Gecko [ v99win.today ]

Name	Size	Permission
2to3.html	63.71 KB	-rw-r--r--
__builtin__.html	11.79 KB	-rw-r--r--
__future__.html	15.58 KB	-rw-r--r--
__main__.html	8.33 KB	-rw-r--r--
_winreg.html	73.99 KB	-rw-r--r--
abc.html	26.82 KB	-rw-r--r--
aepack.html	15.47 KB	-rw-r--r--
aetools.html	18.79 KB	-rw-r--r--
aetypes.html	27.08 KB	-rw-r--r--
aifc.html	29.59 KB	-rw-r--r--
al.html	22.13 KB	-rw-r--r--
allos.html	35.48 KB	-rw-r--r--
anydbm.html	19.31 KB	-rw-r--r--
archiving.html	10.64 KB	-rw-r--r--
argparse.html	269.59 KB	-rw-r--r--
array.html	35.35 KB	-rw-r--r--
ast.html	42.42 KB	-rw-r--r--
asynchat.html	35.84 KB	-rw-r--r--
asyncore.html	43.22 KB	-rw-r--r--
atexit.html	19.23 KB	-rw-r--r--
audioop.html	41.32 KB	-rw-r--r--
autogil.html	9.77 KB	-rw-r--r--
base64.html	24.8 KB	-rw-r--r--
basehttpserver.html	40.6 KB	-rw-r--r--
bastion.html	13.02 KB	-rw-r--r--
bdb.html	50.06 KB	-rw-r--r--
binascii.html	26.64 KB	-rw-r--r--
binhex.html	12.66 KB	-rw-r--r--
bisect.html	28.52 KB	-rw-r--r--
bsddb.html	32.02 KB	-rw-r--r--
bz2.html	31.92 KB	-rw-r--r--
calendar.html	50.16 KB	-rw-r--r--
carbon.html	54.14 KB	-rw-r--r--
cd.html	35.24 KB	-rw-r--r--
cgi.html	58.4 KB	-rw-r--r--
cgihttpserver.html	15.12 KB	-rw-r--r--
cgitb.html	13.5 KB	-rw-r--r--
chunk.html	17.41 KB	-rw-r--r--
cmath.html	32.41 KB	-rw-r--r--
cmd.html	32.69 KB	-rw-r--r--
code.html	28.92 KB	-rw-r--r--
codecs.html	125.92 KB	-rw-r--r--
codeop.html	16.42 KB	-rw-r--r--
collections.html	150.36 KB	-rw-r--r--
colorpicker.html	9.02 KB	-rw-r--r--
colorsys.html	14.38 KB	-rw-r--r--
commands.html	16.63 KB	-rw-r--r--
compileall.html	21.18 KB	-rw-r--r--
compiler.html	78.14 KB	-rw-r--r--
configparser.html	73.92 KB	-rw-r--r--
constants.html	14.68 KB	-rw-r--r--
contextlib.html	22.91 KB	-rw-r--r--
cookie.html	45.38 KB	-rw-r--r--
cookielib.html	102.78 KB	-rw-r--r--
copy.html	14.21 KB	-rw-r--r--
copy_reg.html	15.82 KB	-rw-r--r--
crypt.html	11.62 KB	-rw-r--r--
crypto.html	8.35 KB	-rw-r--r--
csv.html	82.79 KB	-rw-r--r--
ctypes.html	280.57 KB	-rw-r--r--
curses.ascii.html	28.97 KB	-rw-r--r--
curses.html	200.94 KB	-rw-r--r--
curses.panel.html	18.43 KB	-rw-r--r--
custominterp.html	8.59 KB	-rw-r--r--
datatypes.html	18.84 KB	-rw-r--r--
datetime.html	261.02 KB	-rw-r--r--
dbhash.html	18.4 KB	-rw-r--r--
dbm.html	14.75 KB	-rw-r--r--
debug.html	11.28 KB	-rw-r--r--
decimal.html	239.14 KB	-rw-r--r--
development.html	15.27 KB	-rw-r--r--
difflib.html	96.93 KB	-rw-r--r--
dircache.html	13.66 KB	-rw-r--r--
dis.html	96.52 KB	-rw-r--r--
distribution.html	8.27 KB	-rw-r--r--
distutils.html	10.97 KB	-rw-r--r--
dl.html	19.27 KB	-rw-r--r--
doctest.html	193.18 KB	-rw-r--r--
docxmlrpcserver.html	20.02 KB	-rw-r--r--
dumbdbm.html	16.74 KB	-rw-r--r--
dummy_thread.html	11.04 KB	-rw-r--r--
dummy_threading.html	9.96 KB	-rw-r--r--
easydialogs.html	38.83 KB	-rw-r--r--
email-examples.html	47.2 KB	-rw-r--r--
email.charset.html	32.45 KB	-rw-r--r--
email.encoders.html	14.09 KB	-rw-r--r--
email.errors.html	19.2 KB	-rw-r--r--
email.generator.html	24.78 KB	-rw-r--r--
email.header.html	31.12 KB	-rw-r--r--
email.html	55.3 KB	-rw-r--r--
email.iterators.html	14.22 KB	-rw-r--r--
email.message.html	74.91 KB	-rw-r--r--
email.mime.html	34.51 KB	-rw-r--r--
email.parser.html	37.09 KB	-rw-r--r--
email.utils.html	30.04 KB	-rw-r--r--
ensurepip.html	20.21 KB	-rw-r--r--
errno.html	52.31 KB	-rw-r--r--
exceptions.html	73.4 KB	-rw-r--r--
fcntl.html	27.85 KB	-rw-r--r--
filecmp.html	26.49 KB	-rw-r--r--
fileformats.html	10.21 KB	-rw-r--r--
fileinput.html	29.36 KB	-rw-r--r--
filesys.html	11.55 KB	-rw-r--r--
fl.html	71.58 KB	-rw-r--r--
fm.html	15 KB	-rw-r--r--
fnmatch.html	17.78 KB	-rw-r--r--
formatter.html	43.91 KB	-rw-r--r--
