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AudioTimeStretch
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AudioTimeStretch

Updated in 14.1

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AudioTimeStretch[audio,r]

applies time stretching to audio by the specified factor r.

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AudioTimeStretch[video,r]

applies time stretching to the first audio track in video.

Details and Options

  • AudioTimeStretch stretches the input audio signal to the specified duration while preserving the pitch.
  • The factor r can be any of the following:
  • rthe duration will be multiplied by r
    Scaled[r]the duration will be multiplied by r
    Quantity[dur,unit]specifies the resulting duration dur in the given time unit
  • The following options are supported:
  • Method Automaticthe method to use
    PartitionGranularity Automaticcontrol the partitioning used for the computation of the short-time Fourier transform
  • By default, a phase vocoder algorithm is used. Use Method->"Speech" for time stretching speech signals.

Examples

open allclose all

Basic Examples  (2)Summary of the most common use cases

Stretch audio by a factor of two:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-kc30u3
Out[2]=2

Plot the original and stretched audio:

In[3]:=3
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https://wolfram.com/xid/0ywet3v2e7eu-ov9v2b
Out[3]=3

Stretch an Audio object to a full duration of 3 seconds:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-nbpw4x
Out[1]=1

Scope  (3)Survey of the scope of standard use cases

Stretch an Audio object by a factor of 2:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-3wxaq
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0ywet3v2e7eu-k9bfsf
Out[2]=2

AudioTimeStretch alters the duration of complex sound without changing its timbre and pitch:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-m3rklt
Out[1]=1

Stretch the audio object by a factor of 1.5:

In[2]:=2
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https://wolfram.com/xid/0ywet3v2e7eu-biihxy
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0ywet3v2e7eu-wj0ynu
Out[3]=3

Process the audio track of a video:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-l7x9gq
Out[1]=1

Options  (4)Common values & functionality for each option

Method  (1)

Use Method->"Speech" for speech signals to get a better quality result:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-fl2yat
Out[2]=2

In comparison, the normal time stretching sounds less defined:

In[3]:=3
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https://wolfram.com/xid/0ywet3v2e7eu-9p5f9c
Out[3]=3

PartitionGranularity  (3)

Using a bigger partition size will improve the frequency response but will smear the transient components:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-whst33
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0ywet3v2e7eu-3gccat
Out[2]=2

Using a small offset value will in general increase the quality of the result at the cost of more computation time:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-qz25v7
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0ywet3v2e7eu-gni05i
Out[2]=2

By default, HannWindow is used:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-fyptok
Out[1]=1

Use Dirichlet window to perform no smoothing:

In[2]:=2
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https://wolfram.com/xid/0ywet3v2e7eu-c5j3cz
Out[2]=2

Specify a different window:

In[3]:=3
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https://wolfram.com/xid/0ywet3v2e7eu-d1jyce
Out[3]=3

Applications  (1)Sample problems that can be solved with this function

Change the duration of an audio object to match the duration of another one:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-ox1bfs
In[2]:=2
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https://wolfram.com/xid/0ywet3v2e7eu-yph5cs
Out[2]=2

Stretch the audio to match the duration of the target one:

In[3]:=3
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https://wolfram.com/xid/0ywet3v2e7eu-c59922
Out[3]=3
In[4]:=4
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https://wolfram.com/xid/0ywet3v2e7eu-3b7lki
Out[4]=4

Properties & Relations  (1)Properties of the function, and connections to other functions

Change the duration of a recording by using a different sample rate:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-ovulfd

It will also affect the pitch:

In[2]:=2
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https://wolfram.com/xid/0ywet3v2e7eu-uxr4ge
Out[2]=2

AudioTimeStretch does not alter the pitch:

In[3]:=3
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https://wolfram.com/xid/0ywet3v2e7eu-kvfgtq
Out[3]=3

Possible Issues  (2)Common pitfalls and unexpected behavior

The quality of the result degrades with large stretch parameters:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-shsu1w
Out[1]=1

Using Method->"Speech" for non-speech signals may not lead to expected results:

In[1]:=1
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https://wolfram.com/xid/0ywet3v2e7eu-g2l9fu
Out[1]=1
Wolfram Research (2016), AudioTimeStretch, Wolfram Language function, https://reference.wolfram.com/language/ref/AudioTimeStretch.html (updated 2024).
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Wolfram Research (2016), AudioTimeStretch, Wolfram Language function, https://reference.wolfram.com/language/ref/AudioTimeStretch.html (updated 2024).

Text

Wolfram Research (2016), AudioTimeStretch, Wolfram Language function, https://reference.wolfram.com/language/ref/AudioTimeStretch.html (updated 2024).

✖
Wolfram Research (2016), AudioTimeStretch, Wolfram Language function, https://reference.wolfram.com/language/ref/AudioTimeStretch.html (updated 2024).

CMS

Wolfram Language. 2016. "AudioTimeStretch." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2024. https://reference.wolfram.com/language/ref/AudioTimeStretch.html.

✖
Wolfram Language. 2016. "AudioTimeStretch." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2024. https://reference.wolfram.com/language/ref/AudioTimeStretch.html.

APA

Wolfram Language. (2016). AudioTimeStretch. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/AudioTimeStretch.html

✖
Wolfram Language. (2016). AudioTimeStretch. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/AudioTimeStretch.html

BibTeX

@misc{reference.wolfram_2025_audiotimestretch, author="Wolfram Research", title="{AudioTimeStretch}", year="2024", howpublished="\url{https://reference.wolfram.com/language/ref/AudioTimeStretch.html}", note=[Accessed: 21-April-2025 ]}

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@misc{reference.wolfram_2025_audiotimestretch, author="Wolfram Research", title="{AudioTimeStretch}", year="2024", howpublished="\url{https://reference.wolfram.com/language/ref/AudioTimeStretch.html}", note=[Accessed: 21-April-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_audiotimestretch, organization={Wolfram Research}, title={AudioTimeStretch}, year={2024}, url={https://reference.wolfram.com/language/ref/AudioTimeStretch.html}, note=[Accessed: 21-April-2025 ]}

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@online{reference.wolfram_2025_audiotimestretch, organization={Wolfram Research}, title={AudioTimeStretch}, year={2024}, url={https://reference.wolfram.com/language/ref/AudioTimeStretch.html}, note=[Accessed: 21-April-2025 ]}