[FFmpeg-cvslog] swscale: add sws_is_noop()

[Niklas Haas]

ffmpeg | branch: master | Niklas Haas <git at haasn.dev> | Mon Oct 14 15:16:26 2024 +0200| [b03c758600f0767d54ae663dadc8f698b79cd1c4] | committer: Niklas Haas

swscale: add sws_is_noop()

Exactly what it says on the tin.

Sponsored-by: Sovereign Tech Fund
Signed-off-by: Niklas Haas <git at haasn.dev>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b03c758600f0767d54ae663dadc8f698b79cd1c4
---

 doc/APIchanges       |  3 +++
 libswscale/swscale.h |  6 ++++++
 libswscale/utils.c   | 14 ++++++++++++++
 libswscale/version.h |  2 +-
 4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/doc/APIchanges b/doc/APIchanges
index 7d94b7bf97..eeb859b873 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -2,6 +2,9 @@ The last version increases of all libraries were on 2024-03-07
 
 API changes, most recent first:
 
+2024-10-23 - xxxxxxxxxx - lsws 8.9.100 - swscale.h
+  Add sws_is_noop().
+
 2024-10-23 - xxxxxxxxxx - lsws 8.8.100 - swscale.h
   Add frame property testing API:
     - sws_test_format()
diff --git a/libswscale/swscale.h b/libswscale/swscale.h
index e3362d5328..50c705ae06 100644
--- a/libswscale/swscale.h
+++ b/libswscale/swscale.h
@@ -140,6 +140,12 @@ int sws_test_transfer(enum AVColorTransferCharacteristic trc, int output);
  */
 int sws_test_frame(const AVFrame *frame, int output);
 
+/**
+ * Check if a given conversion is a noop. Returns a positive integer if
+ * no operation needs to be performed, 0 otherwise.
+ */
+int sws_is_noop(const AVFrame *dst, const AVFrame *src);
+
 /* values for the flags, the stuff on the command line is different */
 #define SWS_FAST_BILINEAR     1
 #define SWS_BILINEAR          2
diff --git a/libswscale/utils.c b/libswscale/utils.c
index c9c80fdb79..3008d4db4d 100644
--- a/libswscale/utils.c
+++ b/libswscale/utils.c
@@ -2777,3 +2777,17 @@ int sws_test_frame(const AVFrame *frame, int output)
 
     return 1;
 }
+
+int sws_is_noop(const AVFrame *dst, const AVFrame *src)
+{
+    for (int field = 0; field < 2; field++) {
+        SwsFormat dst_fmt = ff_fmt_from_frame(dst, field);
+        SwsFormat src_fmt = ff_fmt_from_frame(src, field);
+        if (!ff_fmt_equal(&dst_fmt, &src_fmt))
+            return 0;
+        if (!dst_fmt.interlaced)
+            break;
+    }
+
+    return 1;
+}
diff --git a/libswscale/version.h b/libswscale/version.h
index c0610fec1e..109bb5cfd9 100644
--- a/libswscale/version.h
+++ b/libswscale/version.h
@@ -28,7 +28,7 @@
 
 #include "version_major.h"
 
-#define LIBSWSCALE_VERSION_MINOR   8
+#define LIBSWSCALE_VERSION_MINOR   9
 #define LIBSWSCALE_VERSION_MICRO 100
 
 #define LIBSWSCALE_VERSION_INT  AV_VERSION_INT(LIBSWSCALE_VERSION_MAJOR, \