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Old 26th May 2014, 11:49   #1  |  Link
Witzig
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What filters to use for grain preservation

I'm encoding full Blurays to about 3000kbps with x264 as encoder, if the result is not as I wish I slightly increase the bitrate till it does. I'm encoding a variety of sources so some are very grainy and others are not.

I currently use Limitedsharpenfaster() for the sharpening but what other filters could I test for a good compression and grain preservation?

Thank you
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Old 26th May 2014, 12:41   #2  |  Link
Mole
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3000kpbs at 1080p or do you resize down?

Frankly 3000 is a bit on the low side even for 720p and since you're also using LSF, it'll probably look even worse with such low bitrates. On top of this, you want to preserve grains at this low bitrate as well? With such low bitrate, you're better off to REMOVE the grains.

Since bitrate is obviously not your main concern, you should just use CRF setting instead of 2-pass bitrate setting. This way you won't need to increase your bitrate if the result is not good enough for you.

Try for example maybe CRF=24 to get around 3000kbps for 720p encodes.
This depends on the source, movies with much dark scenes, the bitrate will be much lower at a given CRF.
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Old 26th May 2014, 12:46   #3  |  Link
Witzig
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Quote:
Originally Posted by Mole View Post
3000kpbs at 1080p or do you resize down?

Frankly 3000 is a bit on the low side even for 720p and since you're also using LSF, it'll probably look even worse with such low bitrates. On top of this, you want to preserve grains at this low bitrate as well? With such low bitrate, you're better off to REMOVE the grains.

Since bitrate is obviously not your main concern, you should just use CRF setting instead of 2-pass bitrate setting. This way you won't need to increase your bitrate if the result is not good enough for you.

Try for example maybe CRF=24 to get around 3000kbps for 720p encodes.
This depends on the source, movies with much dark scenes, the bitrate will be much lower at a given CRF.
I'll be downsizing to 720p. My goal is quality encodes while keeping low bitrate. And with quality I try to get the result as transparent as possible so therefore I would like to preserve the grain.

As you said yourself, 3000kbps can sometimes give a transparent encode and sometimes it cannot. Therefore I try to get the best result with a low bitrate and so my question what filters to use still stands.

Thank you for your reply!
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Old 26th May 2014, 13:16   #4  |  Link
Mole
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But I'm telling you, you're not gonna get a good encode with only 3000 bitrate for 720, regardless.

I never said 3000 will ever give "transparent" encode at 720p. CRF mode is the better method to be sure that you will get constant quality from your encodes regardless of source.

I'm also telling you that you will get better quality by not having grains at this low bitrate. If you keep the grains, the x264 will encode at a worse quality because of the limited low bitrate.

According to the x264 docs, CRF=20 should get an overall good quality, but I doubt any type of source you will get 3000 bitrate with CRF=20 1280x720. It'll be more like at least 4000+. The more grainy and sharp source, the higher bitrate the CRF will use also.

But obviously every of us has different perception of "quality".
I can tell you this that for 1280x720 @ 3000 bitrate, most people aren't gonna consider this a quality encode.
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Old 26th May 2014, 13:25   #5  |  Link
Witzig
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Thank you. I'll definitely take it in account.

Let me put it like this. What filters give a good compression and do not smoothen out the grain?
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Old 26th May 2014, 13:26   #6  |  Link
feisty2
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3000 kbps for 720p is almost equal to u2b quality
and u honestly think that is good quality?
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Old 26th May 2014, 13:28   #7  |  Link
Reel.Deel
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@Witzig

Since you're downsizing to 720p you might want to give STPresso a try.
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Old 26th May 2014, 13:42   #8  |  Link
Witzig
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@feisty2 of course you'll always notice the quality is not the same as on the BD, however it is simply a trade-off between quality and file size and I am therefore trying to get a good quality/filesize ratio. This trade-off is naturally different per person.

@Reel.Deel thanks a lot! Exactly these type of filters I am looking for
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Old 29th May 2014, 01:51   #9  |  Link
aldix
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Quote:
Originally Posted by Mole View Post
But I'm telling you, you're not gonna get a good encode with only 3000 bitrate for 720, regardless.
That depends entirely on the person doing the encoding & the tools used, mate

My m720p encodes @ 3K are definitely not considered "not quality".

Of course, transparency is another issue entirely. It's hardly possible to keep 1:1 ratio with 35K Bitrate grainy movie compressed into 3K encode.

Possibilities in Avisynth, however, are quite endless to overcome this.
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