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Old 21st December 2010, 12:04   #4  |  Link
manono
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Join Date: Oct 2001
Location: Hawaii
Posts: 7,406
You use a matrix that produces an average quant within the values you want. If you're serious about it you have several from which to choose in order to achieve that goal with one of them. HCEnc has a good selection (along with a bunch of crap ones). Most of the included CCE ones are junk, although encoding with the Standard Matrix set up for Q-Matrix Switching can be a good idea. In addition, when shrinking a DVD9 to a DVD5 I have a low-bitrate matrix to encode any extras I might want to keep, in order to free up bits for the main movie. I have no idea what Dark Shikari said in his first sentence, but I know I disagree with his second sentence.
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Originally Posted by Lyris View Post
I've encoded a few DVD titles for the US market (using CCE SP2 and SP3, for what it's worth) and honestly, the Quantization Matrix settings are some of the few that I have never found a use for.
So, you're using the crummy default Standard Matrix? Then you're obviously not working for any major DVD production house because they all gave up that matrix years ago. No major Hollywood movie released on DVD ever uses CCE's Standard Matrix. One can learn a lot just by collecting and studying the matrices they do use. Of course, when shrinking DVD9s to DVD5s, one usually can't use those very good matrices because the average quants will wind up too high and you'll get artifacting, including mosquito noise, color smearing, and maybe even macroblocking.
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In some difficult scenes, in rare cases, I've found that using an alternative matrix or stepping down to 8-bit precision has brought a technically higher SSIM result
And we all know what SSIM results are worth. As I understand it, one should almost never use anything but 10-bit precision. Again, look to the good Hollywood DVDs. The movies may be crap, most of them, but those guys do know how to encode MPEG-2 video, for the most part.
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I also get the idea that most of these people are re-encoding DVDs, and are just trying to use the same matrix that was used to encode the first time, which isn't terribly useful.
I don't get that idea but, if true and if reencoding for DVD5, it's not such a good idea.
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