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QA /technical/2008/04/mp3-decoder-libraries-compared/

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Wesley Moore 2010-03-15 17:14:53 +11:00
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content/technical/2008/04/mp3-decoder-libraries-compared.html
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@ -9,6 +9,7 @@ I did some searching and came up with two other libraries that seemed well suite
I built the two additional libraries with the default configuration options, except for libmad, which I added the <code>--enable-speed</code> option. With the help of example code I made programs out of each that were comparable to the first version for Core Audio. I.e. MP3 file in, 16-bit Linear PCM audio samples out. I built the two additional libraries with the default configuration options, except for libmad, which I added the <code>--enable-speed</code> option. With the help of example code I made programs out of each that were comparable to the first version for Core Audio. I.e. MP3 file in, 16-bit Linear PCM audio samples out.
To provide a benchmark I wrote a script that would run each of the three programs against a source MP3 file. Each program reported the elapsed time (via <a href="http://developer.apple.com/documentation/Darwin/Reference/ManPages/man3/time.3.html">time(3)</a>) and the processor time (via <a href="http://developer.apple.com/documentation/Darwin/Reference/ManPages/man3/clock.3.html">clock(3)</a>) when it finished decoding. The programs were run one after another on the source file 10 times. Their PCM output was written to a new file for each invocation. To provide a benchmark I wrote a script that would run each of the three programs against a source MP3 file. Each program reported the elapsed time (via <a href="http://developer.apple.com/documentation/Darwin/Reference/ManPages/man3/time.3.html">time(3)</a>) and the processor time (via <a href="http://developer.apple.com/documentation/Darwin/Reference/ManPages/man3/clock.3.html">clock(3)</a>) when it finished decoding. The programs were run one after another on the source file 10 times. Their PCM output was written to a new file for each invocation.
<!--more--> <!--more-->
<h3>Environment</h3> <h3>Environment</h3>
@ -22,180 +23,180 @@ The results of the tests for my sample MP3s is below. The individual times were
<!-- 1-08 Pushin.mp3 --> <!-- 1-08 Pushin.mp3 -->
<table class="left_headers"> <table class="left_headers">
<tr> <tr>
<th>Size</th><td>4,296,251 bytes</td> <th>Size</th><td>4,296,251 bytes</td>
</tr> </tr>
<tr> <tr>
<th>Bitrate</th><td>160 kbps</td> <th>Bitrate</th><td>160 kbps</td>
</tr> </tr>
<tr> <tr>
<th>Channels</th><td>2 (Joint Stereo)</td> <th>Channels</th><td>2 (Joint Stereo)</td>
</tr> </tr>
<tr> <tr>
<th>Length</th><td>3:34</td> <th>Length</th><td>3:34</td>
</tr> </tr>
</table> </table>
<table class="top_headers"> <table class="top_headers">
<tr> <tr>
<th>Library</th> <th>Library</th>
<th>Average Elapsed Time</th> <th>Average Elapsed Time</th>
<th>Average Processor Time</th> <th>Average Processor Time</th>
<th>Processor Time Std. Deviation</th> <th>Processor Time Std. Deviation</th>
</tr> </tr>
<tr> <tr>
<td>mpg123</td> <td>mpg123</td>
<td>2.30</td> <td>2.30</td>
<td>1.71</td> <td>1.71</td>
<td>0.95</td> <td>0.95</td>
</tr> </tr>
<tr> <tr>
<td>Core Audio</td> <td>Core Audio</td>
<td>4.10</td> <td>4.10</td>
<td>3.63</td> <td>3.63</td>
<td>0.27</td> <td>0.27</td>
</tr> </tr>
<tr> <tr>
<td>mad</td> <td>mad</td>
<td>4.80</td> <td>4.80</td>
<td>4.42</td> <td>4.42</td>
<td>0.02</td> <td>0.02</td>
</tr> </tr>
</table> </table>
<h4>Medium Mono File</h4> <h4>Medium Mono File</h4>
<!-- Sensation Black 2007 Warm Up Mix.mp3 --> <!-- Sensation Black 2007 Warm Up Mix.mp3 -->
<table class="left_headers"> <table class="left_headers">
<tr> <tr>
<th>Size</th><td>83,091,456 bytes</td> <th>Size</th><td>83,091,456 bytes</td>
</tr> </tr>
<tr> <tr>
<th>Bitrate</th><td>320 kbps</td> <th>Bitrate</th><td>320 kbps</td>
</tr> </tr>
<tr> <tr>
<th>Channels</th><td>1 (Mono)</td> <th>Channels</th><td>1 (Mono)</td>
</tr> </tr>
<tr> <tr>
