GH-60729: Add IEEE format wave audio support (GH-145931)

(this re-applies reverted commit 61f2a1a,
with a test fix)

Co-authored-by: Lionel Koenig <lionelk@google.com>

Author: mbeijen

Doc/library/wave.rst

@@ -9,14 +9,19 @@
 --------------
 
 The :mod:`!wave` module provides a convenient interface to the Waveform Audio
-"WAVE" (or "WAV") file format. Only uncompressed PCM encoded wave files are
-supported.
+"WAVE" (or "WAV") file format.
+
+The module supports uncompressed PCM and IEEE floating-point WAV formats.
 
 .. versionchanged:: 3.12
 
    Support for ``WAVE_FORMAT_EXTENSIBLE`` headers was added, provided that the
    extended format is ``KSDATAFORMAT_SUBTYPE_PCM``.
 
+.. versionchanged:: next
+
+   Support for reading and writing ``WAVE_FORMAT_IEEE_FLOAT`` files was added.
+
 The :mod:`!wave` module defines the following function and exception:
 
 
@@ -60,6 +65,21 @@ The :mod:`!wave` module defines the following function and exception:
    specification or hits an implementation deficiency.
 
 
+.. data:: WAVE_FORMAT_PCM
+
+   Format code for uncompressed PCM audio.
+
+
+.. data:: WAVE_FORMAT_IEEE_FLOAT
+
+   Format code for IEEE floating-point audio.
+
+
+.. data:: WAVE_FORMAT_EXTENSIBLE
+
+   Format code for WAVE extensible headers.
+
+
 .. _wave-read-objects:
 
 Wave_read Objects
@@ -98,6 +118,14 @@ Wave_read Objects
       Returns number of audio frames.
 
 
+   .. method:: getformat()
+
+      Returns the frame format code.
+
+      This is one of :data:`WAVE_FORMAT_PCM`,
+      :data:`WAVE_FORMAT_IEEE_FLOAT`, or :data:`WAVE_FORMAT_EXTENSIBLE`.
+
+
    .. method:: getcomptype()
 
       Returns compression type (``'NONE'`` is the only supported type).
@@ -112,8 +140,8 @@ Wave_read Objects
    .. method:: getparams()
 
       Returns a :func:`~collections.namedtuple` ``(nchannels, sampwidth,
-      framerate, nframes, comptype, compname)``, equivalent to output of the
-      ``get*()`` methods.
+      framerate, nframes, comptype, compname)``, equivalent to output
+      of the ``get*()`` methods.
 
 
    .. method:: readframes(n)
@@ -190,6 +218,9 @@ Wave_write Objects
 
       Set the sample width to *n* bytes.
 
+      For :data:`WAVE_FORMAT_IEEE_FLOAT`, only 4-byte (32-bit) and
+      8-byte (64-bit) sample widths are supported.
+
 
    .. method:: getsampwidth()
 
@@ -238,11 +269,32 @@ Wave_write Objects
       Return the human-readable compression type name.
 
 
+   .. method:: setformat(format)
+
+      Set the frame format code.
+
+      Supported values are :data:`WAVE_FORMAT_PCM` and
+      :data:`WAVE_FORMAT_IEEE_FLOAT`.
+
+      When setting :data:`WAVE_FORMAT_IEEE_FLOAT`, the sample width must be
+      4 or 8 bytes.
+
+
+   .. method:: getformat()
+
+      Return the current frame format code.
+
+
    .. method:: setparams(tuple)
 
-      The *tuple* should be ``(nchannels, sampwidth, framerate, nframes, comptype,
-      compname)``, with values valid for the ``set*()`` methods.  Sets all
-      parameters.
+      The *tuple* should be
+      ``(nchannels, sampwidth, framerate, nframes, comptype, compname, format)``,
+      with values valid for the ``set*()`` methods. Sets all parameters.
+
+      For backwards compatibility, a 6-item tuple without *format* is also
+      accepted and defaults to :data:`WAVE_FORMAT_PCM`.
+
+      For ``format=WAVE_FORMAT_IEEE_FLOAT``, *sampwidth* must be 4 or 8.
 
 
    .. method:: getparams()
@@ -279,3 +331,6 @@ Wave_write Objects
       Note that it is invalid to set any parameters after calling :meth:`writeframes`
       or :meth:`writeframesraw`, and any attempt to do so will raise
       :exc:`wave.Error`.
+
+      For :data:`WAVE_FORMAT_IEEE_FLOAT` output, a ``fact`` chunk is written as
+      required by the WAVE specification for non-PCM formats.

