avutil/pixfmt: Add AV_VIDEO_MAX_PLANES

It seems we do not have a named identifier for the maximum planes of pixel formats

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

doc/APIchanges

@@ -2,6 +2,9 @@ The last version increases of all libraries were on 2023-02-09
 
 API changes, most recent first:
 
+2024-02-16 - xxxxxxxxxx - lavu 58.39.100 - pixfmt.h
+  Add AV_VIDEO_MAX_PLANES
+
 2024-02-13 - xxxxxxxxxx - lavf 60.21.100 - avformat.h
   Add AVStreamGroup.disposition.
 

libavutil/pixfmt.h

@@ -32,6 +32,13 @@
 #define AVPALETTE_SIZE 1024
 #define AVPALETTE_COUNT 256
 
+/**
+ * Maximum number of planes in any pixel format.
+ * This should be used when a maximum is needed, but code should not
+ * be written to require a maximum for no good reason.
+ */
+#define AV_VIDEO_MAX_PLANES 4
+
 /**
  * Pixel format.
  *

libavutil/version.h

@@ -79,7 +79,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  58
-#define LIBAVUTIL_VERSION_MINOR  38
+#define LIBAVUTIL_VERSION_MINOR  39
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \