[LAD] starting out with tux audio

[Justin Smith]

On Fri, Jun 13, 2008 at 6:27 PM, AlgoMantra <algomantra at gmail.com> wrote:
> Sorry, my last reply was meant for the list, not just
> Fons.
>
> On Sat, Jun 14, 2008 at 6:56 AM, AlgoMantra <algomantra at gmail.com> wrote:
>>
>> FYI:
>>
>> http://www.linuxjournal.com/article/3836
>>
>> I was looking for this sort of thing.
>
>
>
> _______________________________________________
> Linux-audio-dev mailing list
> Linux-audio-dev at lists.linuxaudio.org
> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
>
>

If you want to code raw additive synthesis in C, I recommend either
writing a LADSPA plugin or a jack client. You will get one array of 32
bit floats per connection to the outside world at run-time. Audio
input will be an array with data you can read, and you will be
expected to write something to the audio output arrays so the data can
be used by other applications / plugins.

As was mentioned before, using /dev/dsp is depricated. If you want to
go low level, you want the ALSA API, because on any sane modern linux
system, /dev/dsp is probably an emulator  for the OSS interface, built
on top of ALSA. It probably makes more sense for most projects to use
jack and let a user fine tune thier ALSA parameters for their purposes
in thier jack driver configuration, rather than attempting to second
guess thier particular system or force them to set custom buffer sizes
and sample rate and data size for yet another audio application.
Whether you use jack or OSS, both are layers built on top of ALSA, and
jack will perform much better.

cat interprets its input as eight bit characters. If you really wanted
to go the lowest common denominator route and use only old school unix
API's, you can read() from /dev/dsp and then use the chars you get
back as a numeric datatype (this will most likely mean converting them
to floats if you are doing anything halfway interesting). This will
not be as straightforward to code, as flexible to use, or as efficient
at runtime as using jack or LADSPA would be.

For playing with sine waves and beat frequencies, I recommend csound
or PD. Both have sine wave generators built in, and both are easy to
write c plugins for.