[FFmpeg-devel] [PATCH] cbs_h265: Detect more reference combinations which would overflow the DPB

[Michael Niedermayer]

On Wed, Feb 03, 2021 at 09:34:07PM +0000, Mark Thompson wrote:
> In total, the number of short term references (from the selected short
> term ref pic set), the number of long term references (combining both the
> used candidates from the SPS and those defined in the slice header) and
> the number of instances of the current picture (usually one, but can be
> two if current picture reference is enabled) must never exceed the size
> of the DPB.  This is a generalisation of the condition associated with
> num_long_term_pics in 7.4.7.1.
> 
> We use this to apply tighter bounds to the number of long term pictures
> referred to in the slice header, and also to detect the invalid case where
> the second reference to the current picture would not fit in the DPB (this
> case can't be detected earlier because an STRPS with 15 pictures can still
> be valid in the same stream when used with a different PPS which does not
> require two DPB slots for the current picture).
> ---

> Michael: does this fix your fuzz case for num_long_term_sps?

yes

thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No snowflake in an avalanche ever feels responsible. -- Voltaire
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