Can this deal with latency from browser to actual output device?
(As an egregious example, AirPlay 2 has excellent audio sync but latency that is a good fraction of a second or even worse. A browser might be playing through AirPlay.)
Show HN: Beatsync – perfect audio sync across multiple devices
101–110 of 135 posts
Re: Show HN: Beatsync – perfect audio sync across multiple devices
#102If you do RTP with pulseaudio you can know the latency of all devices and have it synced by design - no extra software needed, device agnostic. If it somehow runs linux it will "just work".
Re: Show HN: Beatsync – perfect audio sync across multiple devices
#103If you do RTP with pulseaudio you can know the latency of all devices and have it synced by design - no extra software needed, device agnostic. If it somehow runs linux it will "just work".
Works with pipewire too, although the user-facing docs are pretty sparse
Re: Show HN: Beatsync – perfect audio sync across multiple devices
#104This is very, very cool; it's a thing I've been looking for on my backburner for several years. It's a very interesting problem. There are a ton of directions I can think about you taking it in. The household application: this one is already pretty directly applicable. Have a bunch of wireless speakers and you should be able to make it sound really good from anywhere, yes? You would probably want support for static c…
Silent disco in which everyone brings their own source and headphones.
"Their own source" looks like they are bringing their own files or (more probably) their Spotify or YouTube. It happens all the time on public transport. Or did you mean bringing their own music and taking turns at sharing it with the other people around? That might be against the terms of service of some services.
Re: Show HN: Beatsync – perfect audio sync across multiple devices
#105Earlier quoted context omitted.
Silent disco in which everyone brings their own source and headphones.
"Their own source" looks like they are bringing their own files or (more probably) their Spotify or YouTube. It happens all the time on public transport. Or did you mean bringing their own music and taking turns at sharing it with the other people around? That might be against the terms of service of some services.
Surely, since "silent disco" only really works if everyone is dancing to the same music (which is the only thing that would make sense for a post about synchronizing audio), they're using "source" to mean "device"
Re: Show HN: Beatsync – perfect audio sync across multiple devices
#106Watch out of patent problems. There was a major dust up between Sonos and Google over audio sync technology.
Disclaimer: I've worked for both companies, but not on that
Re: Show HN: Beatsync – perfect audio sync across multiple devices
#107This is very, very cool; it's a thing I've been looking for on my backburner for several years. It's a very interesting problem. There are a ton of directions I can think about you taking it in. The household application: this one is already pretty directly applicable. Have a bunch of wireless speakers and you should be able to make it sound really good from anywhere, yes? You would probably want support for static c…
Thank you for the kind words! Yeah, I think it gets a lot more complicated once you start dealing with speaker hardware. It pretty much only works for the device's native speaker at the moment. The instant you start having wireless speakers (eg. bluetooth) or any sort of significant delay between commanding playback and the actual sound coming out, the latency becomes audible.
Awesome project!
If you support mic input, you can allow the user to select a device as the "nexus" with mic recording on. Then you tell each device in your setup to "chirp" at the same exact time, but at different frequencies. Then you can derive the individual device's "local delay" and compensate.
This allows you to tune the surround setup to full accuracy for a given point in space, and it will take care of ring buffer differences, wireless transfers of non-teathered speakers, etc.
Re: Show HN: Beatsync – perfect audio sync across multiple devices
#108have you considered using webtransport?
When I was developing Glicol (https://glicol.org/) sync, the main challenge is network jitter. Had to give it up eventually.
Furthermore, have you factored in the synchronization as perceived by the listener?
Also, it seems system-level differences, particularly in audio output latency across various OS and hardware setups, would need to be considered.
What I mean is, the variation in inherent audio output latency between different systems (e.g., Mac vs. Windows, different hardware) could easily exceed 10ms in itself.
Re: Show HN: Beatsync – perfect audio sync across multiple devices
#109Earlier quoted context omitted.
It's a less hard problem than the duet. If the round-trip is 38ms, you can estimate that the one-way latency is 19ms. You tell the the other client to play the audio now , and you schedule it for 19ms in the future. That's assuming standard OS and hardware and drivers can manage latency with that degree of precision, which I have serious doubts about. In a duet, your partner needs to hear you now and you need to hear…
You’re right that it’s an easier problem, but it’s still trickier than it looks. Remember the point of this is to be listening together. To do that, you need to be able to communicate your reactions. And then you’re back to the 38ms (in practice it’s probably twice that). Either way, at 120bpm that’s over a bar! If you _don’t_ have real time communication, then you don’t really need to solve this problem. But the pro…
You're basically right, but one 4-beat bar @120bpm is 2000ms.
Also latency demands on conversation are not nearly as tight as those on music performance. See ubiquitous video conferences.
Re: Show HN: Beatsync – perfect audio sync across multiple devices
#110Earlier quoted context omitted.
For those wondering: The rule thumb here is that light travels at one foot per nanosecond. 300 ns =0,3 μsec. Electricity is a bit slower but the same order of magnitude.
And by a happy coincidence it turns out that audio does about one foot in one millisecond making light six orders of magnitude faster
About one foot sounds very american.