diff --git a/avifinfo.c b/avifinfo.c
index 5b93d19..90e02bf 100644
--- a/avifinfo.c
+++ b/avifinfo.c
@@ -34,14 +34,15 @@
 // uint32_t is used everywhere in this file. It is unlikely to be insufficient
 // to parse AVIF headers.
 #define AVIFINFO_MAX_SIZE UINT32_MAX
-// AvifInfoInternalFeatures uses uint8_t to store values and the number of
-// values is clamped to 32 to limit the stack size.
+// Be reasonable. Avoid timeouts and out-of-memory.
+#define AVIFINFO_MAX_NUM_BOXES 4096
+// AvifInfoInternalFeatures uses uint8_t to store values.
 #define AVIFINFO_MAX_VALUE UINT8_MAX
-#define AVIFINFO_UNDEFINED 0
 // Maximum number of stored associations. Past that, they are skipped.
 #define AVIFINFO_MAX_TILES 16
 #define AVIFINFO_MAX_PROPS 32
 #define AVIFINFO_MAX_FEATURES 8
+#define AVIFINFO_UNDEFINED 0
 
 // Reads an unsigned integer from 'input' with most significant bits first.
 // 'input' must be at least 'num_bytes'-long.
@@ -286,7 +287,7 @@
   box->content_size = box->size - box_header_size;
   // Avoid timeouts. The maximum number of parsed boxes is arbitrary.
   ++*num_parsed_boxes;
-  AVIFINFO_CHECK(*num_parsed_boxes < 4096, kAborted);
+  AVIFINFO_CHECK(*num_parsed_boxes < AVIFINFO_MAX_NUM_BOXES, kAborted);
 
   box->version = 0;
   box->flags = 0;
@@ -297,14 +298,14 @@
     // See AV1 Image File Format (AVIF) 8.1
     // at https://aomediacodec.github.io/av1-avif/#avif-boxes (available when
     // https://github.com/AOMediaCodec/av1-avif/pull/170 is merged).
-    uint32_t is_parsable = 1;
-    if (!memcmp(box->type, "meta", 4)) is_parsable = (box->version <= 0);
-    if (!memcmp(box->type, "pitm", 4)) is_parsable = (box->version <= 1);
-    if (!memcmp(box->type, "ipma", 4)) is_parsable = (box->version <= 1);
-    if (!memcmp(box->type, "ispe", 4)) is_parsable = (box->version <= 0);
-    if (!memcmp(box->type, "pixi", 4)) is_parsable = (box->version <= 0);
-    if (!memcmp(box->type, "iref", 4)) is_parsable = (box->version <= 1);
-    if (!memcmp(box->type, "auxC", 4)) is_parsable = (box->version <= 0);
+    const uint32_t is_parsable =
+        (!memcmp(box->type, "meta", 4) && box->version <= 0) ||
+        (!memcmp(box->type, "pitm", 4) && box->version <= 1) ||
+        (!memcmp(box->type, "ipma", 4) && box->version <= 1) ||
+        (!memcmp(box->type, "ispe", 4) && box->version <= 0) ||
+        (!memcmp(box->type, "pixi", 4) && box->version <= 0) ||
+        (!memcmp(box->type, "iref", 4) && box->version <= 1) ||
+        (!memcmp(box->type, "auxC", 4) && box->version <= 0);
     // Instead of considering this file as invalid, skip unparsable boxes.
     if (!is_parsable) memcpy(box->type, "\0skp", 4);  // \0 so not a valid type
   }
@@ -503,6 +504,7 @@
       AVIFINFO_CHECK_NOT_FOUND(
           AvifInfoInternalGetPrimaryItemFeatures(features));
 
