ratecontrol: Dynamically choose a default for rc_max_available_vbv_use

This improves handling of small buffer sizes

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 7 insertions, 0 deletions

diff --git a/libavcodec/ratecontrol.c b/libavcodec/ratecontrol.c
index 7b8e6493f0..4415d8553d 100644
--- a/libavcodec/ratecontrol.c
+++ b/libavcodec/ratecontrol.c
@@ -110,6 +110,13 @@ int ff_rate_control_init(MpegEncContext *s)
     };
     emms_c();
 
+    if (!s->avctx->rc_max_available_vbv_use && s->avctx->rc_buffer_size) {
+        if (s->avctx->rc_max_rate) {
+            s->avctx->rc_max_available_vbv_use = av_clipf(s->avctx->rc_max_rate/(s->avctx->rc_buffer_size*get_fps(s->avctx)), 1.0/0.3, 1.0);
+        } else
+            s->avctx->rc_max_available_vbv_use = 1.0;
+    }
+
     res = av_expr_parse(&rcc->rc_eq_eval, s->avctx->rc_eq ? s->avctx->rc_eq : "tex^qComp", const_names, func1_names, func1, NULL, NULL, 0, s->avctx);
     if (res < 0) {
         av_log(s->avctx, AV_LOG_ERROR, "Error parsing rc_eq \"%s\"\n", s->avctx->rc_eq);