Hi, I'm wanting to use basic synthesis techniques such as ADSRs LFOs hi/lo pass filters, echo, and reverb to generate some kind of ambient sound scape using pre-recorded audio clips, for a game I'm working on. Are there any libraries around to help make this a bit easier than coding it all using SDL_mixer? I'm not keen for a game to have audio, to depend on JACK or LADSPA plugins.

Allowing the game to connect to JACK, and using LADSPA plugins for the effects was just one option I thought of, but it would be a little unusual for a game. But still, it might be interesting to try.

As Paul said (and who would know better?) JACK and LADSPA are different APIs that solve different problems. JACK is for audio routing and syncing between applications and LADSPA for processing. You find them together in many programs but that doesn't mean there is any dependency between them. Another candidate may be Allegro: http://alleg.sourceforge.net/stabledocs/en/allegro.html It is rather simplistic in its DSP capabilities, but perhaps it is enough, or perhaps you can extend it. L _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev(a)lists.linuxaudio.org http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev

Hi, My experiment so far has yielded a WAV played via SDL_mixer and by registering a callback through Mix_RegisterEffect it is processed by the following LADSPA filters: 4x4allpass and Gverb. There might be some problems here though so I am asking if anybody can advise upon using SDL for audio. The problems with SDL_mixer are as follows: 1) The callback registered with Mix_RegisterEffect has a len parameter which is the length of the stream passed to the callback. It's value however seems mysteriously derived and it would be helpful to know in advance, it's precise value or expected ranges so I can create the IO buffers for the LADSPA effects only as large as they need be (rather than excessively large) before the fx call back is registered. ( is it always 1880 samples? ) 2) Currently, I have a mono stream (i think, not entirely sure) and it goes to the FX callback, processed by 4x4allpass, and then by Gverb. I discard one of the output channels from Gverb because, what else can I do with it? Nothing AFAICT. (No buses :( ) Are there solutions to this while still using SDL_mixer? Or should I write a custom mixer, (probably start coding from David Olofson's examples) ? Regards, James. On 3/4/2009, "Paul Davis" <paul(a)linuxaudiosystems.com> wrote: _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev(a)lists.linuxaudio.org http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev

If I understand correctly, what you are talking about is the buffer size.

What about using an external program like Pd or ChucK to design your sounds, and just talk to the sound engine using OSC? (Hm, yes this does seem like my answer for everything these days...) Anyways, you can run a Pd patch for example without the GUI, or a lot of the effects you mention are built into ChucK or SuperCollider as well. I find it nice to be able to separate this stuff out of a program and have it running in another process, particularly if it's going to conflict with a game loop, and allows you to design nice audio routines without worrying about headache-inducing system-level technical details.

I'm wanting to use basic synthesis techniques such as ADSRs LFOs hi/lo pass filters, echo, and reverb to generate some kind of ambient sound scape using pre-recorded audio clips, for a game I'm working on.