[x265] [PATCH] Fix: QP modification bug in Scenecut Aware Frame Quantizer Selection

[Niranjan Bala]

Please ignore the above patch and use the following one.

Thanks & Regards
*Niranjan Kumar B*
Video Codec Engineer
Media & AI Analytics
+91 958 511 1449
<https://multicorewareinc.com/>


On Wed, Jul 1, 2020 at 1:10 PM Niranjan Bala <niranjan at multicorewareinc.com>
wrote:

> # HG changeset patch
> # User Niranjan <niranjan at multicorewareinc.com>
> # Date 1593151129 -19800
> #      Fri Jun 26 11:28:49 2020 +0530
> # Node ID c8bab0857b4ac70e37c70fcde419cc7a2a77badf
> # Parent  ac951f9fef8a019822cac11ab42870b2443a017c
> Fix: QP modification bug in Scenecut Aware Frame Quantizer Selection
>
> diff --git a/source/encoder/ratecontrol.cpp
> b/source/encoder/ratecontrol.cpp
> --- a/source/encoder/ratecontrol.cpp
> +++ b/source/encoder/ratecontrol.cpp
> @@ -3152,12 +3152,13 @@
>
>  double RateControl::scenecutAwareQp(Frame* curFrame, double q)
>  {
> +    double qp = x265_qScale2qp(q);
>      uint32_t maxWindowSize = uint32_t((m_param->scenecutWindow / 1000.0)
> * (m_param->fpsNum / m_param->fpsDenom) + 0.5);
>      uint32_t windowSize = maxWindowSize / 3;
>      int lastScenecut = m_top->m_rateControl->m_lastScenecut;
>      int lastIFrame = m_top->m_rateControl->m_lastScenecutAwareIFrame;
> -    double maxQpDelta = x265_qp2qScale(double(m_param->maxQpDelta));
> -    double iSliceDelta = x265_qp2qScale(double(I_SLICE_DELTA));
> +    double maxQpDelta = double(m_param->maxQpDelta);
> +    double iSliceDelta = double(I_SLICE_DELTA);
>      double sliceTypeDelta = SLICE_TYPE_DELTA * maxQpDelta;
>      double window2Delta = WINDOW2_DELTA * maxQpDelta;
>      double window3Delta = WINDOW3_DELTA * maxQpDelta;
> @@ -3173,11 +3174,11 @@
>          if (!(lastIFrame > lastScenecut && lastIFrame <= (lastScenecut +
> int(maxWindowSize))
>              && curFrame->m_poc > lastIFrame))
>          {
> -            q += maxQpDelta - sliceTypeDelta;
> +            qp += maxQpDelta - sliceTypeDelta;
>              if (((curFrame->m_poc) > (lastScenecut + int(windowSize))) &&
> ((curFrame->m_poc) <= (lastScenecut + 2 * int(windowSize))))
> -                q -= window2Delta;
> +                qp -= window2Delta;
>              else if (curFrame->m_poc > lastScenecut + 2 * int(windowSize))
> -                q -= window3Delta;
> +                qp -= window3Delta;
>          }
>      }
>      else if (isFrameInsideWindow &&
> IS_X265_TYPE_B(curFrame->m_lowres.sliceType))
> @@ -3185,16 +3186,16 @@
>          if (!(lastIFrame > lastScenecut && lastIFrame <= (lastScenecut +
> int(maxWindowSize))
>              && curFrame->m_poc > lastIFrame))
>          {
> -            q += maxQpDelta;
> +            qp += maxQpDelta;
>              if (curFrame->m_lowres.sliceType == X265_TYPE_B)
> -                q += sliceTypeDelta;
> +                qp += sliceTypeDelta;
>              if (((curFrame->m_poc) > (lastScenecut + int(windowSize))) &&
> ((curFrame->m_poc) <= (lastScenecut + 2 * int(windowSize))))
> -                q -= window2Delta;
> +                qp -= window2Delta;
>              else if (curFrame->m_poc > lastScenecut + 2 * int(windowSize))
> -                q -= window3Delta;
> +                qp -= window3Delta;
>          }
>      }
>      if (IS_X265_TYPE_I(curFrame->m_lowres.sliceType) &&
> curFrame->m_lowres.bScenecut)
> -        q = q - iSliceDelta;
> -    return q;
> +        qp = qp - iSliceDelta;
> +    return  x265_qp2qScale(qp);
>  }
>
> Thanks & Regards
> *Niranjan Kumar B*
> Video Codec Engineer
> Media & AI Analytics
> +91 958 511 1449
> <https://multicorewareinc.com/>
>
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