Re: [LAD] Fwd: Re: How can a LV2 plugin know on what host's MIDI Channel it's on?
I agree with Len. On Thu, 2014-10-16 at 12:29 -0700, Len Ovens wrote: That control could have an option to accept all channels too so that the host could do filtering. JFTR accept all channels, as if they were one channel is named omni mode :). ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
[LAD] Fwd: Re: How can a LV2 plugin know on what host's MIDI Channel it's on?
Forwarded Message Subject: Re: [LAD] How can a LV2 plugin know on what host's MIDI Channel it's on? Date: Thu, 16 Oct 2014 13:16:38 -0400 From: Paul Davis p...@linuxaudiosystems.com To: Phil CM phi...@gnu.org On Thu, Oct 16, 2014 at 12:59 PM, Phil CM phi...@gnu.org mailto:phi...@gnu.org wrote: On 16/10/14 17:15, Paul Davis wrote: On Thu, Oct 16, 2014 at 11:42 AM, Phil CM phi...@gnu.org mailto:phi...@gnu.org wrote: Is there a way to retrieve this info (and others, ideally) from the host, thus removing the need for a midi channel control port? I think you're confused. The host doesn't put a plugin on a MIDI channel. It delivers MIDI events to the plugin which might be on any channel. But in Qtractor I do have a choice of what MIDI channel (or any/omni, for that matter) I'm sending signal to on that particular track... So, no? No way for the plugin to retrieve any info from the host (I mean specific info, not just instantiated, port enum et al) I guess it makes sense since it would introduce a breaking point. Sorry, I don't really speak english, I'm just persuaded I do. That is a host-specific issue. The part of the LV2 specification and the existing extensions don't describe that functionality. As far as the plugin is concerned, it just gets MIDI events. If the host is filtering some of them, the plugin has no way to determine this programmatically. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Fwd: Re: How can a LV2 plugin know on what host's MIDI Channel it's on?
On 16/10/14 18:19, Phil CM wrote: Forwarded Message Subject: Re: [LAD] How can a LV2 plugin know on what host's MIDI Channel it's on? Date: Thu, 16 Oct 2014 13:16:38 -0400 From: Paul Davis p...@linuxaudiosystems.com To: Phil CM phi...@gnu.org On Thu, Oct 16, 2014 at 12:59 PM, Phil CM phi...@gnu.org mailto:phi...@gnu.org wrote: On 16/10/14 17:15, Paul Davis wrote: On Thu, Oct 16, 2014 at 11:42 AM, Phil CM phi...@gnu.org mailto:phi...@gnu.org wrote: Is there a way to retrieve this info (and others, ideally) from the host, thus removing the need for a midi channel control port? I think you're confused. The host doesn't put a plugin on a MIDI channel. It delivers MIDI events to the plugin which might be on any channel. But in Qtractor I do have a choice of what MIDI channel (or any/omni, for that matter) I'm sending signal to on that particular track... So, no? No way for the plugin to retrieve any info from the host (I mean specific info, not just instantiated, port enum et al) I guess it makes sense since it would introduce a breaking point. Sorry, I don't really speak english, I'm just persuaded I do. That is a host-specific issue. The part of the LV2 specification and the existing extensions don't describe that functionality. As far as the plugin is concerned, it just gets MIDI events. If the host is filtering some of them, the plugin has no way to determine this programmatically. Wow, not even the very channel it's broadcasting on in readable? Does that mean that I *have* to implement a MIDI channel selection in my synth? There is no way to go around this? --Phil ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Fwd: Re: How can a LV2 plugin know on what host's MIDI Channel it's on?
On Thu, Oct 16, 2014 at 1:44 PM, Phil CM phi...@gnu.org wrote: I think you're confused. The host doesn't put a plugin on a MIDI channel. It delivers MIDI events to the plugin which might be on any channel. But in Qtractor I do have a choice of what MIDI channel (or any/omni, for that matter) I'm sending signal to on that particular track... So, no? No way for the plugin to retrieve any info from the host (I mean specific info, not just instantiated, port enum et al) I guess it makes sense since it would introduce a breaking point. Sorry, I don't really speak english, I'm just persuaded I do. That is a host-specific issue. The part of the LV2 specification and the existing extensions don't describe that functionality. As far as the plugin is concerned, it just gets MIDI events. If the host is filtering some of them, the plugin has no way to determine this programmatically. Wow, not even the very channel it's broadcasting on in readable? Does that mean that I *have* to implement a MIDI channel selection in my synth? There is no way to go around this? Again, you're confused. The host doesn't control what the plugin does when it generates MIDI. The host *might* filter messages from the plugin based on some user preference, or it might not. It sounds as if you need an LV2 extension so that the host and plugin can exchange information on preferred MIDI channel(s). This isn't part of the core LV2 specification. The host is free to deliver zero, one or more MIDI channels to the plugin; the plugin can use any channels it wants, but the host might throw away zero, one or more channels. Sounds as if you want the host to allow the user to select a channel and then have the plugin know about that choice. Not part LV2, and also not part of AudioUnits or the VST plugin APIs. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Fwd: Re: How can a LV2 plugin know on what host's MIDI Channel it's on?
On Thu, 16 Oct 2014, Phil CM wrote: Wow, not even the very channel it's broadcasting on in readable? Does that mean that I have to implement a MIDI channel selection in my synth? There is no way to go around this? A plugin, should take care of it's own midi channel setting/sensing in the same way as a HW synth does, or a hw control surface. Sensing channel is a one step deal and requires almost no cpu cycles (it is always the first byte of a midi event which has to be tested anyway). It would be normal for any one function to use the same channel for input/output unless the plugin itself was doing filtering or other MIDI manipulating. It would be possible to ignore channel and use any channel, but the host should not be expected to do filtering for the plugin. Dispite what people have said about the posibility of the host filtering the MIDI channels, it is unlikey unless the user chooses that in which case they are also responsible for making sure your plugin is also set to the right channel. So you do need to expose a control to do that. That control could have an option to accept all channels too so that the host could do filtering. Note I have written only one MIDI application so far. I do need to finish it and it is not a plugin, but standalone. -- Len Ovens www.ovenwerks.net ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