+      // Mostly if 'data_was_skipped'.
       AVIFINFO_CHECK_FOUND(
           AvifInfoInternalSkip(stream, box.content_size - num_read_bytes));
     } else {
@@ -566,6 +568,10 @@
       // If all features are available now, do not look further.
       AVIFINFO_CHECK_NOT_FOUND(
           AvifInfoInternalGetPrimaryItemFeatures(features));
+
+      // Mostly if 'data_was_skipped'.
+      AVIFINFO_CHECK_FOUND(
+          AvifInfoInternalSkip(stream, box.content_size - num_read_bytes));
     } else {
       AVIFINFO_CHECK_FOUND(AvifInfoInternalSkip(stream, box.content_size));
     }
diff --git a/avifinfo.php b/avifinfo.php
index d46be59..84a2e93 100644
--- a/avifinfo.php
+++ b/avifinfo.php
@@ -18,12 +18,13 @@
 const ABORTED   = 3; // Input correctly parsed until stopped to avoid timeout or crash.
 const INVALID   = 4; // Input incorrectly parsed.
 
-const MAX_SIZE     = 4294967295; // Unlikely to be insufficient to parse AVIF headers.
-const MAX_VALUE    = 255;        // Be reasonable. Avoid timeouts and out-of-memory.
-const MAX_TILES    = 16;         // Be reasonable.
-const MAX_PROPS    = 32;         // Be reasonable.
-const MAX_FEATURES = 8;          // Be reasonable.
-const UNDEFINED    = 0;          // Value was not yet parsed.
+const MAX_SIZE      = 4294967295; // Unlikely to be insufficient to parse AVIF headers.
+const MAX_NUM_BOXES = 4096;       // Be reasonable. Avoid timeouts and out-of-memory.
+const MAX_VALUE     = 255;
+const MAX_TILES     = 16;
+const MAX_PROPS     = 32;
+const MAX_FEATURES  = 8;
+const UNDEFINED     = 0;          // Value was not yet parsed.
 
 /**
  * Reads an unsigned integer with most significant bits first.
@@ -271,7 +272,7 @@
     $this->content_size = $this->size - $header_size;
     // Avoid timeouts. The maximum number of parsed boxes is arbitrary.
     ++$num_parsed_boxes;
-    if ( $num_parsed_boxes >= 4096 ) {
+    if ( $num_parsed_boxes >= MAX_NUM_BOXES ) {
       return ABORTED;
     }
 
@@ -286,22 +287,13 @@
       // See AV1 Image File Format (AVIF) 8.1
       // at https://aomediacodec.github.io/av1-avif/#avif-boxes (available when
       // https://github.com/AOMediaCodec/av1-avif/pull/170 is merged).
-      $is_parsable   = true;
-      if ( $this->type == 'meta' ) {
-        $is_parsable = ( $this->version <= 0 );
-      } else if ( $this->type == 'pitm' ) {
-        $is_parsable = ( $this->version <= 1 );
-      } else if ( $this->type == 'ipma' ) {
-        $is_parsable = ( $this->version <= 1 );
-      } else if ( $this->type == 'ispe' ) {
-        $is_parsable = ( $this->version <= 0 );
-      } else if ( $this->type == 'pixi' ) {
-        $is_parsable = ( $this->version <= 0 );
-      } else if ( $this->type == 'iref' ) {
-        $is_parsable = ( $this->version <= 1 );
-      } else if ( $this->type == 'auxC' ) {
-        $is_parsable = ( $this->version <= 0 );
-      }
+      $is_parsable = ( $this->type == 'meta' && $this->version <= 0 ) ||
+                     ( $this->type == 'pitm' && $this->version <= 1 ) ||
+                     ( $this->type == 'ipma' && $this->version <= 1 ) ||
+                     ( $this->type == 'ispe' && $this->version <= 0 ) ||
+                     ( $this->type == 'pixi' && $this->version <= 0 ) ||
+                     ( $this->type == 'iref' && $this->version <= 1 ) ||
+                     ( $this->type == 'auxC' && $this->version <= 0 );
       // Instead of considering this file as invalid, skip unparsable boxes.
       if ( !$is_parsable ) {
         $this->type = 'unknownversion';