These facilities are also available for WAVE files (the  and 
chunks, the latter instigated by Digidesign, Sonic Foundry and Turtle Beach, and
should therefore have quite wide currency), so a modification of this nature
would not need to be confined to AIFF (indeed I think it is important that it is
not).

This is the sort of thing I would be interested to work on, but probably not
very soon. If anyone else is interested, I have the full details of the WAVE
chunks (part of the Microsoft VC++ documentation).

Of course, in each case these chunks are optional, so loscil will have to ba
able to 'degrade gracefully' in their absence, which implies setting the
required vlues explicitly, somehow, somewhere. The question arises, under what
circumstances might Csound write a file with this information? It must be
considered risky, I think, to have any opcodes too dependent on particulars of
soundfile formats, however widely used. Would it be possible, for example, to
add this information to IRCAM, snd and au formats?


Richard Dobson


Tobiah wrote:
> 

> 
> I use the 'loscil' ugen extensively in my csound comps.
> I would like to have more from it.  I am grateful that
> 'loscil' looks to see what base frequency that a particular
> sample declares, but I see that I need much more information
> in order to choose and play a particular sample at a given
> moment.
> 
> The AIFF spec allows for at least these parameters to be
> specified in the file:
> 
>         Base frequency of sample.  (perceived pitch)
>                 This one is handled in csound, but
>                 one must provide the function number
>                 of a sample in order to get the correct
>                 function to be chosen for a given pitch.
>                 I imagine a mechanism whereby this choice
>                 is dictated in accordance with the
>                 information in a given sample *set*.
> 
>         Low and High allowable Note range
>                 This parameter suggests the need for
>                 software to have the ability to discern
>                 the proper sample to be played from a set
>                 at a given time (i.e. from p5 ).
> 
>         Low and High Velocity
>                 Same notes as above, but corresponding to p4.
> 
>         Gain
>                 Why not?  It is in the file format, and it makes
>                 sense.
> 
>         Looping
>                 I don't approve of looping in the broad sense. I
>                 have enough disk space to house any length of sample
>                 that I have need of at this time.  I can see that
>                 certain instruments (such as the bagpipes) might
>                 lend themselves to this, but I should think that
>                 in general, this feature should be reserved for those
>                 with more limited resources, such as those that rely
>                 on MIDI equipment for their sound generation.  I am
>                 quite happy that 'loscil' utilizes this information.
>                 I am just making it clear here that this is not one
>                 of my larger concerns.  Exceptions include those
>                 instruments that have a 'release' portion that is
> markedly
>                 different in timber from that of the rest of the
> envelope.
> 
> I have a utility ready that I mentioned in another post
> that is able to manipulate these parameters of an AIFF file.
> 
> I would like to revise or reincarnate the 'loscil' ugen to
> take advantage of the virtual features that I have suggested.
> I have yet however, to attempt or succeed in grafting an opcode
> of my own on to csound.
>