99 lines
3.4 KiB
HTML
99 lines
3.4 KiB
HTML
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<figure class="right">
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<img width="400px" src="/images/MIDI_transform.png" alt="MIDI transformation">
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<figcaption>The MIDI transformation dialog</figcaption>
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</figure>
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<p>
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Considering the numerical nature of MIDI events, it can be useful to
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transform a MIDI region by applying mathematical operations to it. Ardour
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makes this kind of powerful transformation very easy with the Transform tool.
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The tool makes possible things such as humanizing (randomizing the velocity,
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start time and duration of all the notes), creating arpeggios, automating
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tedious tasks, transposing, etc.
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</p>
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<p>
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The Transform tool is accessed by <kbd class="mouse">right</kbd>-clicking
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the MIDI region > <em>name_of_the_region</em> > MIDI > Transform….
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</p>
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<p>
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First, the property to be modified in the <kbd class="menu">Set</kbd> field
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is selected, then the target value is changed using the two fields that
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follow. If more operands are desired, the <kbd class="menu">+</kbd> button is
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clicked to create new lines. Any superfluous line can be removed by clicking
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on the <kbd class="menu">-</kbd> button on the right side of the line to be
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removed. Finally, once everything is set as desired, the <kbd
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class=menu>Transform</kbd> button is pressed to apply the transformation.
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</p>
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<p>
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In the image above, the Transform tool has been used to add a bit of
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humanization, by slightly changing the velocity of each note of the region by
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a random number between -19 and +19 from its original velocity. So the
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following three operations are applied:
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</p>
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<ul>
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<li>Set velocity to this note's velocity</li>
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<li>+ a random number from 1 to 20</li>
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<li>- a random number from 1 to 20</li>
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</ul>
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<p>
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Each note will trigger a unique calculation, where its velocity will be
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increased by a random number between 1 and 20, then decreased by a random
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number between 1 and 20. This will result in a new velocity being applied to
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the note, which will be the original velocity plus or minus a value <19.
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</p>
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<p>
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The parameters that can be transformed are:
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</p>
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<ul>
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<li>MIDI note number (e.g. <a href="@@midi-notes-ref">C2 is note number 24,
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C#2 is 25, etc.</a>)</li>
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<li>MIDI velocity (the volume of the note, between 0 and 127)</li>
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<li>start time (in beats)</li>
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<li>length (in beats)</li>
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<li>MIDI channel</li>
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</ul>
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<p>
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and the transformation can be based on any of the following:
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</p>
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<ul>
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<li>this note's</li>
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<li>the previous note's</li>
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<li>this note's index (number of the note, i.e. the first one is 0, the second
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is 1, etc.)</li>
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<li>exactly (for a constant value, between 1 and 127)</li>
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<li>a random number from <em>lower</em> to <em>higher</em> (<em>lower</em> and
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<em>higher</em> being constant values between 1 and 127)</li>
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<li>equal steps from <em>lower</em> to <em>higher</em> (<em>lower</em> and
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<em>higher</em> being constant values between 1 and 127)</li>
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</ul>
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<p>
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The mathematical operators are:
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</p>
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<ul>
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<li>+ (addition)</li>
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<li>- (subtraction)</li>
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<li>* (multiplication)</li>
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<li>/ (euclidean division)</li>
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<li>mod (remainder of the euclidean division)</li>
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</ul>
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<p class="note">
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While the Transform tool is powerful, it is not infallible.
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Things like division by zero (which does nothing), using the note's index and
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thinking that it starts at one (instead of zero), etc. can yield
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unexpected results.
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<p>
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