Re: [linux-audio-dev] ALSA MIDI Sync

From: Alexandre Ratchov <alex-contact@email-addr-hidden>
Date: Mon Dec 12 2005 - 22:23:22 EET

On Sat, Dec 10, 2005 at 02:52:15AM +0100, Peter Brinkmann wrote:
>
>
> Hi,
> I'm trying to figure out how to build an ALSA MIDI sequencer that'll
> sync with other sequencers. I've looked around but didn't see any
> recent information. (The closest hits were a five-year-old page of
> Takashi Iwai's, a three-year-old LAD thread with the subject line
> "MIDI sync and ALSA sequencer", and a LAU thread from last year,
> none of which sounded entirely encouraging.)
>
> So, my question is, what's the recommended way of synchronizing two
> MIDI sequencers these days, using ALSA? Is there any protocol (MTC,
> MMC...) that you would recommend so as to be compatible with a large
> number of other software packages? Any hints would be appreciated.
> Pointers to sample implementations of MIDI sync with ALSA would be
> great.

hello,

imho a simple way to synchonize 2 (or more) midi sequencers is to use
the midi start, stop and clock messages (status codes 0xfa, 0xfc, 0xf8)

i've successfuly used this approcach to synchronize a software
sequencer (midish) to a hardware (external) one. I also could
synchonize multiple instances of midish to each other.

i dont know how to implement this specificaly with the alsa api, since
i used the raw midi devices /dev/midiXX; you can check the source of
midish (http://caoua.org/midish/midish-0.2.2.tar.gz, see mux.c).

this approch should be compatible with most software or hardware
midi sequencers.

regards,

-- 
Alexandre
Received on Tue Dec 13 00:15:09 2005

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