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Old 14th April 2014, 22:18   #1  |  Link
benwaggoner
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Maximum buffer size in HEVC per profile/level?

I am having a hard time finding a definitive reference for the max buffer size (VBV/HRD) for different different HEVC profiles and levels.

I can kinda squint to see how I could figure it out from the spec, but I'm not the world's best spec->parameter translator ?

Has anyone done this already? Given that Main/Main 10 lowered the max bitrate a lot from H.264, I imagine that buffer sizes may have seen a similar (proportional?) reduction. I want to make ensure I'm making spec-compliant test streams. And have a public reference everyone can clearly see for setting their --vbv-bufsize or similar parameters
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Old 14th April 2014, 22:27   #2  |  Link
sneaker_ger
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Quote:
Originally Posted by sneaker_ger View Post
Vbv values can be found in the spec, table A.1 (page 203/217) and A.2 (page 205/219).
http://www.itu.int/rec/T-REC-H.265-201304-I
Table A.1 lists buffers for main and main10 profile. Note that main and main10 profiles are divided into main and high tier.
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Old 14th April 2014, 22:35   #3  |  Link
benwaggoner
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Quote:
Originally Posted by sneaker_ger View Post
Table A.1 lists buffers for main and main10 profile. Note that main and main10 profiles are divided into main and high tier.
And so they are! I got confused because they're also the same as maximum bitrate and assumed it was just repeated data.

As I warned, reading specs isn't my strong suit .

Thanks!
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Old 14th April 2014, 22:38   #4  |  Link
sneaker_ger
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The H.264 and H.265 specs are extremely incomprehensible indeed, so wait for someone to confirm it.
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Old 17th April 2014, 22:26   #5  |  Link
pieter3d
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That should be right. The spec is hard to read like a book, but it is very unambiguous.
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Old 17th April 2014, 22:31   #6  |  Link
benwaggoner
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It is interesting that the buffers for Main Tier are so much lower than for H.264 - HEVC Level 5 is less than H.264 Level 4! Presumably this is to constrain worst-case decoder complexity. And HEVC certainly should be able to get away with a lot less VBV.

Anyone have any sense for whether many real-world decoders will be constrained to Main Tier, or if High Tier is going to be ubiquitous?
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