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19th January 2012, 06:31 | #1 | Link |
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Join Date: Jul 2005
Posts: 359
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aq-strength - grainy/clean sources
When is it better to use a high or low aq-strength?
I've encoded a grainy source where I found an aq-strength of 0.60 worked best. On a clean source, I found that an aq-strength of 0.70 worked best. From what I've heard, it's best to use a lower aq-strength on both clean and grainy sources. So when is it better to use a higher aq-strength; like say, 0.9-1.2? |
19th January 2012, 13:48 | #3 | Link | |
I often say "maybe"...
Join Date: Jul 2009
Location: France
Posts: 583
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Quote:
(But I don't think AQ is that linear) AQ is really a strong knob wich drasticly changes the perceived quality. But since quality is relative to the user, you have to choose what it is looking best for you. To SHORTLY resume : It is Ringing versus Banding. High AQ strength retains more gradients but produces ringing. Low AQ strength preserves edges but produces banding. But dont forget psy-rd |
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19th January 2012, 18:01 | #5 | Link | |
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Join Date: Mar 2008
Posts: 118
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AQ makes a lot of difference under certain conditions.
From an old post on Videohelp (by poisondeathray), about the difference that aq-strength (under mode 1) makes: Quote:
Last edited by creamyhorror; 19th January 2012 at 18:04. |
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19th January 2012, 18:36 | #6 | Link | |
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Posts: 359
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Quote:
BTW, I've used both aq mode 1 and 2. I'm not 100% sure of the differences. I just used whatever works best to my eyes. I do usually find that my QP averages are higher if I use mode 2, but sometimes it still looks better despite the higher QP averages. Regarding psy-rd, my understanding is that it's a sharpness retention by applying less compression to edges/grain and that psy-trellis takes bits from flat/low detail areas and applies it to edges/grain. So with that said, would it be good to decrease it if you do notice some blocking or gradation issues in dark scenes and/or for clean sources? If it's a grainy film, is it better to increase psy to help retain grain? Last edited by rahzel; 19th January 2012 at 18:57. |
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20th January 2012, 06:44 | #7 | Link |
Telewhining
Join Date: Mar 2010
Posts: 272
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I think sources are so different that there is no "better" with AQ, even with sources that appear similar at first glance. You really just have to experiment with every encode if you want the optimal settings. And MatLz is right, I've found the best results come from tweaking psy-rd along with AQ. It also depends on the resolution you are encoding to - I've found HD material looks better with a lower aq while SD material needs a little higher.
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