X264 to X264, better with 2 pass ?

[Nixeus]

Hello,

I have a 720p mp4 encoded in x264 @ 5700kbps.
I would like to reduce this mp4 to 4000kbps.

Do i need to use 2 pass ?
If i use only one pass, will i see a difference between a two pass encoding ?

Thanks a lot :)

Best regards,

Nixeus

[paradoxical]

You need 2 pass if you want to hit a specific bitrate. No, you will not see any quality difference between one-pass and two-pass at similar bitrate.

[Nixeus]

Ok thanks, but if i want to encode to 5600 to 4000 ( so, not the same bitrate) , only one pass will be good ? Or two ?

[paradoxical]

As I said, if you need to hit a specific size use two pass. That is unless you know the CRF value that will give you the bitrate you want then one pass is okay.

[Nixeus]

Ok, you said on the first answers : To hit a specific size, not a specific bitrate !

So, in my case, i will use one pass :)
Thanks

[sneaker_ger]

Specific size and specific bitrate are bascially the same.

Use 2 pass for "best" result when trying to hit a specific file size - or 1 pass abr (just --bitrate without --pass) for okayish result.

[paradoxical]

Ok, you said on the first answers : To hit a specific size, not a specific bitrate !

It's the same thing though. Size is directly proportional to the bitrate when the length is the same.

So, in my case, i will use one pass :)
Thanks

You're welcome.