diff --git a/ChangeLog b/ChangeLog
index ebc1854f6..1d37b7fa6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2005-04-07  Moritz Bunkus  <moritz@bunkus.org>
 
+	* mkvextract: bug fix: WAVPACK extraction did not update the
+	"number of samples" header field. Patch by Steve Lhomme (see
+	AUTHORS).
+
 	* mkvmerge: bug fix: RealMedia files contain a "FPS" field in
 	their track headers. Unfortunately this field does not always
 	contain the actual FPS of a video track but the maximum number of
diff --git a/src/extract/xtr_wav.cpp b/src/extract/xtr_wav.cpp
index 3b036a5df..6784b6fed 100644
--- a/src/extract/xtr_wav.cpp
+++ b/src/extract/xtr_wav.cpp
@@ -211,5 +211,12 @@ xtr_wavpack4_c::handle_block(KaxBlock &block,
 
 void
 xtr_wavpack4_c::finish_file() {
-  delete corr_out;
+  out->setFilePointer(12);
+  out->write_uint32_le(number_of_samples);
+
+  if (NULL != corr_out) {
+    corr_out->setFilePointer(12);
+    corr_out->write_uint32_le(number_of_samples);
+    delete corr_out;
+  }
 }
diff --git a/src/extract/xtr_wav.h b/src/extract/xtr_wav.h
index 2f9e1161d..1aadc2410 100644
--- a/src/extract/xtr_wav.h
+++ b/src/extract/xtr_wav.h
@@ -32,7 +32,7 @@ public:
 
 class xtr_wavpack4_c: public xtr_base_c {
 public:
-  uint64_t number_of_samples;
+  uint32_t number_of_samples;
   int extract_blockadd_level;
   binary version[2];
   mm_file_io_c *corr_out;