fpectl.html	17.84 KB	-rw-r--r--
fpformat.html	12.65 KB	-rw-r--r--
fractions.html	27.17 KB	-rw-r--r--
framework.html	44.24 KB	-rw-r--r--
frameworks.html	8.11 KB	-rw-r--r--
ftplib.html	56.56 KB	-rw-r--r--
functions.html	216.84 KB	-rw-r--r--
functools.html	31.06 KB	-rw-r--r--
future_builtins.html	15.9 KB	-rw-r--r--
gc.html	30.74 KB	-rw-r--r--
gdbm.html	19.35 KB	-rw-r--r--
gensuitemodule.html	14.54 KB	-rw-r--r--
getopt.html	26.56 KB	-rw-r--r--
getpass.html	12.5 KB	-rw-r--r--
gettext.html	91.32 KB	-rw-r--r--
gl.html	26.71 KB	-rw-r--r--
glob.html	15.42 KB	-rw-r--r--
grp.html	12.33 KB	-rw-r--r--
gzip.html	21.95 KB	-rw-r--r--
hashlib.html	27.4 KB	-rw-r--r--
heapq.html	36.72 KB	-rw-r--r--
hmac.html	15.97 KB	-rw-r--r--
hotshot.html	22.69 KB	-rw-r--r--
htmllib.html	29.9 KB	-rw-r--r--
htmlparser.html	45.11 KB	-rw-r--r--
httplib.html	78.55 KB	-rw-r--r--
i18n.html	10.61 KB	-rw-r--r--
ic.html	22.03 KB	-rw-r--r--
idle.html	45.74 KB	-rw-r--r--
imageop.html	20.94 KB	-rw-r--r--
imaplib.html	69.9 KB	-rw-r--r--
imgfile.html	14.91 KB	-rw-r--r--
imghdr.html	13.43 KB	-rw-r--r--
imp.html	41.48 KB	-rw-r--r--
importlib.html	10.27 KB	-rw-r--r--
imputil.html	36.11 KB	-rw-r--r--
index.html	82.54 KB	-rw-r--r--
inspect.html	64.31 KB	-rw-r--r--
internet.html	26.77 KB	-rw-r--r--
intro.html	9.76 KB	-rw-r--r--
io.html	122.3 KB	-rw-r--r--
ipc.html	17.18 KB	-rw-r--r--
itertools.html	129.91 KB	-rw-r--r--
jpeg.html	15.36 KB	-rw-r--r--
json.html	79.09 KB	-rw-r--r--
keyword.html	9.27 KB	-rw-r--r--
language.html	12.35 KB	-rw-r--r--
linecache.html	12.7 KB	-rw-r--r--
locale.html	68.54 KB	-rw-r--r--
logging.config.html	82.23 KB	-rw-r--r--
logging.handlers.html	91.96 KB	-rw-r--r--
logging.html	123.15 KB	-rw-r--r--
mac.html	24.49 KB	-rw-r--r--
macos.html	18.51 KB	-rw-r--r--
macosa.html	14.55 KB	-rw-r--r--
macostools.html	19.67 KB	-rw-r--r--
macpath.html	9.19 KB	-rw-r--r--
mailbox.html	185.53 KB	-rw-r--r--
mailcap.html	15.3 KB	-rw-r--r--
markup.html	20.37 KB	-rw-r--r--
marshal.html	19.88 KB	-rw-r--r--
math.html	50.52 KB	-rw-r--r--
md5.html	16.65 KB	-rw-r--r--
mhlib.html	30.04 KB	-rw-r--r--
mimetools.html	23.84 KB	-rw-r--r--
mimetypes.html	35.82 KB	-rw-r--r--
mimewriter.html	18.19 KB	-rw-r--r--
mimify.html	16.96 KB	-rw-r--r--
miniaeframe.html	14.5 KB	-rw-r--r--
misc.html	7.77 KB	-rw-r--r--
mm.html	10.19 KB	-rw-r--r--
mmap.html	33.52 KB	-rw-r--r--
modulefinder.html	19.85 KB	-rw-r--r--
modules.html	9.68 KB	-rw-r--r--
msilib.html	72.78 KB	-rw-r--r--
msvcrt.html	24.1 KB	-rw-r--r--
multifile.html	28.82 KB	-rw-r--r--
multiprocessing.html	423.97 KB	-rw-r--r--
mutex.html	13.56 KB	-rw-r--r--
netdata.html	19.28 KB	-rw-r--r--
netrc.html	15.51 KB	-rw-r--r--
new.html	16.1 KB	-rw-r--r--
nis.html	13.19 KB	-rw-r--r--
nntplib.html	51.08 KB	-rw-r--r--
numbers.html	40.91 KB	-rw-r--r--
numeric.html	14.85 KB	-rw-r--r--
operator.html	118.32 KB	-rw-r--r--
optparse.html	251.08 KB	-rw-r--r--
os.html	270.49 KB	-rw-r--r--
os.path.html	48.87 KB	-rw-r--r--
ossaudiodev.html	49.79 KB	-rw-r--r--
othergui.html	9.98 KB	-rw-r--r--
parser.html	44.52 KB	-rw-r--r--
pdb.html	41.44 KB	-rw-r--r--
persistence.html	16.25 KB	-rw-r--r--
pickle.html	107.94 KB	-rw-r--r--
pickletools.html	13.21 KB	-rw-r--r--
pipes.html	21.85 KB	-rw-r--r--
pkgutil.html	30.59 KB	-rw-r--r--
platform.html	40.14 KB	-rw-r--r--
plistlib.html	20.96 KB	-rw-r--r--
popen2.html	30.13 KB	-rw-r--r--
poplib.html	27.93 KB	-rw-r--r--
posix.html	17.27 KB	-rw-r--r--
posixfile.html	23.68 KB	-rw-r--r--
pprint.html	36.42 KB	-rw-r--r--
profile.html	76.65 KB	-rw-r--r--
pty.html	11.42 KB	-rw-r--r--
pwd.html	13.53 KB	-rw-r--r--
py_compile.html	13.33 KB	-rw-r--r--
pyclbr.html	18.14 KB	-rw-r--r--
pydoc.html	14.33 KB	-rw-r--r--
