[x265] [PATCH] SEI: remove recovery point SEI messages inserted every keyframe

[Steve Borho]

On 09/03, deepthi at multicorewareinc.com wrote:
> # HG changeset patch
> # User Deepthi Nandakumar <deepthi at multicorewareinc.com>
> # Date 1441254830 -19800
> #      Thu Sep 03 10:03:50 2015 +0530
> # Branch stable
> # Node ID 3ef81a6d10159335be6fce39801b290cdb06da39
> # Parent  575bf6d52e151f7ca950224a7f8fd032dfaf5619
> SEI: remove recovery point SEI messages inserted every keyframe
> 
> It doesnt make sense to insert a recovery point SEI message for every keyframe.
> An IDR is by definition a random access picture. Recovery point SEIs enable
> CRA/BLA pictures, which x265 doesnt support as yet. Recovery Point SEIs are also
> required when intra refresh is supported, to signal a point at which random
> access is feasible.

I was under the impression that an open-gop keyframe was the same as
CRA?

> diff -r 575bf6d52e15 -r 3ef81a6d1015 source/encoder/frameencoder.cpp
> --- a/source/encoder/frameencoder.cpp	Wed Sep 02 14:03:56 2015 +0530
> +++ b/source/encoder/frameencoder.cpp	Thu Sep 03 10:03:50 2015 +0530
> @@ -418,25 +418,6 @@
>  
>              m_top->m_lastBPSEI = m_rce.encodeOrder;
>          }
> -
> -        // The recovery point SEI message assists a decoder in determining when the decoding
> -        // process will produce acceptable pictures for display after the decoder initiates
> -        // random access. The m_recoveryPocCnt is in units of POC(picture order count) which
> -        // means pictures encoded after the CRA but precede it in display order(leading) are
> -        // implicitly discarded after a random access seek regardless of the value of
> -        // m_recoveryPocCnt. Our encoder does not use references prior to the most recent CRA,
> -        // so all pictures following the CRA in POC order are guaranteed to be displayable,
> -        // so m_recoveryPocCnt is always 0.
> -        SEIRecoveryPoint sei_recovery_point;
> -        sei_recovery_point.m_recoveryPocCnt = 0;
> -        sei_recovery_point.m_exactMatchingFlag = true;
> -        sei_recovery_point.m_brokenLinkFlag = false;
> -
> -        m_bs.resetBits();
> -        sei_recovery_point.write(m_bs, *slice->m_sps);
> -        m_bs.writeByteAlignment();
> -
> -        m_nalList.serialize(NAL_UNIT_PREFIX_SEI, m_bs);
>      }
>  
>      if (m_param->bEmitHRDSEI || !!m_param->interlaceMode)
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-- 
Steve Borho