4 Mar
2012
4 Mar
'12
9:18 a.m.
With the advent of NSM, there's a better chance than ever for
autoloaded sessions when working.
One of the challenges of autoswitching between sessions is loading
presets for that session. In, for example LV2rack, it starts, but
presets have to be loaded manually, after it gets going.
Is there a mechanism for LV2rack, and other standalone plugin hosts, to
have a preset automatically load with the selected preset for a session,
when that session is selected?
An example is lv2rack with the IR lv2 plugin, which i've been testing
in NSM. LV2rack comes up ok, but the preset i've built for a specific
session doesn't automatically load. I assume this is the case when using
something like LV2rack in other session managers too.
Where would a call for an autoloaded session saved preset come from?
The session manager, or LV2rack itself?
4 Mar
4 Mar
10:58 a.m.
With the advent of NSM, there's a better chance
than ever for autoloaded
sessions when working.
One of the challenges of autoswitching between sessions is loading presets
for that session. In, for example LV2rack, it starts, but presets have to be
loaded manually, after it gets going.
Is there a mechanism for LV2rack, and other standalone plugin hosts, to have
a preset automatically load with the selected preset for a session, when
that session is selected?
An example is lv2rack with the IR lv2 plugin, which i've been testing in
NSM. LV2rack comes up ok, but the preset i've built for a specific session
doesn't automatically load. I assume this is the case when using something
like LV2rack in other session managers too.
Where would a call for an autoloaded session saved preset come from? The
session manager, or LV2rack itself?
To be clear, applications do have to be patched to support NSM. The
same is true of XSM, LASH, and JACK-Session. The difference is that
the NSM protocol provides much more information to all parties and is
therefore far more useful. Unsupportive applications behave similar to
LADISH level 0, where they can only be started and stopped. That being
said, the changes required are about as complex as those required by
LASH and JACK-Session, but provide greater functionality. The issue of
presets is one I have been thinking about and am probably going to
update the NSM API documentation soon with a recommendation. I believe
that presets under session management should be true
copies/transformations of state. Setting a preset should alter the
parameters involved in such a way that the changes are completely and
permanently stored in the application specific project
file/directory--independent of whatever presets the particular user
may have access to. Most sensible software already works this way, so
it shouldn't be a problem to enforce.
LV2rack seems like a good candidate for patching. That is, it is
something which I might consider useful and has a fair amount of
state. I'll look into patching it, or, if the developer would like to
patch it themselves, I'd be happy to offer assistance.
6:38 p.m.
On Sun, 2012-03-04 at 08:17 +0000, parched2099 wrote:
[...]
An example is lv2rack with the IR lv2 plugin, which
i've been testing
in NSM. LV2rack comes up ok, but the preset i've built for a specific
session doesn't automatically load. I assume this is the case when using
something like LV2rack in other session managers too.
It should be noted that IR does some terrible kludges for saving state
that make it impossible to store its state portably (it saves to a
config file in a location unknown to the host and saves a hash into that
file across several float control ports).
However, the new LV2 state stuff is specifically designed to allow
self-contained archival/export with any session manager[1]. Hopefully a
future version of IR will move to it. I don't know anything about NSM's
facilities for export/archival, though.
-dr
[1] My preferred implementation is using symlinks to refer to external
files, so any tool, even tar -h, can archive correctly. KISS.
9:37 p.m.
On Sun, Mar 4, 2012 at 9:38 AM, David Robillard <d(a)drobilla.net> wrote:
On Sun, 2012-03-04 at 08:17 +0000, parched2099 wrote:
[...]
We must remember not to take this to a level of absurdity. For
instance, I don't believe that it is necessary to, for example,
copy/symlink LADSPA or LV2 plugin binaries themselves into a session.
The data is that the user selected such-and-such plugin. The plugin
can be expected to exist on the same system at another time and on
other systems. If it doesn't exist, it can be made to. Seems to go
without saying that programs which rely on plugins should not fail
horribly when one is missing, but should instead display enough
information to the user for them to be able to fix the problem.
Perhaps it needs saying anyway, though. This doesn't just apply to
plugins, but to soundfonts, generic sample libraries, etc. What should
be stored in the session is only what is specific to the session, and
that sometimes includes a selection between generic external entities.
Parameter presets are another matter, however, because they are often
not generic but are personal libraries of saved preferences which
cannot be expected to be aquirable on another system. This is why when
presets are involved, all the changes that a preset makes to the
parameters should be stored in the session.
If you use symlinks to cover the gray-area case of a non-generic
llibrary of impulse waveforms, that's fine and it would work for
archiving, but the point remains that if you don't create the symlink
and I attempt to load a copy of the session in a different
environment, I would expect to be told by the software what exactly is
missing. Obviously, solving the problem is as simple as going back to
the creator of the session and saying "Hey, I need this external
object in order to fully load your session."
