Subject: Re: [linux-audio-dev] GLAME supports LADSPA now.
From: Richard Guenther (richard.guenther_AT_student.uni-tuebingen.de)
Date: Wed May 24 2000 - 10:57:19 EEST
On Tue, 23 May 2000, David Benson wrote:
> > Well, with this proposed scheme you would be unable to provide host
> > specific additions to the plugins/structure. With XML we could define
> > a standard base and let hosts provide additional information. I think
> > the XML approach is more flexible than just another C-API.
> >
> > Richard.
>
> i think pbd was saying we ought to have both,
> and what the hell, we all *will* need a c-api to it.
>
> and i'm not sure we'll all agree on gnome-xml (is that what you meant?).
> of course, the best alternate (expat) is a sax-parser so it's
> more annoying ...
>
> the api should make the choice equivalent.
> (omitting the provite data the api would look something
> like this...)
>
> here's roughly the .h file i've been considering.
>
> struct _LadspaControlData {
> char* control_name;
> unsigned input : 1;
> unsigned output : 1;
> unsigned control : 1;
> unsigned audio : 1;
> };
See? This is limiting - it does not match the GLAME way of life. Obviously
I like to use the proposed Plugin Catalog scheme not only for LADSPA
plugins but for host specific plugins, too. So there needs to be a common
specified _head_ of such a Catalog Data entry:
> struct _LadspaData {
> char* plugin_name;
> char* author;
> char* copyright;
> int num_controls;
> LadspaControlData* controls;
> };
struct _CatalogData {
char *name, *author, *copyright;
int type;
void *host_specific;
}
Where type denotes LADSPA/GLAME/etc. (of course we need to coordinate
the numbers)
And the LADSPA/GLAME specific data goes into a specific structure.
> LadspaDatabase* ladspa_database_new (const char* fname);
> LadspaData* ladspa_plugin_data_find (LadspaDatabase* db,
> const char* name);
> LadspaData* ladspa_plugin_data_find_by_id (LadspaDatabase* db,
> unsigned long unique_id);
>
> /* user-defined key => string maps. */
> const char* ladspa_plugin_data_get_named_key(LadspaData* data,
> const char* key);
>
> /* user-defined key => xmltree maps. */
> const xmlNode* ladspa_plugin_data_get_subtree (LadspaData* data,
> const char* key);
>
> void ladspa_database_destroy (LadspaDatabase* database);
Thats ok as long as the actual XML format gets defined and one can use
it without fearing that it may change but not the C-API.
>
>
>
> i can implement this in glib + gnome-xml in like 15minutes,
> is this the right api?
No, see above. Its just too special, I dont think the catalog needs
to be tied to LADSPA in any way (other than having special infos
for LADSPA plugins).
> - dave
>
Richard.
-- Richard Guenther <richard.guenther_AT_student.uni-tuebingen.de> WWW: http://www.anatom.uni-tuebingen.de/~richi/ The GLAME Project: http://www.glame.de/
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