Thanks, this is certainly an enhancement to x265 lookahead. We would be
interested in this - especially if you can also include some efficiency
(bitrate vs SSIM) metrics that describe the penalty moving from
X265_LOWRES_SCALE of 4 to higher scales.
On Mon, Jul 21, 2014 at 8:49 PM, Nicolas Morey-Chaisemartin <
nmo...@kalray.eu> wrote:
> Hi,
>
> We recently profiled x265 pre-analysis to estimate what performance we
> could reach using our accelerator and I was quite disappointed by the
> performance.
> When running on a Core-i7 with AVX at roughly 2.7GHz, we barely reached
> the 30fps mark using ultrafast preset on a 4K video.
>
> After a little bit of browsing I realized that work in LosRew is always
> done at 1/4th of the final resolution which seems fair but requires a huge
> amount of work for 4K.
> It seemed straight forward enough to change the divider at LowRes
> initialization but it seems there are a lot of hard coded values that
> depend both on the LowRes divider and the LowRes CU Size.
>
> Here's a patch (definitly not applicable like this but just to give an
> idea of where I'm going) that seems to fix most of the hard-coded value.
> It still works with a X265_LOWRES_SCALE of 4 and the perf is definilty
> improving (29fps => 40fps on a 2048x1024 medium preset on a E5504).
>
> Would you be interested in a clean version of this? At least the
> hard-coded CU_SIZE part?
> IMHO it would be better to have "dynamic" value for LowRes depending on
> preset (or equivalent) and the input resolution...
> 1/4th is fast enough in HD not to be an issue but for RT stream in 4K or
> more, 1/16 will be compulsory.
>
> Nicolas
>
> ---
> x265/source/common/common.h | 1 +
> x265/source/common/lowres.cpp | 4 ++--
> x265/source/encoder/frameencoder.cpp | 7 ++++---
> x265/source/encoder/ratecontrol.cpp | 16 ++++++++--------
> x265/source/encoder/slicetype.cpp | 8 ++++----
> 5 files changed, 19 insertions(+), 17 deletions(-)
>
> diff --git a/x265/source/common/common.h b/x265/source/common/common.h
> index 06f60e7..00e73fc 100644
> --- a/x265/source/common/common.h
> +++ b/x265/source/common/common.h
> @@ -156,6 +156,7 @@ typedef int32_t coeff_t; // transform coefficient
> // high cost estimates (intra and inter both suffer)
> #define X265_LOWRES_CU_SIZE 8
> #define X265_LOWRES_CU_BITS 3
> +#define X265_LOWRES_SCALE 2
> #define X265_MALLOC(type, count) (type*)x265_malloc(sizeof(type) *
> (count))
> #define X265_FREE(ptr) x265_free(ptr)
> diff --git a/x265/source/common/lowres.cpp b/x265/source/common/lowres.cpp
> index 5fc2f6b..6138023 100644
> --- a/x265/source/common/lowres.cpp
> +++ b/x265/source/common/lowres.cpp
> @@ -31,8 +31,8 @@ bool Lowres::create(TComPicYuv *orig, int _bframes, bool
> bAQEnabled)
> {
> isLowres = true;
> bframes = _bframes;
> - width = orig->getWidth() / 2;
> - lines = orig->getHeight() / 2;
> + width = orig->getWidth() / X265_LOWRES_SCALE;
> + lines = orig->getHeight() / X265_LOWRES_SCALE;
> lumaStride = width + 2 * orig->getLumaMarginX();
> if (lumaStride & 31)
> lumaStride += 32 - (lumaStride & 31);
> diff --git a/x265/source/encoder/frameencoder.cpp b/x265/source/encoder/
> frameencoder.cpp
> index 8c3ee26..7213f60 100644
> --- a/x265/source/encoder/frameencoder.cpp
> +++ b/x265/source/encoder/frameencoder.cpp
> @@ -1300,9 +1300,10 @@ int FrameEncoder::calcQpForCu(uint32_t cuAddr,
> double baseQp)
> /* Derive qpOffet for each CU by averaging offsets for all 16x16
> blocks in the cu. */
> double qp_offset = 0;
> - int maxBlockCols = (m_frame->getPicYuvOrg()->getWidth() + (16 - 1))
> / 16;
> - int maxBlockRows = (m_frame->getPicYuvOrg()->getHeight() + (16 - 1))
> / 16;
> - int noOfBlocks = g_maxCUSize / 16;
> + int lowResCu = (X265_LOWRES_CU_SIZE * X265_LOWRES_SCALE);
> + int maxBlockCols = (m_frame->getPicYuvOrg()->getWidth() + (lowResCu
> - 1)) / lowResCu;
> + int maxBlockRows = (m_frame->getPicYuvOrg()->getHeight() + (lowResCu
> - 1)) / lowResCu;
> + int noOfBlocks = g_maxCUSize / lowResCu;
> int block_y = (cuAddr / m_frame->getPicSym()->getFrameWidthInCU()) *
> noOfBlocks;
> int block_x = (cuAddr * noOfBlocks) - block_y * m_frame->getPicSym()->
> getFrameWidthInCU();
> diff --git a/x265/source/encoder/ratecontrol.cpp b/x265/source/encoder/
> ratecontrol.cpp
> index 4358994..5fcc27a 100644
