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📁 MPlayer-mingw32-1.0rc2.zip 经典播放器源码
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>2.5.聽RTC</title><link rel="stylesheet" href="default.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.73.2"><link rel="start" href="index.html" title="MPlayer - The Movie Player"><link rel="up" href="install.html" title="Chapter聽2.聽Installation"><link rel="prev" href="fonts-osd.html" title="2.4.聽Fonts and OSD"><link rel="next" href="usage.html" title="Chapter聽3.聽Usage"><link rel="preface" href="howtoread.html" title="How to read this documentation"><link rel="chapter" href="intro.html" title="Chapter聽1.聽Introduction"><link rel="chapter" href="install.html" title="Chapter聽2.聽Installation"><link rel="chapter" href="usage.html" title="Chapter聽3.聽Usage"><link rel="chapter" href="cd-dvd.html" title="Chapter聽4.聽CD/DVD usage"><link rel="chapter" href="faq.html" title="Chapter聽5.聽Frequently Asked Questions"><link rel="chapter" href="containers.html" title="Chapter聽6.聽Containers"><link rel="chapter" href="codecs.html" title="Chapter聽7.聽Codecs"><link rel="chapter" href="video.html" title="Chapter聽8.聽Video output devices"><link rel="chapter" href="audio.html" title="Chapter聽9.聽Audio output devices"><link rel="chapter" href="tv.html" title="Chapter聽10.聽TV"><link rel="chapter" href="radio.html" title="Chapter聽11.聽Radio"><link rel="chapter" href="ports.html" title="Chapter聽12.聽Ports"><link rel="chapter" href="mencoder.html" title="Chapter聽13.聽Basic usage of MEncoder"><link rel="chapter" href="encoding-guide.html" title="Chapter聽14.聽Encoding with MEncoder"><link rel="appendix" href="bugreports.html" title="Appendix聽A.聽How to report bugs"><link rel="appendix" href="bugs.html" title="Appendix聽B.聽Known bugs"><link rel="appendix" href="skin.html" title="Appendix聽C.聽MPlayer skin format"><link rel="appendix" href="history.html" title="Appendix聽D.聽History"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">2.5.聽RTC</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="fonts-osd.html">Prev</a>聽</td><th width="60%" align="center">Chapter聽2.聽Installation</th><td width="20%" align="right">聽<a accesskey="n" href="usage.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="rtc"></a>2.5.聽RTC</h2></div></div></div><p>
There are three timing methods in <span class="application">MPlayer</span>.

</p><div class="itemizedlist"><ul type="disc"><li><p>
  <span class="bold"><strong>To use the old method</strong></span>, you don't have to do
  anything. It uses <code class="systemitem">usleep()</code> to tune
  A/V sync, with +/- 10ms accuracy. However sometimes the sync has to be
  tuned even finer.
</p></li><li><p>
  <span class="bold"><strong>The new timer</strong></span> code uses the RTC (RealTime
  Clock) for this task, because it has precise 1ms timers.
  The <tt class="option">-rtc</tt> option enables it,
  but a properly set up kernel is required.
  If you are running kernel 2.4.19pre8 or later you can adjust the maximum RTC
  frequency for normal users through the <code class="systemitem">/proc
  </code> filesystem. Use one of the following two commands to
  enable RTC for normal users:
  </p><pre class="screen">echo 1024 &gt; /proc/sys/dev/rtc/max-user-freq</pre><p>
  </p><pre class="screen">sysctl dev/rtc/max-user-freq=1024</pre><p>
  You can make this setting permanent by adding the latter to
  <tt class="filename">/etc/sysctl.conf</tt>.
  </p><p>
  You can see the new timer's efficiency in the status line.
  The power management functions of some notebook BIOSes with speedstep CPUs
  interact badly with RTC. Audio and video may get out of sync. Plugging the
  external power connector in before you power up your notebook seems to help.
  In some hardware combinations (confirmed during usage of non-DMA DVD drive
  on an ALi1541 board) usage of the RTC timer causes skippy playback. It's
  recommended to use the third method in these cases.
  </p></li><li><p>
  <span class="bold"><strong>The third timer code</strong></span> is turned on with the
  <tt class="option">-softsleep</tt> option. It has the efficiency of the RTC, but it
  doesn't use RTC. On the other hand, it requires more CPU.
</p></li></ul></div><p>
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