Muldersoft/LameXP
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Updated FAQ document.

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LoRd_MuldeR 2011-12-11 01:55:22 +01:00
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<li><a href="#4213adbc">Can LameXP be used to convert/extract tracks from an Audio CD?</a>
<li><a href="#434f2578">Why is the maximum normalization level limited to -0.5 dB?</a>
<li><a href="#9f8ff13a">What do the different 'Equalization' modes do?</a>
<li><a href="#c6d9dfed">Why does my encoded file come out slightly longer than the original?</a>
<li><a href="#ed4d30ed">Why is the Hibernation option disabled (greyed out) on my system?</a>
<li><a href="#e7c9ae2b">Why do I get the error 'Executable doesn't support Windows compatibility mode' on startup?</a>
<li><a href="#328b0a18">Why do I get the error 'Executable requires Windows XP or later' on startup?</a>
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<br><br>
<a name="c6d9dfed"></a><b>Why does my encoded file come out slightly longer than the original?</b><br>
<br>
Because of the way most (lossy) audio compressors work, a number of "silent" samples have to be prepended to<br>
the first input sample. Also a number of silent samples may be appended to the last input sample. Obviously<br>
these additional "padding" samples will make the encoded file longer than the original input. If the decoder<br>
does not compensate for the padding samples that have been added by the encoder, the padding samples at the<br>
beginning of the encoded file will cause a certain delay/shift, compared to the (uncompressed) original file.<br>
Another effect is that there will be a "gap" between the files, when playing multiple files in sequence.<br>
<br>
It has to be noted that the padding is an inherent property of the audio compressor that can not be avoided.<br>
But, as mentioned before, the padding samples can be removed by the decoder. In that case, the decoded output<br>
will have the exactly same length (in samples) as the original file. However this can only be done, if the<br>
decoder is able to determine the exact number of padding samples that had been added. While the Vorbis audio<br>
format stores the number of padding samples in the stream and thus any compliant decoder will remove them,<br>
the MP3 and AAC audio formats do NOT define an "official" way to store the the number of padding samples!<br>
<br>
Nonetheless, the LAME MP3 encoder, which is used by LameXP, uses its own "non-standard" way to indicate the<br>
exact number of padding samples. This is done by adding a so-called "LAME header" to the MP3 file. Hence MP3<br>
decoders, which recognize the LAME header, will be able to remove the padding samples. This feature often is<br>
referred to as "gapless" decoding/playback. The 'mpg123' decoder, which is used by LameXP, does support the<br>
gapless decoding. This means that if you encode MP3 files with LameXP/LAME, then gapless decoding will be<br>
possible. And if you decode these files with LameXP/mpg123 again, they will come out at the original length.<br>
<br>
Still you have to be aware that NOT all MP3 decoders support the LAME header. So if you encode MP3 files with<br>
LameXP and then decode them with an arbitrary MP3 decoder, they may come out at a "wrong" length. And there<br>
is absoloutely nothing that LameXP could do about that! Furthermore, if you decode a MP3 file in LameXP that<br>
has been created with some MP3 decoder which did not add a LAME header, then it is impossible to remove the<br>
padding samples. That's because in this situation there is NO way to know the number of padding samples!<br>
<br>
Some more info on this topic can be found here:<br><ul>
<li><a href="http://en.wikipedia.org/wiki/Gapless_playback" target="_blank">http://en.wikipedia.org/wiki/Gapless_playback</a>
<li><a href="http://lame.sourceforge.net/tech-FAQ.txt" target="_blank">http://lame.sourceforge.net/tech-FAQ.txt</a>
<li><a href="http://cas.web.cern.ch/cas/Denmark-2010/Caspers/Tektronix%20%20primer%20on%20overlapping%20FFT%20signals%202009%20CAS2010.pdf" target="_blank">Understanding FFT Overlap Processing
Fundamental</a></ul>
<br><br>
<a name="ed4d30ed"></a><b>Why is the Hibernation option disabled (greyed out) on my system?</b><br>
<br>
In order to use "Hibernation", your system must support the S4 power saving mode (aka "Suspend-to-Disk") and<br>