Mail Archives: djgpp/1997/06/20/11:18:33
On Tue, 17 Jun 1997 23:02:42 GMT, Andrew Ellem <krand AT ican DOT net> wrote:
>Is is possible to create a bitstream to the sound card? I'm trying to get a
>MPEG Layer 3 player working, but it requires a streamed output to the sound
>device. Is there anyway to get this to work, or will I have to resort to
>filling out a SAMPLE and playing it?
I don't know if this is possible with Allegro, might be, but I suggest you
also check out MIDAS Sound System 1.0 beta 1. It isn't really recommended
for most DOS users (use 0.7beta1 instead), but it includes stream support
also in DOS, for all supported sound cards. After initializing the system,
you can just start playing a stream, and feed the decompressed data from a
memory buffer to MIDAS. The stream feed function can even block until all
data from the buffer has been fed, working almost exactly like write()ing
the data to /dev/audio or something.
I originally ported splay to Win32 platforms by using MIDAS myself, I
think the whole porting process took about a half an hour - and I used
Watcom C, not GCC. I might have the MIDAS-using version of splay still
around somewhere, mail me if you think it would be useful. I have also
ported both splay and mpg123 to Win32 using the Win32 audio API directly.
The downside of using MIDAS for this is, that you end up mixing the whole
stream in software before outputting it to the sound card. This can take
quite a bit of CPU time, especially as the MIDAS mixing routines for
16-bit samples are really not all that well optimized in 1.0b1 (read: not
at all :) It has its benefits though - you can play a 44.1kHz 16-bit
stereo stream on an old mono 8-bit Sound Blaster :)
MIDAS is free for non-commercial use, check
http://kalahari.ton.tut.fi/s2/midas/. 1.0 beta 1 includes stream support
for DOS, as well as DJGPP support, 0.7 beta 1 doesn't support stream
playback in DOS, but might be a better idea for other DOS use. Earlier
versions do not support DJGPP.
Petteri, one of the authors
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