We tell you everything you need to know about Opus, the new audio format of SoundCloud. The outrage came after a SoundCloud user believed he had discovered that the platform had halved the bitrate of his audio file. Actually, SoundCloud has transitioned from the transmission of MP3 files to Opus files, a supposedly superior audio file format.

An uproar went on after tweets from the New Jersey Direct producer about an alleged degradation in SoundCloud’s audio quality, something that went viral. Although the “death” of MP3 in 2017 was great news, it is still one of the main formats used to compress and store audio files for both consumers and DJs.

Here is the reality: SoundCloud has deleted 128kbps MP3 files for 64kbps Opus files and the company itself does not claim any change in audio quality. “We have been using the Opus codec (among others) since 2016, and we regularly test different combinations of coding and transmission to offer listeners a quality experience on any device,” a spokesman told Billboard in response to violent reactions. “In addition, we store all the content of the creators in its originally loaded quality level so that we can continually adapt to advances in coding and reproduction.” So why, then, is the bit rate reduced by half?

First, let’s talk about codecs

A codec is software that compresses data for faster transmission. Both MP3 and Opus are examples of a codec that takes audio data and compresses it in a smaller size, so it takes up much less space or bandwidth and it is faster to send them over networks. Both are also considered “lossy” codecs, which means that the software analyzes the data and filters what is considered unnecessary. With audio data, that could mean high frequency sounds generally unheard of for human ears or even quieter sounds that can be masked with louder sounds in the audio.

However, one of the benefits of lossless codecs is that you can determine how much you keep or filter. That is the bit rate, which tells the file the amount of data to send to its recipient. Naturally, a 128 kbit / s MP3 file sounds much better than a 64 kbit / s MP3; Compression is less than reduced quality. But although MP3 and Opus files do the same, Opus is supposed to be better at choosing the details of the file it should keep. Some of this has to do with updated technology. MP3 is a dinosaur, last year, its creators even declared him dead, and it was finalized as software in 1993; Opus was finalized in 2012.

Using better software seems a sufficient reason for SoundCloud to start using Opus files. Opus is also “open standard”, which means it is 100% free for anyone to use. (The MP3 files were proprietary software and included copyright).

Companies like Mozilla and Microsoft support the software, while Google uses Opus for Google Hangouts. Many tracks on YouTube also use Opus. But how else does the use of Opus files benefit the listener? The lower bit rate means using less bandwidth, which allows faster start times (less delays between playing and listening), higher reliability on lower quality or slower connections, such as cellular service and less monetary charges (one possible advantage for SoundCloud users in states where the repeal of net neutrality means that Internet providers can start raising prices for subscribers who use more data).

For SoundCloud itself, reducing bandwidth use by half will significantly reduce internal costs and saving money is probably a priority after a financially unstable 2017.

In general, you can get excellent sound from 64 kbit / s Opus files and most listeners will have difficulty distinguishing them from the original audio. Some will argue that 64kbit / s is too ambitious a reduction and that Opus 96kbit / s files would be a better alternative that would still reduce costs without degradation in audio quality.

Actually, most people won’t be able to tell the difference at all.

You may also be interested: Has SoundCloud lowered the audio quality?