pyexpat.html	93.28 KB	-rw-r--r--
python.html	13.53 KB	-rw-r--r--
queue.html	29.64 KB	-rw-r--r--
quopri.html	14.5 KB	-rw-r--r--
random.html	47.78 KB	-rw-r--r--
re.html	163.11 KB	-rw-r--r--
readline.html	41.2 KB	-rw-r--r--
repr.html	24.57 KB	-rw-r--r--
resource.html	30.86 KB	-rw-r--r--
restricted.html	12.69 KB	-rw-r--r--
rexec.html	43.59 KB	-rw-r--r--
rfc822.html	51.25 KB	-rw-r--r--
rlcompleter.html	15.29 KB	-rw-r--r--
robotparser.html	15.01 KB	-rw-r--r--
runpy.html	23.55 KB	-rw-r--r--
sched.html	21.76 KB	-rw-r--r--
scrolledtext.html	10.67 KB	-rw-r--r--
select.html	50.17 KB	-rw-r--r--
sets.html	39.92 KB	-rw-r--r--
sgi.html	11.09 KB	-rw-r--r--
sgmllib.html	38.77 KB	-rw-r--r--
sha.html	14.55 KB	-rw-r--r--
shelve.html	32.93 KB	-rw-r--r--
shlex.html	38.43 KB	-rw-r--r--
shutil.html	49.49 KB	-rw-r--r--
signal.html	36.52 KB	-rw-r--r--
simplehttpserver.html	21.57 KB	-rw-r--r--
simplexmlrpcserver.html	40.41 KB	-rw-r--r--
site.html	29 KB	-rw-r--r--
smtpd.html	15.64 KB	-rw-r--r--
smtplib.html	51.86 KB	-rw-r--r--
sndhdr.html	12.05 KB	-rw-r--r--
socket.html	126.94 KB	-rw-r--r--
socketserver.html	81.38 KB	-rw-r--r--
someos.html	17.09 KB	-rw-r--r--
spwd.html	12.25 KB	-rw-r--r--
sqlite3.html	154.12 KB	-rw-r--r--
ssl.html	214.5 KB	-rw-r--r--
stat.html	41.11 KB	-rw-r--r--
statvfs.html	13.24 KB	-rw-r--r--
stdtypes.html	309.83 KB	-rw-r--r--
string.html	129.58 KB	-rw-r--r--
stringio.html	21.1 KB	-rw-r--r--
stringprep.html	21.4 KB	-rw-r--r--
strings.html	16.42 KB	-rw-r--r--
struct.html	47.68 KB	-rw-r--r--
subprocess.html	117 KB	-rw-r--r--
sun.html	7.83 KB	-rw-r--r--
sunau.html	35.43 KB	-rw-r--r--
sunaudio.html	21.05 KB	-rw-r--r--
symbol.html	9.06 KB	-rw-r--r--
symtable.html	29.03 KB	-rw-r--r--
sys.html	118.12 KB	-rw-r--r--
sysconfig.html	28.8 KB	-rw-r--r--
syslog.html	21.29 KB	-rw-r--r--
tabnanny.html	12.78 KB	-rw-r--r--
tarfile.html	99.54 KB	-rw-r--r--
telnetlib.html	30.46 KB	-rw-r--r--
tempfile.html	35.02 KB	-rw-r--r--
termios.html	19.22 KB	-rw-r--r--
test.html	61.42 KB	-rw-r--r--
textwrap.html	32.28 KB	-rw-r--r--
thread.html	22.67 KB	-rw-r--r--
threading.html	92.04 KB	-rw-r--r--
time.html	65.55 KB	-rw-r--r--
timeit.html	44.38 KB	-rw-r--r--
tix.html	56.73 KB	-rw-r--r--
tk.html	26.76 KB	-rw-r--r--
tkinter.html	86.67 KB	-rw-r--r--
token.html	27.31 KB	-rw-r--r--
tokenize.html	21.69 KB	-rw-r--r--
trace.html	33.91 KB	-rw-r--r--
traceback.html	44.22 KB	-rw-r--r--
ttk.html	123.83 KB	-rw-r--r--
tty.html	10.95 KB	-rw-r--r--
turtle.html	246.17 KB	-rw-r--r--
types.html	33.66 KB	-rw-r--r--
undoc.html	25.54 KB	-rw-r--r--
unicodedata.html	22.64 KB	-rw-r--r--
unittest.html	246.75 KB	-rw-r--r--
unix.html	11.9 KB	-rw-r--r--
urllib.html	71.61 KB	-rw-r--r--
urllib2.html	128.77 KB	-rw-r--r--
urlparse.html	49.04 KB	-rw-r--r--
user.html	13.41 KB	-rw-r--r--
userdict.html	32.96 KB	-rw-r--r--
uu.html	13.25 KB	-rw-r--r--
uuid.html	33.55 KB	-rw-r--r--
warnings.html	51.86 KB	-rw-r--r--
wave.html	29.08 KB	-rw-r--r--
weakref.html	41.14 KB	-rw-r--r--
webbrowser.html	29.53 KB	-rw-r--r--
whichdb.html	10.44 KB	-rw-r--r--
windows.html	10.37 KB	-rw-r--r--
winsound.html	22.56 KB	-rw-r--r--
wsgiref.html	94.38 KB	-rw-r--r--
xdrlib.html	38.05 KB	-rw-r--r--
xml.dom.html	110.39 KB	-rw-r--r--
xml.dom.minidom.html	45.23 KB	-rw-r--r--
xml.dom.pulldom.html	16.32 KB	-rw-r--r--
xml.etree.elementtree.html	124.2 KB	-rw-r--r--
xml.html	18.76 KB	-rw-r--r--
xml.sax.handler.html	47.5 KB	-rw-r--r--
xml.sax.html	26.04 KB	-rw-r--r--
xml.sax.reader.html	51.4 KB	-rw-r--r--
xml.sax.utils.html	18.11 KB	-rw-r--r--
xmlrpclib.html	71.79 KB	-rw-r--r--
zipfile.html	67.26 KB	-rw-r--r--
zipimport.html	24.32 KB	-rw-r--r--
zlib.html	34.41 KB	-rw-r--r--

