diff --git a/src/dwarfs/categorizer/pcmaudio_categorizer.cpp b/src/dwarfs/categorizer/pcmaudio_categorizer.cpp
index ae7df3a1..bc0cd1eb 100644
--- a/src/dwarfs/categorizer/pcmaudio_categorizer.cpp
+++ b/src/dwarfs/categorizer/pcmaudio_categorizer.cpp
@@ -316,12 +316,13 @@ class iff_parser final {
           c.reset();
           return c;
         }
+        pos_ += c->header.size;
+        c->header.size -= sizeof(ChunkHeaderType);
       } else {
         pos_ += sizeof(ChunkHeaderType);
+        pos_ += c->header.size;
       }
 
-      pos_ += c->header.size;
-
       if (pos_ > data_.size()) {
         LOG_WARN << "[" << name_ << "] " << path_
                  << ": unexpected end of file (pos=" << pos_