Re: [fluid-dev] Patch for fast midi file rendering

[Josh Green]

On Mon, 2009-04-20 at 22:08 +0200, David Henningsson wrote:
> Josh Green skrev:
> > I agree that render fits the function of what FluidSynth is doing
> > (rendering SoundFont instruments and MIDI files to audio).  I'd just as
> > well do away with the file writer driver, since I don't see a need for
> > live file writing using FluidSynth directly (since you would likely want
> > to hear it as well, which means something like Jack would be better) and
> > other APIs, such as what you are suggesting, would be better suited for
> > faster than realtime rendering.  I suppose there isn't too much harm
> > done by leaving it around though.
> 
> Perhaps if you have a hardware sequencer which the input comes from, and
> you want to output that to a file?
> 

I would still think you would want to be able to monitor the audio that
FluidSynth is producing.  No big deal though, we can leave it for now
and perhaps someone is specifically using it in their software.

> > Hmm, I'm not sure about this one.  The settings seem like a nice way to
> > group options in one place, a registry of sorts.  Its useful to the user
> > and helps prevent the need to modify API function calls.  I can see in
> > that case how period_size could make sense, as it is already there.  The
> > filename on the other hand, seems more specific to the case where the
> > renderer is writing to a file (rather than say a user callback
> > function).  I could see that as being a parameter to
> > new_fluid_file_renderer().
> 
> But the file name is already a setting as well. And the word "period
> size" might sound like something more universal that "file name", but
> both of them are only used in the audio drivers. Anyway this is not a
> big deal to me, so if it is a big deal to anyone else, I'm willing to
> adjust :-)
> 

I'm also pretty flexible on this one, in the case of the audio renderer.
Using the settings parameters seems to be consistent.

> > I like the use of '-' to indicate stdout.  That is common to many
> > applications and would save the user from accidentally getting a
> > terminal full of seemingly endless junk.
> 
> Seems like a good idea. Hopefully noone wants to create a file named "-"?
> 

Then they can do:
fluidsynth my.sf2 my.mid -F - >'-'

I think some applications have a way around that (an extra switch or
something), but who wants a file called -?  Maybe -.wav or -.au ;)

> // David
> 

One thing I think would be good to add to the renderer API is a public
function for calling a callback instead of using a file handle.

Best regards,
        Josh