diff --git a/src/http.h b/src/http.h
index 3e3efd4..cf2d52f 100644
--- a/src/http.h
+++ b/src/http.h
@@ -238,6 +238,8 @@ class FileSlices : public FileSlice {
     size_ = new_size;
   }
 
+  size_t num_slices() const { return slices_.size(); }
+
   int64_t size() const final { return size_; }
   int64_t AddRange(ByteRange range, EvBuffer *buf,
                    std::string *error_message) const final;
diff --git a/src/mp4.cc b/src/mp4.cc
index 91bbfff..479cea6 100644
--- a/src/mp4.cc
+++ b/src/mp4.cc
@@ -548,7 +548,8 @@ class Mp4File : public VirtualFile {
       etag_digest->Update(segment->recording.sample_file_sha1);
     }
     etag_ = StrCat("\"", ToHex(etag_digest->Finalize()), "\"");
-    VLOG(1) << "Constructed .mp4 has " << slices_.size() << " slices.";
+    VLOG(1) << "Constructed .mp4 has " << slices_.num_slices() << " slices for "
+            << segments_.size() << " segments, " << slices_.size() << " bytes.";
   }
 
   time_t last_modified() const final { return last_modified_; }