Hanspeter Portner wrote: > On 16.02.2015 18:36, Harry van Haaren wrote: >> No, the MIDI "cable" baud rate is 31250, while MIDI over USB runs >> at 112500. > > Where do these 112500 Baud come from? > Just curious... > > Does this refer to low-speed USB-MIDI (e.g. 1.5Mbit/s)? USB MIDI must use bulk transfers, which are not allowed for low-speed devices. > high-speed USB has a maximal packet size for bulk transfers of 512 > bytes, I'm not sure though whether this applies to USB-MIDI, too? 512 is the _only_ allowed value for the maximum high-speed bulk packet size, so every high-speed device must be able to handle such packets. >> -Bandwidth: lots better than DIN-cable MIDI, but limited > > Depends on underlying USB speed, I guess While MIDI over DIN is asynchronous, USB bulk transfers have an implicit throttling mechanism, i.e., a packet transfer is not complete until the device has chosen to accept it. This means that the bandwidth is just as high as the device can process the data. USB/MIDI interfaces cannot run faster than DIN cable speed, and there might be devices where the USB interface has been duct-taped onto an existing MIDI interface. (And the really stupid MFM0860 chip is _slower_ than 3125 bytes/s.) Regards, Clemens _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
