Audio displayobject

IPython/lib/display.py

@@ -4,6 +4,13 @@
 """
 from os.path import exists, isfile, splitext, abspath, join, isdir
 from os import walk, sep
+import struct
+import base64
+import sys
+from io import BytesIO
+from IPython.core.display import DisplayObject
+from IPython.utils.py3compat import string_types
+import mimetypes
 
 
 class IFrame(object):
@@ -341,3 +348,101 @@ def __repr__(self):
         for dirname, subdirs, fnames in walked_dir:
             result_lines += self.terminal_display_formatter(dirname, fnames, self.included_suffixes)
         return '\n'.join(result_lines)
+
+class Audio(DisplayObject):
+    def __init__(self, data=None, url=None, filename=None, rate=None, autoplay=False):
+        """Create an audio player given raw PCM data.
+
+        When this object is returned by an expression or passed to the
+        display function, it will result in an audio player widget
+        displayed in the frontend.
+
+        Parameters
+        ----------
+        data : unicode, str or bytes
+            The raw audio data.
+        url : unicode
+            A URL to download the data from.
+        filename : unicode
+            Path to a local file to load the data from.
+        rate : integer
+            The sampling rate of the raw data.
+            Only required when data parameter is being used
+        autoplay : bool
+            Set to True if the audio should immediately start playing.
+
+            Default is `False`.
+
+        Examples
+        --------
+        # embedded raw audio data
+        Audio(data=(2**13*numpy.sin(2*numpy.pi*440/44100*numpy.arange(44100))).astype(numpy.int16),
+            rate=44100)
+
+        # Specifying Audio(url=...) or Audio(filename=...) will load the data
+        # from an existing WAV file and embed it into the notebook.
+        Audio(filename='something.wav', autoplay=True)
+
+        """
+        self.rate = rate
+        self.autoplay = autoplay
+        super(Audio, self).__init__(data=data, url=url, filename=filename)
+
+    def reload(self):
+        super(Audio, self).reload()
+
+        if self.filename is not None:
+            self.mimetype = mimetypes.guess_type(self.filename)[0]
+        elif self.url is not None:
+            self.mimetype = mimetypes.guess_type(self.url)[0]
+        else:
+            self.mimetype = "audio/wav"
+
+            buffer = BytesIO()
+            buffer.write(b'RIFF')
+            buffer.write(b'\x00\x00\x00\x00')
+            buffer.write(b'WAVE')
+
+            buffer.write(b'fmt ')
+            if self.data.ndim == 1:
+                noc = 1
+            else:
+                noc = self.data.shape[1]
+            bits = self.data.dtype.itemsize * 8
+            sbytes = self.rate*(bits // 8)*noc
+            ba = noc * (bits // 8)
+            buffer.write(struct.pack('<ihHIIHH', 16, 1, noc, self.rate, sbytes, ba, bits))
+
+            # data chunk
+            buffer.write(b'data')
+            buffer.write(struct.pack('<i', self.data.nbytes))
+
+            if self.data.dtype.byteorder == '>' or (self.data.dtype.byteorder == '=' and sys.byteorder == 'big'):
+                self.data = self.data.byteswap()
+
+            buffer.write(self.data.tostring())
+            size = buffer.tell()
+            buffer.seek(4)
+            buffer.write(struct.pack('<i', size-8))
+            self.data = buffer.getvalue()
+
+    def _repr_html_(self):
+        src = """
+        <audio controls="controls" {autoplay}>
+          <source controls src="{src}" type="{type}" />
+          Your browser does not support the audio element.
+        </audio>
+        """.format(src=self.src_attr(),type=self.mimetype, autoplay=self.autoplay_attr())
+        return src
+
+    def src_attr(self):
+        if(self.data is not None):
+            return """data:{type};base64,{base64}""".format(type=self.mimetype, base64=base64.encodestring(self.data))
+        else:
+            return ""
+
+    def autoplay_attr(self):
+        if(self.autoplay):
+            return 'autoplay="autoplay"'
+        else:
+            return ''