Code Editor : audioop.html

<!DOCTYPE html>

<title>21.1. audioop — Manipulate raw audio data &#8212; Python 2.7.18 documentation</title>
 <link rel="stylesheet" type="text/css" href="../_static/pygments.css" />
 <link rel="stylesheet" type="text/css" href="../_static/classic.css" />
 
 <script data-url_root="../" id="documentation_options" src="../_static/documentation_options.js"></script>
 <script src="../_static/jquery.js"></script>
 <script src="../_static/underscore.js"></script>
 <script src="../_static/doctools.js"></script>
 
 <script src="../_static/sidebar.js"></script>
 
 <link rel="search" type="application/opensearchdescription+xml"
 title="Search within Python 2.7.18 documentation"
 href="../_static/opensearch.xml"/>
 <link rel="author" title="About these documents" href="../about.html" />
 <link rel="index" title="Index" href="../genindex.html" />
 <link rel="search" title="Search" href="../search.html" />
 <link rel="copyright" title="Copyright" href="../copyright.html" />
 <link rel="next" title="21.2. imageop — Manipulate raw image data" href="imageop.html" />
 <link rel="prev" title="21. Multimedia Services" href="mm.html" />
 <link rel="shortcut icon" type="image/png" href="../_static/py.png" />
 <link rel="canonical" href="file:///usr/share/doc/python2.7/html/library/audioop.html" />
 <script type="text/javascript" src="../_static/copybutton.js"></script>

