[x265] [PATCH] get same output between single and multi threading

[Steve Borho]

On Mon, Sep 30, 2013 at 1:23 AM, Min Chen <chenm003 at 163.com> wrote:

> # HG changeset patch
> # User Min Chen <chenm003 at 163.com>
> # Date 1380521904 -28800
> # Node ID cd4d431e292d0935c154daf0917dbb6816cdbca8
> # Parent  55edc34e253c14d3eccb83a7d1db43774349ff9a
> get same output between single and multi threading
>
> Output mistake reasons:
>
> 1. CABAC Table Initialize
>    The HM have decide best table for CABAC, but in frame parallelism,
>    we can't get this information before thread start, we have to
>    disable it now.
> Side effect: maybe lost some compress performance
>
> 2. SAO Global Disable
>    The HM decide SAO global disable flag depend previous same type of
>    slice. but here, we can get right statistics informat before start,
>    so we have to disable it.
> Side effect: more computer cost since we always try SAO on every LCU
>
> 3. CABAC status m_frac not reset.
>     This HM bug still alive, we found more here.
>
> diff -r 55edc34e253c -r cd4d431e292d source/Lib/TLibEncoder/TEncTop.cpp
> --- a/source/Lib/TLibEncoder/TEncTop.cpp        Sat Sep 28 22:54:44 2013
> -0500
> +++ b/source/Lib/TLibEncoder/TEncTop.cpp        Mon Sep 30 14:18:24 2013
> +0800
> @@ -823,7 +823,7 @@
>      pps->setDeblockingFilterOverrideEnabledFlag(!m_loopFilterOffsetInPPS);
>      pps->setPicDisableDeblockingFilterFlag(!param.bEnableLoopFilter);
>      pps->setLog2ParallelMergeLevelMinus2(m_log2ParallelMergeLevelMinus2);
> -    pps->setCabacInitPresentFlag(CABAC_INIT_PRESENT_FLAG);
> +    pps->setCabacInitPresentFlag(param.frameNumThreads > 1 ? 0 :
> CABAC_INIT_PRESENT_FLAG);
>
>      pps->setNumRefIdxL0DefaultActive(1);
>      pps->setNumRefIdxL1DefaultActive(1);
> diff -r 55edc34e253c -r cd4d431e292d source/encoder/cturow.h
> --- a/source/encoder/cturow.h   Sat Sep 28 22:54:44 2013 -0500
> +++ b/source/encoder/cturow.h   Mon Sep 30 14:18:24 2013 +0800
> @@ -63,9 +63,22 @@
>
>      void destroy();
>
> -    void init()
> +    void init(TComSlice *slice)
>      {
>          m_active = 0;
> +
> +        // Note: Reset status to avoid frame parallelism output mistake
> on different thread number
> +        for (UInt depth = 0; depth < g_maxCUDepth + 1; depth++)
> +        {
> +            for (int ciIdx = 0; ciIdx < CI_NUM; ciIdx++)
> +            {
> +                m_rdSbacCoders[depth][ciIdx]->setSlice(slice);
> +                m_rdSbacCoders[depth][ciIdx]->resetEntropy();
> +                m_binCodersCABAC[depth][ciIdx]->m_fracBits = 0;
> +            }
> +        }
> +        m_rdGoOnSbacCoder.setSlice(slice);
> +        m_rdGoOnSbacCoder.resetEntropy();
>      }
>
>      void processCU(TComDataCU *cu, TComSlice *slice, TEncSbac
> *bufferSBac, bool bSaveCabac);
> diff -r 55edc34e253c -r cd4d431e292d source/encoder/frameencoder.cpp
> --- a/source/encoder/frameencoder.cpp   Sat Sep 28 22:54:44 2013 -0500
> +++ b/source/encoder/frameencoder.cpp   Mon Sep 30 14:18:24 2013 +0800
> @@ -877,12 +877,14 @@
>  void FrameEncoder::compressCTURows()
>  {
>      PPAScopeEvent(FrameEncoder_compressRows);
> +    TComSlice* slice = m_pic->getSlice();
> +
>      // reset entropy coders
>      m_sbacCoder.init(&m_binCoderCABAC);
>      for (int i = 0; i < this->m_numRows; i++)
>      {
> -        m_rows[i].init();
> -        m_rows[i].m_entropyCoder.setEntropyCoder(&m_sbacCoder,
> m_pic->getSlice());
> +        m_rows[i].init(slice);
> +        m_rows[i].m_entropyCoder.setEntropyCoder(&m_sbacCoder, slice);
>          m_rows[i].m_entropyCoder.resetEntropy();
>
>          m_rows[i].m_rdSbacCoders[0][CI_CURR_BEST]->load(&m_sbacCoder);
> @@ -891,7 +893,6 @@
>      }
>
>      UInt refLagRows = ((m_cfg->param.searchRange + NTAPS_LUMA/2 +
> g_maxCUHeight - 1) / g_maxCUHeight) + 1;
> -    TComSlice* slice = m_pic->getSlice();
>      int numPredDir = slice->isInterP() ? 1 : slice->isInterB() ? 2 : 0;
>
>      m_frameFilter.start(m_pic);
> diff -r 55edc34e253c -r cd4d431e292d source/encoder/framefilter.cpp
> --- a/source/encoder/framefilter.cpp    Sat Sep 28 22:54:44 2013 -0500
> +++ b/source/encoder/framefilter.cpp    Mon Sep 30 14:18:24 2013 +0800
> @@ -98,6 +98,13 @@
>          SAOParam* saoParam = pic->getPicSym()->getSaoParam();
>          m_sao.resetSAOParam(saoParam);
>          m_sao.rdoSaoUnitRowInit(saoParam);
> +
> +        // NOTE: Disable SAO automatic turn off when Frame Parallelism
> for output exact
> +        if (m_cfg->param.frameNumThreads)
>

param.frameNumThreads is always != 0.  should this be checking for > 1?

+        {
> +            saoParam->bSaoFlag[0] = true;
> +            saoParam->bSaoFlag[1] = true;
> +        }
>      }
>  }
>
>
-- 
Steve Borho
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