[x265] [PATCH 1 of 2] rc: separate frame bits predictor objects for BRef and B frames
Steve Borho
steve at borho.org
Wed Apr 8 20:38:55 CEST 2015
On 04/08, aarthi at multicorewareinc.com wrote:
> # HG changeset patch
> # User Aarthi Thirumalai
> # Date 1427820381 -19800
> # Tue Mar 31 22:16:21 2015 +0530
> # Node ID 6f159ec858f4eec484d722916c41911e3e4540f9
> # Parent 3e416dec8024b8339b18568cf65e48eb3448bed1
> rc: separate frame bits predictor objects for BRef and B frames
>
> improves frame size prediction for BRef frames in VBV.
this probably deserves a follow up commit introducing an inline helper
method that maps from Slice* to predictor type, so we can be sure the
logic stays consistent going forward and is self-documenting
> diff -r 3e416dec8024 -r 6f159ec858f4 source/encoder/ratecontrol.cpp
> --- a/source/encoder/ratecontrol.cpp Tue Apr 07 16:00:39 2015 -0500
> +++ b/source/encoder/ratecontrol.cpp Tue Mar 31 22:16:21 2015 +0530
> @@ -370,7 +370,7 @@
> m_accumPQp = (m_param->rc.rateControlMode == X265_RC_CRF ? CRF_INIT_QP : ABR_INIT_QP_MIN) * m_accumPNorm;
>
> /* Frame Predictors and Row predictors used in vbv */
> - for (int i = 0; i < 5; i++)
> + for (int i = 0; i < 4; i++)
> {
> m_pred[i].coeff = 1.5;
> m_pred[i].count = 1.0;
> @@ -945,6 +945,9 @@
> m_curSlice = curEncData.m_slice;
> m_sliceType = m_curSlice->m_sliceType;
> rce->sliceType = m_sliceType;
> + if (!m_2pass)
> + rce->keptAsRef = IS_REFERENCED(curFrame);
> + m_predType = m_sliceType == B_SLICE && rce->keptAsRef ? 3 : m_sliceType;
> rce->poc = m_curSlice->m_poc;
> if (m_param->rc.bStatRead)
> {
> @@ -1074,7 +1077,7 @@
> m_lastQScaleFor[m_sliceType] = x265_qp2qScale(rce->qpaRc);
> if (rce->poc == 0)
> m_lastQScaleFor[P_SLICE] = m_lastQScaleFor[m_sliceType] * fabs(m_param->rc.ipFactor);
> - rce->frameSizePlanned = predictSize(&m_pred[m_sliceType], m_qp, (double)m_currentSatd);
> + rce->frameSizePlanned = predictSize(&m_pred[m_predType], m_qp, (double)m_currentSatd);
> }
> }
> m_framesDone++;
> @@ -1397,10 +1400,10 @@
> qScale = clipQscale(curFrame, rce, qScale);
> /* clip qp to permissible range after vbv-lookahead estimation to avoid possible
> * mispredictions by initial frame size predictors */
> - if (m_pred[m_sliceType].count == 1)
> + if (m_pred[m_predType].count == 1)
> qScale = x265_clip3(lmin, lmax, qScale);
> m_lastQScaleFor[m_sliceType] = qScale;
> - rce->frameSizePlanned = predictSize(&m_pred[m_sliceType], qScale, (double)m_currentSatd);
> + rce->frameSizePlanned = predictSize(&m_pred[m_predType], qScale, (double)m_currentSatd);
> }
> else
> rce->frameSizePlanned = qScale2bits(rce, qScale);
> @@ -1544,7 +1547,7 @@
> q = clipQscale(curFrame, rce, q);
> /* clip qp to permissible range after vbv-lookahead estimation to avoid possible
> * mispredictions by initial frame size predictors */
> - if (!m_2pass && m_isVbv && m_pred[m_sliceType].count == 1)
> + if (!m_2pass && m_isVbv && m_pred[m_predType].count == 1)
> q = x265_clip3(lqmin, lqmax, q);
> }
> m_lastQScaleFor[m_sliceType] = q;
> @@ -1554,7 +1557,7 @@
> if (m_2pass && m_isVbv)
> rce->frameSizePlanned = qScale2bits(rce, q);
> else
> - rce->frameSizePlanned = predictSize(&m_pred[m_sliceType], q, (double)m_currentSatd);
> + rce->frameSizePlanned = predictSize(&m_pred[m_predType], q, (double)m_currentSatd);
