The input width and height is known at parse time so there's no
reason ow/oh should not be usable when using 0 as the width or
height expression.
Previously in "scale=0:ow" ow would be set to "0" which works,
conveniently, as "scale=0:0" is perfectly valid input but this breaks
down when you do something like "scale=0:ow/4" which one could
reasonably expect to work as well, but does not as ow is 0 not the
real value.
This change handles the 0 case for w/h immediately so the ow/oh
variables work as expected. Consequently, the rest of the code does
not need to handle 0 input. w/h will always be > 0 or < 0.
Signed-off-by: Kevin Mark <kmark...@gmail.com>
---
libavfilter/scale.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/libavfilter/scale.c b/libavfilter/scale.c
index 03745ddcb8..cc2bea5caf 100644
--- a/libavfilter/scale.c
+++ b/libavfilter/scale.c
@@ -158,19 +158,19 @@ int ff_scale_eval_dimensions(void *log_ctx,
av_expr_parse_and_eval(&res, (expr = w_expr),
names, var_values,
NULL, NULL, NULL, NULL, NULL, 0, log_ctx);
- eval_w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
+ eval_w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res == 0.0 ?
inlink->w : res;
if ((ret = av_expr_parse_and_eval(&res, (expr = h_expr),
names, var_values,
NULL, NULL, NULL, NULL, NULL, 0,
log_ctx)) < 0)
goto fail;
- eval_h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;
+ eval_h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res == 0.0 ?
inlink->h : res;
/* evaluate again the width, as it may depend on the output height */
if ((ret = av_expr_parse_and_eval(&res, (expr = w_expr),
names, var_values,
NULL, NULL, NULL, NULL, NULL, 0,
log_ctx)) < 0)
goto fail;
- eval_w = res;
+ eval_w = res == 0.0 ? inlink->w : res;
w = eval_w;
h = eval_h;
@@ -186,13 +186,10 @@ int ff_scale_eval_dimensions(void *log_ctx,
factor_h = -h;
}
- if (w < 0 && h < 0)
- eval_w = eval_h = 0;
-
- if (!(w = eval_w))
+ if (w < 0 && h < 0) {
w = inlink->w;
- if (!(h = eval_h))
h = inlink->h;
+ }
/* Make sure that the result is divisible by the factor we determined
* earlier. If no factor was set, it is nothing will happen as the default
--
2.13.0
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