[x265] [PATCH] x265: implemented crf-min that specifies a minimum rate factor value for encode
Aarthi Priya Thirumalai
aarthi at multicorewareinc.com
Thu May 8 07:37:23 CEST 2014
On Thu, May 8, 2014 at 10:39 AM, <gopu at multicorewareinc.com> wrote:
> # HG changeset patch
> # User Gopu Govindaswamy
> # Date 1399524053 -19800
> # Thu May 08 10:10:53 2014 +0530
> # Node ID 7a3657ff29e24b7832002b76b3f9096736d20a36
> # Parent 6494bb2e64253fc0f9413b88933634d1f37c4881
> x265: implemented crf-min that specifies a minimum rate factor value for
> encode
>
> diff -r 6494bb2e6425 -r 7a3657ff29e2 source/common/param.cpp
> --- a/source/common/param.cpp Wed May 07 14:03:25 2014 -0500
> +++ b/source/common/param.cpp Thu May 08 10:10:53 2014 +0530
> @@ -604,6 +604,7 @@
> OPT("vbv-bufsize") p->rc.vbvBufferSize = atoi(value);
> OPT("vbv-init") p->rc.vbvBufferInit = atof(value);
> OPT("crf-max") p->rc.rfConstantMax = atof(value);
> + OPT("crf-min") p->rc.rfConstantMin = atoi(value);
> OPT("crf")
> {
> p->rc.rfConstant = atof(value);
> diff -r 6494bb2e6425 -r 7a3657ff29e2 source/encoder/encoder.cpp
> --- a/source/encoder/encoder.cpp Wed May 07 14:03:25 2014 -0500
> +++ b/source/encoder/encoder.cpp Thu May 08 10:10:53 2014 +0530
> @@ -1342,6 +1342,12 @@
> x265_log(p, X265_LOG_WARNING, "Support for interlaced video is
> experimental\n");
> }
>
> + if (p->rc.rfConstantMin > p->rc.rfConstant)
> + {
> + x265_log(param, X265_LOG_WARNING, "CRF min must be less than
> CRF\n");
> + p->rc.rfConstantMin = 0;
> + }
> +
> m_bframeDelay = p->bframes ? (p->bBPyramid ? 2 : 1) : 0;
>
> //====== Coding Tools ========
> diff -r 6494bb2e6425 -r 7a3657ff29e2 source/encoder/ratecontrol.cpp
> --- a/source/encoder/ratecontrol.cpp Wed May 07 14:03:25 2014 -0500
> +++ b/source/encoder/ratecontrol.cpp Thu May 08 10:10:53 2014 +0530
> @@ -207,6 +207,7 @@
> param->rc.rfConstant = Clip3((double)-QP_BD_OFFSET, (double)51,
> param->rc.rfConstant);
> param->rc.rfConstantMax = Clip3((double)-QP_BD_OFFSET, (double)51,
> param->rc.rfConstantMax);
> rateFactorMaxIncrement = 0;
> + rateFactorMaxDecrement = 0;
>
> if (param->rc.rateControlMode == X265_RC_CRF)
> {
> @@ -226,6 +227,8 @@
> rateFactorMaxIncrement = 0;
> }
> }
> + if (param->rc.rfConstantMin)
> + rateFactorMaxDecrement = param->rc.rfConstant -
> param->rc.rfConstantMin;
> }
>
> isAbr = param->rc.rateControlMode != X265_RC_CQP; // later add 2pass
> option
> @@ -851,10 +854,15 @@
> /* tweak quality based on difference from predicted size */
> double prevRowQp = qpVbv;
> double qpAbsoluteMax = MAX_MAX_QP;
> + double qpAbsoluteMin = MIN_QP;
> if (rateFactorMaxIncrement)
> qpAbsoluteMax = X265_MIN(qpAbsoluteMax, rce->qpNoVbv +
> rateFactorMaxIncrement);
> +
> + if (rateFactorMaxDecrement)
> + qpAbsoluteMin = X265_MAX(qpAbsoluteMin, rce->qpNoVbv -
> rateFactorMaxIncrement);
> +
>
should not the above line be maximum of qpAbsoluteMin and qpNoVbv -
rateFactorMaxDecrement?
