Re: [fluid-dev] File output with FluidSynth API

[Felix Krause]

On 06.03.2010, at 19:09, David Henningsson wrote:

> Felix Krause wrote:
>> On 04.03.2010, at 09:21, David Henningsson wrote:
>>> So the FS command (fluidsynth -a file -i -n -T wav -o
>>> audio.file.name=output.wav soundfont.sf2 midifile.mid) still just
>>> produces a 4 KB file? It works here.
>> 
>> Yes, I still get a 4KB file.
> 
> Does it exit immediately or after the midi file has completed? That is,
> if the midi file is two minutes long, does it wait two minutes before
> exiting?

Good point, I totally forgot to mention this: fluidsynth never stops.
At least it takes much longer than the midi file actually is, so I have to stop 
it with ^C.

> I think either something is wrong with fluid_curtime on MacOSX, or with
> libsndfile. Could you try building it without libsndfile and see if it
> works better?

Without libsndfile, FluidSynth creates a 0KB file.

> For the former problem I think a debug print in fluid_file_audio_run_s16
> might be helpful, something like:
> 
> /.../
>       sample_time = (unsigned int) (dev->samples / dev->sample_rate * 1000.0);
>       fprintf(stderr, "Sample_time = %d, clock_time = %d\n", sample_time,
> clock_time);
> 
>       if (sample_time > clock_time) {
>               return 1;
>       }
> /.../
> 
> A debug print of the delay variable in fluid_timer_run might also be
> helpful (just before the call to g_usleep).

Here's what I got as debug output when rendering to a wave file with libsndfile:

Sample_time = 0, clock_time = 0
delay = 1
Sample_time = 1, clock_time = 0
delay = 2
Sample_time = 1, clock_time = 0
delay = 3
Sample_time = 1, clock_time = 0
delay = 4
Sample_time = 1, clock_time = 0
delay = 5
Sample_time = 1, clock_time = 0
delay = 6
Sample_time = 1, clock_time = 0
delay = 7
Sample_time = 1, clock_time = 0
delay = 8
Sample_time = 1, clock_time = 0
delay = 9
Sample_time = 1, clock_time = 0
delay = 10
... and so on

I hope this helps.


Cheers,
Felix