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Audio equivalent of LUT (look up tables)


chrisnewton
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EQ would be the EQ(sorry)uivalent of LUT I guess... Or every other dynamic process like Compression, limiting, gating, phasing, flanging, distortion, reverb, delay, echo, filtering... 

 

When our company shoot short films I'm often the on set mixer and I also do the post on those films, and I now have a set of presets to help me find the direction with certain voices in certain environments. I don't simply add a chain of effects to a track or a clip to get "the right sound", but it helps me get there. The complexity of audio and the way it's captured and the tricks to get it to sound right in the first place makes it hard to really use a LUT in the way that DPs would use it. 

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"LUT is the means to make up the difference between source and result" - http://nofilmschool.com/2011/05/what-is-a-look-up-table-lut-anyway/

 

That sounds like a good definition to me. The comparable audio LUT would have include information about the mic, transmitter, cabling, pre amp and associated circuitry, converter, recording file type, sample rate, bit depth, frequency range specs...

 

It becomes just as complex as picture.

 

Mark O.

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No. A lookup table predicts and/or converts colorspace. I don't agree with the trend to use LUTs as a look -- I think that's the work of the colorist. I don't have a problem applying a LUT to place a raw Log file in linear color space (like normal HD Rec709). In truth, a LUT can be anything you want it to be, as long as the display device is accurate.

 

It has no real relationship in the audio world, because the audio signal is already in the right colorspace. I'd say it's more about dynamic range compression than it is EQ per se, but it's all part of the same thing. Whether for picture or sound, there is no automatic tool that suddenly makes them look and sound "right." You need a human to make those creative decisions. 

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  • 8 years later...

audio developer here :

 

LUTs are used in many places internally in audio DSP, such as for oscillators and waveshaping distortion effects - compressor response curves even.

 

what might be more analogous to colour-space LUTs would be the use of convolution processing, such as for a finite impulse response filter, or a nice juicy reverb effect. These are not LUTs in an exact sense as the output relies on convolution (MUL/ADD) operations stretching over many samples (in the case of reverbs, perhaps many seconds-worth of samples) ... and are often calculated using FFT for the sake of performance ... but in essence, a convolution process in audio determines what the output contribution of a single sample becomes via the process, so, it is *kinda* in the same ballpark : an impulse response is just another audio file, but rather than being used for playback, is used as a transform.

 

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Old topic but I also have my own answer ;)

 

As I have understood it LUTs are generally used for non linear color encoding schemes used in contemporary digital imaging sensors. 

 

An old example of an "audio LUT" could be the µ-Law or m-Law curve used for telephone voice encoding. Nowadays anyway I guess all the equipment we have uses linear coding.

 

In the analog domain the rough equivalent could be a noise reduction companding system such as the Dolby family but with multi band dynamics processing it's no longer something you can specify with a straoghtforward calculation or, as its name says, a look up tablle. So, not really valid. 

 

 

 

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