When force_original_aspect_ratio and force_divisible_by are both
used, dimensions are now rounded to the nearest allowed multiple of
force_divisible_by rather than first rounding to the nearest integer and
then rounding in a static direction. This results in less distortion of
the aspect ratio.
Reviewed-by: Thierry Foucu <tfo...@google.com>
Signed-off-by: Tristan Schmelcher <tschmelc...@google.com>
---
libavfilter/scale_eval.c | 11 +++++++----
libavfilter/scale_eval.h | 3 ++-
2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/libavfilter/scale_eval.c b/libavfilter/scale_eval.c
index dfec081e15..75ed503f15 100644
--- a/libavfilter/scale_eval.c
+++ b/libavfilter/scale_eval.c
@@ -148,14 +148,17 @@ int ff_scale_adjust_dimensions(AVFilterLink *inlink,
* dimensions so that it is not divisible by the set factors anymore
* unless force_divisible_by is defined as well */
if (force_original_aspect_ratio) {
- int tmp_w = av_rescale(h, inlink->w, inlink->h);
- int tmp_h = av_rescale(w, inlink->h, inlink->w);
+ // Including force_divisible_by here rounds to the nearest multiple of
it.
+ int tmp_w = av_rescale(h, inlink->w, inlink->h *
(int64_t)force_divisible_by)
+ * force_divisible_by;
+ int tmp_h = av_rescale(w, inlink->h, inlink->w *
(int64_t)force_divisible_by)
+ * force_divisible_by;
if (force_original_aspect_ratio == 1) {
w = FFMIN(tmp_w, w);
h = FFMIN(tmp_h, h);
if (force_divisible_by > 1) {
- // round down
+ // round down in case provided w or h is not divisible.
w = w / force_divisible_by * force_divisible_by;
h = h / force_divisible_by * force_divisible_by;
}
@@ -163,7 +166,7 @@ int ff_scale_adjust_dimensions(AVFilterLink *inlink,
w = FFMAX(tmp_w, w);
h = FFMAX(tmp_h, h);
if (force_divisible_by > 1) {
- // round up
+ // round up in case provided w or h is not divisible.
w = (w + force_divisible_by - 1) / force_divisible_by *
force_divisible_by;
h = (h + force_divisible_by - 1) / force_divisible_by *
force_divisible_by;
}
diff --git a/libavfilter/scale_eval.h b/libavfilter/scale_eval.h
index fceb023fec..2eb6970aad 100644
--- a/libavfilter/scale_eval.h
+++ b/libavfilter/scale_eval.h
@@ -38,7 +38,8 @@ int ff_scale_eval_dimensions(void *ctx,
* Transform evaluated width and height obtained from ff_scale_eval_dimensions
* into actual target width and height for scaling. Adjustment can occur if one
* or both of the evaluated values are of the form '-n' or if
- * force_original_aspect_ratio is set.
+ * force_original_aspect_ratio is set. force_divisible_by is used only when
+ * force_original_aspect_ratio is set and must be at least 1.
*
* Returns 0.
*/
--
2.37.3.998.g577e59143f-goog
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