Spotify's streaming maxes out at 320Kbps.
The service will offer the highest quality the artist and label offers. Sometimes that'll be 192kHz, 24-bit, sometimes it'll be 44.1kHz, 16-bit (aka CD-quality, or what Tidal offers). That'll be the default. If you don't have the bandwidth required to support that bitrate -- 192kHz, 24-bit can be as high as 9Mbps -- six times that of Tidal and around 30-100 times more than Spotify -- then the stream will seamlessly step down in quality, down to CD, through FLAC and all the way down to something like OGG or ACC at 128Kbps.
Exactly how this will work isn't clear. It seems likely that every song will be encoded at many rates and then cut into small segments, each a few seconds long. Then, depending on the speed of the connection and the length of your streaming buffer, the Pono app would choose between the various bitrates on the fly. "You'll be able to move around and there won't be any break in the music, but the resolution of the sound will change and you'll be able to tell what happens when you look at your screen," Young told Rolling Stone.
"...There won't be any break in the music, but the resolution of the sound will change."
Users will have some exposure to adaptive bitrate from YouTube and Netflix -- we've all experienced a crisp video suddenly turning into a pixelated mess at one point. The effect would be jarring if you were suddenly kicked from a 9Mbps lossless file down to a 128Kbps stream, but in reality it's more likely you'd jump between 9Mbps, 4Mbps, 2Mbps, et cetera in smaller increments. To me, the difference between all these encoding methods is nigh impossible to hear, which is both a good and a bad thing. On one hand, it'll make the experience pretty seamless, on the other, it kind of negates the point of a super-high quality streaming service in the first place.
Apple Music's quality slider.
Young hopes that this adaptive bitrate streaming method will "educate people on the difference between high-resolution music and regular streaming level music, which would be the bottom level for our streaming service."
Hopefully other streaming services will take note. It's not like Pono is about to persuade the many, many paying subscribers of Spotify and Apple Music to jump ships. But these services could learn a little here. It's incredibly annoying to have a song cut off when your data connection can't support 320Kbps audio, but would probably be fine at 192Kbps. Spotify does offer an "automatic" bitrate option, but it tops out at 96Kbps. As far as I can tell (I've reached out to Spotify for clarification) it's not adaptive in the same way.
One big question left to answer for Pono, though, is what devices the service will work with. Almost every phone lacks the ability to playback 192kHz audio through its headphone jack. Audiophiles typically use an external solution to playback the highest quality files, which would work here too.
There's light at the end of the tunnel for those not willing to go to those lengths, though: Now that Apple has dropped the headphone jack, and other companies seem to be following suit, the onboard digital-to-analog-converter (DAC) is bypassed in favor of one inside the headphones. That means if your Lightning, USB-C or wireless headphones support 24-bit/192kHz audio you won't have a problem.
When exactly Pono will launch or even formally reveal the streaming service isn't clear. (Nor is how much it will cost). Young says Pono is working with a Singaporean company to enable adaptive bitrate streaming, while negotiating the necessary audio rights to fill the service with music. Given the original Pono made an appearance at CES 2015, and the electronics show is just a few weeks away, there's hope it could come soon, and hopefully push more-conventional streaming services into upping their game a little.