Deblock

[Chengbin]

Using mediainfo, how come some videos's deblock setting is 1:-3:-3, some are 1:-1:-1.

What is the difference? Which one provides better quality?

[LoRd_MuldeR]

Using mediainfo, how come some videos's deblock setting is 1:-3:-3, some are 1:-1:-1.

What is the difference? Which one provides better quality?

There is no better! Higher deblocking means lower risk of visible blocks, but results in smoother (less detailed picture).
Lower deblocking results in sharper image, but also means a higher risk to get ugly blocks...

So it's a trade-off. You need to find the optimal value for your eyes ;)

The "inloop deblocking" is an integral part of H.264. Any H.264 decoder needs to apply it. P- and B-Frames refer to deblocked pictures.
Note that the H.264 deblocking filter is not used to remove blocks from your source video, but to prevent blocks added in the H.264 encoding!

When using x264 you can control the inloop deblocking filter with the "--filter a:b" option, default is "--filter 0:0".

More info about H.264 deblocking:
http://www.rgu.ac.uk/files/Perceptual%20quality%20of%20H264AVC%20deblocking%20filter_final.pdf

[poisondeathray]

Using mediainfo, how come some videos's deblock setting is 1:-3:-3, some are 1:-1:-1.

What is the difference? Which one provides better quality?

It depends on the source attributes, the bitrate used, your specific goals. "Quality" is subjective; some like sharper images and don't mind a bit of ringing , some don't, etc...

http://mewiki.project357.com/wiki/X264_Settings#deblock

http://forum.doom9.org/showthread.php?t=109747

You should do some test encodes on small representative samples, change the settings and see what you like better.

EDIT: Mr. Lord Mulder beat me to it :)

[Chengbin]

Thanks.

I was afraid that you can change the value to improve visual quality, like subme kind of. I don't mind encoding time.

Well, thanks a lot. Good thing I don't have to encode all my videos again because of that.

[LoRd_MuldeR]

I was afraid that you can change the value to improve visual quality, like subme kind of. I don't mind encoding time.

Well, you can change the deblocking value (alpha and beta). Depending on your personal preferences this might improve the results indeed.

However this is not a "higher is better/slower" setting. It needs to be adjusted carefully!

If you don't want to test various deblocking settings, you can safely stick with the default. Many people seem to prefer a slightly lowered deblocking though...

[Esurnir]

Thanks.

I was afraid that you can change the value to improve visual quality, like subme kind of. I don't mind encoding time.

Well, thanks a lot. Good thing I don't have to encode all my videos again because of that.

Try differents ones, general consensus is that movies require a bit less deblocking (because some people hate blur) and anime wouldn't mind a bit more deblocking (cause ringing sucks on anime)

[yaous]

In the case of encoding with sufficient bitrate, effect of inloop deblocking may be negligible.

is that right?

[wyti]

Yes the lower the quantizer, the lower the strength the deblocking is.

[Esurnir]

In the case of encoding with sufficient bitrate, effect of inloop deblocking may be negligible.

is that right?

the lower the quantitiser the lower the number of macroblocks that will pass the threshold that activate the deblocking filter.

[Dark Shikari]

the lower the quantitiser the lower the number of macroblocks that will pass the threshold that activate the deblocking filter.And the weaker on those that do.

[Mr VacBob]

If you're looking for deblocking advice, make sure to test everything you read; most of the old posts about it were written before AQ. That lowers quants, so reducing deblock will result in flat areas not being deblocked at all, which can cause many bad and surprising artifacts.

[Sagekilla]

What? AQ lowers the quants on blocks, specifically flat blocks. Since the quant is lower, you have more bits to prevent blocking from occurring. The lower your quant, the less of a problem deblocking is. Yes, if you lower strength or sensitivity deblocking will be an issue. But that will be an issue regardless of whether AQ is on or not.

[Dark Shikari]

What? AQ lowers the quants on blocks, specifically flat blocks. Since the quant is lower, you have more bits to prevent blocking from occurring. The lower your quant, the less of a problem deblocking is. Yes, if you lower strength or sensitivity deblocking will be an issue. But that will be an issue regardless of whether AQ is on or not.He actually has a good point; the issue is that lowering deblock strength raises the point at which deblocking is no longer active, and AQ can make this point occur on more blocks.