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Re: SetProperty/GetProperty

In terms of general handling of files in AU Presets, we have this capability - I'm not sure we have this in any official documentation, so we will make sure we include it

>>>
This document describes a proposed extension to the Audio Unit preset format in order to make it possible for host applications to collect all external file assets used in a project. This allows a user to archive a project with confidence that all of the external files it uses (e.g. samples, sample banks, etc.) are also archived.

It also permits Audio Unit developers to create smaller presets by storing only references to large external files, rather than embedding the contents of a large file in the preset -- an Audio Unit should not do this.

For example, the DLS synth does not store the contents of its current sound bank, just a reference to it (though not in this new proposed way). When loading a preset, it attempts to find the bank by name in certain known search directories.


1. Audio Unit behavior

Audio Units whose presets contain references to files should store a new key/value in their preset dictionaries:
key "file-references" ($$$ need a symbolic name) --> dictionary
dictionary contents:
AU-defined key (string) --> full path (string)
...

Thus, a preset may refer to any number of files, identifying each file's role in the preset with a key of the AU's choosing.

When an Audio Unit receives a preset from a host, it should be prepared to search for any missing files.


2. Host behavior

Hosts may present the user with a command to consolidate the external files referenced by a collection of Audio Units, by copying the files into a single directory or even by archiving them into a single file (a zip or tar archive, for example).

The details of this are up to the host's implementation.

When the host restores an archived project, extracting presets and their referenced files, each preset's file-references dictionary must be modified as necessary to reference a valid file.

If, for whatever reason, a referenced file cannot be located, the host should pass the last known valid full path for the referenced file, and in particular, that path MUST end with the same file name that the Audio Unit had stored. This makes it possible for the Audio Unit to display the name of the missing file.
>>>


Bill


On 16/11/2006, at 6:37 AM, Sebastien Beaulieu wrote:

Hi all,

William Stewart wrote:
At some point the host would have to marshall this... So the care that needs to be taken is this - don't embed pointers in these structs, but rather have the memory you pass in to the Get/Set calls be flat and complete. So, in your example above how you have this is fine (presuming of course that retval is a value not an address!). 

While we are on the subject, here's one I don't remember being
discussed before:

How would the AU / View residing on different machines work with files?

The file dialog would be showing up on the "View" machine and would
select file(s) the "AU" machine can't access. While for small files
it would be possible to either have the View know what to do or
send/receive a blob to/from the AU, there are cases where this makes
no sense. As a concrete example, audio files being streamed from or to
disk.

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Montreal. http://www.plogue.com
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References: 
 >SetProperty/GetProperty (From: "Art Gillespie" <email@hidden>)
 >Re: SetProperty/GetProperty (From: William Stewart <email@hidden>)
 >Re: SetProperty/GetProperty (From: Sebastien Beaulieu <email@hidden>)



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