<p>
The Rhythm Ferret is a dedicated tool to speed up the usually labor intensive
- task to slice and adjust a sound region to match a specific time grid. It is
- especially usefull for drum tracks, either to match a different tempo, or to
+ task of slicing and adjusting a sound region to match a specific time grid. It is
+ especially useful for drum tracks, either to match a different tempo, or to
adjust a slightly out of tempo performance.
</p>
<p>
<h2>Accessing the Rhythm Ferret</h2>
<p>
- The Rhythm Ferret window can be accessed by <kbd class="mouse">Right</kbd> clicking
+ The Rhythm Ferret window can be accessed by <kbd class="mouse">right</kbd> clicking
any audio region, then <kbd class="menu"><em>Name_Of_The_Region</em> > Edit
> Rhythm Ferret</kbd>.
</p>
</p>
<ul>
<li><dfn>Percussive Onset</dfn> will detect the start of each hit based
- on the sudden change in energy (&eq; volume) of the waveform</li>
+ on the sudden change in energy (= volume) of the waveform</li>
<li><dfn>Note Onset</dfn> will detect the start of each note based on the changes
in the frequency domain.</li>
</ul>
<p>
In this mode, only two parameters are active:
</p>
-<dl>
- <dt><dfn>Sensitivity</dfn> (%)</dt><dd>The proportion of the samples that must exceed the
+<table class="dl">
+ <tr><th><dfn>Sensitivity</dfn> (%)</th><td>The proportion of the samples that must exceed the
energy rise threshold in order for an onset to be detected (at frames in which
the detection function peaks). This roughly corresponds to how "noisy" a percussive
- sound must be in order to be detected.</dd>
- <dt><dfn>Cut Pos Threshold</dfn> (dB)</dt><dd>The rise in energy amongst a group of samples
+ sound must be in order to be detected.</td></tr>
+ <tr><th><dfn>Cut Pos Threshold</dfn> (dB)</th><td>The rise in energy amongst a group of samples
that is required for that to be counted toward the detection function's count.
This roughly corresponds to how "loud" a percussive sound must be in order to
- be detected.</dd>
-</dl>
+ be detected.</td></tr>
+</table>
<p>
As those parameters are very material-related, there is no recipe for a perfect
match, and a good peak detection is a matter of adjusting those two parameters
<p>
Vertical grey markers will appear on the selected region, showing where Ardour
detects onsets as per the parameters. This markers can be manually adjusted, see
- bellow.
+ below.
</p>
<h2>The Note Onset Mode</h2>
<p>
In the Note Onset mode, more parameters are active:
</p>
-<dl>
- <dt><dfn>Detection function</dfn></dt><dd>The method used to detect note changes. More on
- this bellow.</dd>
- <dt><dfn>Trigger gap (postproc)</dfn> (ms)</dt><dd>Set the minimum inter-onset interval,
+<table class="dl">
+ <tr><th><dfn>Detection function</dfn></th><td>The method used to detect note changes. More on
+ this below.</td></tr>
+ <tr><th><dfn>Trigger gap (postproc)</dfn> (ms)</th><td>Set the minimum inter-onset interval,
in milliseconds, i.e. the shortest interval between two consecutive onsets.
- </dd>
- <dt><dfn>Peak threshold</dfn></dt><dd>Set the threshold value for the onset peak picking.
+ </td></tr>
+ <tr><th><dfn>Peak threshold</dfn></th><td>Set the threshold value for the onset peak picking.
Lower threshold values imply more onsets detected. Increasing this threshold
- should reduce the number of incorrect detections.</dd>
- <dt><dfn>Silence threshold</dfn> (dB)</dt><dd>Set the silence threshold, in dB, under which
+ should reduce the number of incorrect detections.</td></tr>
+ <tr><th><dfn>Silence threshold</dfn> (dB)</th><td>Set the silence threshold, in dB, under which
the onset will not be detected. A value of -20.0 would eliminate most onsets
- but the loudest ones. A value of -90.0 would select all onsets.</dd>
-</dl>
+ but the loudest ones. A value of -90.0 would select all onsets.</td></tr>
+</table>
<p>
The Detection function, used in Note Onset mode to choose the mathematical strategy
used to detect the note changes, is user-selectable:
</p>
-<dl>
- <dt><dfn>Energy based</dfn></dt><dd>This function calculates the local energy of the input
- spectral frame</dd>
- <dt><dfn>Spectral Difference</dfn></dt><dd>Spectral difference onset detection function
- based on Jonhatan Foote and Shingo Uchihashi's "The beat spectrum: a new
- approach to rhythm analysis" (2001)</dd>
- <dt><dfn>High-Frequency Content</dfn></dt><dd> This method computes the High Frequency
+<table class="dl">
+ <tr><th><dfn>Energy based</dfn></th><td>This function calculates the local energy of the input
+ spectral frame</td></tr>
+ <tr><th><dfn>Spectral Difference</dfn></th><td>Spectral difference onset detection function
+ based on Jonathan Foote and Shingo Uchihashi's "The beat spectrum: a new
+ approach to rhythm analysis" (2001)</td></tr>
+ <tr><th><dfn>High-Frequency Content</dfn></th><td> This method computes the High Frequency
Content (HFC) of the input spectral frame. The resulting function is efficient
at detecting percussive onsets. Based on Paul Masri's "Computer modeling
- of Sound for Transformation and Synthesis of Musical Signal" (1996)</dd>
- <dt><dfn>Complex Domain</dfn></dt><dd>This function uses information both in frequency and
+ of Sound for Transformation and Synthesis of Musical Signal" (1996)</td></tr>
+ <tr><th><dfn>Complex Domain</dfn></th><td>This function uses information both in frequency and
in phase to determine changes in the spectral content that might correspond
to musical onsets. It is best suited for complex signals such as polyphonic
- recordings.</dd>
- <dt><dfn>Phase Deviation</dfn></dt><dd>This function uses information both energy and in
- phase to determine musical onsets.</dd>
- <dt><dfn>Kullback-Liebler</dfn></dt><dd>Kulback-Liebler onset detection function based on
+ recordings.</td></tr>
+ <tr><th><dfn>Phase Deviation</dfn></th><td>This function uses information both energy and in
+ phase to determine musical onsets.</td></tr>
+ <tr><th><dfn>Kullback-Liebler</dfn></th><td>Kulback-Liebler onset detection function based on
Stephen Hainsworth and Malcom Macleod's "Onset detection in music audio
- signals" (2003)</dd>
- <dt><dfn>Modified Kullback-Liebler</dfn></dt><dd>Modified Kulback-Liebler onset detection
+ signals" (2003)</td></tr>
+ <tr><th><dfn>Modified Kullback-Liebler</dfn></th><td>Modified Kulback-Liebler onset detection
function based on Paul Brossier's "Automatic annotation of musical audio for
- interactive systems" (2006)</dd>
-</dl>
+ interactive systems" (2006)</td></tr>
+</table>
<p>
- Ardour defaults to Complex domain, which usually gives good result for harmonic
+ Ardour defaults to Complex Domain, which usually gives good result for harmonic
material.
</p>
Those regions can then be manually aligned, or have their sync points set to
the closest grid (as per the <a href="@@grid-controls">Grid settings</a> in
effect), by selecting all the regions, and using the
- <kbd class="mouse">RIGHT</kbd> click > Selected Regions > Position >
- Snap posiiton to grid.
+ <kbd class="mouse">right</kbd> click then <kbd class="menu">Selected Regions > Position >
+ Snap position to grid</kbd>.
</p>
+
projects / ardour-manual / blobdiff