What is dithering and how does it work?
If you want to output audio in 16bit that was originally produced in 24bit or 32bit, it is recommended that you use the technology called dithering that will prevent sound degradation.
Dithering is a technique that will add a small noise that helps the sound become closer to the original audio.
Introduction To Dither | iZotope Insider Tips
In the digital world, you need to first understand about bit depth.
In easy terms, bit depth is the number of blocks that can be used to express the amplitude of the sound, from silence to maximum volume.
24bit has more blocks than 16bit so audio can be expressed in a higher definition.
Let’s say you have created your music in 24bit resolution.
To upload your music on the Internet, you want to convert your audio to MP3, so you want to convert your audio to 16bit first.
By lowering your bit resolution, you are decreasing the number of blocks to express the amplitude of the song.
This figure is overly simplified, but it shows you that you originally had 24 blocks to represent the sound.
Now you can only represent your sound using 16 blocks.
Then you will come across an intermediate sound that cannot be expressed.
You will need to force to move the intermediate sound to the nearest value.
The situation where this intermediate sound cannot be represented is called “quantization error.” When quantization error occurs, you will get a sound degradation called “truncate distortion.”
Truncate distortion is an unpleasant sound, so it must be handled properly.
So, that’s where dithering comes in.
As I mentioned at the beginning, you are able to prevent sound degradation by adding a small noise. Basically, you are masking the truncate distortion in exchange for noise.
However, the distortion is still noticeable at this point.
That is why you need to use the “noise shaping” option.
By applying an EQ to the noise, it is possible to move the energy of the noise to an inaudible band.
By utilizing the noise shaping option, you can further mask the truncate distortion.
Now you know how to convert your 24bit or 32 bit audio to 16bit without a significant deterioration of sound quality.
Dithering is also widely used in other areas
The technology of dithering is widely used in other genres as well. For example, the world of image processing and photo is a good example.
See the image below.
When you convert to a 8bit image to 1bit, image is divided clearly into black and white.
If you add a dithering noise before converting from 8bit to 1bit, you can create an image closer to the original image quality than simply converting to 1bit.
Furthermore, if you add a noise shaping dithering noise before converting from 8bit to 1bit, the image quality is even closer to the original image quality.
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