LOS ANGELES, June 17 — As consumer interest in high definition audio increases, music labels and tech companies are coming together to standardise music file types and definitions.

Unlike for video, where if a clip is called HD it has to be 1080p, or for television where the much-heralded 4K UHD image quality has to be of an aspect ratio of at least 16:9 and resolution must be a minimum of 3840x2160 pixels, when it comes to music, things aren’t so clear.

However, thanks in part to the overwhelming success of Pono, Neil Young’s HD audio download store and music player that raised a phenomenal US$6.2 million on Kickstarter -- making it the third most successful campaign in the crowdfunding site’s history -- the labels are tuned in and listening intently.

As first reported by Twice, a unifying definition of what constitutes high resolution audio has been agreed on. So, to qualify, a song, be it on a disc or offered as a digital file, has to be capable of “reproducing the full range of sound from recordings that have been mastered from better than CD-quality music sources.”

Four file formats have also been agreed and they are: MQ-P; MQ-A; MQ-C; and MQ-D. In each instance, the ‘M’ stands for Master -- i.e., the file is produced from the master recording, whether that master is digital or analog (as in MQ-A). The MQ-C file denotes a master that came from a CD but one in which legacy CD masters are employed as source material and up-sampled to high resolution.

This is one of the issues surrounding HD audio. CDs offer excellent sound quality but at a 44.1kHz sampling rate, and in 16-bit resolution. So, some audio information will be lost. By upping the sampling rate to 48kHz and resolution to 20-bit, some of those gaps can be filled in.

At the same time, there is also a debate raging, with publications taking sides on the issue of whether or not the human ear is capable of discerning the difference between CD and better-than-CD quality. Although the four file types put forward by the record labels all offer sound quality in above CD 20-bit resolution, none of them goes as far as the files that Neil Young will be offering on his Pono Music site -- 24-bit audio sampled at 192 kHz.

The move is a welcome one, especially for audiophiles still clinging to their turntables and vinyl while dreaming of something more mobile, but so far everything that has been agreed to is voluntary.

Demand will have to move closer to the mainstream before we start seeing HD Audio logos for instance. — AFP Relaxnews