On Thu, Jun 16, 2022 at 08:37:49PM +0100, Will Godfrey wrote: > Over a hardware DIN port this is of course approx. 1mS, but does anyone know > if it's the same over a USB link? > > Presumably, it would have to be if the source was also sending to the DIN > route.
Not really, it could be much faster. When the source starts transmitting the first byte on the standard MIDI port, it probably has the complete message (3 bytes for a note on/off) ready. There is no reason why the USB message should be derived from the serial MIDI data. > Following on from that, what about the multiport adaptors that have 4 hardware > ports going down one USB cable. I would guess that these could be interleaved > so that (assuming the 1mS granularity holds) the overall rate is still 1mS > with > the ports spaced up to 250uS apart. AFAIK, USB transfers are not interleaved at byte level, doing that would create a lot of overhead. So even if you have a note event on all four ports at the same time, that would probably be 4 separate USB transfers, one after the other. Still this could take less than 1 ms, it just depends on the USB data rate. Ciao, -- FA _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org https://lists.linuxaudio.org/listinfo/linux-audio-dev
