Re: [linux-audio-dev] ALSA MIDI latency correction

I have a sequencer application that has several MIDI output ports, each connected to some device that accepts MIDI input. Those devices may have vastly different latencies ... but of course I don't want to hear a time lag between those devices. I'm currently scheduling all my events through one queue (is that the recommended method? I've been wondering whether it would make more sense to have, say, one queue per output port, but I don't see how this would help),

and the only solution I have been able to think of is to explicitly schedule events for faster devices at a later time. This is clumsy, and it's exacerbated by the fact that I'd like to schedule events in terms of ticks rather than milliseconds. Since latencies are usually measured in milliseconds, that means I have to convert them to ticks, considering the current tempo of the queue. There's gotta be a better way. Ideally, there are two things I'd like to do: 1. Assign a delay dt to each output port, so that an event scheduled at time t0 will be sent at time t0+dt. Like this, I could compute the maximum latency of all my devices, and the output port attached to a device would get a delay of (max latency - latency of device), so that everything would be in sync.

2. Automatically determine the latencies of the devices I'm talking to. In theory, this should be possible. For instance, if timidity is connected to jack, it could get jack's current latency, add its own latency, and report the result. Is this science fiction?