It is well known that selecting an encoder is not an easy task! It is important to know? the characteristics of each encoder, and then compare the advantages and disadvantages of each one before making a final decision. In this article, we will share our views on the evaluation criteria for choosing an encoder. But first, let’s talk about…
Basic knowledge of how to choose an encoder:
Before we start to distinguish different encoders based on their own characteristics, it would be better if we know a bit about them first. Because usually after weighing up all the factors or specifications, it would come down to personal preferences in the end.
There are mainly four types of encoders: Analogue/Digital/DVS, and Hardware/Software.
- Analogue/Digital: Analog is a signal that never changes in form, but instead changes only in strength; digital is an indication of the number (0 or 1) that represents the signal strength. Digital can be transmitted through wires or streamed through the air via radiofrequency. The advantage of analog is you don’t need any processor power to decode it, and it can be converted into sound immediately (hence the name). The downside is that analog signals tend to be unstable and susceptible to interference (crosstalk). The more stable the signal, the better it can be processed.
- DVS: Digital signal that is transmitted through wires or over radiofrequency. The advantage of digital is it can be losslessly encoded and decoded and can reach longer distances than analog. The downside is that it demands more processing power.
- Hardware/Software: Hardware is a transmitter that uses its program to send data in an encrypted format over wires or radio frequencies (think of your personal computer keyboard sending every keystroke to another computer). The software also uses a program to encrypt data but instead sends the necessary information through a network (think of your Netflix subscription). The advantage of hardware is that it is a simple one-way data transfer. The downside is that because the information has to pass through multiple steps, it should be stable to avoid errors. The software allows for two-way communication, but because it doesn’t have to pass through as many steps, it doesn’t necessarily have to be as stable.
This would be important when choosing an encoder for a multi-channel system, and even more so for receiving digital signals from a hard drive or radiofrequency transmission. There are two main types of input: output and input. Output is when an encoder takes a signal and converts it to light that then travels through a fiber optic cable (usually 10-100m) to another computer. Input would be the opposite, taking the light that comes from another computer through fiber optic cable and decoding it with an encoder (usually located on and in the same case as a DJ controller). Both of these types of input/output have their pros and cons, which we will discuss later, but for now, it is important to know which type you need.
The samples per second rate is how many times per second does the encoder sends data to be decoded by a receiver. Some common rates are 44100, 48000, and 96000. The higher the sample rate, the greater the resolution. The disadvantage is that the data flow would be too great to process (remember, this is dependent on the encoder and receiver) so distortion is likely to occur if there isn’t enough processing power (the hardware or software must be able to handle this rate).
This describes how much information there can be per sample; usually from 8 bits to 16 bits. The greater this number, the more information can be transmitted within a second. The disadvantage is that it requires more processing power from your computer (or DVS if you are using that) and you may experience some distortion.
It indicates how much data is transmitted between two points of communication within a certain amount of time. The higher the bandwidth, the more you can transfer.
How can you now choose an encoder?
After knowing some of these encoder basics, how can you now choose an encoder? Let’s take a look at these characteristics one by one to find out!
Analogue/Digital: These are two different encoding methods that each have their pros and cons. Analogue generally has more noise than digital but doesn’t need as much processing power to encode/decode it. Digital has more noise during transmission than analog but is also faster and more stable than analog (due to less interference from other signals). The main advantage of analog is that it can be decoded instantly, but the disadvantage is that it can also be easily distorted and susceptible to interference. The main advantage of digital is that it doesn’t require as much processing power, which means less distortion is likely to occur.
Encoder type: Unless you are a multi-user server where you need to cut down on noise and keep your signal stable, you would want the least amount of processing power from your encoder (it will always be more efficient investing your money towards hardware or software). For example, if you are only playing 2 decks out of 3 then a Hardware encoder will suffice.
If you were to be transmitting data through radio frequency, then a Software encoder is more applicable. In the case of an analog signal, you would want an analog encoder (as it doesn’t require as much processing power).
Input: Generally, people would prefer to have input that comes from the computer directly. The main reason is that if there is no interference, it will be lower in noise. However, this also has its disadvantages such as less stable signal and greater distortion. In the case of radio frequency transmission, it would be best to have input from a computer (as it will be lossless) or input directly from a DVS (as DVS doesn’t suffer loss and interference).
Output: This is dependent on the type of input and output you have. For example, if you have an analogue input and output, then an analogue output is the better option because it will be less noisy. If it was digital input and either analog or digital output then a digital output would be better (as there will be less noise). The disadvantage of not having both analog and digital as your inputs/outputs are that it can’t be connected to other systems (you would need to convert from one format to another).
Sample Rate: The higher the sample rate, the greater your resolution and the more processing power that’ll be required. The disadvantages are that higher sample rates may result in more distortion.