> --- a/x265/source/encoder/ratecontrol.cpp
> +++ b/x265/source/encoder/ratecontrol.cpp
> @@ -161,8 +161,8 @@ void RateControl::calcAdaptiveQuantFrame(Frame *pic)
> if (m_param->rc.aqMode == X265_AQ_NONE || m_param->rc.aqStrength == 0)
> {
> /* Need to init it anyways for CU tree */
> - int cuWidth = ((maxCol / 2) + X265_LOWRES_CU_SIZE - 1) >>
> X265_LOWRES_CU_BITS;
> - int cuHeight = ((maxRow / 2) + X265_LOWRES_CU_SIZE - 1) >>
> X265_LOWRES_CU_BITS;
> + int cuWidth = ((maxCol / X265_LOWRES_SCALE) + X265_LOWRES_CU_SIZE
> - 1) >> X265_LOWRES_CU_BITS;
> + int cuHeight = ((maxRow / X265_LOWRES_SCALE) +
> X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
> int cuCount = cuWidth * cuHeight;
> if (m_param->rc.aqMode && m_param->rc.aqStrength == 0)
> @@ -194,9 +194,9 @@ void RateControl::calcAdaptiveQuantFrame(Frame *pic)
> if (m_param->rc.aqMode == X265_AQ_AUTO_VARIANCE)
> {
> double bit_depth_correction = pow(1 << (X265_DEPTH - 8), 0.5);
> - for (block_y = 0; block_y < maxRow; block_y += 16)
> + for (block_y = 0; block_y < maxRow; block_y +=
> (X265_LOWRES_CU_SIZE * X265_LOWRES_SCALE))
> {
> - for (block_x = 0; block_x < maxCol; block_x += 16)
> + for (block_x = 0; block_x < maxCol; block_x +=
> (X265_LOWRES_CU_SIZE * X265_LOWRES_SCALE))
> {
> uint32_t energy = acEnergyCu(pic, block_x, block_y);
> qp_adj = pow(energy + 1, 0.1);
> @@ -216,9 +216,9 @@ void RateControl::calcAdaptiveQuantFrame(Frame *pic)
> strength = m_param->rc.aqStrength * 1.0397f;
> block_xy = 0;
> - for (block_y = 0; block_y < maxRow; block_y += 16)
> + for (block_y = 0; block_y < maxRow; block_y +=
> (X265_LOWRES_CU_SIZE * X265_LOWRES_SCALE))
> {
> - for (block_x = 0; block_x < maxCol; block_x += 16)
> + for (block_x = 0; block_x < maxCol; block_x +=
> (X265_LOWRES_CU_SIZE * X265_LOWRES_SCALE))
> {
> if (m_param->rc.aqMode == X265_AQ_AUTO_VARIANCE)
> {
> @@ -260,8 +260,8 @@ void RateControl::calcAdaptiveQuantFrame(Frame *pic)
> RateControl::RateControl(x265_param *p)
> {
> m_param = p;
> - int lowresCuWidth = ((m_param->sourceWidth / 2) + X265_LOWRES_CU_SIZE
> - 1) >> X265_LOWRES_CU_BITS;
> - int lowresCuHeight = ((m_param->sourceHeight / 2) +
> X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
> + int lowresCuWidth = ((m_param->sourceWidth / X265_LOWRES_SCALE) +
> X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
> + int lowresCuHeight = ((m_param->sourceHeight / X265_LOWRES_SCALE) +
> X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
> m_ncu = lowresCuWidth * lowresCuHeight;
> if (m_param->rc.cuTree)
> diff --git a/x265/source/encoder/slicetype.cpp b/x265/source/encoder/
> slicetype.cpp
> index 34d0b3b..4a2f2cb 100644
> --- a/x265/source/encoder/slicetype.cpp
> +++ b/x265/source/encoder/slicetype.cpp
> @@ -65,8 +65,8 @@ Lookahead::Lookahead(x265_param *param, ThreadPool*
> pool)
> m_lastNonB = NULL;
> m_bFilling = true;
> m_bFlushed = false;
> - m_widthInCU = ((m_param->sourceWidth / 2) + X265_LOWRES_CU_SIZE - 1)
> >> X265_LOWRES_CU_BITS;
> - m_heightInCU = ((m_param->sourceHeight / 2) + X265_LOWRES_CU_SIZE -
> 1) >> X265_LOWRES_CU_BITS;
> + m_widthInCU = ((m_param->sourceWidth / X265_LOWRES_SCALE) +
> X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
> + m_heightInCU = ((m_param->sourceHeight / X265_LOWRES_SCALE) +
> X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
> m_scratch = (int*)x265_malloc(m_widthInCU * sizeof(int));
> memset(m_histogram, 0, sizeof(m_histogram));
> }
> @@ -1201,8 +1201,8 @@ CostEstimate::~CostEstimate()
> void CostEstimate::init(x265_param *_param, Frame *pic)
> {
> m_param = _param;
> - m_widthInCU = ((m_param->sourceWidth / 2) + X265_LOWRES_CU_SIZE - 1)
> >> X265_LOWRES_CU_BITS;
> - m_heightInCU = ((m_param->sourceHeight / 2) + X265_LOWRES_CU_SIZE -
> 1) >> X265_LOWRES_CU_BITS;
> + m_widthInCU = ((m_param->sourceWidth / X265_LOWRES_SCALE) +
> X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
> + m_heightInCU = ((m_param->sourceHeight / X265_LOWRES_SCALE) +
> X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
> m_rows = new EstimateRow[m_heightInCU];
> for (int i = 0; i < m_heightInCU; i++)
> _______________________________________________
> x265-devel mailing list
> x265-devel@videolan.org
> https://mailman.videolan.org/listinfo/x265-devel
>
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