[x265] [PATCH 1 of 3 RFC] rc: define function for updating rate control statistics in processRowEncoder

[Steve Borho]

On Fri, Jul 11, 2014 at 6:24 AM,  <santhoshini at multicorewareinc.com> wrote:
> # HG changeset patch
> # User Santhoshini Sekar <santhoshini at multicorewareinc.com>
> # Date 1405070640 -19800
> #      Fri Jul 11 14:54:00 2014 +0530
> # Node ID 902e1d37847f0bc222fdc05dcd4a7f6dd26b0751
> # Parent  e171ad8bc8a3611b75e084587f4c07c41427c73d
> rc: define function for updating rate control statistics in processRowEncoder

this description is pretty sparse; why is much more important than what or how.

Please explain why is it helpful to update rate control stats after two rows?

> diff -r e171ad8bc8a3 -r 902e1d37847f source/encoder/ratecontrol.cpp
> --- a/source/encoder/ratecontrol.cpp    Fri Jul 11 01:44:43 2014 -0500
> +++ b/source/encoder/ratecontrol.cpp    Fri Jul 11 14:54:00 2014 +0530
> @@ -274,6 +274,7 @@
>      m_residualCost = 0;
>      m_rateFactorMaxIncrement = 0;
>      m_rateFactorMaxDecrement = 0;
> +    m_startEndOrder.set(0);

this change probably belongs in a different patch

>
>      if (m_param->rc.rateControlMode == X265_RC_CRF)
>      {
> @@ -781,6 +782,46 @@
>      }
>  }
>
> +void RateControl::rateControlUpdateStats(RateControlEntry* rce)
> +{
> +    ScopedLock scope(m_lock);

is m_lock necessary given the way access to the functions is currently
restricted? it seems redundant now

> +
> +    if (rce->sliceType == I_SLICE)
> +    {
> +        /* previous I still had a residual; roll it into the new loan */
> +        if (m_residualFrames)
> +            rce->rowTotalBits += m_residualCost * m_residualFrames;
> +
> +        m_residualFrames = X265_MIN(s_amortizeFrames, m_param->keyframeMax);
> +        m_residualCost = (int)((rce->rowTotalBits * s_amortizeFraction) / m_residualFrames);
> +        rce->rowTotalBits -= m_residualCost * m_residualFrames;
> +    }
> +    else if (m_residualFrames)
> +    {
> +         rce->rowTotalBits += m_residualCost;
> +    }
> +
> +    if (rce->sliceType != B_SLICE)
> +    {
> +        rce->rowCplxrSum =  rce->rowTotalBits * x265_qp2qScale(rce->qpaRc) / rce->qRceq;
> +    }
> +    else
> +    {
> +        rce->rowCplxrSum = rce->rowTotalBits * x265_qp2qScale(rce->qpaRc) / (rce->qRceq * fabs(m_param->rc.pbFactor));
> +    }

please don't use braces around single-line expressions

> +
> +    m_cplxrSum += rce->rowCplxrSum;
> +    m_totalBits += rce->rowTotalBits;
> +    m_startEndOrder.incr();
> +
> +    /* delay incrementing m_startEndOrder until here to sync with rateControlStart() */
> +    if (rce->encodeOrder < m_param->frameNumThreads - 1)
> +    {
> +        m_startEndOrder.incr(); // faked rateControlEnd calls for negative frames
> +    }
> +

we don't normally have trailing white-space within functions

> +}
> +
>  void RateControl::checkAndResetABR(RateControlEntry* rce, bool isFrameDone)
>  {
>      double abrBuffer = 2 * m_param->rc.rateTolerance * m_bitrate;
> diff -r e171ad8bc8a3 -r 902e1d37847f source/encoder/ratecontrol.h
> --- a/source/encoder/ratecontrol.h      Fri Jul 11 01:44:43 2014 -0500
> +++ b/source/encoder/ratecontrol.h      Fri Jul 11 14:54:00 2014 +0530
> @@ -68,6 +68,8 @@
>      double frameSizePlanned;  /* frame Size decided by RateCotrol before encoding the frame */
>      double bufferRate;
>      double movingAvgSum;
> +    double   rowCplxrSum;
> +    int64_t  rowTotalBits;  /* update cplxrsum and totalbits at the end of 2 rows */
>      double qpNoVbv;
>      double bufferFill;
>      Predictor rowPreds[3][2];
> @@ -135,6 +137,8 @@
>      int64_t  m_totalBits;        /* total bits used for already encoded frames */
>      int      m_framesDone;       /* # of frames passed through RateCotrol already */
>
> +    ThreadSafeInteger m_startEndOrder;
> +
>      /* hrd stuff */
>      SEIBufferingPeriod m_bufPeriodSEI;
>      double   m_nominalRemovalTime;
> @@ -158,11 +162,13 @@
>      // to be called for each frame to process RateControl and set QP
>      void rateControlStart(Frame* pic, Lookahead *, RateControlEntry* rce, Encoder* enc);
>      void calcAdaptiveQuantFrame(Frame *pic);
> +    void rateControlUpdateStats(RateControlEntry* rce);
>      int rateControlEnd(Frame* pic, int64_t bits, RateControlEntry* rce, FrameStats* stats);
>      int rowDiagonalVbvRateControl(Frame* pic, uint32_t row, RateControlEntry* rce, double& qpVbv);
>      void hrdFullness(SEIBufferingPeriod* sei);
>      bool init(TComSPS* sps);
>      void initHRD(TComSPS* sps);
> +    Lock                m_lock;
>  protected:
>
>      static const double s_amortizeFraction;
> _______________________________________________
> x265-devel mailing list
> x265-devel at videolan.org
> https://mailman.videolan.org/listinfo/x265-devel



-- 
Steve Borho