9 Sep
2016
9 Sep
'16
7:37 p.m.
Hi!
I'm currently implementing a LV2 plugin for SpectMorph, and so far I only
defined one audio port in the ttl file/source, as the output of the morphing
algorithm is just mono.
I have tested with Ardour and Qtractor. Ardour does what I'd expect: it plays
my instrument output on both channels. Qtractor however just plays my mono data
on one channel, the other is silent. Which is not what I want.
So I am considering making my LV2 instrument always stereo, and just copy the
output buffer from left to right - this is cheap, and probably not much more
expensive than what the host would need to do anyway.
Does this sound like the reasonable way to go?
Cu... Stefan
--
Stefan Westerfeld, http://space.twc.de/~stefan
9 Sep
9 Sep
7:42 p.m.
Hi Stefan:
Cool to see spectmorph come as a plugin!
IMO I'd let the host deal with it how they see fit. There's probably a
panner in Qtractor to put it in the center. To have a "stereo" output
with no actual stereo data seems wasteful and misleading to me. My lv2
CA synth is mono and I haven't had complaints (though I don't have
high usership either).
_Spencer
p.s. there's also an lv2_dev mailing list if you have other lv2 questions.
On Fri, Sep 9, 2016 at 11:33 AM, Stefan Westerfeld <stefan(a)space.twc.de> wrote:
Hi!
I'm currently implementing a LV2 plugin for SpectMorph, and so far I only
defined one audio port in the ttl file/source, as the output of the morphing
algorithm is just mono.
I have tested with Ardour and Qtractor. Ardour does what I'd expect: it plays
my instrument output on both channels. Qtractor however just plays my mono data
on one channel, the other is silent. Which is not what I want.
So I am considering making my LV2 instrument always stereo, and just copy the
output buffer from left to right - this is cheap, and probably not much more
expensive than what the host would need to do anyway.
Does this sound like the reasonable way to go?
Cu... Stefan
--
Stefan Westerfeld, http://space.twc.de/~stefan
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11:56 p.m.
On 09/09/2016 06:33 PM, Stefan Westerfeld wrote:
I have tested with Ardour and Qtractor. Ardour does what I'd expect: it plays
my instrument output on both channels. Qtractor however just plays my mono data
on one channel, the other is silent. Which is not what I want.
until the last release, qtractor used to replicate mono plugins as much
as audio output channels is for where it's inserted, so that you would
have exactly as many instances of a mono plugin as there are audio
output channels.
unfortunately this "cleverness" didn't work well for all cases,
specially regarding instrument plugins vs. its own GUI state and
communication--quite often, only one plugin instance reflects some
changes done via the GUI, being one notable example about selection of
presets (only one instance would get it loaded one time). you would need
to save and reload the whole session to get everything in sync again.
So I am considering making my LV2 instrument always
stereo, and just copy the
output buffer from left to right - this is cheap, and probably not much more
expensive than what the host would need to do anyway.
you don't really need to make it stereo all the way. at least on
qtractor, you can make use of balance.lv2 [1], inserted right after the
mono instrument and then set channel assignemnt = 1 (L->L, L->R) ...
[1] http://gareus.org/oss/lv2/balance
hth.
cheers
--
rncbc aka. Rui Nuno Capela
10 Sep
10 Sep
4:24 p.m.
Hi!
On Fri, Sep 09, 2016 at 09:55:59PM +0000, Rui Nuno Capela wrote:
Ok, I tried that, and this produces the intended result.
If you as host author say that this is the way Qtractor users should go for
mono instruments, I'll keep my plugin as it is, the other way would have been
kind-of a workaround. Still from the user experience I prefer what Ardour does,
as it automatically gets the intended result without the user needing to do
anything.
Cu... Stefan
--
Stefan Westerfeld, http://space.twc.de/~stefan
On 09/09/2016 06:33 PM, Stefan Westerfeld wrote:
Right. This particular "cleverness" would be wrong for the SpectMorph plugin as
well. Computing the audio data is quite CPU intensive, so if you would
instantiate it twice, you'd be wasting precious resources (for computing the
same data twice). Plugin UI problems would also occur.
I have tested with Ardour and Qtractor. Ardour does what I'd expect: it plays
my instrument output on both channels. Qtractor however just plays my mono data
on one channel, the other is silent. Which is not what I want.
until the last release, qtractor used to replicate mono plugins as much
as audio output channels is for where it's inserted, so that you would
have exactly as many instances of a mono plugin as there are audio
output channels.
unfortunately this "cleverness" didn't work well for all cases,
specially regarding instrument plugins vs. its own GUI state and
communication--quite often, only one plugin instance reflects some
changes done via the GUI, being one notable example about selection of
presets (only one instance would get it loaded one time). you would need
to save and reload the whole session to get everything in sync again. So I am
considering making my LV2 instrument always stereo, and just copy the
output buffer from left to right - this is cheap, and probably not much more
expensive than what the host would need to do anyway.
you don't really need to make it stereo all the way. at least on
qtractor, you can make use of balance.lv2 [1], inserted right after the
mono instrument and then set channel assignemnt = 1 (L->L, L->R) ...
9:19 p.m.
On 09/10/2016 03:21 PM, Stefan Westerfeld wrote:
If you as host author say that this is the way Qtractor users should
go for
mono instruments, I'll keep my plugin as it is,
the other way would
have been
kind-of a workaround. Still from the user experience I
prefer what
Ardour does,
as it automatically gets the intended result without
the user needing
to do
anything.
well, if you really want to keep the mono audio chain all the way, you
should make it to a mono audio output bus that you create on purpose,
instead of relying on the default Master stereo out.
byee
--
rncbc aka. Rui Nuno Capela
2792
days inactive
2793
days old
linux-audio-dev@lists.linuxaudio.org
4 comments
3 participants
participants (3)
-
Rui Nuno Capela -
Spencer Jackson -
Stefan Westerfeld