[x264-devel] Fix VBV with true VFR streams

[Anton Mitrofanov]

x264 | branch: master | Anton Mitrofanov <BugMaster at narod.ru> | Tue Sep  2 01:48:00 2014 +0400| [204a9bd0a1bc507cbd69a77f3318afcb56ede65d] | committer: Fiona Glaser

Fix VBV with true VFR streams

> http://git.videolan.org/gitweb.cgi/x264.git/?a=commit;h=204a9bd0a1bc507cbd69a77f3318afcb56ede65d
---

 encoder/ratecontrol.c |   12 ++++++++----
 encoder/slicetype.c   |    5 +----
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/encoder/ratecontrol.c b/encoder/ratecontrol.c
index 8893c1f..86aad96 100644
--- a/encoder/ratecontrol.c
+++ b/encoder/ratecontrol.c
@@ -2191,6 +2191,8 @@ static double clip_qscale( x264_t *h, int pict_type, double q )
 
     if( rcc->b_vbv && rcc->last_satd > 0 )
     {
+        double fenc_cpb_duration = (double)h->fenc->i_cpb_duration *
+                                   h->sps->vui.i_num_units_in_tick / h->sps->vui.i_time_scale;
         /* Lookahead VBV: raise the quantizer as necessary such that no frames in
          * the lookahead overflow and such that the buffer is in a reasonable state
          * by the end of the lookahead. */
@@ -2206,6 +2208,7 @@ static double clip_qscale( x264_t *h, int pict_type, double q )
                 double buffer_fill_cur = rcc->buffer_fill - cur_bits;
                 double target_fill;
                 double total_duration = 0;
+                double last_duration = fenc_cpb_duration;
                 frame_q[0] = h->sh.i_type == SLICE_TYPE_I ? q * h->param.rc.f_ip_factor : q;
                 frame_q[1] = frame_q[0] * h->param.rc.f_pb_factor;
                 frame_q[2] = frame_q[0] / h->param.rc.f_ip_factor;
@@ -2213,8 +2216,8 @@ static double clip_qscale( x264_t *h, int pict_type, double q )
                 /* Loop over the planned future frames. */
                 for( int j = 0; buffer_fill_cur >= 0 && buffer_fill_cur <= rcc->buffer_size; j++ )
                 {
-                    total_duration += h->fenc->f_planned_cpb_duration[j];
-                    buffer_fill_cur += rcc->vbv_max_rate * h->fenc->f_planned_cpb_duration[j];
+                    total_duration += last_duration;
+                    buffer_fill_cur += rcc->vbv_max_rate * last_duration;
                     int i_type = h->fenc->i_planned_type[j];
                     int i_satd = h->fenc->i_planned_satd[j];
                     if( i_type == X264_TYPE_AUTO )
@@ -2222,6 +2225,7 @@ static double clip_qscale( x264_t *h, int pict_type, double q )
                     i_type = IS_X264_TYPE_I( i_type ) ? SLICE_TYPE_I : IS_X264_TYPE_B( i_type ) ? SLICE_TYPE_B : SLICE_TYPE_P;
                     cur_bits = predict_size( &rcc->pred[i_type], frame_q[i_type], i_satd );
                     buffer_fill_cur -= cur_bits;
+                    last_duration = h->fenc->f_planned_cpb_duration[j];
                 }
                 /* Try to get to get the buffer at least 50% filled, but don't set an impossible goal. */
                 target_fill = X264_MIN( rcc->buffer_fill + total_duration * rcc->vbv_max_rate * 0.5, rcc->buffer_size * 0.5 );
@@ -2286,13 +2290,13 @@ static double clip_qscale( x264_t *h, int pict_type, double q )
             double bframe_cpb_duration = 0;
             double minigop_cpb_duration;
             for( int i = 0; i < nb; i++ )
-                bframe_cpb_duration += h->fenc->f_planned_cpb_duration[1+i];
+                bframe_cpb_duration += h->fenc->f_planned_cpb_duration[i];
 
             if( bbits * nb > bframe_cpb_duration * rcc->vbv_max_rate )
                 nb = 0;
             pbbits += nb * bbits;
 
-            minigop_cpb_duration = bframe_cpb_duration + h->fenc->f_planned_cpb_duration[0];
+            minigop_cpb_duration = bframe_cpb_duration + fenc_cpb_duration;
             space = rcc->buffer_fill + minigop_cpb_duration*rcc->vbv_max_rate - rcc->buffer_size;
             if( pbbits < space )
             {
diff --git a/encoder/slicetype.c b/encoder/slicetype.c
index 0f4d831..dd5e318 100644
--- a/encoder/slicetype.c
+++ b/encoder/slicetype.c
@@ -1853,14 +1853,11 @@ void x264_slicetype_decide( x264_t *h )
         if( i )
         {
             x264_calculate_durations( h, h->lookahead->next.list[i], h->lookahead->next.list[i-1], &h->i_cpb_delay, &h->i_coded_fields );
-            h->lookahead->next.list[0]->f_planned_cpb_duration[i-1] = (double)h->lookahead->next.list[i-1]->i_cpb_duration *
+            h->lookahead->next.list[0]->f_planned_cpb_duration[i-1] = (double)h->lookahead->next.list[i]->i_cpb_duration *
                                                                       h->sps->vui.i_num_units_in_tick / h->sps->vui.i_time_scale;
         }
         else
             x264_calculate_durations( h, h->lookahead->next.list[i], NULL, &h->i_cpb_delay, &h->i_coded_fields );
-
-        h->lookahead->next.list[0]->f_planned_cpb_duration[i] = (double)h->lookahead->next.list[i]->i_cpb_duration *
-                                                                h->sps->vui.i_num_units_in_tick / h->sps->vui.i_time_scale;
     }
 }