Doc/whatsnew/3.15.rst

@@ -1511,6 +1511,21 @@ typing
 wave
 ----
 
+* Added support for IEEE floating-point WAVE audio
+  (``WAVE_FORMAT_IEEE_FLOAT``) in :mod:`wave`.
+
+* Added :meth:`wave.Wave_read.getformat`, :meth:`wave.Wave_write.getformat`,
+  and :meth:`wave.Wave_write.setformat` for explicit frame format handling.
+
+* :meth:`wave.Wave_write.setparams` accepts both 7-item tuples including
+  ``format`` and 6-item tuples for backwards compatibility (defaulting to
+  ``WAVE_FORMAT_PCM``).
+
+* ``WAVE_FORMAT_IEEE_FLOAT`` output now includes a ``fact`` chunk,
+  as required for non-PCM WAVE formats.
+
+(Contributed by Lionel Koenig and Michiel W. Beijen in :gh:`60729`.)
+
 * Removed the ``getmark()``, ``setmark()`` and ``getmarkers()`` methods
   of the :class:`~wave.Wave_read` and :class:`~wave.Wave_write` classes,
   which were deprecated since Python 3.13.

Lib/test/audiodata/pluck-float32.wav

@@ -27,17 +27,18 @@ def tearDown(self):
         unlink(TESTFN)
 
     def check_params(self, f, nchannels, sampwidth, framerate, nframes,
-                     comptype, compname):
+                     comptype, compname, format):
         self.assertEqual(f.getnchannels(), nchannels)
         self.assertEqual(f.getsampwidth(), sampwidth)
         self.assertEqual(f.getframerate(), framerate)
         self.assertEqual(f.getnframes(), nframes)
         self.assertEqual(f.getcomptype(), comptype)
         self.assertEqual(f.getcompname(), compname)
+        self.assertEqual(f.getformat(), format)
 
         params = f.getparams()
         self.assertEqual(params,
-                (nchannels, sampwidth, framerate, nframes, comptype, compname))
+            (nchannels, sampwidth, framerate, nframes, comptype, compname))
         self.assertEqual(params.nchannels, nchannels)
         self.assertEqual(params.sampwidth, sampwidth)
         self.assertEqual(params.framerate, framerate)
@@ -51,13 +52,17 @@ def check_params(self, f, nchannels, sampwidth, framerate, nframes,
 
 
 class AudioWriteTests(AudioTests):
+    readonly = False
 
     def create_file(self, testfile):
+        if self.readonly:
+            self.skipTest('Read only file format')
         f = self.fout = self.module.open(testfile, 'wb')
         f.setnchannels(self.nchannels)
         f.setsampwidth(self.sampwidth)
         f.setframerate(self.framerate)
         f.setcomptype(self.comptype, self.compname)
+        f.setformat(self.format)
         return f
 
     def check_file(self, testfile, nframes, frames):
@@ -67,13 +72,14 @@ def check_file(self, testfile, nframes, frames):
             self.assertEqual(f.getframerate(), self.framerate)
             self.assertEqual(f.getnframes(), nframes)
             self.assertEqual(f.readframes(nframes), frames)
+            self.assertEqual(f.getformat(), self.format)
 
     def test_write_params(self):
         f = self.create_file(TESTFN)
         f.setnframes(self.nframes)
         f.writeframes(self.frames)
         self.check_params(f, self.nchannels, self.sampwidth, self.framerate,
-                          self.nframes, self.comptype, self.compname)
+                          self.nframes, self.comptype, self.compname, self.format)
         f.close()
 
     def test_write_context_manager_calls_close(self):
@@ -257,7 +263,7 @@ def test_read_params(self):
         f = self.f = self.module.open(self.sndfilepath)
         #self.assertEqual(f.getfp().name, self.sndfilepath)
         self.check_params(f, self.nchannels, self.sampwidth, self.framerate,
-                          self.sndfilenframes, self.comptype, self.compname)
+                          self.sndfilenframes, self.comptype, self.compname, self.format)
 
     def test_close(self):
         with open(self.sndfilepath, 'rb') as testfile:
@@ -298,6 +304,8 @@ def test_read(self):
             f.setpos(f.getnframes() + 1)
 
     def test_copy(self):
+        if self.readonly:
+            self.skipTest('Read only file format')
         f = self.f = self.module.open(self.sndfilepath)
         fout = self.fout = self.module.open(TESTFN, 'wb')
         fout.setparams(f.getparams())