BTW, I don't know if LV2 supports this, but if it allows plugins to
*SAVE* non-generic (that is to say, session specific) data wherever
they want on the filesystem, then that, IMHO, is badly broken. There
may be nothing technical that can be done about it, but you should at
the very least be able to point at a section of the API document and
say to the developer of such a plugin: Fix it, it's broken.
An example is lv2rack with the IR lv2 plugin,
which i've been testing
in NSM. LV2rack comes up ok, but the preset i've built for a specific
session doesn't automatically load. I assume this is the case when using
something like LV2rack in other session managers too.
It should be noted that IR does some terrible kludges for saving state
that make it impossible to store its state portably (it saves to a
config file in a location unknown to the host and saves a hash into that
file across several float control ports).
However, the new LV2 state stuff is specifically designed to allow
self-contained archival/export with any session manager[1]. Hopefully a
future version of IR will move to it. I don't know anything about NSM's
facilities for export/archival, though.
-dr
[1] My preferred implementation is using symlinks to refer to external
files, so any tool, even tar -h, can archive correctly. KISS.
10:17 p.m.
On Sun, Mar 4, 2012 at 3:37 PM, J. Liles <malnourite(a)gmail.com> wrote:
BTW, I don't know if LV2 supports this, but if it
allows plugins to
*SAVE* non-generic (that is to say, session specific) data wherever
they want on the filesystem, then that, IMHO, is badly broken. There
its not always LV2 that is the cause of this.
consider the SFZ file format. it refers to other audio samples. it
doesn't require that the references use absolute paths, but they can.
so now create a plugin that allows the user to alter what samples are
used for various note numbers or velocity values or whatever (i.e. a
reasonably capable sampler) and ask it to save its current state. it
gives you an SFZ file to stash away in a location of the host's own
choosing. but what do the contents refer to?
10:47 p.m.
On Sun, 2012-03-04 at 16:17 -0500, Paul Davis wrote:
On Sun, Mar 4, 2012 at 3:37 PM, J. Liles
<malnourite(a)gmail.com> wrote:
Well, LV2 is never the *cause* of this, it's an inherent problem to
plugins that use files.
BTW, I don't know if LV2 supports this, but
if it allows plugins to
*SAVE* non-generic (that is to say, session specific) data wherever
they want on the filesystem, then that, IMHO, is badly broken. There
its not always LV2 that is the cause of this. consider the SFZ file format. it refers to other audio
samples. it
doesn't require that the references use absolute paths, but they can.
so now create a plugin that allows the user to alter what samples are
used for various note numbers or velocity values or whatever (i.e. a
reasonably capable sampler) and ask it to save its current state. it
gives you an SFZ file to stash away in a location of the host's own
choosing. but what do the contents refer to?
Yeah, this problem sucks. The only solution is for the plugin to map
the paths inside that SFZ file.
It is (inherently) necessary for the plugin to map *ALL* paths in its
state for this to work. If they happen to be in some pre-existing file,
well, that's probably going to be pretty annoying, but you have to map
them all the same.
-dr
11:17 p.m.
Am 4. März 2012 22:47 schrieb David Robillard <d(a)drobilla.net>et>:
On Sun, 2012-03-04 at 16:17 -0500, Paul Davis wrote:
On Sun, Mar 4, 2012 at 3:37 PM, J. Liles
<malnourite(a)gmail.com> wrote:
> consider the SFZ file format. it refers to other audio samples. it
> doesn't require that the references use absolute paths, but they can.
> so now create
a plugin that allows the user to alter what samples are
used for various note numbers or velocity values or whatever (i.e. a
reasonably capable sampler) and ask it to save its current state. it
gives you an SFZ file to stash away in a location of the host's own
choosing. but what do the contents refer to?
Yeah, this problem sucks. The only solution is for the plugin to map
the paths inside that SFZ file.
It is (inherently) necessary for the plugin to map
*ALL* paths in its
state for this to work. If they happen to be in some pre-existing file,
well, that's probably going to be pretty annoying, but you have to map
them all the same.
For simplification, one could assume all samples had a common parent directory ?
Then the user could simply re-locate that common parent directory,
if the samples were not found ?
example:
/home /user /store /samples /shapewavs /sine.ogg
moved to:
/home /user /newplace /samples /shapewavs /sine.ogg
common parent directory: samples/
11:32 p.m.
On Sun, 2012-03-04 at 23:17 +0100, Emanuel Rumpf wrote:
Unfortunate the SFZ file format does not have any such rule, so you
can't make that assumption in general. Well... you can (on POSIX
anyway), but in the worst case it might be the root, which means you end
up with the entire file system in your session. Oops :)
-dr
Am 4. März 2012 22:47 schrieb David Robillard
<d(a)drobilla.net>et>:
> On Sun, 2012-03-04 at 16:17 -0500, Paul Davis wrote:
>> On Sun, Mar 4, 2012 at 3:37 PM, J. Liles <malnourite(a)gmail.com> wrote:
>> consider the SFZ file format. it refers to other audio samples. it
>> doesn't require that the references use absolute paths, but they can.
[...]
