[FFmpeg-cvslog] swscale/swscale: don't reject scaling when color parameters are not supported but conversion is not required

[James Almer]

ffmpeg | branch: master | James Almer <jamrial at gmail.com> | Wed Jan 22 12:12:48 2025 -0300| [e20ee9f9aec94f8cea1bf4fd8ed3fb096fb205e5] | committer: James Almer

swscale/swscale: don't reject scaling when color parameters are not supported but conversion is not required

Values in csp, prim, trc, etc, are irrelevant if there's no conversion needed.

Reviewed-by: Niklas Haas <ffmpeg at haasn.xyz>
Signed-off-by: James Almer <jamrial at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e20ee9f9aec94f8cea1bf4fd8ed3fb096fb205e5
---

 libswscale/swscale.c |  2 +-
 libswscale/utils.h   | 16 +++++++++++-----
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/libswscale/swscale.c b/libswscale/swscale.c
index 84657bb17c..98f94d029f 100644
--- a/libswscale/swscale.c
+++ b/libswscale/swscale.c
@@ -1452,7 +1452,7 @@ int sws_frame_setup(SwsContext *ctx, const AVFrame *dst, const AVFrame *src)
 
         src_ok = ff_test_fmt(&src_fmt, 0);
         dst_ok = ff_test_fmt(&dst_fmt, 1);
-        if ((!src_ok || !dst_ok)) {
+        if ((!src_ok || !dst_ok) && !ff_props_equal(&src_fmt, &dst_fmt)) {
             err_msg = src_ok ? "Unsupported output" : "Unsupported input";
             ret = AVERROR(ENOTSUP);
             goto fail;
diff --git a/libswscale/utils.h b/libswscale/utils.h
index d76fea1133..8e0cdf26ec 100644
--- a/libswscale/utils.h
+++ b/libswscale/utils.h
@@ -98,12 +98,10 @@ static inline int ff_color_equal(const SwsColor *c1, const SwsColor *c2)
             ff_prim_equal(&c1->gamut, &c2->gamut);
 }
 
-/* Tests only the static components of a colorspace, ignoring per-frame data */
-static inline int ff_fmt_equal(const SwsFormat *fmt1, const SwsFormat *fmt2)
+/* Tests only the static components of a colorspace, ignoring dimensions and per-frame data */
+static inline int ff_props_equal(const SwsFormat *fmt1, const SwsFormat *fmt2)
 {
-    return fmt1->width      == fmt2->width      &&
-           fmt1->height     == fmt2->height     &&
-           fmt1->interlaced == fmt2->interlaced &&
+    return fmt1->interlaced == fmt2->interlaced &&
            fmt1->format     == fmt2->format     &&
            fmt1->range      == fmt2->range      &&
            fmt1->csp        == fmt2->csp        &&
@@ -111,6 +109,14 @@ static inline int ff_fmt_equal(const SwsFormat *fmt1, const SwsFormat *fmt2)
            ff_color_equal(&fmt1->color, &fmt2->color);
 }
 
+/* Tests only the static components of a colorspace, ignoring per-frame data */
+static inline int ff_fmt_equal(const SwsFormat *fmt1, const SwsFormat *fmt2)
+{
+    return fmt1->width      == fmt2->width      &&
+           fmt1->height     == fmt2->height     &&
+           ff_props_equal(fmt1, fmt2);
+}
+
 static inline int ff_fmt_align(enum AVPixelFormat fmt)
 {
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);