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OpenAudio_ArduinoLibrary/docs/audio_html/AudioPlaySdWav.html

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<script type="text/x-red" data-help-name="AudioPlaySdWav">
<h3>Summary</h3>
<div class=tooltipinfo>
<p>Play a WAV file, stored on a SD card.</p>
</div>
<h3>Audio Connections</h3>
<table class=doc align=center cellpadding=3>
<tr class=top><th>Port</th><th>Purpose</th></tr>
<tr class=odd><td align=center>Out 0</td><td>Left Channel Output</td></tr>
<tr class=odd><td align=center>Out 1</td><td>Right Channel Output</td></tr>
</table>
<h3>Functions</h3>
<p class=func><span class=keyword>play</span>(filename);</p>
<p class=desc>Begin playing a WAV file. If a file is already playing,
it is stopped and this file starts playing from the beginning.
</p>
<p class=func><span class=keyword>stop</span>();</p>
<p class=desc>Stop playing. If not playing, this function has no effect.
</p>
<p class=func><span class=keyword>isPlaying</span>();</p>
<p class=desc>Return true (non-zero) if playing, or false (zero)
when not playing. See the note below about delayed start.
</p>
<p class=func><span class=keyword>positionMillis</span>();</p>
<p class=desc>While playing, return the current time offset, in
milliseconds. When not playing, the return from this function
is undefined.
</p>
<p class=func><span class=keyword>lengthMillis</span>();</p>
<p class=desc>Return the total length of the current sound clip,
in milliseconds. When not playing, the return from this function
is undefined.
</p>
<h3>Examples</h3>
<p class=exam>File &gt; Examples &gt; Audio &gt; WavFilePlayer
</p>
<h3>Notes</h3>
<p>Only 16 bit PCM, 44100 Hz WAV files are supported. When mono
files are played, both output ports transmit a copy of the
single sound. Of course, stereo WAV files play with the left
channel on port 0 and the right channel on port 1.
</p>
<p>A brief delay after calling play() will usually occur before
isPlaying() returns true and positionMillis() returns valid
time offset. WAV files have a header at the beginning of the
file, which the audio library must read and parse before
playing can begin.
</p>
<p>While playing, the audio library accesses the SD card automatically.
If card access is required, you must
<a href="http://www.pjrc.com/teensy/td_libs_AudioProcessorUsage.html" target="_blank">use AudioNoInterrupts()</a>
to prevent the library from accessing the SD card while you use it.
Disabling the audio library interrupt for too long may cause audible
dropouts or glitches.
</p>
<p>An experimental SD library optimization exists, which can remove these
SD library restrictions. It also allows reliable playback of more
files at the same time. To enable this special code, find and edit
the SD_t3.h file within your Arduino folder. See the comments within
that file for details.
</p>
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