[FFmpeg-devel] [PATCH] vf_scale: give a clue in case of invalid expression self-reference

[Stefano Sabatini]

Address trac ticket #706.
---
 libavfilter/vf_scale.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/libavfilter/vf_scale.c b/libavfilter/vf_scale.c
index 8483536..b640f1c 100644
--- a/libavfilter/vf_scale.c
+++ b/libavfilter/vf_scale.c
@@ -240,7 +240,9 @@ static int config_props(AVFilterLink *outlink)
 
 fail:
     av_log(NULL, AV_LOG_ERROR,
-           "Error when evaluating the expression '%s'\n", expr);
+           "Error when evaluating the expression '%s'.\n"
+           "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
+           expr, scale->w_expr, scale->h_expr);
     return ret;
 }
 
-- 
1.7.5.4