Tempo manipulation with SWS
From CockosWiki
This is a part of Breeder's SWS actions for dealing with tempo. You need to have the latest beta of SWS extension installed.
First page: Tempo-mapping in Reaper
Contents |
Tweaking tempo
Assuming that you've built a tempo-map according to step A and B explained in Tempo-mapping in Reaper (or by other means).
If you now play your song through, maybe with an added metronome or basic beat (drum-vsti), you'll possibly find that the tempo map is less accurate than desired. Or you'd like to polish/change tempo in other ways.
Note: All actions described are designed to modify any number of selected tempo markers without screwing the rest of the tempo map.
Move tempo marker
Name in the action list: SWS/BR: Move tempo marker back/forward
It's recommended to keybind versions without ms attribute. Those move points depending on zoom level.
The more zoomed project is, less the point gets moved.
These actions are designed to help you reposition your tempo markers without having to go through process of remapping
tempo every time you want to change position of some tempo markers. They move selected tempo marker while preserving
time positions of the rest of the tempo markers in the project:
Note: Because of their characteristic to preserve time position of other markers - they will not work reliably in a situation when there is a linear tempo marker(s) 2 points behind selected point. The reason is that additional tempo acrobatics are needed in order to preserve time positions of those tempo markers. Illustration
Edit tempo marker
Name in the action list: SWS/BR: Increase/Decrease tempo marker (preserve it's time position)
These actions are designed to let you tweak your tempo markers up/down while preserving the overall sync/tempo. Their main characteristic is that they will always preserve time position of the selected tempo marker. It is done so by changing the value and position of surrounding tempo markers - sometimes just one and in other cases both. It depends on which which type (linear/square) of tempo markers are present around the selected marker
Intended usage for these actions is to smooth so called "peaks" in a tempo map that consists of linear tempo markers:
Delete tempo marker
Name in the action list: SWS/BR: Delete tempo marker (preserve overall tempo and positions if possible)
Deleting tempo markers using standard reaper procedure ends with changed musical position after the deleted tempo marker.
"Delete tempo marker" allows for deletion of selected tempo markers while at the same time preserving musical and time position of the rest of the tempo map:
Note
- For linear points, the point after the deleted point will change time-position and value, to make the necessary compensation.
- For square points the point in front changes value.
- Some corner-cases will have different behaviour.
You can use this action to reduce a number of points in tempo map to ease editing. To do it in bulk you might want to use Select and adjust tempo markers...
Change tempo marker shape
Name in the action list: SWS/BR: Set tempo marker shape to linear/square
Changing tempo shape via standard reaper procedure preserves musical position but screws time positions.
However, sometimes you want to change shape without disturbing anything. These actions are here to help. They work by the same principle presented in SWS tempo mapping - by creating additional middle point(s) which help preserving all time positions.
Settings that affect creation of middle points when changing shapes can be found in action list: SWS/BR: Set tempo marker shape (options)...:
Explanation on how it works:
- Splitting turned off: one tempo marker is created in the musical middle
- Splitting turned on: two tempo markers are created - ratio (between 0 and 1) can be typed (decimal or fraction) or chosen from the list. Dictates by how much created markers will get moved from the musical middle. Recommended ratios are 1/2 and 1/3.
- When changing shape to linear, middle point(s) always get created after the selected point
- When changing shape to square, middle point(s) may get created before the selected point
Tips:
- When tempo mapping and creating gradual tempo changes you might find yourself in a situation where fixing anything requires a complete remap. Instead of tempo mapping with linear points it may be more productive to tempo map using square points since they are easier to move and delete. Once you are completely satisfied with the result you can change shape to linear and obtain fluctuating tempo.
- Leave settings dialog open while changing shapes - actions will react to changes of settings immediately
Alter slope of gradual tempo marker
Name in the action list: SWS/BR: Alter slope of gradual tempo marker (increase/decrease)
It alters the BPM of selected gradual (linear) tempo marker and in turns moves next tempo marker in order to preserve tempo map - result is alteration of the slope. Selected tempo marker might move, depending if there is a linear tempo marker behind it.
This is intended to be a helper action used for fixing things up:
- When deleting tempo in linear tempo map, tempo marker in front of the deleted marker might get moved and produce undesired results. Using this action on tempo marker that was positioned behind deleted tempo will let you dictate position of two points surrounding deleted tempo marker:
- When tempo mapping gradual tempo it is not so easy to move markers around using existing move actions. You can try and use this action on middle point (or second middle point if split) to move a tempo marker in front of it
- When tempo mapping gradual tempo - with option turned on to split middle point - you can use this action on the first middle point(select only the first) to fix the slope of two middle points
Create project markers from tempo markers
Name in the action list: SWS/BR: Create project markers from selected tempo markers
Tempo mapping is performed using project markers. It may happen that you accidentally removed those project markers which is a bummer if you want to delete existing tempo map and remap everything.
This action let you go back to start:
- For square tempo map it is enough to select all tempo markers and run this action
- For linear tempo map, before running the action, you should select all of tempo markers, open Select and adjust tempo markers... dialog from the action list and use option Deselect every... to deselect every 2nd selected tempo marker.
- For linear tempo map with split middle point you need to perform the same thing but this time first deselect every 3rd and then again deselect every 2nd tempo marker
Randomize selected tempo markers
Name in the action list: SWS/BR: Randomize selected tempo markers...
Use this dialog to randomize the value of selected tempo markers:
- Set minimum and maximum values to taste and decide on which unit you want to use, BPM or %
- Obey absolute threshold lets you impose minimum and maximum limits on the resulting tempo map
- New random seed creates a new randomization. Once satisfied, apply. Or just cancel and get your tempo map back
Tips:
- If you have only a few tempo markers in your project you might want to copy/paste more points between them to get more realistic randomization
- Once randomized, change their shape to linear (with SWS actions or default reaper procedure) to get fluctuating tempo
- It can also be used to set all of the selected points to ONE value. Check absolute threshold and set the value you want in both min and max. Make sure you're using BPM. Press New random seed and Apply
Select and adjust tempo markers
Selecting tempo markers
- BPM range: Check to set a range for you selection.
- Time-signature:
- Time range
- All: The whole project is used
- Time selection: Only points within your time-selection is affected
- Ignore time selection: Only points that are outside your time selection are affected
- Shape
- All, linear or square
- Type
- All, tempo markers or time signatures
- Add to current selection
- Iverting obeys criteria
- Select
- Invert
- Deselect every..
Adjust tempo markers
Note: This action will alter overall tempo.
- Current
Displays value for first selected point, value at cursor and value for last selected point.
- Target: Please enter target value for your adjsustment
- Adjust selected markers by:
Here you can choose bpm or percent and enter your desired amount.
- Shape of selected markers
- Preserve: No changes
- Invert: Invert shapes of selected points
- Linear: Set all selected points to linear
- Square: Set all selected points to square
For changing shape and preserving time-positions, you have to use actions Set tempo markers shape to..
Notice:
- The number of selected points are displayed in the dialogs header
Other tools
Split selected items at tempo markers
Use this action to split all affected audio-items on each tempo marker. This is necessary if you want the audio to stay in sync while changing tempo. Works best with square points.
Alternate method for linear points:
Split all affected items in affected area on grid set to typical 1/8 with auto-crossfade (2ms) on.
Action: Split items at timeline grid
