[x265] [PATCH] SAO: initialize bottom and right line numbers to be skipped for SAO statistics calculation only once

[Ashok Kumar Mishra]

Yes, this idea is from HM, but our SAO module is HM code only, except some
asm code.
Here the bottom and right line numbers to be skipped is initialized once in
SAO:create() function before the start of encoding.
So, in calculating SAO statistics for every CTU, we are just reading those
values from a array.

But in our existing SAO code which is the old HM version, we are repeatedly
calculating the bottom and right line numbers  to be skipped
for every CTU as well as for every plane. And also checking the condition
below for every CTU for all components and for all EO and BO classes.

        if (m_param->bSaoNonDeblocked)
        {
            skipB = 3;
            skipR = 4;
        }

I believe all those things can be avoided by initializing those values
before the start of encoding and that is only once. So when we are
calculating SAO
statistics for every CTU, we can just read those values from that array.

On Fri, Nov 20, 2015 at 12:33 AM, chen <chenm003 at 163.com> wrote:

>
>
> At 2015-11-19 18:03:09,ashok at multicorewareinc.com wrote:
> ># HG changeset patch
> ># User Ashok Kumar Mishra<ashok at multicorewareinc.com>
> ># Date 1446119115 -19800
> >#      Thu Oct 29 17:15:15 2015 +0530
> ># Node ID 4a273947c8d54b4de3c05e0e04c9c915f554e6e5
> ># Parent  f722fb55404bb80b26a55ba0a0a1b98d8f20b362
> >SAO: initialize bottom and right line numbers to be skipped for SAO statistics calculation only once
> >
> >diff -r f722fb55404b -r 4a273947c8d5 source/encoder/frameencoder.cpp
> >--- a/source/encoder/frameencoder.cpp	Wed Nov 18 12:28:03 2015 +0530
> >+++ b/source/encoder/frameencoder.cpp	Thu Oct 29 17:15:15 2015 +0530
> >@@ -1091,7 +1091,7 @@
> >
> >         /* SAO parameter estimation using non-deblocked pixels for CTU bottom and right boundary areas */
> >         if (m_param->bEnableSAO && m_param->bSaoNonDeblocked)
> >-            m_frameFilter.m_sao.calcSaoStatsCu_BeforeDblk(m_frame, col, row);
> >+            m_frameFilter.m_sao.calcPreDeblockSaoStatsCu(m_frame, col, row);
> >
> >         if (m_param->bEnableWavefront && curRow.completed >= 2 && row < m_numRows - 1 &&
> >             (!m_bAllRowsStop || intRow + 1 < m_vbvResetTriggerRow))
> >diff -r f722fb55404b -r 4a273947c8d5 source/encoder/sao.cpp
> >--- a/source/encoder/sao.cpp	Wed Nov 18 12:28:03 2015 +0530
> >+++ b/source/encoder/sao.cpp	Thu Oct 29 17:15:15 2015 +0530
> >@@ -138,6 +138,68 @@
> >     CHECKED_MALLOC(m_countPreDblk, PerPlane, numCtu);
> >     CHECKED_MALLOC(m_offsetOrgPreDblk, PerPlane, numCtu);
> >
> >+    for (int typeIdc = 0; typeIdc < MAX_NUM_SAO_TYPE; typeIdc++)
> >+    {
> >+        m_skipLinesR[TEXT_LUMA][typeIdc] = 5;
> >+        m_skipLinesR[TEXT_CHROMA_U][typeIdc] = m_skipLinesR[TEXT_CHROMA_V][typeIdc] = 3;
> >+
> >+        m_skipLinesB[TEXT_LUMA ][typeIdc] = 4;
> >+        m_skipLinesB[TEXT_CHROMA_U][typeIdc] = m_skipLinesB[TEXT_CHROMA_V][typeIdc] = 2;
> >+
> >+        if (!m_param->bSaoNonDeblocked)
> >+        {
> >+            for (int typeIdc = 0; typeIdc < MAX_NUM_SAO_TYPE; typeIdc++)
> >+            {
> >+                m_skipLinesR[TEXT_LUMA][typeIdc] = 5;
> >+                m_skipLinesR[TEXT_CHROMA_U][typeIdc] = m_skipLinesR[TEXT_CHROMA_V][typeIdc] = 3;
> >+
> >+                m_skipLinesB[TEXT_LUMA ][typeIdc] = 4;
> >+                m_skipLinesB[TEXT_CHROMA_U][typeIdc] = m_skipLinesB[TEXT_CHROMA_V][typeIdc] = 2;
> >+            }
> >+        }
> >+        else
> >+        {
> >+            for (int typeIdc = 0; typeIdc < MAX_NUM_SAO_TYPE; typeIdc++)
> >+            {
> >+                switch (typeIdc)
> >+                {
> >+                case SAO_EO_0:
> >+                    m_skipLinesR[TEXT_LUMA ][typeIdc] = 5;
> >+                    m_skipLinesR[TEXT_CHROMA_U][typeIdc] = m_skipLinesR[TEXT_CHROMA_V][typeIdc] = 3;
> >+
> >+                    m_skipLinesB[TEXT_LUMA ][typeIdc] = 3;
> >+                    m_skipLinesB[TEXT_CHROMA_U][typeIdc] = m_skipLinesB[TEXT_CHROMA_V][typeIdc] = 1;
> >+                    break;
> >+                case SAO_EO_1:
> >+                    m_skipLinesR[TEXT_LUMA][typeIdc] = 4;
> >+                    m_skipLinesR[TEXT_CHROMA_U][typeIdc] = m_skipLinesR[TEXT_CHROMA_V][typeIdc] = 2;
> >+
> >+                    m_skipLinesB[TEXT_LUMA][typeIdc] = 4;
> >+                    m_skipLinesB[TEXT_CHROMA_U][typeIdc] = m_skipLinesB[TEXT_CHROMA_V][typeIdc] = 2;
> >+                    break;
> >+                case SAO_EO_2:
> >+                case SAO_EO_3:
> >+                    m_skipLinesR[TEXT_LUMA][typeIdc] = 5;
> >+                    m_skipLinesR[TEXT_CHROMA_U][typeIdc] = m_skipLinesR[TEXT_CHROMA_V][typeIdc] = 3;
> >+
> >+                    m_skipLinesB[TEXT_LUMA][typeIdc] = 4;
> >+                    m_skipLinesB[TEXT_CHROMA_U][typeIdc] = m_skipLinesB[TEXT_CHROMA_V][typeIdc] = 2;
> >+                    break;
> >+                case SAO_BO:
> >+                    m_skipLinesR[TEXT_LUMA][typeIdc] = 4;
> >+                    m_skipLinesR[TEXT_CHROMA_U][typeIdc] = m_skipLinesR[TEXT_CHROMA_V][typeIdc] = 2;
> >+
> >+                    m_skipLinesB[TEXT_LUMA][typeIdc] = 3;
> >+                    m_skipLinesB[TEXT_CHROMA_U][typeIdc] = m_skipLinesB[TEXT_CHROMA_V][typeIdc] = 1;
> >+                    break;
> >+                default:
> >+                    X265_CHECK(0, "Not a supported
> type");
> >+                    break;
> >+                }
> >+            }
> >+        }
> >+    }
> >+
> this idea from HM, it more clear but more memory operators and compiler difficult to optimize code, e.g. MOV+CMP+CMOV replace by series address calculate and memory loading operator
>
>
>
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