Subject: Re: [linux-audio-dev] a question re: the MIDI spec
From: John Check (j4strngs_AT_bitless.net)
Date: Sat Sep 11 2004 - 05:56:36 EEST
On Friday 10 September 2004 05:40 pm, Martijn Sipkema wrote:
> [...]
>
> > > > > The problem here is that class compliant devices suffer bad timing
> > > > > because they use bulk transfers for MIDI data. The standard for
> > > > > MIDI over FireWire is much better.
>
> [...]
>
> > > > Is the timing really that bad? I don't even think a firewire 8x8
> > > > rackmount MIDI interface exists, so my options are kinda limited. :/
> > >
> > > Timing is especially bad when there is other data being transferred on
> >
> > "Especially bad" is still pretty vague. What might look bad on paper
> > might be acceptable in context...
>
> It's not unusable, but IIRC it can get to several ms of jitter.
>
> > > the same USB bus, as is the case with combined audio/midi interfaces.
> >
> > Perhaps, but midi takes a lot less bandwidth than audio so how much worse
> > could it get? It sounds like it wouldn't be a problem if you were
> > overdubbing, but potentially in a live recording/performance if you are
> > using the audio ins for a vocal mic or whatnot.
>
> I'm by no means an expert on this, but I think MIDI taking less bandwidth
> than audio is not really relevant; it's audio data being isochronous and
True
> using a lot of bandwidth causing the MIDI timing to suffer.
>
Right, but still, if one isn't planning on using the audio in concurrently
it's not an intolerable situation.
> --ms
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