[x264-devel] [PATCH] 2-pass ratecontrol

[Loren Merritt]

Use average qp instead of last qp in the frame for 2pass rc.
(Improves quality and rate accuracy if the first pass was cbr.)

--Loren Merritt
-------------- next part --------------
Index: encoder/ratecontrol.c
===================================================================
--- encoder/ratecontrol.c	(revision 44)
+++ encoder/ratecontrol.c	(working copy)
@@ -6,7 +6,7 @@
  *
  * Authors: M?ns Rullg?rd <mru at mru.ath.cx>
  * 2 pass code: Michael Niedermayer <michaelni at gmx.at>
- *              Loren Merritt
+ *              Loren Merritt <lorenm at u.washington.edu>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -101,7 +101,7 @@
     double last_qscale;
     double last_qscale_for[5];  /* last qscale for a specific pict type, used for max_diff & ipb factor stuff  */
     int last_non_b_pict_type;
-    double lmin[5];                /* min qscale by frame type */
+    double lmin[5];             /* min qscale by frame type */
     double lmax[5];
     double i_cplx_sum[5];       /* estimated total texture bits in intra MBs at qscale=1 */
     double p_cplx_sum[5];
@@ -115,7 +115,7 @@
 
 /* Terminology:
  * qp = h.264's quantizer
- * qscale = an arbitrary linear scale, mappable to qp
+ * qscale = linearized quantizer = Lagrange multiplier
  */
 static inline double qp2qscale(double qp)
 {
@@ -551,7 +551,7 @@
         fprintf( rc->p_stat_file_out,
                  "in:%d out:%d type:%d q:%.3f itex:%d ptex:%d mv:%d misc:%d imb:%d pmb:%d smb:%d;\n",
                  h->fenc->i_frame, h->i_frame-1,
-                 rc->slice_type, (float)rc->qpm,
+                 rc->slice_type, (float)rc->qpa,
                  h->stat.frame.i_itex_bits, h->stat.frame.i_ptex_bits,
                  h->stat.frame.i_hdr_bits, h->stat.frame.i_misc_bits,
                  h->stat.frame.i_mb_count[I_4x4] + h->stat.frame.i_mb_count[I_16x16],
@@ -613,8 +613,6 @@
 
     x264_cpu_restore( h->param.cpu );
 
-    //avg_cplx = (rcc->i_cplx_sum[pict_type] + rcc->p_cplx_sum[pict_type]) / rcc->frame_count[pict_type];
-
     double const_values[]={
         rce->i_tex_bits * rce->qscale,
         rce->p_tex_bits * rce->qscale,