double qpMax = X265_MIN(prevRowQp + param->rc.qpStep, qpAbsoluteMax);
> - double qpMin = X265_MAX(prevRowQp - param->rc.qpStep, MIN_QP);
> + double qpMin = X265_MAX(prevRowQp - param->rc.qpStep, qpAbsoluteMin);
> double stepSize = 0.5;
> double bufferLeftPlanned = rce->bufferFill - rce->frameSizePlanned;
>
> @@ -922,6 +930,12 @@
> qpVbv = Clip3(prevRowQp + 1.0f, qpMax, (prevRowQp + qpVbv) *
> 0.5);
> return -1;
> }
> +
> + if (qpVbv < qpMin && prevRowQp > qpMin && canReencodeRow)
> + {
> + qpVbv = Clip3(prevRowQp + 1.0f, (prevRowQp + qpVbv) * 0.5,
> qpMin);
> + return -1;
> + }
>
i think the above condition needs to be executed only
when param->rc.rfConstantMin is set. else we dont need to reencode if qp
falls lesser in normal scenarios.
also, the clip should be done as Clip3(qpMin, (prevRowQp - qpVbv) *
0.5, prevRowQp - 1.0f); - find a value between qpMin and prevRowQp.
}
> else
> {
> diff -r 6494bb2e6425 -r 7a3657ff29e2 source/encoder/ratecontrol.h
> --- a/source/encoder/ratecontrol.h Wed May 07 14:03:25 2014 -0500
> +++ b/source/encoder/ratecontrol.h Thu May 08 10:10:53 2014 +0530
> @@ -96,6 +96,7 @@
> double vbvMinRate; /* in kbps */
> bool singleFrameVbv;
> double rateFactorMaxIncrement; /* Don't allow RF above (CRF + this
> value). */
> + double rateFactorMaxDecrement; /* don't allow RF below (this value).
> */
> bool isVbv;
> Predictor pred[5];
> Predictor predBfromP;
> diff -r 6494bb2e6425 -r 7a3657ff29e2 source/x265.cpp
> --- a/source/x265.cpp Wed May 07 14:03:25 2014 -0500
> +++ b/source/x265.cpp Thu May 08 10:10:53 2014 +0530
> @@ -129,6 +129,7 @@
> { "weightb", no_argument, NULL, 0 },
> { "crf", required_argument, NULL, 0 },
> { "crf-max", required_argument, NULL, 0 },
> + { "crf-min", required_argument, NULL, 0 },
> { "vbv-maxrate", required_argument, NULL, 0 },
> { "vbv-bufsize", required_argument, NULL, 0 },
> { "vbv-init", required_argument, NULL, 0 },
> @@ -360,6 +361,8 @@
> H0(" --crf <float> Quality-based VBR (0-51).
> Default %f\n", param->rc.rfConstant);
> H0(" --crf-max <float> With CRF+VBV, limit RF to this
> value. 0 for no limit (default)\n");
> H0(" May cause VBV underflows!\n");
> + H0(" --crf-min <float> With CRF+VBV, limit RF to this
> value. 0 for no limit (default)\n");
> + H0(" this specifies a minimum rate
> factor value for encode!\n");
> H0(" --vbv-maxrate <integer> Max local bitrate (kbit/s).
> Default %d\n", param->rc.vbvMaxBitrate);
> H0(" --vbv-bufsize <integer> Set size of the VBV buffer
> (kbit). Default %d\n", param->rc.vbvBufferSize);
> H0(" --vbv-init <float> Initial VBV buffer occupancy
> (fraction of bufsize or in kbits). Default %f\n", param->rc.vbvBufferInit);
> diff -r 6494bb2e6425 -r 7a3657ff29e2 source/x265.h
> --- a/source/x265.h Wed May 07 14:03:25 2014 -0500
> +++ b/source/x265.h Thu May 08 10:10:53 2014 +0530
> @@ -703,6 +703,9 @@
>
> /* In CRF mode, maximum CRF as caused by VBV. 0 implies no limit
> */
> double rfConstantMax;
> +
> + /* In CRF mode, minimum CRF as caused by VBV */
> + double rfConstantMin;
> } rc;
>
> /*== Video Usability Information ==*/
> _______________________________________________
> x265-devel mailing list
> x265-devel at videolan.org
> https://mailman.videolan.org/listinfo/x265-devel
>
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