Firstly, what is an audio codec?
Put simply, an audio codec is a programme that encodes and decodes audio data between devices. Audio codecs allow us to stream and receive audio at lower bit rates without affecting the quality of the audio.
There are two different types of audio codec, Lossy and Lossless.
Lossy audio formats don’t decompress back to their original file size. This is because some data that our ears can’t perceive is lost during transmission to make the file size smaller.
Lossless formats, however, decompress back to their original size. This allows us to maintain the exact same size/quality when streaming audio.
LISTENTO allows you to transmit with either AAC (Advanced Audio Coding), PCM (Pulse Code Manipulation) and most recently, the OPUS Codec.
So, what’s the difference between these 3 audio formats?
Let’s start with our newest addition, OPUS Codec.
OPUS Codec is a lossy audio format primarily used for low bit rate VoIP (Voice Over Internet Protocol) OPUS has been named ‘the Swiss army knife of audio codecs’ for good reason!
OPUS performs well at low bit rates making it a great format to choose when transmitting to or from locations with sub-optimal internet speeds while maintaining high quality audio. For example, OPUS is great for transmitting speech and music with minimal latency.
Next, we have AAC (Advanced Audio Coding).
AAC is also a lossy audio format primarily used for streaming audio for internet radio. AAC provides great audio quality and is used by YouTube and Apple Music.
AAC’s encoders/decoders are more processor-heavy than OPUS and may require higher latency than OPUS.
Finally, we have PCM (Pulse Code Modulation).
PCM is another method of translating analogue signals into digital data. It makes use of the binary language to store information about an audio signal in a digital medium.
PCM takes place over three stages:
- Sampling – Samples are snapshots of the incoming signal which record the amplitude of the signal at that given moment.
- Quantization – Quantization rounds those amplitude values to the nearest available value in the digital system, based on its bit depth.
- Encoding – Encoding is the final stage where the newly sampled audio information is written to a hard drive or other digital storage medium in a given format to be used elsewhere.
For bandwidth details, please refer to page 9 of the LISTENTO User Guide under ‘Resources’ to see our recommended streaming and internet settings.
