If you stream music from an Android phone to a pair of wireless headphones, there’s a very good chance your devices are relying on a compression algorithm known as AptX, which is supposed to squeeze high-quality sound into the limited bandwidth provided by a Bluetooth connection. But existing AptX options have their limits, so Qualcomm — the company behind AptX since 2015 — is introducing a new version that’s supposed to grow and contract the size of audio data to meet the demands of whatever and wherever you’re actually streaming.
The new version of AptX is called AptX Adaptive, and its key feature is the ability to compress audio at a variable bitrate. That means if you’re in an environment with a lot of competing wireless signals, your phone will be able to compress your audio into a smaller file size so that it’s easier to stream to your headphones. And if you’re in an empty room listening to music, AptX Adaptive will allow your phone to send a higher bitrate file so that you get better audio quality.
Audio quality adjusts based on what you’re playing
Qualcomm says AptX Adaptive’s abilities go beyond just responding to signal strength. The codec will also take into account what kind of audio you’re streaming — if it sees the audio is coming from Netflix, it’ll know it’s a movie or TV show, for instance — and can adjust its settings according to the situation’s needs. This will all happen behind-the-scenes, Qualcomm stresses, without any need for users to select a mode on their phone or identify what they’re listening to.
AptX Adaptive is meant as a replacement to traditional AptX and the newer AptX HD. Its bitrate can actually go lower than normal AptX (down to 280kbps, whereas AptX was a flat 384kbps), but it can’t reach quite as high as AptX HD (only going up to 420kbps, instead of 576kbps). Chris Havell, senior director of product marketing at Qualcomm, says that the limit doesn’t mean worse audio because compression improvements have allowed AptX to achieve the same level of quality in a smaller file size.
“We basically improved the codec so what you were getting at 576 you now get at 420,” Havell says. Reducing the bitrate also means more bandwidth for resending data that didn’t make it over to your headphones, meaning the connection could be stronger, too. Havell also says AptX Adaptive isn’t stuck at just those two points — 280kbps and 420kbps — it can fluctuate anywhere in between as the situation demands.
AptX Adaptive is supposed to be built into Android Pie, so phones coming out over the next year will have support for it. Havell says he expects headphones with AptX Adaptive support to arrive in the first half of 2019. Those headphones will be backward compatible with older versions of AptX, too, so they’ll work even if your phone isn’t on the latest version of Android.
Unfortunately, the iPhone doesn’t support AptX, so this upgrade will really only impact Android phones. Beats headphones don’t use AptX either, which means customers of one of the most popular wireless headphone brands will miss out.
If you’re buying wireless headphones in the future though, you can always check the box to find out if they support AptX. Companies have to license the technology from Qualcomm, and part of the deal is a requirement that it be advertised on the box, so you’ll know it’s there.