Time travel? Or, just clever technology

https://www.syncdna.com/blog/time-travel-or-just-clever-tech

by yabones • 10 months ago

75 31 10 months ago

Latency compensation. This why most people do not perceive any latency or lipsync issue when browsing YouTube on their phones with their expensive bluetooth headsets that have ridiculous amounts of latency (>250ms).

kgwxd• 10 months ago

destroys game sounds and music-making apps though. Guess these things are designed for pure consumption though, no fun or creativity allowed.

toast0• 10 months ago

Large delays in audio/video aren't condusive to interactive applications. But chat up someone who plays a pipe organ; they often play in ensembles and have to deal with serious latency (but probably they just worry about hitting their notes in time to be on time and the ensemble has to match up with them)

ricardobeat2• 10 months ago

these things are designed for pure consumption

This is an old trope that needs to die. I used to play synths on a 1st gen iPad back in 2010, it had amazing <5ms latency at a time when you'd struggle to hit that on a PC using external hardware.

Wired headphones have always been around, even now all it takes is a $5 adapter. Bluetooth "aptX Low Latency" has also been around for years, though adoption has been a bit slow. It is quite standard on Android phones. On the Apple side, Airpods have had decent ~100ms latency for a few years (enough for casual gaming), and more recently have a custom wireless, low-latency lossless connection (Apple Vision only atm), and <20ms latency on the new iPhone 17 using Bluetooth 6.

It really is a wireless technology problem. Bluetooth LE audio only came around 2020, and barely adopted. Bluetooth 6 was announced late last year and just starting to show up in devices now.

zenmac• 10 months ago

Caching in the headset. Yeah like the sibling comments. People who makes music and sound stuff hates Bluetooth! And hate those companies that takes the mini jack out of the phone.

reactordev• 10 months ago

Oh man, any guitarist that comes by with those wireless Bluetooth connectors always is an eighth beat behind… no matter how we tweak it, they just can’t play on time when using them.

Plug them in directly, no problem.

jama2112• 10 months ago

Err you know they match the video to the audio delay on modern smart phone apps right? The only time you actually experience latency is when you attempt to pause/play the media, or you’re trying to do something in real time (like record with people around you). If you use airpods and an iphone or something the video will not be out of sync with the audio.

You can literally even see the video lag when you hit play as it ensures it syncs with the audio.

alganet3• 10 months ago

I don't know about podcasts and stuff, but for music, you can already OBS this puzzle out real quick and use the natural song bars as synchronization steps.

1. One musician plays simple bars, repetitive stuff, and streams it.

2. Second musician receives the audio from musician 1, records a multi audio track video of himself alone (in one track) and the musician 1 output in another.

3. Stack undefinitely.

You play to what you hear, in real time. All tracks are recorded separately in separate computers and can be edited together quite easily.

Plus, this is already how most jams work in real life.

"now" isn't a single universal instant, it's a moving target

Rhythm is already a moving target, a delay cycle. Musicians just need to know the beat 1 for each bar (which they should already know, as it is their job).

curtisblaine3• 10 months ago

Yes, but musician 1 can't possibly react to musician 2's output meaningfully, because it happens after musician 2 listened to musician 1 and played its part. That's not how jams with musicians physically in the same room work.

alganet3• 10 months ago

Fair enough, you couldn't have something like the vocalist cueing the bassist and the drummer picking it up out of thing air and doing an improvised roll, like it happens here:

https://youtu.be/eg_rgm9VDAw?t=1597

The drummer takes a little bit more than a second to react to it (higher than a lot of stream delays by the way, but I can see how the stacking could mess it up).

That is, however, a bunch of experienced jazz musicians improvising at a high level. In most jams, these conversations happen very often on the next bar (1 and 2 and 3 and 4 and you react on the next 1).

You can see a drummer using the end of a bar to cue the flourish used on the organ in this part, for example:

https://youtu.be/jhicDUgXyNg&t=587s

It takes multiple seconds for the organist to recognize the cue, that is actually for the next bar, then he joins in. This sort of stuff is actually doable just with just video chat and OBS.

Please also note that the product's example workflow is actually worse in that "reaction jammyness" regard than what I proposed:

The performer receives the track early, and waits the rest of the delay period to play it

This is designed for recording. It sounds more like a studio arrangement in which you have to record your part than a jam session.

The fidelity of the live stream isn't high enough to record

Seems like an incomplete product. OBS can already record multi-tracks and monitor tracks, which you can leverage to produce high quality artifact recordings. I use to sync them manually using a DAW, but with all those auto-timers, it's a surprise it doesn't do it automatically.

belter2• 10 months ago

Our Universe has one very inconvenient problem: it has an unbreakable speed limit. While it may seem instant, light takes quite a while to get around, traveling at just under 300,000 KM per second.

Google and Azure Availability Zones seem to break that limit daily ... ;-)

belter2• 10 months ago

This was a test and you failed...

curtisblaine3• 10 months ago

This works for a listener down the chain, but obviously can't work for performers playing together. The article mentions a producer listening to remotely located performers as they were playing together, but fails to mention how these remotely located performers can sync to each other in the first place.

FrancoisBosun• 10 months ago

Explained in the article:

A producer sends a backing track to a performer - SyncDNA adds a slight delay to the outbound feed

The "backing track" is probably the beat or something similar.

curtisblaine3• 10 months ago

I still fail to understand why this is a thing. Two possibilities:

1) the beat is created live by a human performer who can't meaningfully hear the other performer(s) in time. He / she is stuck with playing blindly.

2) the beat is pre-recorded - sampled or electronically generated on a sequencer. Then what's the use case in the first place? The other performer can download it offline and play on it live.

All this is done to get something that mimics a live performance (but isn't, because the band components can't hear each other in real time) to someone listen-only at the end of the chain. What's the advantage in doing so? What's the use case?

Xmd5a• 10 months ago

I think this would be easier to explain using strips of paper. Start by placing the strips horizontally, drawing a vertical line across all of them with a red pen. Then, shift the strips to the right relative to each other to represent latency. Next, having fold a section of each strip onto itself to shorten them beforehand, unfold them to show an extended length representing delay. Finally, fold them back again to represent waiting for the remaining delay from the transmit track.

Nurbek-F• 10 months ago

No. It's not easier mate. I don't know what I just read...

jama2112• 10 months ago

To be fair, you read a description of their method, rather than them using the method in front of you.

k__• 10 months ago

Wouldn't this only work for DAGs?

For example, you got a drummer that does their thing.

The bass can react to the drummer.

The guitar and vocals can react to drummer and bass.

Each one could get a finished version, but with so much delay that they can't meaningfully react to each one coming after them or being on the same level.

supermatt• 10 months ago

Each performer plays to a backing track, and their performances are synchronised by artificial delay. They don’t hear the composite performance in realtime while playing (although they can hear a delayed version, if desired).

vivzkestrel• 10 months ago

I request you to edit the article and also add the point that "30 mins is only from the perspective of the observer on earth or mars" For a person who is actually making the voyage at the speed of light (impossible if you mass honestly) it is instantaneous

verzali• 10 months ago

...are you calling me fat?

Time travel? Or, just clever technology

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