#5024: whichhdr now returns the frame count for WAV files.

bitdancer · bitdancer · commit 1a48b9dd7dac · 2013-03-18T17:42:42.000-04:00
Patch by Ned Jackson Lovely based on a suggestion by Robert Pyle.
diff --git a/Lib/sndhdr.py b/Lib/sndhdr.py
@@ -137,14 +137,17 @@ def test_voc(h, f):
 
 
 def test_wav(h, f):
+    import wave
     # 'RIFF' <len> 'WAVE' 'fmt ' <len>
     if not h.startswith(b'RIFF') or h[8:12] != b'WAVE' or h[12:16] != b'fmt ':
         return None
-    style = get_short_le(h[20:22])
-    nchannels = get_short_le(h[22:24])
-    rate = get_long_le(h[24:28])
-    sample_bits = get_short_le(h[34:36])
-    return 'wav', rate, nchannels, -1, sample_bits
+    f.seek(0)
+    try:
+        w = wave.openfp(f, 'r')
+    except (EOFError, wave.Error):
+        return None
+    return ('wav', w.getframerate(), w.getnchannels(),
+                   w.getnframes(), 8*w.getsampwidth())
 
 tests.append(test_wav)
 
diff --git a/Lib/test/test_sndhdr.py b/Lib/test/test_sndhdr.py
@@ -12,7 +12,7 @@ def test_data(self):
             ('sndhdr.hcom', ('hcom', 22050.0, 1, -1, 8)),
             ('sndhdr.sndt', ('sndt', 44100, 1, 5, 8)),
             ('sndhdr.voc', ('voc', 0, 1, -1, 8)),
-            ('sndhdr.wav', ('wav', 44100, 2, -1, 16)),
+            ('sndhdr.wav', ('wav', 44100, 2, 5, 16)),
         ):
             filename = findfile(filename, subdir="sndhdrdata")
             what = sndhdr.what(filename)
diff --git a/Misc/ACKS b/Misc/ACKS
@@ -746,6 +746,7 @@ Hugo Lopes Tavares
 Anne Lord
 Tom Loredo
 Justin Love
+Ned Jackson Lovely
 Jason Lowe
 Tony Lownds
 Ray Loyzaga
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -287,6 +287,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #5024: sndhdr.whichhdr now returns the frame count for WAV files
+  rather than -1.
+
 - Issue #17460: Remove the strict argument of HTTPConnection and removing the
   DeprecationWarning being issued from 3.2 onwards.
 
