diff --git a/libavutil/hdr_dynamic_metadata.c b/libavutil/hdr_dynamic_metadata.c
index 9c89625421..4c9ac25970 100644
--- a/libavutil/hdr_dynamic_metadata.c
+++ b/libavutil/hdr_dynamic_metadata.c
@@ -64,7 +64,7 @@ int av_dynamic_hdr_plus_from_t35(AVDynamicHDRPlus *s, const uint8_t *data,
     int ret;
 
     if (!s)
-        return AVERROR(ENOMEM);
+        return AVERROR(EINVAL);
 
     if (size > AV_HDR_PLUS_MAX_PAYLOAD_SIZE)
         return AVERROR(EINVAL);
diff --git a/libavutil/hdr_dynamic_metadata.h b/libavutil/hdr_dynamic_metadata.h
index a051ac7471..5881c35220 100644
--- a/libavutil/hdr_dynamic_metadata.h
+++ b/libavutil/hdr_dynamic_metadata.h
@@ -248,7 +248,11 @@ typedef struct AVDynamicHDRPlus {
 
     /**
      * Application version in the application defining document in ST-2094
-     * suite. The value shall be set to 0.
+     * suite. CTA-861-H sets this to 1 for the HDR10+ payload carried in a
+     * Rec. ITU-T T.35 message.
+     *
+     * av_dynamic_hdr_plus_from_t35() sets this field from the parsed payload.
+     * av_dynamic_hdr_plus_to_t35() ignores it and always writes 1.
      */
     uint8_t application_version;