Date: Sun, 20 Feb 2022 22:07:11 +0100 From: Hans Petter Selasky <hps@selasky.org> To: Florian Walpen <dev@submerge.ch>, freebsd-multimedia@freebsd.org Subject: Re: New FreeBSD port ALSA to JACK MIDI, a2jmidid Message-ID: <50bd092c-9d5e-645d-2e5a-16a92d83a0db@selasky.org> In-Reply-To: <22854640.gYbqZ1YImA@z800> References: <a1f43e5a-5d1f-1980-e771-00a0064f74bb@selasky.org> <2571899.TYJnH3iKXO@z800> <2bd0bb3f-0cae-ad9f-138b-f0a66b883b30@selasky.org> <22854640.gYbqZ1YImA@z800>
next in thread | previous in thread | raw e-mail | index | archive | help
Hi, On 2/20/22 16:54, Florian Walpen wrote: > Sorry for the delay. > > On Saturday, February 12, 2022 2:07:03 PM CET Hans Petter Selasky wrote: >> On 2/12/22 12:52, Florian Walpen wrote: >>> Does it have an impact on usability or latency (or latency correction)? >> >> No, jack is already slow, so no implications here. > > That's probably due to jack processing in cycles, but I'd have to verify. > Unfortunately I can't measure MIDI latency right now, have to get some cables > from the practice room next week. Cool! > > I suppose MIDI messages are sent out-of-band for USB devices? Thus not being > subject to the OSS queuing delays? I'm not sure yet how jack and clients deal > with the different latency. > >> My idea is to have one MIDI server (ALSA based) to allow the same MIDI >> device to be shared by multiple devices. Also applications can create >> virtual ports. Yeah, MIDI is a bit complicated. Too many APIs. > > I gave it a test run, and both bridging and device detection seem to be fine. > Nice work there! > > One thing I noticed was that our hardware MIDI ports are detected as software > ports by a2jmidid. Or at least they were bridged, even though a2jmidid > excludes hardware ports by default. Intentional? > This may confuse some client applications, if they rely on this distinction. You can change that easily. See: https://github.com/hselasky/alsa-seq-server/blob/8dc8bae3900b5c6332be723308d8033423d9e66c/alsa-seq-server.c#L1709 port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC; > > On a side note, there's also an ALSA sequencer MIDI backend in jack, but it's > tied to the ALSA driver and not available when choosing the OSS driver. So we > can't use that instead of a2jmidid. BTW the ALSA option of our jack port is > off by default. Yes, I tried to look at that too, but a2jmidid was easier. > > But all in all this looks like a promising approach. > Thank you! --HPS
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?50bd092c-9d5e-645d-2e5a-16a92d83a0db>