Some question about fades.

[Daniel_Lechu]

Hi friends, first of all i'm sorry for my english.

Well, I've some question about compression quality. I want to compress some films to reduce its size and i've one with fades. I did some test and i've some questions about a good compression command line:

I use a patched x264 with "Fade Compensate" and this is part of full command i've used: --tune film --weightp 2 --fade-compensate 1 --crf 20

I've tried some pressets: ultrafast, superfast, veryfast, faster, veryslow and placebo and my questions are.

-Which is a good command line to help fades quality?
-how is possible that superfast give better quality than slower pressets? (and higher filesize too).
-Someone knows a good manual with options in x264 full explained?, for example --direct, --me... what exactly does in video?.

I've i slow PC (Core2Duo), and with veryslow and placebo it take about 50 hours and 250 hours to compress a film. I need to use faster pressets and i need to understand what every option does to decide what is a good cmd...

I'm very new in x264, and any help would be appreciated. Thanks.

[Blue_MiSfit]

The default preset (medium) is a pretty good balance. I wouldn't go any faster than --preset faster, or any slower than --preset slower generally.

At the same CRF value, a faster preset might produce better quality results than a slower preset, but definitely at the cost of larger file size. If you care about the size of your output being exact, then CRF is not for you. Set a --bitrate, and use 2 passes if you can afford the time.

Don't bother with individual quality settings. Just set a rate control mode and be done with it. The developers made the presets for a reason. Generally, just use the slowest preset you can stand, and a --tune that is appropriate for your content. I use --tune film 99% of the time.

I've never tried the fade compensate patch, and have no idea about its impact on encoding.

[CarlEdman]

The default preset (medium) is a pretty good balance. I wouldn't go any faster than --preset faster, or any slower than --preset slower generally.

Sound advice.

I'd just slightly disagree with going no lower than "slower." In my experience, on a system which was relatively fast when built two years ago, "veryslow" gives appreciably better results and, even with demanding avisynth filters, will encode standard definition at about real-time and 1080p at about a quarter of that speed.

Now, as the name suggests, "placebo" really is a waste of time unless you have more cycles than you can use due to some other system restraints.

[Daniel_Lechu]

Thanks to both for answers.

My PC is slow (Core2Duo 2GHZ), and take about 4/5 times to encode in normal presset (5fps), then with a film of 2 hours it take about 16 hours in a 2pass encode...
With fade compensate patch i've get a better quality in fades, works very well...
I'll try to use veryfast (15fps) with two pass or crf, because others is too slow and i really don't care about file size. With Veryfast and crf 22 i can compress a film to a 1/3 size wih a good quality.

Thanks.

[Blue_MiSfit]

CRF 22 is a bit high for archival quality encoding in my opinion, especially with a fast preset. I'd probably do --crf 18 to 20 depending on the content.

But, that's just my eyes and my opinion. Everyone is different!

[Daniel_Lechu]

CRF 22 is a bit high for archival quality encoding in my opinion, especially with a fast preset. I'd probably do --crf 18 to 20 depending on the content.

But, that's just my eyes and my opinion. Everyone is different!

Well i'm using 18, 20 and 22 depends of it's content, i've used 22 for a animation film that really don't need high bitrates to have a good quality, but i've changed to 20 or 18 in some films.

[Blue_MiSfit]

Sure thing, whatever works for you :)