this post was submitted on 05 Sep 2024
577 points (99.7% liked)

Technology

59446 readers
4775 users here now

This is a most excellent place for technology news and articles.


Our Rules


  1. Follow the lemmy.world rules.
  2. Only tech related content.
  3. Be excellent to each another!
  4. Mod approved content bots can post up to 10 articles per day.
  5. Threads asking for personal tech support may be deleted.
  6. Politics threads may be removed.
  7. No memes allowed as posts, OK to post as comments.
  8. Only approved bots from the list below, to ask if your bot can be added please contact us.
  9. Check for duplicates before posting, duplicates may be removed

Approved Bots


founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
[–] Chozo@fedia.io 6 points 2 months ago (1 children)

My layman's understanding (so please correct me if I'm wrong) is that BT audio works by taking the audio stream from your playing device, and breaks up pieces of that stream into small packets. These packets get sent individually to your speaker, which then plays them all seamlessly in order as they flow in. But because these packets have to be cut out from the main stream in the first place before they can be sent, you're always hearing something from just a few moments ago, as you can't start playing a packet until it's finished playing and transferring from the main device, first.

So by breaking these packets up into smaller pieces, you're reducing how far back your speaker is, chronologically-speaking. So let's just say that the current version of BT breaks up audio into 0.5-second increments (it doesn't, this is just an example). This means that every 0.5 seconds, your device snips a half-second of audio into a packet and sends it to your speaker, which then plays that packet. But the transfer takes time, too, so let's say 0.25 seconds to send (again, just made-up numbers for the sake of explaining the concept). So everything your speaker would be playing in this situation would be, at minimum, 0.75 seconds behind. Not a huge deal for listening to music, but it quickly gets out of sync with video content.

So pretend the new BT version instead breaks up the original audio into 0.1-second increments. So instead of generating 2 packets every second, it's generating 10. Even if we keep the same transfer rate of 0.25 seconds in mind, this reduces the delay from 0.75 seconds to 0.35, which puts the audio much closer into sync with video content.

[–] AlotOfReading@lemmy.world 8 points 2 months ago

Not bad, but you're missing that the Bluetooth device can report audio latency back to the source so it can delay anything that needs to synchronize. In practice there's half a dozen more buffers in between and a serious tradeoff between latency, noise sensitivity, and bandwidth.