Steinberg Nuendo 3 Operation Manual

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11.Click and drag the grid to the right until the second bar in the ruler is 
aligned with the position of the second downbeat of the sample, and 
release the mouse button.
The correct tempo is automatically calculated, based on the time it takes for one bar to 
finish.
12.Now you can enter Musical mode, and the audio clip will adapt to the 
tempo in Nuendo.   
						

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Warp tabs and the Warp Samples tool
Warp tabs are a kind of marker or anchor that can be attached to mu-
sically relevant time positions in an audio event, e.g. the first beat of 
every bar. Warp tabs can be dragged to the corresponding time posi-
tions in the project, and the audio will be stretched accordingly. 
A typical application of warp tabs is to make an audio file with a vary-
ing tempo lock to a strict tempo. Using this method, any performance 
recorded “live” with natural tempo variations can be adapted to a spe-
cific, exact tempo. 
Using warp tabs
Warp tabs are created using the Warp Samples tool in the Sample Ed-
itor, but can also be created from hitpoints (see page 448) or by using 
Quantize Audio (see page 449). In this example we will demonstrate 
how a file with a slightly varying tempo can be locked to a steady tempo 
by using warp tabs.
1.Open an audio file you wish to process in the Sample Editor.
2.Select the Audio Tempo Definition tool and enter the original tempo 
(if this is non-varying) or the length of the file.
3.Enter Musical mode so that the audio event is stretched to the project 
tempo.  
						

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4.Select the Warp Samples tool (the arrow and clock button) on the 
Sample Editor toolbar.
A grid appears in the waveform display, and warp tabs are automatically added at the 
start and end of the audio clip. These are locked and cannot be removed. 
The Warp Samples tool.
For aligning the tempo you should use Bars and Beats as the ruler 
resolution. When you place the mouse pointer in the waveform display 
it changes to a clock with arrows on either side, and a vertical line in 
the middle which represents the pointer. When you move the pointer 
in the waveform window it shows the position in bars, beats and ticks 
as well as in seconds.
5.Line up the audio file so that the first beat of the first bar (in the audio 
event) starts on the first beat of a bar in the project.
If the audio file doesn’t start on a downbeat you can use the Event Start handle in the 
Sample Editor and adjust the position in the Project window so that the first downbeat 
in the sample is aligned with the first beat of a bar in the grid.
Now the musical first downbeat should be aligned with the first beat of a bar in the 
project. The next step is to see where the first warp tab needs to be added. It may be 
useful to hear the metronome click to determine when the tempo of the audio clip drifts 
from the project tempo. To hear the metronome you have to activate Click on the 
Transport panel and play back using the transport controls.
6.Play back the audio file, either by auditioning in the Sample Editor or 
from the Transport panel, and see (and listen for) where the first beat 
of a bar in the audio event does not match the corresponding ruler po-
sition in the project.
If you find it difficult to pinpoint an exact position in the audio event you can switch to 
the Scrub tool and/or zoom in the view. Switch back to the Warp Samples tool when 
you have found the position.  
						

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18 – 444 Audio warp realtime processing
7.In our example the first beat of bar 3 in the audio event is slightly offset 
from the corresponding grid position and thus needs to be moved 
back a bit.
The arrow points to the third downbeat in the audio event.
8.Place the pointer at the position of the first beat in the audio event and 
click and hold.
When you click a warp tab is added.
9.With the mouse button still pressed, drag the warp tab so that the po-
sition lines up with the first beat of the bar in the ruler.   
						

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Audio warp realtime processing 18 – 445
10.Release the mouse button.
Now the first beat in the audio event is perfectly aligned with the corresponding posi-
tion in the project! 
•If you prefer, you can first add warp tabs at the relevant musical posi-
tions and change their positions later – see page 446.
Beside the warp tab handle in the ruler, a number is shown. This num-
ber indicates the warp factor, i.e. the amount of stretch. Warp factor 
numbers higher than 1.0 indicate that the audio region preceding the 
warp tab is expanded and will play back slower. Warp factor numbers 
lower than 1.0 indicate that the audio region preceding the warp tab 
is compressed and will play back faster. 
11.Continue to use the same general method to align the first beat in 
each bar to the corresponding ruler position.
You only have to add warp tabs where the downbeat in the audio file drifts from the 
ruler position, and/or if you want to fixate a warp tab so that it is not moved when edit-
ing other points. 
When you are done, the previously varying tempo of the audio event 
will be metronome steady and will adapt to any tempo in Nuendo.
This example illustrates the general methods of using warp tabs and 
the Warp Samples tool. But you can of course use warp tabs for other 
operations than aligning downbeats to grid positions. With the Warp 
Samples tool you can literally stretch any region within a sample to 
any position!  
						

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18 – 446 Audio warp realtime processing
Editing warp tabs
Moving the destination position of existing warp tabs
•To move an anchored destination position of a warp tab (and thus 
stretch the audio), select the Warp Samples tool and position the 
pointer on the Warp line in the waveform so that the line in the middle 
of the pointer becomes blue. Then click and hold to move the position 
of the warp tab. 
Moving the source position of existing warp tabs
•If you simply wish to move the position of a warp tab without stretch-
ing the audio, click and drag the warp tab header in the ruler.
Deleting warp tabs
•To delete a warp tab, press [Shift] so that the pointer becomes an 
eraser and click on the warp tab.    
						

