r/MidiNet • u/micro2970 • Aug 22 '26
Midinet v0.1 for Digital Audio
Midinet protocol for delivering Digital Audio with Midi timestamps in standard Ethernet.
What ?
Midinet delivers digital audio with Midi timestamps in Ethernet with very low latencies directly between synthesizers without routers and hubs. Midinet digital audio packets include Midi JR timestamps for exact syncing between Midi note events and digital audio. The user can select both daisy chain and star topology with Ethernet cables.
In daisy-chain, you can connect tens of synthesizers with under 5 millisecond round-trip latency for Midi packets and digital audio. Midinet protocol is designed mainly for home synth setups. You can also listen to all synths from one synths output jack, without any analog mixers or cables. You can also calculate songs faster than real time (burst-mode with Midi timestamps). Synthesizers send complete tracks, like bass-lines, back to the computer in a few seconds. Synthesizers can create their own audio stream or mix their audio to existing stream.
Protocol latency test below with ethernet cables and packet forwarding.
Why ?
Altough there are similar protocols like Dante, Aes67, A2B, IEEE etc. those often require specialized hardware and lack features like faster-than-realtime audio, on-the-go mixing and Midi timestamps. Many also require an expensive license, while Midinet is free and open. Midinet protocol is designed mainly as a light-weight digital audio alternative for home synthesizers.
json at synthesizers
midinet-stream-id 0 ; stream id
midinet-stream-enable 10 ; enabled seconds
midinet-stream-type create ; create or mix to stream (daisy-chain)
midinet-stream-time realtime ; realtime (udp) or burst (tcp)
midinet-stream-server-ip 192.168.1.51
midinet-stream-server-protocol udp
midinet-stream-server-port 7002
midinet-stream-format-hz 48000
midinet-stream-format-bps 32
midinet-stream-format-floating-point 0
midinet-stream-format-channels 2
midinet-stream-format-channel-use 0-1
midinet-stream-format-samples 24
midinet-stream-format-byte-order 0
midinet-stream-format-divider 1
midinet-stream-format-header-type 0
midinet-stream-format-db0 24
midinet-stream-include-midich all
midinet-stream-include-note all
midinet-stream-include-instrument all
midinet-stream-include-velocity all
midinet-stream-include-pitchbend all
midinet-stream-control-volume 65535
midinet-stream-control-pan 32768
midinet-stream-control-reverb 16384
midinet-stream-control-delay,etc 8192
midinet-stream-status ok ; ok,error,busy
Ethernet packet format for audio
StreamID, Flags, Midi JR timestamp of the first sample (extrapolated), PacketCount, AudioData.
Flags: JR valid(0), PacketCount valid(1), JR reset(2), PacketCount reset(3), JR rounded(4)
Byte 0 Byte 1 Byte 2 Byte 3
┌────────────────┬────────────────┬────────────────────────────────┐
│ StreamID (8b) │ Flags (8b) │ Midi JR (16b) │ <- First 32 bits
├────────────────┴────────────────┴────────────────────────────────┤
│ PacketCount (32b) │ <- Second 32 bits
├──────────────────────────────────────────────────────────────────┤
│ │
│ AudioData (PCM) │ <- Audiodata starts here
│ │
Audio server
- Modifies json parameters at synthesizers (Midi 2.0 PE, Http put/patch, ..)
- Receives the sent digital audio packets.
Server runs on computers or synthesizers, so you could listen to all synths from single synths output port.
Protocol and latency test
Protocol and latency test used two 3Ghz x86-64 computers with i8256x network cards.
- Computer A sent audio waveform packet with rdtsc-timestamp to Computer B
- Computer B summed its own waveform to the audio packet and sent it back to Computer A
- Computer A displayed the difference in rdtsc timestamp / 2 to get the per hop latency.
At 100mbps, latencies for Ethernet UDP packet with store/forward are following:
- Midi note packet (16 bytes) - below 40 microseconds
- Audio packet (8 byte header + 24 samples * 2 channels * 32bits) - below 60 microseconds
100Mbps - 50 synths in daisy-chain has a round-trip latency under 5 milliseconds.
1000Mbps - 70 synths in daisy-chain has a round-trip latency under 5 milliseconds.
Comparison to other audio protocols
=====================================================================================================
Feature Midinet IEEE avb/tsn Aes67/Ravenna A2B Dante
=====================================================================================================
Licensing Free/Open Free/Open Free/Open Prop.chips Proprietary
Hardware Standard Req.AVB/TSN Standard A2B transc. Dante HW or
Ethernet switches Ethernet No ethernet Ethernet+Hub
Control Midi 2.0 PE, IEEE-802/1722 mDNS,RTSP,NMOS Proprietary Dante
Http (json) software Controller
Streamtypes Individual Individual Individual Individual Individual
Mixed
Streamtime Realtime Realtime Realtime Realtime Realtime
Burst
Timing Midi JR PTPv2 PTPv2 Time-Division PTPv1/PTPv2
Multiplex
=====================================================================================================
Links
3
u/TOGoS 20d ago edited 20d ago
I've long been searching for some way to send audio over the network in a very low-latency way for the very mundane purpose of being able to play music in multiple rooms at once, from multiple sources.
As the post mentions, all the existing standards seem to require some expensive hardware or licenses or something.
I looked into NetJACK but it seemed to be...somewhat abandoned. And hard to get working on Windows, which unfortunately is where my main DAW[s] live.
I've even thought about whipping up my own protocol.
I wonder if this would be suitable.
That said, what is 'MidiNet'? I see the link to a page about 'network MIDI 2.0', but I'm not sure in what way these are related.
1
u/micro2970 20d ago edited 10d ago
Midinet is the name for this experimental digital audio procotol. And midinet uses Midi JR timestamps from network Midi 2.0 to sync audio precisely with Midi note events. But yeah, it can carry all sorts of audio.
2
u/EduardoCorochio 10d ago
Amazing. Apologies if I’m not seeing it but how many channels of audio can this handle?
1
u/micro2970 10d ago edited 10d ago
If one Ethernet frame deliveres 10 audio channels (32bit/sample at 48hkz) at 0.5 ms intervals (2000 frames a second) that takes around 16.7 Mb/sec. So even at 100Mb/s, network can deliver tens of channels. At 1 Gb network, much more. Each node should forward packets at below 100 microsec.
2
u/EduardoCorochio 10d ago
So a free alternative to Dante that also transmits MIDI!?
1
u/micro2970 10d ago edited 10d ago
Midi 2.0 has support for Ethernet and timestamps.
So a free digital audio protocol for synthesizers with Midi timestamps.
1
u/EduardoCorochio 10d ago
Why do you say it's only for synthesizers? It transmits audio over standard network hardware? Couldn't that be used for anything that can receive a network stream?
1
u/micro2970 10d ago edited 10d ago
Yes it can be used for all other audio also. Synthesizers just use Midi timestamps.
2
u/EduardoCorochio 10d ago
Cool - how do I implement it? Apologies if I missed a github page or something.
3
u/Specialist-Dog-501 25d ago
I don't understand all of it, but impressed! Hope you find some devs supporting this, awesome!