<th>Length</th><td>34:37</td> <th>Length</th><td>34:37</td>
</tr> </tr>
</table> </table>
<table class="top_headers"> <table class="top_headers">
<tr> <tr>
<th>Library</th> <th>Library</th>
<th>Average Elapsed Time</th> <th>Average Elapsed Time</th>
<th>Average Processor Time</th> <th>Average Processor Time</th>
<th>Processor Time Std. Deviation</th> <th>Processor Time Std. Deviation</th>
</tr> </tr>
<tr> <tr>
<td>mpg123</td> <td>mpg123</td>
<td>11.10</td> <td>11.10</td>
<td>9.40</td> <td>9.40</td>
<td>0.03</td> <td>0.03</td>
</tr> </tr>
<tr> <tr>
<td>mad</td> <td>mad</td>
<td>26.90</td> <td>26.90</td>
<td>24.60</td> <td>24.60</td>
<td>0.03</td> <td>0.03</td>
</tr> </tr>
<tr> <tr>
<td>Core Audio</td> <td>Core Audio</td>
<td>33.60</td> <td>33.60</td>
<td>30.33</td> <td>30.33</td>
<td>1.18</td> <td>1.18</td>
</tr> </tr>
</table> </table>
<h4>Large File</h4> <h4>Large File</h4>
<!-- 1-01 Clubbers Guide 2007 - CD 1.mp3 --> <!-- 1-01 Clubbers Guide 2007 - CD 1.mp3 -->
<table class="left_headers"> <table class="left_headers">
<tr> <tr>
<th>Size</th><td>126,083,072 bytes</td> <th>Size</th><td>126,083,072 bytes</td>
</tr> </tr>
<tr> <tr>
<th>Bitrate</th><td>224 kbps</td> <th>Bitrate</th><td>224 kbps</td>
</tr> </tr>
<tr> <tr>
<th>Channels</th><td>2 (Joint Stereo)</td> <th>Channels</th><td>2 (Joint Stereo)</td>
</tr> </tr>
<tr> <tr>
<th>Length</th><td>1:15:02</td> <th>Length</th><td>1:15:02</td>
</tr> </tr>
</table> </table>
<table class="top_headers"> <table class="top_headers">
<tr> <tr>
<th>Library</th> <th>Library</th>
<th>Average Elapsed Time</th> <th>Average Elapsed Time</th>
<th>Average Processor Time</th> <th>Average Processor Time</th>
<th>Processor Time Std. Deviation</th> <th>Processor Time Std. Deviation</th>
</tr> </tr>
<tr> <tr>
<td>mpg123</td> <td>mpg123</td>
<td>37.00</td> <td>37.00</td>
<td>32.21</td> <td>32.21</td>
<td>0.19</td> <td>0.19</td>
</tr> </tr>
<tr> <tr>
<td>Core Audio</td> <td>Core Audio</td>
<td>84.00</td> <td>84.00</td>
<td>78.34</td> <td>78.34</td>
<td>0.34</td> <td>0.34</td>
</tr> </tr>
<tr> <tr>
<td>mad</td> <td>mad</td>
<td>100.10</td> <td>100.10</td>
<td>94.44</td> <td>94.44</td>
<td>0.15</td> <td>0.15</td>
</tr> </tr>
</table> </table>
<h4>Large VBR File</h4> <h4>Large VBR File</h4>
<!-- 1-01 Clubbers Guide to 2007 (AU Edition).mp3 --> <!-- 1-01 Clubbers Guide to 2007 (AU Edition).mp3 -->
<table class="left_headers"> <table class="left_headers">
<tr> <tr>
<th>Size</th><td>123,028,672 bytes</td> <th>Size</th><td>123,028,672 bytes</td>
</tr> </tr>
<tr> <tr>
<th>Bitrate</th><td>210 kbps (VBR)</td> <th>Bitrate</th><td>210 kbps (VBR)</td>
</tr> </tr>
<tr> <tr>
<th>Channels</th><td>2 (Joint Stereo)</td> <th>Channels</th><td>2 (Joint Stereo)</td>
</tr> </tr>
<tr> <tr>
<th>Length</th><td>1:17:46</td> <th>Length</th><td>1:17:46</td>
</tr> </tr>
</table> </table>
<table class="top_headers"> <table class="top_headers">
<tr> <tr>
<th>Library</th> <th>Library</th>
<th>Average Elapsed Time</th> <th>Average Elapsed Time</th>
<th>Average Processor Time</th> <th>Average Processor Time</th>
<th>Processor Time Std. Deviation</th> <th>Processor Time Std. Deviation</th>
</tr> </tr>
<tr> <tr>
<td>mpg123</td> <td>mpg123</td>
<td>37.90</td> <td>37.90</td>
<td>32.96</td> <td>32.96</td>
<td>0.13</td> <td>0.13</td>
</tr> </tr>
<tr> <tr>
<td>Core Audio</td> <td>Core Audio</td>
<td>86.40</td> <td>86.40</td>
<td>80.52</td> <td>80.52</td>
<td>0.18</td> <td>0.18</td>
</tr> </tr>
<tr> <tr>
<td>mad</td> <td>mad</td>
<td>104.30</td> <td>104.30</td>
<td>98.43</td> <td>98.43</td>
<td>0.10</td> <td>0.10</td>
</tr> </tr>
</table> </table>
<br /> <br />

17
output/css/screen.css
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@ -330,4 +330,19 @@ ul.inline li:first-child {
border-top-color: #999; border-top-color: #999;
width: 10em; width: 10em;
margin: 0; margin: 0;
} }
/* Styles for MP3 Decoder post */
table.left_headers, table.top_headers {
border: 1px solid #D8D8D8;
border-collapse: collapse;
margin: 1em 0;
}
table.left_headers td, table.left_headers th,
table.top_headers td, table.top_headers th {
border: 1px solid #D8D8D8;
padding: 0.3em 0.7em 0.3em 0.7em;
}
table.left_headers th {
text-align: right;
}