[x265] [PATCH] A few small performance improvements for intrapred c code
chen
chenm003 at 163.com
Wed Oct 1 22:10:34 CEST 2014
>- bool modeHor = (dirMode < 18);
>- bool modeVer = !modeHor;
>- int intraPredAngle = modeVer ? (int)dirMode - VER_IDX : modeHor ? -((int)dirMode - HOR_IDX) : 0;
>+ int intraPredAngle = dirMode > 17 ? (int)dirMode - VER_IDX : -((int)dirMode - HOR_IDX);
for this example, origin code easy to know it is a horizon mode and easy to find in specification,
In new code, we have to find where is the constant 17 and reason
New code difficult match to HEVC specification, it means more jobs during port or understand.
At 2014-10-02 01:54:15,dave <dtyx265 at gmail.com> wrote:
I know the C model is not a priority, I just felt like doing it. Also, I don't think I really changed the core algorithms. As my comment states, "A few small performance improvements".
On 10/01/2014 08:32 AM, chen wrote:
We don't worry about C model performance, it is for reference only.
I like clear code, it easy to port to different platform with algorithm re-design.
At 2014-10-01 09:43:15,dtyx265 at gmail.com wrote:
># HG changeset patch
># User David T Yuen <dtyx265 at gmail.com>
># Date 1412127675 25200
># Node ID 353ccf9c2b2adc37cfb1bc7124fcca131599e0ad
># Parent 5a6845566d1492d29af29ecc0cf75d644994735c
>A few small performance improvements for intrapred c code
>
>diff -r 5a6845566d14 -r 353ccf9c2b2a source/common/intrapred.cpp
>--- a/source/common/intrapred.cpp Mon Sep 29 17:37:47 2014 -0500
>+++ b/source/common/intrapred.cpp Tue Sep 30 18:41:15 2014 -0700
>@@ -35,10 +35,6 @@
> for (w = 0; w < width; w++)
> {
> sum += above[w];
>- }
>-
>- for (w = 0; w < width; w++)
>- {
> sum += left[w];
> }
>
>@@ -57,11 +53,10 @@
> dst[x] = (pixel)((above[x] + 3 * dst[x] + 2) >> 2);
> }
>
>- dst += dststride;
> for (int y = 1; y < size; y++)
> {
>+ dst += dststride;
> *dst = (pixel)((left[y] + 3 * *dst + 2) >> 2);
>- dst += dststride;
> }
> }
>
>@@ -134,13 +129,11 @@
> }
>
> template<int width>
>-void intra_pred_ang_c(pixel* dst, intptr_t dstStride, pixel *refLeft, pixel *refAbove, int dirMode, int bFilter)
>+void intra_pred_ang_c1(pixel* dst, intptr_t dstStride, pixel *refLeft, pixel *refAbove, int dirMode, int bFilter)
> {
> // Map the mode index to main prediction direction and angle
> int k, l;
>- bool modeHor = (dirMode < 18);
>- bool modeVer = !modeHor;
>- int intraPredAngle = modeVer ? (int)dirMode - VER_IDX : modeHor ? -((int)dirMode - HOR_IDX) : 0;
>+ int intraPredAngle = dirMode > 17 ? (int)dirMode - VER_IDX : -((int)dirMode - HOR_IDX);
> int absAng = abs(intraPredAngle);
> int signAng = intraPredAngle < 0 ? -1 : 1;
>
>@@ -154,27 +147,12 @@
>
> // Do angular predictions
> {
>- pixel* refMain;
>- pixel* refSide;
>-
>- // Initialise the Main and Left reference array.
>- if (intraPredAngle < 0)
>+ pixel* refMain = refLeft;
>+ pixel* refSide = refAbove;
>+ if (dirMode > 17)
> {
>- refMain = (modeVer ? refAbove : refLeft); // + (width - 1);
>- refSide = (modeVer ? refLeft : refAbove); // + (width - 1);
>-
>- // Extend the Main reference to the left.
>- int invAngleSum = 128; // rounding for (shift by 8)
>- for (k = -1; k > width * intraPredAngle >> 5; k--)
>- {
>- invAngleSum += invAngle;
>- refMain[k] = refSide[invAngleSum >> 8];
>- }
>- }
>- else
>- {
>- refMain = modeVer ? refAbove : refLeft;
>- refSide = modeVer ? refLeft : refAbove;
>+ refMain = refAbove;
>+ refSide = refLeft;
> }
>
> if (intraPredAngle == 0)
>@@ -197,6 +175,18 @@
> }
> else
> {
>+ // Initialise the Main and Left reference array.
>+ if (intraPredAngle < 0)
>+ {
>+ // Extend the Main reference to the left.
>+ int invAngleSum = 128; // rounding for (shift by 8)
>+ for (k = -1; k > width * intraPredAngle >> 5; k--)
>+ {
>+ invAngleSum += invAngle;
>+ refMain[k] = refSide[invAngleSum >> 8];
>+ }
>+ }
>+
> int deltaPos = 0;
> int deltaInt;
> int deltaFract;
>@@ -227,18 +217,24 @@
> }
> }
> }
>+ }
>+}
>
>- // Flip the block if this is the horizontal mode
>- if (modeHor)
>+template<int width>
>+void intra_pred_ang_c(pixel* dst, intptr_t dstStride, pixel *refLeft, pixel *refAbove, int dirMode, int bFilter)
>+{
>+ int k, l;
>+ intra_pred_ang_c1<width>(dst, dstStride, refLeft, refAbove, dirMode, bFilter);
>+
>+ if (dirMode < 18)
>+ {
>+ for (k = 0; k < width - 1; k++)
> {
>- for (k = 0; k < width - 1; k++)
>+ for (l = k + 1; l < width; l++)
> {
>- for (l = k + 1; l < width; l++)
>- {
>- pixel tmp = dst[k * dstStride + l];
>- dst[k * dstStride + l] = dst[l * dstStride + k];
>- dst[l * dstStride + k] = tmp;
>- }
>+ dst[l * dstStride + k] ^= dst[k * dstStride + l];
>+ dst[k * dstStride + l] ^= dst[l * dstStride + k];
>+ dst[l * dstStride + k] ^= dst[k * dstStride + l];
> }
> }
> }
>@@ -250,28 +246,22 @@
> const int size = 1 << log2Size;
> for (int mode = 2; mode <= 34; mode++)
> {
>- pixel *left = (g_intraFilterFlags[mode] & size ? left1 : left0);
>- pixel *above = (g_intraFilterFlags[mode] & size ? above1 : above0);
>+ pixel *left;
>+ pixel *above;
>+
>+ if (g_intraFilterFlags[mode] & size)
>+ {
>+ left = left1;
>+ above = above1;
>+ }
>+ else
>+ {
>+ left = left0;
>+ above = above0;
>+ }
> pixel *out = dest + ((mode - 2) << (log2Size * 2));
>
>- intra_pred_ang_c<size>(out, size, left, above, mode, bLuma);
>-
>- // Optimize code don't flip buffer
>- bool modeHor = (mode < 18);
>-
>- // transpose the block if this is a horizontal mode
>- if (modeHor)
>- {
>- for (int k = 0; k < size - 1; k++)
>- {
>- for (int l = k + 1; l < size; l++)
>- {
>- pixel tmp = out[k * size + l];
>- out[k * size + l] = out[l * size + k];
>- out[l * size + k] = tmp;
>- }
>- }
>- }
>+ intra_pred_ang_c1<size>(out, size, left, above, mode, bLuma);
> }
> }
> }
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