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I have noticed a number of unbelievably badly encoded Blu-ray discs lately. This is probably for the same marketing reasons as previously mentioned; many companies are still marketing really bad encoders. Its ironic to see that real-time broadcast encoders can do better jobs than Blu-ray encoders!
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Yeah, I'm a judge for the DVDA Excellence Awards, and just got done judging a number of DVD and BD discs. I was really surprised how problematic many of the BD discs were, particularly in dark areas. Tons of blocking in black and other problems.
Keeping low-luma looking good was a major focus of all our work in PEP for VC-1, and one of the reasons why many compressionists prefer it over the H.264 products. Apropos of what what I was saying above, I don't think there's anything particular about VC-1 that made it easeir to do this; it was a matter of hearing the feedback that this had become a big problem due to all the consumer displays with non-perceptually-uniform gamma an elevated blacks, and then our spending a ton of time tweaking the encoder to do well in that case.
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One particularly bad one I saw had the following properties:
1. No P or B subpartitions.
2. 8x8dct only.
3. i8x8 only; no other block types.
4. Ridiculously long motion vectors throughout the frame in nearly static scenes.
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Wow. Can you share what title that was?
I'm not aware of any commercial BD encoders that are THAT bad, although I haven't done stream analysis of the output of all of them by any means. Being all 8x8 seems particularly odd.