>
> /* Always use up the whole VBV in this case. */
> if (m_singleFrameVbv)
> @@ -1707,7 +1710,7 @@
> {
> double frameQ[3];
> double curBits;
> - curBits = predictSize(&m_pred[m_sliceType], q, (double)m_currentSatd);
> + curBits = predictSize(&m_pred[m_predType], q, (double)m_currentSatd);
> double bufferFillCur = m_bufferFill - curBits;
> double targetFill;
> double totalDuration = m_frameDuration;
> @@ -1726,7 +1729,8 @@
> bufferFillCur += wantedFrameSize;
> int64_t satd = curFrame->m_lowres.plannedSatd[j] >> (X265_DEPTH - 8);
> type = IS_X265_TYPE_I(type) ? I_SLICE : IS_X265_TYPE_B(type) ? B_SLICE : P_SLICE;
> - curBits = predictSize(&m_pred[type], frameQ[type], (double)satd);
> + int predType = curFrame->m_lowres.plannedType[j] == X265_TYPE_BREF ? 3 : type;
> + curBits = predictSize(&m_pred[predType], frameQ[type], (double)satd);
> bufferFillCur -= curBits;
> }
>
> @@ -1766,7 +1770,7 @@
> }
> // Now a hard threshold to make sure the frame fits in VBV.
> // This one is mostly for I-frames.
> - double bits = predictSize(&m_pred[m_sliceType], q, (double)m_currentSatd);
> + double bits = predictSize(&m_pred[m_predType], q, (double)m_currentSatd);
>
> // For small VBVs, allow the frame to use up the entire VBV.
> double maxFillFactor;
> @@ -1783,14 +1787,14 @@
> bits *= qf;
> if (bits < m_bufferRate / minFillFactor)
> q *= bits * minFillFactor / m_bufferRate;
> - bits = predictSize(&m_pred[m_sliceType], q, (double)m_currentSatd);
> + bits = predictSize(&m_pred[m_predType], q, (double)m_currentSatd);
> }
>
> q = X265_MAX(q0, q);
> }
>
> /* Apply MinCR restrictions */
> - double pbits = predictSize(&m_pred[m_sliceType], q, (double)m_currentSatd);
> + double pbits = predictSize(&m_pred[m_predType], q, (double)m_currentSatd);
> if (pbits > rce->frameSizeMaximum)
> q *= pbits / rce->frameSizeMaximum;
>
> @@ -2099,8 +2103,10 @@
>
> void RateControl::updateVbv(int64_t bits, RateControlEntry* rce)
> {
> + int predType = rce->sliceType;
> + predType = rce->sliceType == B_SLICE && rce->keptAsRef ? 3 : predType;
> if (rce->lastSatd >= m_ncu)
> - updatePredictor(&m_pred[rce->sliceType], x265_qp2qScale(rce->qpaRc), (double)rce->lastSatd, (double)bits);
> + updatePredictor(&m_pred[predType], x265_qp2qScale(rce->qpaRc), (double)rce->lastSatd, (double)bits);
> if (!m_isVbv)
> return;
>
> diff -r 3e416dec8024 -r 6f159ec858f4 source/encoder/ratecontrol.h
> --- a/source/encoder/ratecontrol.h Tue Apr 07 16:00:39 2015 -0500
> +++ b/source/encoder/ratecontrol.h Tue Mar 31 22:16:21 2015 +0530
> @@ -157,10 +157,9 @@
> double m_rateFactorMaxIncrement; /* Don't allow RF above (CRF + this value). */
> double m_rateFactorMaxDecrement; /* don't allow RF below (this value). */
>
> - Predictor m_pred[5];
> - Predictor m_predBfromP;
> -
> + Predictor m_pred[4]; /* Slice predictors to preidct bits for each Slice type - I,P,Bref and B */
> int64_t m_leadingNoBSatd;
> + int m_predType; /* Type of slice predictors to be used - depends on the slice type */
> double m_ipOffset;
> double m_pbOffset;
> int64_t m_bframeBits;
> _______________________________________________
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> x265-devel at videolan.org
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--
Steve Borho
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