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25th November 2010, 10:33 | #1 | Link |
Registered User
Join Date: Sep 2007
Posts: 50
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h.264 level_prefix
Hello,
In Iain E. Richardson's h.264 book "the h.264 advanced video compression standard", details are missing in "Chap 7.4.2 -> 3.Encoding the levels of the remaining non-zero coefficients" It states that Level VLC is composed of level_prefix and level_suffix, but he doesn't explain how level_prefix is derived from level from encoding point of view. This part is hard to be reverse engineered from decoder spec. Where can I find more precisions regarding this? This topic has been discussed here previously without 100% accuracy: http://forum.doom9.org/archive/index.php/t-111926.html Thanks, malikcis |
26th November 2010, 16:53 | #3 | Link |
Registered User
Join Date: Sep 2007
Posts: 50
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Thanks,
I downloaded the doc. This kind of doc gives me headache at friday afternoon. Found a nice PDF on that topic: http://iris.ee.iisc.ernet.in/Courses...LC_Example.pdf Cheers |
30th November 2010, 14:52 | #4 | Link |
Video compressionist
Join Date: Jun 2009
Location: Israel
Posts: 126
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Perhaps, it is interesting to know also what's maximal value of the level_prefix (since the maximal code size of level is derived from level_prefix).
In the document JVT-X210, in the item #83 is said: Gary Sullivan suggests: People keep asking what the range of level_prefix is for FRExt profiles. It would be nice to figure out the answer and supply it in a NOTE. The same idea applies to other aspects where some helpful (but not strictly necessary) information has been left out of the standard – e.g., ranges of various things that are specified only indirectly but that need to be understood by implementers. Lowell Winger reports on 17 Oct 2006 that the maximum value of level_prefix is =19+(bitDepth – 8). |
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