</head><body>
<div id="outdated-warning" style="padding: .5em; text-align: center; background-color: #FFBABA; color: #6A0E0E;">
 This document is for an old version of Python that is <a href="https://devguide.python.org/devcycle/#end-of-life-branches">no longer supported</a>.
 You should install the python3 and python3-doc packages and read the 
 <a href="file:///usr/share/doc/python3-doc/html/library/audioop.html"> Python documentation for the Python3 version packaged in this release</a>.
</div>
 
 <div class="related" role="navigation" aria-label="related navigation">
 <h3>Navigation</h3>
 <ul>
 <li class="right" style="margin-right: 10px">
 <a href="../genindex.html" title="General Index"
 accesskey="I">index</a></li>
 <li class="right" >
 <a href="../py-modindex.html" title="Python Module Index"
 >modules</a> |</li>
 <li class="right" >
 <a href="imageop.html" title="21.2. imageop — Manipulate raw image data"
 accesskey="N">next</a> |</li>
 <li class="right" >
 <a href="mm.html" title="21. Multimedia Services"
 accesskey="P">previous</a> |</li>
 <li><img src="../_static/py.png" alt=""
 style="vertical-align: middle; margin-top: -1px"/></li>
 <li><a href="https://www.python.org/">Python</a> &#187;</li>
 <li>
 <a href="../index.html">Python 2.7.18 documentation</a> &#187;
 </li>

<li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
 <li class="nav-item nav-item-2"><a href="mm.html" accesskey="U">21. Multimedia Services</a> &#187;</li>
 <li class="nav-item nav-item-this"><a href="">21.1. <code class="xref py py-mod docutils literal notranslate">audioop</code> — Manipulate raw audio data</a></li> 
 </ul>
 </div>

<div class="document">
 <div class="documentwrapper">
 <div class="bodywrapper">
 <div class="body" role="main">
 
