DVD series. x264 CRF 20-22?

[valnar]

I can't decide. Simple as that. Maybe I don't have a discerning eye or my TV isn't up to snuff to tell the difference, but when I do get a high-resolution HDTV, I don't want to be disappointed.

I am going to convert a bunch of TV episodes to x264/MKV files. I have all parameters decisions down except CRF. These will be one-pass quality based since particular file size is not important, but as always, total disk space is. The difference between CRF 20-22 is quite a bit taking in 22 episodes per season.

Has anyone done comparisons on a good HDTV or have a personal preference of what is near-transparent and good enough to watch in place of the original DVD's? TV series in question is Buffy the Vampire Slayer.

-Robert

[Blue_MiSfit]

I usually start at CRF21 for HD material. It all depends :) Some SD stuff needs even CRF16 to look transparent to my eyes.

We can't tell you how to encode your content.

It really does depend on how big / good your HDTV is, how close to it you plan on sitting, how the video is decoded / post-processed / displayed etc...

For example, if you use DeBand / noise after upscaling to the TV's resolution, you can most likely get away with a higher CRF value, since these post-processing operations can improve subjective quality.

I would really suggest encoding some test clips, and testing them out on a friend's TV if possible. Surely you must know someone with a half decent HDTV?

~MiSfit

[Warpman]

mhm, for my favorite Anime shows i use crf 16 for the rest crf 18

Anime compresses quite well so files won't become so large anyway... for "real life" footage i think crf 20 is acceptable :>

[ToS_Maverick]

i like to use crf 20 for my sd encodes, and in your case, if you plan to upgrade your tv, a little quality-overhead makes sense.

be also sure to use AQ (which is on by default, with a recend build) and try and see if you like FGO ;)

[valnar]

Considering that 20 is my limit because of file size, and recommendations in this thread go even lower, it looks like that is my answer. I'll do the math between 20 or 21 and see how it works out.

Robert

[guada2]

Excuse me but i have a little question:

Is there a method or a particular calculation to determine the rate that represents any CRF.

for example: CRF 40 = bitrate?, CRF 54 = bitrate?

Thanks.

[Atak_Snajpera]

No!!!!!!!!

[Dark Shikari]

Excuse me but i have a little question:

Is there a method or a particular calculation to determine the rate that represents any CRF.

for example: CRF 40 = bitrate?, CRF 54 = bitrate?

Thanks.By definition, CRF is a mode which does not determine a bitrate at all. The bitrate is what happens to result from CRF's quantizer choices; CRF has no idea what the bitrate will be.

[guada2]

OK Dark & Atak_Snajpera,

If it can not determine the bitrate, it can give me the size requested.
Let me explain, for a CRF X = V and a mode 2pass = W and a size T = Z

I managed (after a few test) to find for this CRF X in the same size as the mode 2pass.

What do you think about this?

[Manao]

You can expect that bitrate(CRF(20)) = 2 x bitrate(CRF(26)), since CRF scales like quantizers.

It's not an absolute. You'll find videos (especially short ones) on which the relationship will be 1.5x or 3x, but on average it should be OK.

[Atak_Snajpera]

I managed (after a few test) to find for this CRF X in the same size as the mode 2pass.
Use completely different source and your theory will fall :)

For god sake! If you want specific size then you must use 2-pass. If you don't care about final size then you should use CQ (CRF).

[valnar]

I'm going with CRF 20, and that may not even be good enough, but I'll live. Early Buffy seasons were quite grainy and dark. Some graininess will be traded for a bit of macro blocking in the darkest of scenes, but that is acceptable. CRF 16 is not.

Thanks everyone.

Robert

[Inventive Software]

If you want to keep the grain, use an x264 build with FGO.

[guada2]

Thank you very much Manao. :)

AS, you may be right, but for now I'm feeling lucky. :)

I admit, there was not so long ago that I adopted the CRF.

However, apart from the performance of the CRF, in what circumstances I have to call the method 2pass.

stupid question:
Can we adjust a Quantizer fixed?