[LAD] SDL_mixer+LADSPA was:basic in-game audio synthesis api?

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: