate and thus the resulting file size can be calculated easily. Hence, if you need to hit a specific file size and you want the "best" quality for that size, use 2-Pass mode. If, however, the file size doesn't matter (that much), use CRF mode and choose the CRF value that gives the desired quality level...

(BTW: If you really want the "best possible quality", then you have to use lossless mode, i.e. CRF=0. But you probably don't want a "true" lossless compression. Try CRF=~18 instead!)