[Openal] Isn't AL_DATA parameter work correctly yet?
garinh at cheesetoast.net
Wed Aug 17 08:44:45 PDT 2005
> AL_DATA is an unused token, probably a relict from the dark history
> of OpenAL... :-) You can only specify the buffer data via
> alBufferData, but you can't read the sound data itself back, only
> the AL_FREQUENCY, AL_SIZE. AL_BITS, and AL_CHANNELS attributes (see
> section 5.3.3 of the OpenAL 1.1 spec). I would really like to be
> OpenAL a bit more symmetrical in this respect, but alas, it isn't...
There's a good reason for this -- AL libraries have the option of
changing the format or even sending the data somewhere other than
locally-accessible memory, so symmetry is not even _possible_ in some
Since it is now public information, I can reveal that -- for instance
-- the new X-Fi boards from Creative that have on-board memory can
fall into this category. Once the data is sent to AL, on these
boards it is then moved over to the sound card and may not be in the
original format anymore (warning -- I'm simplifying the situation to
illustrate a point -- more details later).
This would also happen if someone were to release a USB sound device
with on-board memory...
> Garin: If it's OK, I'll remove AL_DATA from the SI (Linux and Win32
> part at least).
More information about the Openal