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AIFF_and_AIFC_files.html
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AIFF_and_AIFC_files.html
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<html><head><meta name="robots" content="index,follow">
<title>AIFF and AIFC files</title></head><body bgcolor="#FFFFFF">
<table border=0 cellpadding=0 cellspacing=0><tr><td bgcolor="#CCCC00"><table border=4 cellpadding=9><tr><td align=middle bgcolor="#000000"><font face="Palatino,Times" size=6 color="#999900"><b>
AIFF and AIFC files
</b></font></table></table>
<p>
Ways for storing a <a href="Sound.html">Sound</a> object on disk.</p>
<h3>
File format</h3>
<h3>
Reading</h3>
<p>
<a href="Read_from_file___.html">Read from file...</a> recognizes AIFF and AIFC files with 8-bit and 16-bit encoding, but not compressed AIFC files. It recognizes any sampling frequency. The two channels of stereo files are averaged. <b>Read two Sounds from AIFF file...</b> reads both channels separately and names them <i>left</i> and <i>right</i>.</p>
<p>
The sample values are divided by 2<sup>(<i>numberOfBitsPerSample</i> – 1)</sup>, so that the amplitude of the resulting Sound is between –1.0 and +1.0; the maximum sound pressure level for a sine wave is therefore: 20 · <sup>10</sup>log (√2 / 2·10<sup>–5</sup>) = 91 dB.</p>
<p>
The resulting Sound will appear in the List of Objects; its name will be equal to the file name, without extension.</p>
<h3>
Saving</h3>
<p>
With <a href="Save_as_AIFF_file___.html">Save as AIFF file...</a>.</p>
<p>
The samples of the Sound are multiplied by 32768 and quantized between –32768 and 32767.</p>
<p>
To avoid clipping, keep the absolute amplitude below 1.000. If the maximum sound pressure level is 91 dB (top = 32767), the quantization threshold is (top = 1/2) –5 dB.</p>
<hr>
<address>
<p>© ppgb, January 31, 2011</p>
</address>
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