9. 多媒体相关模块
9. 多媒体相关模块
"Wot? No quote?"
- Guido van Rossum
9.1. 概览
Python 提供了一些用于处理图片和音频文件的模块.
另请参阅 Pythonware Image Library ( PIL , http://www.pythonware.com/products/pil/ ), 以及 PythonWare Sound Toolkit (PST , http://www.pythonware.com/products/pst/ ).
译注: 别参阅 PST 了, 废了, 用 pymedia 代替吧.
9.2. imghdr 模块
imghdr 模块可识别不同格式的图片文件. 当前版本可以识别 bmp , gif , jpeg , pbm , pgm , png , ppm ,rast (Sun raster), rgb (SGI), tiff , 以及 xbm 图像. 如 Example 9-1 所示.
9.2.0.1. Example 9-1. 使用 imghdr 模块
File: imghdr-example-1.py
import imghdr
result = imghdr.what("samples/sample.jpg")
if result:
print "file format:", result
else:
print "cannot identify file"
file format: jpeg
# 使用 PIL
import Image
im = Image.open("samples/sample.jpg")
print im.format, im.mode, im.size
9.3. sndhdr 模块
sndhdr 模块, 可来识别不同的音频文件格式, 并提取文件内容相关信息. 如 Example 9-2 所示.
执行成功后, what 函数将返回一个由文件类型, 采样频率, 声道数, 音轨数和每个采样点位数组成的元组. 具体含义请参考 help(sndhdr) .
9.3.0.1. Example 9-2. 使用 sndhdr 模块
File: sndhdr-example-1.py
import sndhdr
result = sndhdr.what("samples/sample.wav")
if result:
print "file format:", result
else:
print "cannot identify file"
file format: ('wav', 44100, 1, -1, 16)
9.4. whatsound 模块
(已废弃) whatsound 是 sndhdr 模块的一个别名. 如 Example 9-3 所示.
9.4.0.1. Example 9-3. 使用 whatsound 模块
File: whatsound-example-1.py
import whatsound # same as sndhdr
result = whatsound.what("samples/sample.wav")
if result:
print "file format:", result
else:
print "cannot identify file"
file format: ('wav', 44100, 1, -1, 16)
9.5. aifc 模块
aifc 模块用于读写 AIFF 和 AIFC 音频文件(在 SGI 和 Macintosh 的计算机上使用). 如 Example 9-4 所示.
9.5.0.1. Example 9-4. 使用 aifc 模块
File: SimpleAsyncHTTP.py
import asyncore
import string, socket
import StringIO
import mimetools, urlparse
class AsyncHTTP(asyncore.dispatcher_with_send):
# HTTP requestor
def _ _init_ _(self, uri, consumer):
asyncore.dispatcher_with_send._ _init_ _(self)
self.uri = uri
self.consumer = consumer
# turn the uri into a valid request
scheme, host, path, params, query, fragment = urlparse.urlparse(uri)
assert scheme == "http", "only supports HTTP requests"
try:
host, port = string.split(host, ":", 1)
port = int(port)
except (TypeError, ValueError):
port = 80 # default port
if not path:
path = "/"
if params:
path = path + ";" + params
if query:
path = path + "?" + query
self.request = "GET %s HTTP/1.0/r/nHost: %s/r/n/r/n" % (path, host)
self.host = host
self.port = port
self.status = None
self.header = None
self.data = ""
