John wrote:
>But this would require an addition to the standard itself ...
I haven't been following this discussion closely enough; these
MIDI details are beyond my understanding without a much closer
reading of the MIDI spec. But I just want to emphasize that
if the community of developers decides that fixes in the
SA spec are warranted, it's better to make the spec do the
right thing through corrigenda. So if you guys decide what
the right answer is, I'm happy to help move it into the spec
through a corrigendum.
I would say that the basis for community-based corrigenda
should be: a strong consensual opinion on the change, no
hard-fought veto from someone with a committed implementation,
and no ulterior motives to the change. This kind of discussion
surely meets these criteria, so if the right behavior (for
RPNs and NPRNs, for example) is settled, I'll include it in
the upcoming corrigendum.
>Finally, there may be a possible errata in the Structured Audio
>spec concerning params[] -- if I read the MPEG 4 Systems spec
>correctly, params[] is meant for bi-directional communication
>between SAOL program and the decoder. But the relevent sections
>of the Structured Audio spec (5.8.6.6.2, for example, defining
>assignment statements) note that MIDIctrl[] may be an lval, but
>says nothing about params[]. Eric, which document is correct here?
params[] should definitely be allowed to be an lval. If the
spec seems to prohibit it (I don't have one in front of me at
the moment) it's an oversight and should be fixed.
A bigger problem is that I recall that params[] only gets exposed
to the Systems layer in the AudioFX node (for effects-
processing orchestras), not in the AudioSource node (for normal
use of SA as a media decoder). This is a problem (because you'd
like to be able to control the SA decoder with user interaction
at the Systems level in a normative end-to-end system. But it will
require more political work to correct (if I'm right that it's
presently broken) since I don't "own" the Systems stuff in
MPEG as I do the SA stuff.
Best,
-- Eric
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