2015 has seen high-resolution audio (HRA) hit the mainstream, thanks to the release of more devices and services that support the audio format.

From Neil Young’s PonoPlayer to high-res audio support on the Sony Xperia Z3 and high-res streaming on Qobuz, there’s been plenty of noise around HD audio.

But how did it all start and where is the market heading?

As the music industry shifted away from physical media such as CD and vinyl (the vinyl resurgence not withstanding), many of us moved to digital downloads from sites such as Amazon and iTunes, and latterly streaming services, such as Spotify.

These sites use compressed file formats with relatively and low bitrates, such as 256kbps AAC files on iTunes and 320kbps MP3 streams on Spotify.

And with regards to sound quality, these formats aren’t telling the full story of our favourite songs. The use of lossy compression means that data is lost in the encoding process, which means resolution is sacrificed for the sake of convenience and smaller file sizes.

This might be fine on the bus when you’re listening to your iPod or smartphone, but some serious music fans want better. This is where high-resolution audio – or HRA, the term coined by the Consumer Electronics Association – steps in.

Astell & Kern, LG, Samsung, Sony and FiiO are just some of the companies to have launched high-resolution audio compatible products so far, while several download sites now offer better-than-CD quality music files, with the likes of HDtracks and Qobuz now live in the UK. HRA also has the support of major labels and musicians.

But what does high-resolution audio actually mean? Where can you get it? And what do you need to play it on? Don’t worry – all your questions and more are answered on this page.