# Retrieving entire timeline's sound file spectrum

**URL:** <https://qa.fmod.com/t/retrieving-entire-timelines-sound-file-spectrum/18359>\
**Category:** FMOD Engine\
**Tags:** csharp, cpp\
**Created:** [February 14, 2022, 6:05pm UTC](https://qa.fmod.com/t/retrieving-entire-timelines-sound-file-spectrum/18359 "2022-02-14T18:05:04Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![intofin](https://avatars.discourse-cdn.com/v4/letter/i/ea666f/32.png) [@intofin](https://qa.fmod.com/u/intofin)\
**Post date:** [February 14, 2022, 6:05pm UTC](https://qa.fmod.com/t/retrieving-entire-timelines-sound-file-spectrum/18359/1 "2022-02-14T18:05:04Z")

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Hi ,

I need to get FFT of a sound file to display a spectrogram for entire sound file timeline.  
I was able to get the FFT after calling play on the sound file, however, as far as I understand it just gives me the first window, how do I go about and “move” that sliding on the entire file(without missing windows)? Is there a callback I should hook into where I could call “getParameterData”

Any help will be appreciated!

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**Author:** ![jeff\_fmod](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/jeff_fmod/32/1766_2.png) [@jeff\_fmod](https://qa.fmod.com/u/jeff_fmod)\
**Post date:** [February 18, 2022, 3:28am UTC](https://qa.fmod.com/t/retrieving-entire-timelines-sound-file-spectrum/18359/2 "2022-02-18T03:28:52Z")

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I think I might need to see how you are using the FFT to understand the question here- is this audio file being played back in real-time? The spectrum data is populated during `System::update`, so while playing back an audio file the FFT spectrum data will also be filled.