Check that a1lx is not marked as essential
diff --git a/src/read.c b/src/read.c
index 2755bcc..ca0be89 100644
--- a/src/read.c
+++ b/src/read.c
@@ -1976,7 +1976,27 @@
}
}
if (supportedType) {
- if (!essential) {
+ if (essential) {
+ // Verify that it is legal for this property to be flagged as essential. Any
+ // types in this list are *required* in the spec to not be flagged as essential
+ // when associated with an item.
+ static const char * const nonessentialTypes[] = {
+
+ // AVIF: Section 2.3.2.3.2: "If associated, it shall not be marked as essential."
+ "a1lx"
+
+ };
+ size_t nonessentialTypesCount = sizeof(nonessentialTypes) / sizeof(nonessentialTypes[0]);
+ for (size_t i = 0; i < nonessentialTypesCount; ++i) {
+ if (!memcmp(srcProp->type, nonessentialTypes[i], 4)) {
+ avifDiagnosticsPrintf(diag,
+ "Item ID [%u] has a %s property association which must not be marked essential, but is",
+ itemID,
+ nonessentialTypes[i]);
+ return AVIF_FALSE;
+ }
+ }
+ } else {
// Verify that it is legal for this property to not be flagged as essential. Any
// types in this list are *required* in the spec to be flagged as essential when
// associated with an item.