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Unstretching audio files
By selecting “Unstretch Audio” from the Realtime Processing sub-
menu on the Audio menu, all time stretching (by sizing or by warp 
tabs) can be removed.
Whether the “Unstretch Audio” menu item is available depends on 
whether the time stretching was applied on the event or clip level: 
•If you sized an audio event in the Project window using the “Sizing 
Applies Time Stretch” tool (see page 138), you can undo the time 
stretching by selecting the event in the Project window and then ap-
plying “Unstretch Audio”.
This will remove all time stretching and warp tabs.
•If you added warp tabs to a clip in the Sample Editor, you have to 
open the audio file in the Sample Editor to be able to invoke the 
“Unstretch Audio” function. 
Selecting “Unstretch Audio” will then remove all warp tabs in the clip, but not any time 
stretching applied in the Project window (on the event level).
• Note that if Musical Mode is activated, realtime stretching is still active. 
When you have entered a tempo and/or length using the Audio Tempo 
Definition tool, this information is saved for the source clip.
Showing/hiding warp tabs
When you are using other Sample Editor tools than the Warp Samples 
tool you can decide whether to show or hide warp tabs by clicking the 
Show Warp Tab button.  
						

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18 – 448 Audio warp realtime processing
Warp settings
The “warp settings” pop-up menu, which is located on the Sample 
Editor toolbar, contains various presets affecting the realtime time 
stretching sound quality. These presets have self-explanatory names 
like “Drums” and “Mix”, where the parameters involved have been 
optimized for the corresponding type of audio material. 
Advanced settings
If you select the Advanced menu item, a dialog opens where you can 
manually change the three parameters that govern the sound quality 
of the time stretching:
Creating warp tabs from hitpoints
You can also create warp tabs from hitpoints selecting “Create Warp 
Tabs from Hitpoints” on the Audio menu – Realtime Processing sub-
menu. This can be useful when applying Audio Quantize, see below.
For descriptions of how hitpoints are created and edited please refer 
to the chapter “Working with hitpoints and slices”.
Parameter Description
Grainsize The realtime time stretching algorithm splits the audio into small pieces 
called “grains”. This parameter determines the size of the grains. For 
material with a lot of transients you should use low Grainsize values for 
best results. 
Overlap Overlap is the percentage of the whole grain that will overlap with 
other grains.
Variance Variance is also a percentage of the whole length of the grains, and 
sets a variation in positioning so that the overlapping area will sound 
smooth. A Variance setting of 0 will produce a sound akin to time 
stretching used in early samplers, whereas higher settings will pro-
duce more “smearing” effects but less audio artefacts. 
						

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Quantizing audio
You can use realtime time stretch to quantize audio. This is achieved 
by using hitpoint detection and adding warp tabs at the positions of 
each detected transient in the audio clip. When you apply audio quan-
tize the warp tabs stretch the detected “hits” to the grid positions the 
selected quantize-grid is set to. Warp tabs that are not quantized will 
be removed.
The quantizing can either be applied by automatically creating warp 
tabs at the position of existing hitpoints, or you can first create hitpoints, 
then create warp tabs from these before finally applying the quantizing.
For descriptions of how hitpoints are created and edited please refer 
to the chapter “Working with hitpoints and slices”.
In the following description we shall apply Quantize Audio after first 
creating hitpoints, and then creating warp tabs from these. 
1.Open the audio clip in the Sample Editor, specify the length or tempo 
with the Audio Tempo Definition tool selected, and activate Musical 
mode.
2.Calculate hitpoints in the audio event using the normal methods, but 
don’t create slices.
Note that if Q points are used (see page 466), the quantizing will be applied to the po-
sition of the Q point. Also note that when creating hitpoints for audio quantizing – as 
opposed to for creating audio slices – it is not necessary to have hitpoints at all “hits” 
in the sample. You might just want to quantize a section of an audio clip, and leave the 
rest unprocessed. 
3.When you have finished setting hitpoints, select “Create Warp Tabs 
from Hitpoints” from the Audio menu - Realtime Processing submenu.
4.Close the Sample Editor and select the audio event in the Project 
window. 
						

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18 – 450 Audio warp realtime processing
5.Select a quantize resolution from the Quantize Type pop-up, e.g. 1/8.
Here is a section of the sample before applying Quantize Audio. The hitpoints are 
not on exact grid positions.
6.Select “Quantize Audio” from the Audio menu – Realtime Processing 
submenu.
Now the audio event is quantized by applying time stretch.
7.Open the audio event in the Sample Editor, and either select the Warp 
Samples tool or activate the “Show Warp Tabs” button on the toolbar.
Warp tabs have automatically been added at the hitpoint positions needed to quantize 
the audio to the set resolution.
Here is the same audio event after applying Quantize Audio with a 1/8 quantize 
resolution. The hitpoints are now quantized (or stretched) to exact grid positions.
•To remove the quantizing from an audio clip, select “Unstretch Audio” 
from the Realtime Processing submenu on the Audio menu.