Web   ·   Wiki   ·   Activities   ·   Blog   ·   Lists   ·   Chat   ·   Meeting   ·   Bugs   ·   Git   ·   Translate   ·   Archive   ·   People   ·   Donate
summaryrefslogtreecommitdiffstats
path: root/arch_src/pyalsaaudio-0.2/doc/node7.html
diff options
context:
space:
mode:
Diffstat (limited to 'arch_src/pyalsaaudio-0.2/doc/node7.html')
-rw-r--r--arch_src/pyalsaaudio-0.2/doc/node7.html169
1 files changed, 0 insertions, 169 deletions
diff --git a/arch_src/pyalsaaudio-0.2/doc/node7.html b/arch_src/pyalsaaudio-0.2/doc/node7.html
deleted file mode 100644
index f58333a..0000000
--- a/arch_src/pyalsaaudio-0.2/doc/node7.html
+++ /dev/null
@@ -1,169 +0,0 @@
-<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
-<html>
-<head>
-<link rel="STYLESHEET" href="pyalsaaudio.css" type='text/css' />
-<link rel="first" href="pyalsaaudio.html" title='PyAlsaAudio' />
-<link rel='contents' href='contents.html' title="Contents" />
-<link rel='last' href='about.html' title='About this document...' />
-<link rel='help' href='about.html' title='About this document...' />
-<link rel="next" href="pcm-objects.html" />
-<link rel="prev" href="module-alsaaudio.html" />
-<link rel="parent" href="module-alsaaudio.html" />
-<link rel="next" href="pcm-objects.html" />
-<meta name='aesop' content='information' />
-<title>4.1 PCM Terminology and Concepts</title>
-</head>
-<body>
-<DIV CLASS="navigation">
-<div id='top-navigation-panel' xml:id='top-navigation-panel'>
-<table align="center" width="100%" cellpadding="0" cellspacing="2">
-<tr>
-<td class='online-navigation'><a rel="prev" title="4 alsaaudio"
- href="module-alsaaudio.html"><img src='previous.png'
- border='0' height='32' alt='Previous Page' width='32' /></A></td>
-<td class='online-navigation'><a rel="parent" title="4 alsaaudio"
- href="module-alsaaudio.html"><img src='up.png'
- border='0' height='32' alt='Up One Level' width='32' /></A></td>
-<td class='online-navigation'><a rel="next" title="4.2 PCM Objects"
- href="pcm-objects.html"><img src='next.png'
- border='0' height='32' alt='Next Page' width='32' /></A></td>
-<td align="center" width="100%">PyAlsaAudio</td>
-<td class='online-navigation'><a rel="contents" title="Table of Contents"
- href="contents.html"><img src='contents.png'
- border='0' height='32' alt='Contents' width='32' /></A></td>
-<td class='online-navigation'><img src='blank.png'
- border='0' height='32' alt='' width='32' /></td>
-<td class='online-navigation'><img src='blank.png'
- border='0' height='32' alt='' width='32' /></td>
-</tr></table>
-<div class='online-navigation'>
-<b class="navlabel">Previous:</b>
-<a class="sectref" rel="prev" href="module-alsaaudio.html">4 alsaaudio</A>
-<b class="navlabel">Up:</b>
-<a class="sectref" rel="parent" href="module-alsaaudio.html">4 alsaaudio</A>
-<b class="navlabel">Next:</b>
-<a class="sectref" rel="next" href="pcm-objects.html">4.2 PCM Objects</A>
-</div>
-<hr /></div>
-</DIV>
-<!--End of Navigation Panel-->
-
-<H2><A NAME="SECTION002410000000000000000">
-4.1 PCM Terminology and Concepts</A>
-</H2>
-
-<P>
-In order to use PCM devices it is useful to be familiar with some concepts and
-terminology.
-
-<P>
-<DL>
-<DT><STRONG>Sample</STRONG></DT>
-<DD>PCM audio, whether it is input or output, consists at the lowest level
-of a number of single samples. A sample represents the sound in a single channel in
-a brief interval. If more than one channel is in use, more than one sample is required
-for each interval to describe the sound. Samples can be of many different sizes, ranging
-from 8 bit to 64 bit presition. The specific format of each sample can also vary - they
-can be big endian byte order, little endian byte order, or even floats.
-
-<P>
-</DD>
-<DT><STRONG>Frame</STRONG></DT>
-<DD>A frame consists of exactly one sample per channel. If there is only one
-channel (Mono sound) a frame is simply a single sample. If the sound is stereo, each frame
-consists of two samples, etc.
