Re: [LAD] mixing music and sound effects using libao

Am 30.04.2015 um 10:41 schrieb dave@email-addr-hidden:
>
> I've been playing around with libsndfile, libvorbisfile, libmodplug,
> and libao to provide background music and sound effects for a game
> engine. I have a solid handle on making one noise at a time, but I
> don't understand mixing. At first I thought I would have to write my
> own mixer and handle the channels, sample rate, and sample size issues
> myself. I really don't want to have to do that. Then I noticed in
> the libao documentation that nothing says that I cannot spawn two
> threads, each of which calls ao_open_live() and ao_play() on different
> sound files. Indeed, the docs for ao_initialize() seem to suggest
> this can be done with the statement that it be called in the main thread.
>
> I tried this and it works so erratically that I'm not sure libao was
> written with this in mind. I get these results in order of likelihood:
>
> 1) "Segmentation fault"
>
> 2) "*** glibc detected *** ./threadtest7: malloc(): memory corruption
> (fast): 0x0000000001bc5390 *** Bus error"
>
> 3) "*** glibc detected *** ./threadtest7: double free or corruption
> (out):
> 0x00000000018ba2e0 ***"
>
> 4) A bit of the first file, then the second file.
>
> 5) Only the second file.
>
> 6) Both files messily mixed with a zipping noise. (very rare)
>
> Is libao in fact intentionally capable of doing this? If not, what
> are my options for mixing music and sound effects? I really don't
> want to use SDL_mixer for a variety of reasons, chiefly because my
> program is terminal-only. Virtual beer if you can guess what the
> program is.
>
>

Hi

It seems libao is able to do this. Attached is the example code from the
libao side, roughly hacked in a second thread to play to signals
simultaneous. Works stable here.

regards
hermann

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