Airplay's dirty little secret
by Volker Weber
Waiting for the AirPlay 2 upgrade? Part of that upgrade is a larger latency, which is the opposite of what you want. What is latency? It is a delay in the signal. Why is Apple doing it? It is a lazy way to solve dropouts.This is quite noticeable if you play a piece of video on your computer and send the sound via Airplay 2 to a speaker.
If you send music across a network, packets don't arrive in a steady stream. Some packets are fast, others take more time. You can solve this by creating a buffer at the receiving end that makes sure you always have the next piece of music ready so you can continue to play. With Airplay 2 the problem got worse since Apple now needs to be able to serve the same signal to multiple speakers and keep them all in sync.
A large latency isn't tolerable if you do real time communications. Can you remember a time when long distance calls would have this terrible latency so that you couldn't easily have a normal conversation because you would not know if the other person has started talking? That is no longer the case. VoIP development is all about reducing latency. Not Apple. They just increased the latency. Airplay continues to be a terrible design.
Comments
Please watch live TV for a few minutes, the exact same channel in parallel, and only discriminated by the transport channel:
* coax cable
* satellite
* IPTV (multicast)
* IPTV (unicast)
Enjoy your neighbours cheering the freaking fantastic goal while the attacking team prepares to kick the corner.
*That* is latency.
Still Airplay works so much better than Bluetooth or dlna.
After the Homepod was introduced during that keynote, I‘ve ordered a bunch of Sonos Speakers for my home.
Some of the speakers are connected to my TV and I experience no noticeable delay with that setup. I still think that Sonos is superior in any aspect to the Apple solution.
Hm. Control latency with AirPlay 2 is much improved. Playing/pausing playback happens immediately, compared to the up to two seconds delay over regular Bluetooth.
Beim Starten und Beenden der Wiedergabe merkt man die Latenz mehr als deutlich (Wiedergabe startet und endet 2-3 Sekunden verzögert).
Aber bei Videowiedergabe habe ich kein Problem. Da wird das Bild ebenfalls verzögert, so dass dann alles lippensynchron abgespielt wird.
Jedenfalls in der Kombination Mac -> Airplay 2 -> Sonos (Sonos Player gruppiert, da Play:5 1.gen im Büro nicht Airplay-fähig). Sowohl mit Musikvideos in iTunes als auch mit Youtube Videos in Google Chrome getestet.
Hätte nicht gedacht, dass das so gut funktioniert.
Sehr interessant. Wähle ich Sonos nicht in macOS als Ausgabegerät aus, sondern im Airplay Menü von iTunes, ist die Verzögerung beim Starten und Beenden der Wiedergabe deutlich geringer (<0,5 Sekunden).
Musikvideos sind auch dann lippensynchron.