 <section id="module-audioop">
<h1>21.1. <a class="reference internal" href="#module-audioop" title="audioop: Manipulate raw audio data."><code class="xref py py-mod docutils literal notranslate">audioop</code></a> — Manipulate raw audio data<a class="headerlink" href="#module-audioop" title="Permalink to this headline">¶</a></h1>
The <a class="reference internal" href="#module-audioop" title="audioop: Manipulate raw audio data."><code class="xref py py-mod docutils literal notranslate">audioop</code></a> module contains some useful operations on sound fragments.
It operates on sound fragments consisting of signed integer samples 8, 16 or 32
bits wide, stored in Python strings. This is the same format as used by the
<a class="reference internal" href="al.html#module-al" title="al: Audio functions on the SGI. (deprecated) (IRIX)"><code class="xref py py-mod docutils literal notranslate">al</code></a> and <a class="reference internal" href="sunaudio.html#module-sunaudiodev" title="sunaudiodev: Access to Sun audio hardware. (deprecated) (SunOS)"><code class="xref py py-mod docutils literal notranslate">sunaudiodev</code></a> modules. All scalar items are integers, unless
specified otherwise.
This module provides support for a-LAW, u-LAW and Intel/DVI ADPCM encodings.
A few of the more complicated operations only take 16-bit samples, otherwise the
sample size (in bytes) is always a parameter of the operation.
The module defines the following variables and functions:
<dl class="py exception">
<dt class="sig sig-object py" id="audioop.error">
exception audioop.error<a class="headerlink" href="#audioop.error" title="Permalink to this definition">¶</a></dt>
<dd>This exception is raised on all errors, such as unknown number of bytes per
sample, etc.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.add">
audioop.add(fragment1, fragment2, width)<a class="headerlink" href="#audioop.add" title="Permalink to this definition">¶</a></dt>
<dd>Return a fragment which is the addition of the two samples passed as parameters.
width is the sample width in bytes, either <code class="docutils literal notranslate">1</code>, <code class="docutils literal notranslate">2</code> or <code class="docutils literal notranslate">4</code>. Both
fragments should have the same length. Samples are truncated in case of overflow.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.adpcm2lin">
audioop.adpcm2lin(adpcmfragment, width, state)<a class="headerlink" href="#audioop.adpcm2lin" title="Permalink to this definition">¶</a></dt>
<dd>Decode an Intel/DVI ADPCM coded fragment to a linear fragment. See the
description of <a class="reference internal" href="#audioop.lin2adpcm" title="audioop.lin2adpcm"><code class="xref py py-func docutils literal notranslate">lin2adpcm()</code></a> for details on ADPCM coding. Return a tuple
<code class="docutils literal notranslate">(sample, newstate)</code> where the sample has the width specified in width.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.alaw2lin">
audioop.alaw2lin(fragment, width)<a class="headerlink" href="#audioop.alaw2lin" title="Permalink to this definition">¶</a></dt>
<dd>Convert sound fragments in a-LAW encoding to linearly encoded sound fragments.
a-LAW encoding always uses 8 bits samples, so width refers only to the sample
width of the output fragment here.
<div class="versionadded">
New in version 2.5.
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.avg">
audioop.avg(fragment, width)<a class="headerlink" href="#audioop.avg" title="Permalink to this definition">¶</a></dt>
<dd>Return the average over all samples in the fragment.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.avgpp">
audioop.avgpp(fragment, width)<a class="headerlink" href="#audioop.avgpp" title="Permalink to this definition">¶</a></dt>
<dd>Return the average peak-peak value over all samples in the fragment. No
filtering is done, so the usefulness of this routine is questionable.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.bias">
audioop.bias(fragment, width, bias)<a class="headerlink" href="#audioop.bias" title="Permalink to this definition">¶</a></dt>
<dd>Return a fragment that is the original fragment with a bias added to each
sample. Samples wrap around in case of overflow.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.cross">
audioop.cross(fragment, width)<a class="headerlink" href="#audioop.cross" title="Permalink to this definition">¶</a></dt>
<dd>Return the number of zero crossings in the fragment passed as an argument.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.findfactor">
audioop.findfactor(fragment, reference)<a class="headerlink" href="#audioop.findfactor" title="Permalink to this definition">¶</a></dt>
<dd>Return a factor F such that <code class="docutils literal notranslate">rms(add(fragment, mul(reference, -F)))</code> is
minimal, i.e., return the factor with which you should multiply reference to
make it match as well as possible to fragment. The fragments should both
contain 2-byte samples.
The time taken by this routine is proportional to <code class="docutils literal notranslate">len(fragment)</code>.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.findfit">
audioop.findfit(fragment, reference)<a class="headerlink" href="#audioop.findfit" title="Permalink to this definition">¶</a></dt>
<dd>Try to match reference as well as possible to a portion of fragment (which
should be the longer fragment). This is (conceptually) done by taking slices
out of fragment, using <a class="reference internal" href="#audioop.findfactor" title="audioop.findfactor"><code class="xref py py-func docutils literal notranslate">findfactor()</code></a> to compute the best match, and
minimizing the result. The fragments should both contain 2-byte samples.
Return a tuple <code class="docutils literal notranslate">(offset, factor)</code> where offset is the (integer) offset into
fragment where the optimal match started and factor is the (floating-point)
factor as per <a class="reference internal" href="#audioop.findfactor" title="audioop.findfactor"><code class="xref py py-func docutils literal notranslate">findfactor()</code></a>.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.findmax">
audioop.findmax(fragment, length)<a class="headerlink" href="#audioop.findmax" title="Permalink to this definition">¶</a></dt>
<dd>Search fragment for a slice of length length samples (not bytes!) with
maximum energy, i.e., return i for which <code class="docutils literal notranslate">rms(fragment[i*2:(i+length)*2])</code>
is maximal. The fragments should both contain 2-byte samples.
The routine takes time proportional to <code class="docutils literal notranslate">len(fragment)</code>.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.getsample">
audioop.getsample(fragment, width, index)<a class="headerlink" href="#audioop.getsample" title="Permalink to this definition">¶</a></dt>
<dd>Return the value of sample index from the fragment.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.lin2adpcm">
audioop.lin2adpcm(fragment, width, state)<a class="headerlink" href="#audioop.lin2adpcm" title="Permalink to this definition">¶</a></dt>
<dd>Convert samples to 4 bit Intel/DVI ADPCM encoding. ADPCM coding is an adaptive
coding scheme, whereby each 4 bit number is the difference between one sample
and the next, divided by a (varying) step. The Intel/DVI ADPCM algorithm has
been selected for use by the IMA, so it may well become a standard.
state is a tuple containing the state of the coder. The coder returns a tuple
<code class="docutils literal notranslate">(adpcmfrag, newstate)</code>, and the newstate should be passed to the next call
of <a class="reference internal" href="#audioop.lin2adpcm" title="audioop.lin2adpcm"><code class="xref py py-func docutils literal notranslate">lin2adpcm()</code></a>. In the initial call, <code class="docutils literal notranslate">None</code> can be passed as the state.
adpcmfrag is the ADPCM coded fragment packed 2 4-bit values per byte.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.lin2alaw">
audioop.lin2alaw(fragment, width)<a class="headerlink" href="#audioop.lin2alaw" title="Permalink to this definition">¶</a></dt>
<dd>Convert samples in the audio fragment to a-LAW encoding and return this as a
Python string. a-LAW is an audio encoding format whereby you get a dynamic
range of about 13 bits using only 8 bit samples. It is used by the Sun audio
hardware, among others.
<div class="versionadded">
New in version 2.5.
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.lin2lin">
audioop.lin2lin(fragment, width, newwidth)<a class="headerlink" href="#audioop.lin2lin" title="Permalink to this definition">¶</a></dt>
<dd>Convert samples between 1-, 2- and 4-byte formats.
<div class="admonition note">
Note
In some audio formats, such as .WAV files, 16 and 32 bit samples are
signed, but 8 bit samples are unsigned. So when converting to 8 bit wide
samples for these formats, you need to also add 128 to the result:
<div class="highlight-default notranslate"><div class="highlight"><pre>new_frames = audioop.lin2lin(frames, old_width, 1)
new_frames = audioop.bias(new_frames, 1, 128)
</pre></div>
</div>
The same, in reverse, has to be applied when converting from 8 to 16 or 32
bit width samples.
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.lin2ulaw">
audioop.lin2ulaw(fragment, width)<a class="headerlink" href="#audioop.lin2ulaw" title="Permalink to this definition">¶</a></dt>
<dd>Convert samples in the audio fragment to u-LAW encoding and return this as a
Python string. u-LAW is an audio encoding format whereby you get a dynamic
range of about 14 bits using only 8 bit samples. It is used by the Sun audio
hardware, among others.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.max">
audioop.max(fragment, width)<a class="headerlink" href="#audioop.max" title="Permalink to this definition">¶</a></dt>
<dd>Return the maximum of the absolute value of all samples in a fragment.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.maxpp">
audioop.maxpp(fragment, width)<a class="headerlink" href="#audioop.maxpp" title="Permalink to this definition">¶</a></dt>
<dd>Return the maximum peak-peak value in the sound fragment.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.minmax">
audioop.minmax(fragment, width)<a class="headerlink" href="#audioop.minmax" title="Permalink to this definition">¶</a></dt>
<dd>Return a tuple consisting of the minimum and maximum values of all samples in
the sound fragment.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.mul">
audioop.mul(fragment, width, factor)<a class="headerlink" href="#audioop.mul" title="Permalink to this definition">¶</a></dt>
<dd>Return a fragment that has all samples in the original fragment multiplied by
the floating-point value factor. Samples are truncated in case of overflow.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.ratecv">
audioop.ratecv(fragment, width, nchannels, inrate, outrate, state[, weightA[, weightB]])<a class="headerlink" href="#audioop.ratecv" title="Permalink to this definition">¶</a></dt>
<dd>Convert the frame rate of the input fragment.
state is a tuple containing the state of the converter. The converter returns
a tuple <code class="docutils literal notranslate">(newfragment, newstate)</code>, and newstate should be passed to the next
call of <a class="reference internal" href="#audioop.ratecv" title="audioop.ratecv"><code class="xref py py-func docutils literal notranslate">ratecv()</code></a>. The initial call should pass <code class="docutils literal notranslate">None</code> as the state.
The weightA and weightB arguments are parameters for a simple digital filter
and default to <code class="docutils literal notranslate">1</code> and <code class="docutils literal notranslate">0</code> respectively.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.reverse">
audioop.reverse(fragment, width)<a class="headerlink" href="#audioop.reverse" title="Permalink to this definition">¶</a></dt>
<dd>Reverse the samples in a fragment and returns the modified fragment.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.rms">
audioop.rms(fragment, width)<a class="headerlink" href="#audioop.rms" title="Permalink to this definition">¶</a></dt>
<dd>Return the root-mean-square of the fragment, i.e. <code class="docutils literal notranslate">sqrt(sum(S_i^2)/n)</code>.
This is a measure of the power in an audio signal.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.tomono">
audioop.tomono(fragment, width, lfactor, rfactor)<a class="headerlink" href="#audioop.tomono" title="Permalink to this definition">¶</a></dt>
<dd>Convert a stereo fragment to a mono fragment. The left channel is multiplied by
lfactor and the right channel by rfactor before adding the two channels to
give a mono signal.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.tostereo">
audioop.tostereo(fragment, width, lfactor, rfactor)<a class="headerlink" href="#audioop.tostereo" title="Permalink to this definition">¶</a></dt>
<dd>Generate a stereo fragment from a mono fragment. Each pair of samples in the
stereo fragment are computed from the mono sample, whereby left channel samples
are multiplied by lfactor and right channel samples by rfactor.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="audioop.ulaw2lin">
audioop.ulaw2lin(fragment, width)<a class="headerlink" href="#audioop.ulaw2lin" title="Permalink to this definition">¶</a></dt>
<dd>Convert sound fragments in u-LAW encoding to linearly encoded sound fragments.
u-LAW encoding always uses 8 bits samples, so width refers only to the sample
width of the output fragment here.
</dd></dl>