# get things going!
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
self.connect((host, port))
def handle_connect(self):
# connection succeeded
self.send(self.request)
def handle_expt(self):
# connection failed; notify consumer (status is None)
self.close()
try:
http_header = self.consumer.http_header
except AttributeError:
pass
else:
http_header(self)
def handle_read(self):
data = self.recv(2048)
if not self.header:
self.data = self.data + data
try:
i = string.index(self.data, "/r/n/r/n")
except ValueError:
return # continue
else:
# parse header
fp = StringIO.StringIO(self.data[:i+4])
# status line is "HTTP/version status message"
status = fp.readline()
self.status = string.split(status, " ", 2)
# followed by a rfc822-style message header
self.header = mimetools.Message(fp)
# followed by a newline, and the payload (if any)
data = self.data[i+4:]
self.data = ""
# notify consumer (status is non-zero)
try:
http_header = self.consumer.http_header
except AttributeError:
pass
else:
http_header(self)
if not self.connected:
return # channel was closed by consumer
self.consumer.feed(data)
def handle_close(self):
self.consumer.close()
self.close()
9.6. sunau 模块
sunau 模块用于读写 Sun AU 音频文件. 如 Example 9-5 所示.
9.6.0.1. Example 9-5. 使用 sunau 模块
File: sunau-example-1.py
import sunau
w = sunau.open("samples/sample.au", "r")
if w.getnchannels() == 1:
print "mono,",
else:
print "stereo,",
print w.getsampwidth()*8, "bits,",
print w.getframerate(), "Hz sampling rate"
mono, 16 bits, 8012 Hz sampling rate
9.7. sunaudio 模块
sunaudio 模块用于识别 Sun AU 音频文件, 并提取其基本信息. sunau 模块为 Sun AU 文件提供了更完成的支持. 如 Example 9-6 所示
9.7.0.1. Example 9-6. 使用 sunaudio 模块
File: sunaudio-example-1.py
import sunaudio
file = "samples/sample.au"
print sunaudio.gethdr(open(file, "rb"))
(6761, 1, 8012, 1, 'sample.au')
9.8. wave 模块
wave 模块用于读写 Microsoft WAV 音频文件, 如 Example 9-7 所示.
9.8.0.1. Example 9-7. 使用 wave 模块
File: wave-example-1.py
import wave
w = wave.open("samples/sample.wav", "r")
if w.getnchannels() == 1:
print "mono,",
else:
print "stereo,",
print w.getsampwidth()*8, "bits,",
print w.getframerate(), "Hz sampling rate"
mono, 16 bits, 44100 Hz sampling rate
9.9. audiodev 模块
(只用于 Unix) audiodev 为 Sun 和 SGI 计算机提供了音频播放支持. 如 Example 9-8 所示.
9.9.0.1. Example 9-8. 使用 audiodev 模块
File: audiodev-example-1.py
import audiodev
import aifc
sound = aifc.open("samples/sample.aiff", "r")
player = audiodev.AudioDev()
player.setoutrate(sound.getframerate())
player.setsampwidth(sound.getsampwidth())
player.setnchannels(sound.getnchannels())
bytes_per_frame = sound.getsampwidth() * sound.getnchannels()
bytes_per_second = sound.getframerate() * bytes_per_frame
while 1:
data = sound.readframes(bytes_per_second)
if not data:
break
player.writeframes(data)
player.wait()
9.10. winsound 模块
(只用于 Windows ) winsound 模块允许你在 Winodws 平台上播放 Wave 文件. 如 Example 9-9 所示.
9.10.0.1. Example 9-9. 使用 winsound 模块
File: winsound-example-1.py
import winsound
file = "samples/sample.wav"
winsound.PlaySound(
file,
winsound.SND_FILENAME|winsound.SND_NOWAIT,
)
flag 变量说明:
- SND_FILENAME - sound 是一个 wav 文件名
- SND_ALIAS - sound 是一个注册表中指定的别名
- SND_LOOP - 重复播放直到下一次 PlaySound ; 必须指定 SND_ASYNC
- SND_MEMORY - sound 是一个 wav 文件的内存映像
- SND_PURGE - 停止指定 sound 的所有实例
- SND_ASYNC - 异步播放声音, 声音开始播放后函数立即返回
- SND_NODEFAULT - 找不到 sound 时不播放默认的 beep 声音
- SND_NOSTOP - 不打断当前播放中的任何 sound
- SND_NOWAIT - sound 驱动忙时立即返回
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