The engine
The tape is always perfect.
Here’s the proof.
SessionLinked streams lossless 24-bit multitrack between DAWs. Underneath it is a transport engine built for hostile networks: forward error correction that heals losses without waiting a round trip, retransmission for whatever’s left, FLAC compression on the wire, and a clock that never guesses. We measure it the way we expect you to doubt it.
Torture matrix
One stereo 24-bit/48kHz track of musical material, streamed at the real packet rate through simulated network profiles. “Retransmit only” is a conventional recovery design; “Full engine” is what two SessionLinked Macs negotiate automatically.
| Network | Engine | Delivered | Permanent gaps | Wire data |
|---|---|---|---|---|
| Studio LAN1ms, lossless | Retransmit only | 100% | 0 | 100% of raw |
| Studio LAN1ms, lossless | Full engine | 100% | 0 | 39% of raw |
| Transatlantic75ms, 0.5% loss | Retransmit only | 100% | 0 | 100% of raw |
| Transatlantic75ms, 0.5% loss | Full engine | 100% | 0 | 40% of raw |
| Bad Wi-Fi3% loss + fades | Retransmit only | 99.5% | 1 | 156% of raw |
| Bad Wi-Fi3% loss + fades | Full engine | 100% | 0 | 54% of raw |
| Choked uplinknarrower than one raw track | Retransmit only | 65.5% | 51 | 208% of raw |
| Choked uplinknarrower than one raw track | Full engine | 100% | 0 | 39% of raw |
Measured 2026-06-11, engine 1.7.54, 200-packet runs at the real packet cadence.
And then we left it running for two hours
Sessions are hours, not seconds. The full engine streamed the transatlantic profile continuously for 120 minutes — 337,500 packets, 100.000% delivered, zero gaps, 16,511 losses healed in-flight, and flat memory across every checkpoint.
Compression is resilience, not just savings
The choked-uplink row is the whole story. When the pipe is too narrow for a raw track, retransmitting harder just fills the queue faster — a third of the audio never arrives. FLAC shrinks the stream to ~39% of raw, the queue never fills, and the problem ceases to exist: 100% delivered on a link that drops 34% of a raw stream.
Losses heal without waiting a round trip
Parity packets travel with the audio, so a lost packet is rebuilt from its neighbours the moment they arrive — no “please resend” across the Atlantic. Retransmission still backstops anything parity can’t reach. On a clean link, neither costs you a byte: parity stops flowing entirely.
Lossless means lossless
Every delivered packet is byte-exact — FLAC is lossless and every packet is checksummed end-to-end. And the recording never depends on the network at all: your collaborator’s DAW captures everything locally, and the cloud reconciles any take the stream couldn’t complete.
Honest methodology
Simulated profiles are seeded and deterministic, but configurations aren’t packet-for-packet A/B comparable; read the columns as representative behavior. Engine layers were forced on/off to isolate them — a real session negotiates everything automatically, including falling back to raw PCM whenever that’s the better choice.
Hear it yourself
The engine ships in every SessionLinked install — there is no “pro transport” tier. Download it, run the five-minute setup, and record someone an ocean away.
Download SessionLinked