Note that operations such as <a class="reference internal" href="#audioop.mul" title="audioop.mul"><code class="xref py py-func docutils literal notranslate">mul()</code></a> or <a class="reference internal" href="#audioop.max" title="audioop.max"><code class="xref py py-func docutils literal notranslate">max()</code></a> make no distinction
between mono and stereo fragments, i.e. all samples are treated equal. If this
is a problem the stereo fragment should be split into two mono fragments first
and recombined later. Here is an example of how to do that:
<div class="highlight-default notranslate"><div class="highlight"><pre>def mul_stereo(sample, width, lfactor, rfactor):
 lsample = audioop.tomono(sample, width, 1, 0)
 rsample = audioop.tomono(sample, width, 0, 1)
 lsample = audioop.mul(lsample, width, lfactor)
 rsample = audioop.mul(rsample, width, rfactor)
 lsample = audioop.tostereo(lsample, width, 1, 0)
 rsample = audioop.tostereo(rsample, width, 0, 1)
 return audioop.add(lsample, rsample, width)
</pre></div>
</div>
If you use the ADPCM coder to build network packets and you want your protocol
to be stateless (i.e. to be able to tolerate packet loss) you should not only
transmit the data but also the state. Note that you should send the initial
state (the one you passed to <a class="reference internal" href="#audioop.lin2adpcm" title="audioop.lin2adpcm"><code class="xref py py-func docutils literal notranslate">lin2adpcm()</code></a>) along to the decoder, not the
final state (as returned by the coder). If you want to use
<a class="reference internal" href="struct.html#struct.Struct" title="struct.Struct"><code class="xref py py-class docutils literal notranslate">struct.Struct</code></a> to store the state in binary you can code the first
element (the predicted value) in 16 bits and the second (the delta index) in 8.
The ADPCM coders have never been tried against other ADPCM coders, only against
themselves. It could well be that I misinterpreted the standards in which case
they will not be interoperable with the respective standards.
The <code class="xref py py-func docutils literal notranslate">find*()</code> routines might look a bit funny at first sight. They are
primarily meant to do echo cancellation. A reasonably fast way to do this is to
pick the most energetic piece of the output sample, locate that in the input
sample and subtract the whole output sample from the input sample:
<div class="highlight-default notranslate"><div class="highlight"><pre>def echocancel(outputdata, inputdata):
 pos = audioop.findmax(outputdata, 800) # one tenth second
 out_test = outputdata[pos*2:]
 in_test = inputdata[pos*2:]
 ipos, factor = audioop.findfit(in_test, out_test)
 # Optional (for better cancellation):
 # factor = audioop.findfactor(in_test[ipos*2:ipos*2+len(out_test)],
 # out_test)
 prefill = &#39;\0&#39;*(pos+ipos)*2
 postfill = &#39;\0&#39;*(len(inputdata)-len(prefill)-len(outputdata))
 outputdata = prefill + audioop.mul(outputdata, 2, -factor) + postfill
 return audioop.add(inputdata, outputdata, 2)
</pre></div>
</div>
</section>