It is
(inherently) necessary for the plugin to map *ALL* paths in its
state for this to work. If they happen to be in some pre-existing file,
well, that's probably going to be pretty annoying, but you have to map
them all the same.
For simplification, one could assume all samples had a common parent directory ?
10:29 p.m.
On Sun, 2012-03-04 at 12:37 -0800, J. Liles wrote:
I agree. Some fancy automatic mechanism to resolve missing plugins
somehow might be nice, but that's orthogonal. Plugin binaries
definitely do not belong in saved sessions.
(Plugins using files *whatsoever* should be discouraged, but sometimes
it's truly necessary)
On Sun, Mar 4, 2012 at 9:38 AM, David Robillard
<d(a)drobilla.net> wrote:
[...]
However, the
new LV2 state stuff is specifically designed to allow
self-contained archival/export with any session manager[1]. Hopefully a
future version of IR will move to it. I don't know anything about NSM's
facilities for export/archival, though.
-dr
[1] My preferred implementation is using symlinks to refer to external
files, so any tool, even tar -h, can archive correctly. KISS.
We must remember not to take this to a level of absurdity. For
instance, I don't believe that it is necessary to, for example,
copy/symlink LADSPA or LV2 plugin binaries themselves into a session. This doesn't just apply to
plugins, but to soundfonts, generic sample libraries, etc. What should
be stored in the session is only what is specific to the session, and
that sometimes includes a selection between generic external entities.
This is only true *sometimes*. If you are saving a session locally,
sure, you don't want to copy everything it touches into the save
directory (possibly many times).
However, the ability to completely archive a session, including samples
and such, is a very important ability. Sessions aren't very useful if I
can't make one, send it to you, and have us collaborate. Or make one,
archive it, and load it up later on some other machine and actually have
it work. If you get hundreds of unresolved file references to
mysterious paths on some other machine, the system has utterly failed to
do its job.
Put in other terms, the session shouldn't *always* be archived, but the
ability to archive sessions is crucial.
If you use symlinks to cover the gray-area case of a
non-generic
llibrary of impulse waveforms, that's fine and it would work for
archiving, but the point remains that if you don't create the symlink
and I attempt to load a copy of the session in a different
environment, I would expect to be told by the software what exactly is
missing.
In terms of the plugin interface, all that happens is the host gets the
opportunity to map any paths the plugin saves to its state. This way,
it can implement any behaviour.
Symlinks just happen to be the best and simplest one, all things
considered. Instead of inventing some new file format everyone has to
deal with and erecting some bloated framework to accomplish all this,
you just archive the thing and resolve symlinks. Good old fashioned tar
can even do it (both full and shallow archival). It's also very
convenient that what's going on is very clear at the file system level,
you can see precisely what files are referred to just by looking at a
directory listing, and you can even resolve broken links manually with
generic tools (i.e. ln). All of this becomes a real nightmare if the
paths are buried in some XML file, or whatever.
I guess it's summed up nicely by the fact that you can do all of the
following without any dependency on a particular API or file format
whatsoever:
* Report and/or resolve missing files in the session
* Do a shallow archival of the session
* Do a deep archival of the session which will load on other systems
without any missing data
* Do all of the above recursively (sessions within sessions) with zero
additional effort
Of course, this isn't mandated by LV2 or anything, but the friction
you'd have to overcome to achieve the same with a bloated pile of
unnecessary garbage is so massive it's the only realistic solution for
"plugins with files in hosts in session managers". It relieves the
burden of session managers having to have an interface specifically for
this and hosts having to implement it (which, even if you did, means
you'd have to launch the host just to export an existing session).
Obviously, solving the problem is as simple as going
back to
the creator of the session and saying "Hey, I need this external
object in order to fully load your session."
This might be simple, but it might also be completely impossible. I
agree it should be possible to implement this behaviour (to share
lightweight sessions among people who do share a common set of data),
but it also must be possible to do a true self-contained export.
Luckily though, all of this boils down to a very simple requirement: the
host must be given the opportunity to do <whatever> to paths.
BTW, I don't know if LV2 supports this, but if it
allows plugins to
*SAVE* non-generic (that is to say, session specific) data wherever
they want on the filesystem, then that, IMHO, is badly broken. There
may be nothing technical that can be done about it, but you should at
the very least be able to point at a section of the API document and
say to the developer of such a plugin: Fix it, it's broken.
I fully agree. Plugins that create files in some random location are
the ultimate evil. The above basically boils down to "you can use
files, but the host must know about it". It is indeed explicitly
mentioned in the state spec.
(A sometimes overlooked sidenote: this applies to ALL files, not just at
save time. I have heard that the commercial stuff fails in this regard,
so advanced plugins (e.g. that record) tend to create files in random
locations, thus breaking sessions. The LV2 spec explicitly requires ALL
paths to be created via the host callback, including those used at
runtime for recording and such. This is also necessary to ensure
possibly large files are created on the correct volume.)
-dr
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8 comments
5 participants
participants (5)
-
David Robillard -
Emanuel Rumpf -
J. Liles -
parched2099 -
Paul Davis