-
-<P>
-</DD>
-<DT><STRONG>Frame size</STRONG></DT>
-<DD>This is the size in bytes of each frame. This can vary a lot: if each sample is
-8 bits, and we're handling mono sound, the frame size is one byte. Similarly in 6 channel audio with
-64 bit floating point samples, the frame size is 48 bytes
-
-<P>
-</DD>
-<DT><STRONG>Rate</STRONG></DT>
-<DD>PCM sound consists of a flow of sound frames. The sound rate controls how often
-the current frame is replaced. For example, a rate of 8000 Hz means that a new frame is played
-or captured 8000 times per second.
-
-<P>
-</DD>
-<DT><STRONG>Data rate</STRONG></DT>
-<DD>This is the number of bytes, which must be recorded or provided per second
-at a certain frame size and rate.
-
-<P>
-8000 Hz mono sound with 8 bit (1 byte) samples has a data rate of 8000 * 1 * 1 = 8 kb/s
-
-<P>
-At the other end of the scale, 96000 Hz, 6 channel sound with 64 bit (8 bytes) samples
-has a data rate of 96000 * 6 * 8 = 4608 kb/s (almost 5 Mb sound data per second)
-
-<P>
-</DD>
-<DT><STRONG>Period</STRONG></DT>
-<DD>When the hardware processes data this is done in chunks of frames. The time interval
-between each processing (A/D or D/A conversion) is known as the period. The size of the period has
-direct implication on the latency of the sound input or output. For low-latency the period size should
-be very small, while low CPU resource usage would usually demand larger period sizes. With ALSA, the
-CPU utilization is not impacted much by the period size, since the kernel layer buffers multiple
-periods internally, so each period generates an interrupt and a memory copy, but userspace can be
-slower and read or write multiple periods at the same time.
-
-<P>
-</DD>
-<DT><STRONG>Period size</STRONG></DT>
-<DD>This is the size of each period in Hz. <em>Not bytes, but Hz!.</em> In <tt class="module">alsaaudio</tt>
-the period size is set directly, and it is therefore important to understand the significance of this
-number. If the period size is configured to for example 32, each write should contain exactly 32 frames
-of sound data, and each read will return either 32 frames of data or nothing at all.
-
-<P>
-</DD>
-</DL>
-
-<P>
-Once you understand these concepts, you will be ready to actually utilize PCM API. Read on.
-
-<P>
-
-<DIV CLASS="navigation">
-<div class='online-navigation'>
-<p></p><hr />
-<table align="center" width="100%" cellpadding="0" cellspacing="2">
-<tr>
-<td class='online-navigation'><a rel="prev" title="4 alsaaudio"
- href="module-alsaaudio.html"><img src='previous.png'
- border='0' height='32' alt='Previous Page' width='32' /></A></td>
-<td class='online-navigation'><a rel="parent" title="4 alsaaudio"
- href="module-alsaaudio.html"><img src='up.png'
- border='0' height='32' alt='Up One Level' width='32' /></A></td>
-<td class='online-navigation'><a rel="next" title="4.2 PCM Objects"
- href="pcm-objects.html"><img src='next.png'
- border='0' height='32' alt='Next Page' width='32' /></A></td>
-<td align="center" width="100%">PyAlsaAudio</td>
-<td class='online-navigation'><a rel="contents" title="Table of Contents"
- href="contents.html"><img src='contents.png'
- border='0' height='32' alt='Contents' width='32' /></A></td>
-<td class='online-navigation'><img src='blank.png'
- border='0' height='32' alt='' width='32' /></td>
-<td class='online-navigation'><img src='blank.png'
- border='0' height='32' alt='' width='32' /></td>
-</tr></table>
-<div class='online-navigation'>
-<b class="navlabel">Previous:</b>
-<a class="sectref" rel="prev" href="module-alsaaudio.html">4 alsaaudio</A>
-<b class="navlabel">Up:</b>
-<a class="sectref" rel="parent" href="module-alsaaudio.html">4 alsaaudio</A>
-<b class="navlabel">Next:</b>
-<a class="sectref" rel="next" href="pcm-objects.html">4.2 PCM Objects</A>
-</div>
-</div>
-<hr />
-<span class="release-info">Release 0.2.</span>
-</DIV>
-<!--End of Navigation Panel-->
-
-</BODY>
-</HTML>