<div class="clearer"></div>
 </div>
 </div>
 </div>
 <div class="sphinxsidebar" role="navigation" aria-label="main navigation">
 <div class="sphinxsidebarwrapper">
 <h4>Previous topic</h4>
 <a href="mm.html"
 title="previous chapter">21. Multimedia Services</a>
 <h4>Next topic</h4>
 <a href="imageop.html"
 title="next chapter">21.2. <code class="xref py py-mod docutils literal notranslate">imageop</code> — Manipulate raw image data</a>
 <div role="note" aria-label="source link">
 <h3>This Page</h3>
 <ul class="this-page-menu">
 <li><a href="../_sources/library/audioop.rst.txt"
 rel="nofollow">Show Source</a></li>
 </ul>
 </div>
<div id="searchbox" style="display: none" role="search">
 <h3 id="searchlabel">Quick search</h3>
 <div class="searchformwrapper">
 <form class="search" action="../search.html" method="get">
 <input type="text" name="q" aria-labelledby="searchlabel" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false"/>
 <input type="submit" value="Go" />
 </form>
 </div>
</div>
<script>$('#searchbox').show(0);</script>
 </div>
 </div>
 <div class="clearer"></div>
 </div> 
 <div class="related" role="navigation" aria-label="related navigation">
 <h3>Navigation</h3>
 <ul>
 <li class="right" style="margin-right: 10px">
 <a href="../genindex.html" title="General Index"
 >index</a></li>
 <li class="right" >
 <a href="../py-modindex.html" title="Python Module Index"
 >modules</a> |</li>
 <li class="right" >
 <a href="imageop.html" title="21.2. imageop — Manipulate raw image data"
 >next</a> |</li>
 <li class="right" >
 <a href="mm.html" title="21. Multimedia Services"
 >previous</a> |</li>
 <li><img src="../_static/py.png" alt=""
 style="vertical-align: middle; margin-top: -1px"/></li>
 <li><a href="https://www.python.org/">Python</a> &#187;</li>
 <li>
 <a href="../index.html">Python 2.7.18 documentation</a> &#187;
 </li>

<li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
 <li class="nav-item nav-item-2"><a href="mm.html" >21. Multimedia Services</a> &#187;</li>
 <li class="nav-item nav-item-this"><a href="">21.1. <code class="xref py py-mod docutils literal notranslate">audioop</code> — Manipulate raw audio data</a></li> 
 </ul>
 </div> 
 <div class="footer">
 &copy; <a href="../copyright.html">Copyright</a> 1990-2024, Python Software Foundation.
 
 The Python Software Foundation is a non-profit corporation.
 <a href="https://www.python.org/psf/donations/">Please donate.</a>
 
 Last updated on December 09, 2024.
 <a href="../bugs.html">Found a bug</a>?
 
 Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 4.3.2.
 </div>

</body>
</html>

${this.title}

Code Editor : audioop.html