5 ms·

Can anything be done to reduce SBC latency? Although I'd be surprised if the answer was yes...

dmitrygr 6y ago
SBC itself, as a codec, can have latency as low as 64 samples. But it is up to your implementation to make that happen (and bandwidth use goes up as you use smaller packets)
jchw 6y ago
SBC and LDAC (via PulseAudio) on my XM3s feel fairly decent in terms of latency; it’s probably on the order of 100ms, maybe less. I suspect Bluetooth audio latency is mostly a result of implementation details.
- lxgr 6y ago
  It's a specific design decision: The non-call audio profile (A2DP) prioritizes a low error rate over low latency by intentionally introducing a retransmit buffer on both ends of the connection.
eggsome 6y ago
Use the following when loading the module with PulseAudio: tsched=no fixed_latency_range=yes fragments=1 fragment_size=15 This was not enough for me. In the end I replaced my bluetooth (QC35 II) headset with a non-bluetooth (HyperX Cloud S) model that had a low-latency proprietary link.
- vardump 6y ago
  Have issues with QC35 latency as well. Definitely not buying Bose after a glacially slow support to fix bluetooth stack issues and lack of support for aptX or other low latency protocol. I'd also love to have high fidelity Bluetooth headset + microphone support. That 8 kHz disaster is a constant annoyance.
mjevans 6y ago
I remember a videogame streamer I watch having major issues with latency. Their answer was finding a device that ran "aptX Low Latency" (40mS) https://en.wikipedia.org/wiki/AptX#aptX_LL https://en.wikipedia.org/wiki/AptX#aptX_LL All of the other alternatives probably work OK for non-interactive content or anything we already tolerate distance speed of light delays for (E.G. videocalls); but do so largely by delaying the video to match the audio.
lxgr 6y ago
The problem for Bluetooth non-call audio isn't (just) codec latency, but rather that A2DP is using a quite large buffer and TCP-style retransmissions. SDP itself has pretty decent latency.

SBC itself, as a codec, can have latency as low as 64 samples. But it is up to your implementation to make that happen (and bandwidth use goes up as you use smaller packets)

jchw 6y ago

SBC and LDAC (via PulseAudio) on my XM3s feel fairly decent in terms of latency; it’s probably on the order of 100ms, maybe less. I suspect Bluetooth audio latency is mostly a result of implementation details.

lxgr 6y ago
It's a specific design decision: The non-call audio profile (A2DP) prioritizes a low error rate over low latency by intentionally introducing a retransmit buffer on both ends of the connection.

eggsome 6y ago

Use the following when loading the module with PulseAudio: tsched=no fixed_latency_range=yes fragments=1 fragment_size=15 This was not enough for me. In the end I replaced my bluetooth (QC35 II) headset with a non-bluetooth (HyperX Cloud S) model that had a low-latency proprietary link.

vardump 6y ago
Have issues with QC35 latency as well. Definitely not buying Bose after a glacially slow support to fix bluetooth stack issues and lack of support for aptX or other low latency protocol. I'd also love to have high fidelity Bluetooth headset + microphone support. That 8 kHz disaster is a constant annoyance.

mjevans 6y ago

I remember a videogame streamer I watch having major issues with latency. Their answer was finding a device that ran "aptX Low Latency" (40mS) https://en.wikipedia.org/wiki/AptX#aptX_LL https://en.wikipedia.org/wiki/AptX#aptX_LL All of the other alternatives probably work OK for non-interactive content or anything we already tolerate distance speed of light delays for (E.G. videocalls); but do so largely by delaying the video to match the audio.

lxgr 6y ago

The problem for Bluetooth non-call audio isn't (just) codec latency, but rather that A2DP is using a quite large buffer and TCP-style retransmissions. SDP itself has pretty decent latency.