x264 questions

[PurpleMan]

Hello.

I'm encoding from a Blu-ray source to x264 video file intended for PC playback. I don't care about standalone compatiblity or encoding speed (5fps vs 3fps doesn't make much difference to me, I wait overnight anyway).

What I do care about is achieving the best filesize for a given quality. My questions are:

1) Assuming all other parameters are the same, when encoding in 1-pass CRF mode (--crf 18), will the --preset option only affect the resulting filesize or the output quality as well? ("slow" vs "veryslow")
It is my understanding that the CRF value I use determines the quality while the preset I use determines compression efficiency (hence - filesize for that quality).

2) I'm using the following parameters for encoding:
--preset veryslow --ref 4 --b-adapt 2 --b-pyramid normal --weightp 2 --slow-firstpass --qpmin=0 --crf 18 --level 4.1 --aud --nal-hrd vbr --vbv-bufsize 30000 --keyint 24 --min-keyint 1 --ipratio 1.1 --pbratio 1.1 --vbv-maxrate 30000
Would you recommend changing anything to achieve better quality or smaller filesize or both?

Thank you.

[iSeries]

Hello.

I'm encoding from a Blu-ray source to x264 video file intended for PC playback. I don't care about standalone compatiblity or encoding speed (5fps vs 3fps doesn't make much difference to me, I wait overnight anyway).

What I do care about is achieving the best filesize for a given quality. My questions are:

1) Assuming all other parameters are the same, when encoding in 1-pass CRF mode (--crf 18), will the --preset option only affect the resulting filesize or the output quality as well? ("slow" vs "veryslow")
It is my understanding that the CRF value I use determines the quality while the preset I use determines compression efficiency (hence - filesize for that quality).

2) I'm using the following parameters for encoding:
--preset veryslow --ref 4 --b-adapt 2 --b-pyramid normal --weightp 2 --slow-firstpass --qpmin=0 --crf 18 --level 4.1 --aud --nal-hrd vbr --vbv-bufsize 30000 --keyint 24 --min-keyint 1 --ipratio 1.1 --pbratio 1.1 --vbv-maxrate 30000
Would you recommend changing anything to achieve better quality or smaller filesize or both?

Thank you.

If it's PC playback you're after and not worried about standalone compatability then I'd say just --preset veryslow --crf 18 would do just fine. The other settings are either unnecessary or unnecessarily restrict x264.

As for preset vs quality when encoding with crf, it's my understanding is that it affects both file size AND quality. And --preset veryslow is erm very slow lol, I see no reason to go above --preset slow. Thats all subjective though ;)

[Atak_Snajpera]

if you don't care about hardware compatibilty so why you use settings for blu-ray???
for pc just use x264 10 bit .

[PurpleMan]

if you don't care about hardware compatibilty so why you use settings for blu-ray???
for pc just use x264 10 bit .

1) Which settings would you change/remove (and why)?
2) If my source is Blu-ray 8-bit, what advantage would I have in encoding x264 10bit?

Thank you.

[PurpleMan]

If it's PC playback you're after and not worried about standalone compatability then I'd say just --preset veryslow --crf 18 would do just fine. The other settings are either unnecessary or unnecessarily restrict x264.

Which of my settings restrict x264? what would you change/remove?

Thank you.

[iSeries]

Which of my settings restrict x264? what would you change/remove?

Thank you.

Some of your other settings are for blu ray compatibility (as Atak says), which you don't need.

If PC playback is your goal, just use the presets - they set all these parameters for you. Thats what they're for.

[Atak_Snajpera]

1) x264.10bit.exe --profile high10 --preset slow --crf 18
that's all

2) it does not matter. higher internal precision means better quality (NO BANDING for example)

[PurpleMan]

1) x264.10bit.exe --profile high10 --preset slow --crf 18
that's all

2) it does not matter. higher internal precision means better quality (NO BANDING for example)

Hmm... won't 10-bit encoding with the same CRF result in a higher filesize?

Also, the 10bit version of x264 (x64) currently complains about my .AVS input file (which works fine in any other software). Do I need something to special to feed that AVS into the 10bit version?

Thank you.

[Atak_Snajpera]

Hmm... won't 10-bit encoding with the same CRF result in a higher filesize?
http://x264.nl/x264/10bit_02-ateme-why_does_10bit_save_bandwidth.pdf

Also, the 10bit version of x264 (x64) currently complains about my .AVS input file (which works fine in any other software). Do I need something to special to feed that AVS into the 10bit version?
No. Also try to use 32 bit.

[nm]

Hmm... won't 10-bit encoding with the same CRF result in a higher filesize?

10-bit encoding of an 8-bit source is about 10-20 % more efficient than 8-bit encoding at the same quality. But you might need to adjust CRF to get that lower file size. (I don't remember now how it behaves).

Also, the 10bit version of x264 (x64) currently complains about my .AVS input file (which works fine in any other software). Do I need something to special to feed that AVS into the 10bit version?

You need 64-bit AviSynth and plugins for 64-bit x264. (Or pipe from 32-bit AviSynth with avs2yuv or one of the other piping tools).