Date: Mon, 27 Feb 2006 22:52:22 +0900
Message-ID: <871wxo29k9.dancerj%dancer@netfort.gr.jp>
From: Junichi Uekawa <dancer@netfort.gr.jp>
To: Takashi Iwai <tiwai@suse.de>
Cc: Junichi Uekawa <dancer@netfort.gr.jp>, alsa-devel@lists.sourceforge.net,
       linux-kernel@vger.kernel.org
Subject: Re: [Alsa-devel] [BUG] 2.6.16-rc4 git, ALSA USB-MIDI does not give NOTEOFF event for M-Audio Keystation 88es, but NOTEON with velocity=0
In-Reply-To: <s5hek1pt2xs.wl%tiwai@suse.de>
References: <87vev2w2hd.dancerj%dancer@netfort.gr.jp>
	<s5hek1pt2xs.wl%tiwai@suse.de>
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Hi,

> > I'm seeing that USB MIDI keyboard (M-Audio Keystation 88es) is
> > generating note-on events on both note-on and note-off. The difference
> > being that note-off is generating an note-on event with velocity '0'.
> > 
> > The following code in seq_midi_emul.c(snd_midi_process_event) looks
> > suspiciously like what's needed for this device:
> > 
> >         /* Make sure that we don't have a note on that should really be
> >          * a note off */
> >         if (ev->type == SNDRV_SEQ_EVENT_NOTEON && ev->data.note.velocity == 0)
> >                 ev->type = SNDRV_SEQ_EVENT_NOTEOFF;
> 
> This code is irrelevant.  This is for MIDI emulation like emu10k1
> WaveTable, not for the real MIDI device.
> 
> Basically the given behavior is not a bug.  The sequencer handles
> note-on with velocity 0 as it is.  As a strict definition, note-off
> and note-on with zero velocity are different although they are used
> widely as identical in order to save bytes.

Thanks; I've looked into MIDI specs, and it was documented everywhere;
it was just not obvious when I was looking into ALSA docs.

regards,
	junichi
-- 
dancer@{debian.org,netfort.gr.jp}   Debian Project
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