107 lines
3.4 KiB
HTML
107 lines
3.4 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<title>mod588.txt</title>
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<style type="text/css">
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@font-face {
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font-family: nfo;
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font-style: normal;
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font-weight: normal;
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src: url(nfo.eot);
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}
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.nfo {
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padding: 12px;
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font-family: nfo, courier new;
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font-size: 11px;
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line-height: 1em;
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}
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</style>
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</head>
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<body>
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<pre class="nfo">________________________________________________________________________________
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protip: Breaking news! l0Rd3z3C aka DiViNiTY aka ThEgH0sT- can't read!
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( Sorry, I forgets your nick on LocalNet :( )
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protip: it isn't deemed to be a valid nuke reason, although it is a
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good indicator for possible reencodes (retail sources only).
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Try reading the whole page.
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________________________________________________________________________________
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First, an explanation of mod588:
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"
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The mod operator returns the remainder obtained by dividing its operands.
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In other words, x mod y = x - (x div y) * y.
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"
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Oh, div is of course:
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"
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The value of x div y is the value of x/y rounded in the direction of zero to
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the nearest integer.
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"
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Since one second on a CD is divided in to 75 frames, each has 588 samples.
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A mp3 is divided into frames and each has 1152 samples.
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That's why we do "samples mod 588" to see if the source for the mp3 was a
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CD and not a transcode from a mp3.
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________________________________________________________________________________
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To obtain samples length of an mp3, a suitable and accurate program to use is
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foobar (any version), other programs don't seem to be as accurate.
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Drag a scene mp3 on to foobar, and right click -> properties. You will see
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something like "Duration: 3:06.972 (10774512 samples)."
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take the (10774512 samples) and follow through with the process below.
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________________________________________________________________________________
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A proper file encoded from a CD source.
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Samples length: 10774512
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10774512 mod 588 = 0
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because:
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10774512 / 588 = 18324
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the result is a whole number, an integer.
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Now, if the file was not created from a CD source:
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Samples length: 10775855
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10775855 mod 588 = 167
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because:
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10775855 / 588 = 18326,28401360544217687074829932
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the result is not an integer, so:
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18326 * 588 = 10775688
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and:
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10775855 - 10775688 = 167
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________________________________________________________________________________
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Notes:
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. Don't forget that only recent versions of LAME give sample accurate length.
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Old LAME (pre-3.90) and non-LAME mp3 encoders won't work.
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. MP3's with LameTag and with the enc_delay/enc_padding values should be fine.
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Word from mp3c members:
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"
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Only dumb scene nukers are doing this.
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That is NOT an official nuke reason. I was 1 of the guys who came up with some
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of the methods of checking and THAT was NEVER 1 of them. Specta anyalsis and
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bitrate are FAR better indicators esp if u have 2 sources with 1 known and 1
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unknown. There are some variables which can vary even with wav ripping between
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1 cdrom to another hence why a couple of bits off 2 encodes can happen. CLearly
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this is a over jealous site nuker.
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"
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[Last updated: 2008-05-20]
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[Main text last updated: 2008-05-20, Prelude last updated: 2009-09-17]
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</pre>
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</body>
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</html>
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