+++ /dev/null
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-layout: default
-title: Create Region Fades and Crossfades
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-
-<p class="fixme">Add images--an image is worth more than 1,000 words</p>
-<p>
- Every Region has a fade-in and fade-out. By default, the region fade
- is very short, and serves to de-click the transitions at the start and
- end of the region. By adjusting the regions fade length, a more
- gradual transition can be accomplished.
-</p>
-
-<h2>Region Fades</h2>
-<p>
- <dfn>Region fades</dfn> are possible at the beginning and end of
- all audio regions. In object mode, a grip appears at the top left and
- top right of an audio region when the cursor hovers over it. Placing
- the cursor over the top of the grip displays the region fade cursor
- tip. Click and drag the grip left or right in the timeline to
- adjust the length of the fade.
-</p>
-
-<h2>Crossfades</h2>
-<p>
- <dfn>Crossfades</dfn> refer to the behavior when you want to make
- a smooth transition (mix) from one audio region to another on the same
- track. Historically, this was done by splicing 2 pieces of analog
- tape together, and this concept was carried forward into digital
- editing. Each track is a sequence of sound files (regions). If
- two regions are butted against each other, there needs to be a method
- to splice them smoothly together. The crossfade allows one region
- to fade smoothly out, while the next region fades smoothly in, like 2
- pieces of tape that have been cut at and angle, and overlapped.
-</p>
-
-<p>
- But Ardour uses a more refined "layered" editing model, and
- therefore it is possible for multiple regions to be stacked on a single
- location with arbitrary overlaps between different layers. For
- this reason, crossfades must be implemented differently. We can't
- assume that a crossfade is an entitry that exists between 2 regions;
- instead each region must have its own associated crossfades at each
- end, and the topmost region must always crossfade down to the
- underlying region(s), if any.
-</p>
-
-<p>
- Ardour solves this problem by putting a crossfade at the beginning
- and end of every region. The fades of the bottom-most region are
- first rendered, and then each region is rendered on top of the one
- below it, with fades at the end of each region providing a crossfade to
- the region(s) beneath it.
-</p>
-
-<p>
- It is important to understand that region fades <em>are</em> crossfades. When one region has
- another region or multiple regions beneath its fade area, then you will
- hear the topmost region fade-out be mirrored as a fade-in on the
- underlying region(s). The grip for the topmost region will allow
- changing the length and type of the crossfade into the underlying
- region(s). In this way you can create a complicated series of
- crossfades, and then layer another region atop the others, and fade
- into <em>that</em> complicated series.
-</p>
-<p class="fixme">An image here would probably help.</p>
-
-<p>
- If a region doesn't have any region(s) under it, then the region is
- crossfaded to silence; for convenience we call this a "fade"
- rather than a crossfade.
-</p>
-
-<h2>Fade Shapes</h2>
-<p>
- To activate/deactivate or change the shape of a region's fade-in or
- fade-out, hover the cursor over the region fade grip till the cursor tip
- indicates region fade editing and context-click to bring up a context
- menu. In the context menu there is a list of options for the
- region fade. <kbd class="menu">Activate/Deactivate</kbd> enables and
- disables the region fade.
-</p>
-
-<p>
- Because each fade is also a crossfade, it has an inverse fade shape
- for the audio beneath the fade. It is important to know how the
- shapes differ, and which are most suitable for various editing tasks.
-</p>
-
-<p>
- The different types of fades are:
-</p>
-
-<dl class="narrower-table">
- <dt><kbd class="menu">Linear</kbd></dt>
- <dd>A simple linear coefficient decrease, and its mathematical inverse. A Linear fade starts attentuating quickly and then cuts off even more abruptly at lower levels. When used as a crossfade, the signals are each -6dB attenuated at the midpoint. This is the correct crossfade to use with highly-correlated signals for a smooth transition.</dd>
- <dt><kbd class="menu">Constant Power</kbd></dt>
- <dd>The constant power curve starts fading slowly and then cuts off abruptly. When used as a crossfade between 2 audio regions, the signals are symetrically attenuated, and they each reach -3dB at the midpoint. This is the correct crossfade to use when you want to splice audio in the general (uncorrelated) case.</dd>
- <dt><kbd class="menu">Symmetric</kbd></dt>
- <dd>The Symmetric fade starts slowly, then attenuates significantly before transitioning to a slower fade-out near the end of the fade. When used as a crossfade, the Symmetric curve is not mathematically correct like the Equal Power or Linear curves, but it provides a slower fade-out at low volumes. This is sometimes useful when editing two entire works of music together so that the transition is more gradual.</dd>
- <dt><kbd class="menu">Fast</kbd></dt>
- <dd>The Fast curve is a linear decibel fade; It sounds like a perfectly smooth fader or knob moved to silence. This shape is excellent as a general-purpose fade-in. When used as a crossfade, the inverse fade curve maintains constant power but is therefore non-symmetric; so its use is limited to those cases where the user finds it appropriate.</dd>
- <dt><kbd class="menu">Slow</kbd></dt>
- <dd>The Slow curve is a modified linear decibel fade. The initial curve starts more gradually so that it has a less abrupt transition near unity. After that, it sounds like a perfectly smooth fader or knob moved to silence. This shape is excellent as a general-purpose fade-out. When used as a crossfade, the inverse fade curve maintains constant power but is therefore non-symmetric; so its use is limited to those cases where the user finds it appropriate.</dd>
-</dl>
-
-<p>
- Although these fade shapes serve specific purposes, any of the shapes is usable in certain situations. The final decision is an artistic choice rather than a rigidly prescribed one.
-</p>
-
-<p>
- These fade curves are developed to provide a range of common uses, and
- are developed with the least possible amount of changes in the "slope"
- of the line. This provides artifact-free crossfades. Some
- DAWs provide complicated fade editors with parametric "spline" controls
- of the fade curves. While it might be interesting to develop a
- fade curve with a faster cutoff, the mathematical difference between
- this and simply shortening the fade is vanishingly small; the
- amount of effort to shorten the fade is much easier than fooling around with a
- crossfade editor dialog.
-</p>
-
projects / ardour-manual-diverged / blobdiff