3 Apr
2009
3 Apr
'09
2:50 p.m.
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.
Cheers,
James
3 Apr
3 Apr
4:34 p.m.
That would be for C btw.
On 3/4/2009, "james morris" <james(a)jwm-art.net> wrote:
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.
Cheers,
James
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4:46 p.m.
On Fri, Apr 3, 2009 at 3:50 PM, james morris <james(a)jwm-art.net> wrote:
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.
why would you worry about LADSPA plugins?
5:14 p.m.
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.
On 3/4/2009, "Paul Davis" <paul(a)linuxaudiosystems.com> wrote:
why would you worry about LADSPA plugins?
On Fri, Apr 3, 2009 at 3:50 PM, james morris
<james(a)jwm-art.net> wrote:
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.
6:12 p.m.
On Fri, Apr 3, 2009 at 6:13 PM, james morris <james(a)jwm-art.net> wrote:
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.
i wasn't suggesting JACK. just ladspa.
10:30 p.m.
On Fri, Apr 3, 2009 at 3:12 PM, Paul Davis <paul(a)linuxaudiosystems.com> wrote:
On Fri, Apr 3, 2009 at 6:13 PM, james morris
<james(a)jwm-art.net> wrote:
For in game synthesis, I recommend STK, which is c++ IIRC, but has
library functions for the sorts of things you are mentioning, another
option would be to use the csound api, and spawn csound events from
the main game thread.
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.
i wasn't suggesting JACK. just ladspa.
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4 Apr
4 Apr
5:02 a.m.
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
7:28 a.m.
Yeah I like the LADSPA idea now my confusion's cleared. I'm thinking it
will be the solution and should work with SDL_mixer. Choosing a popular
plugin set like SWH (included in Debian stable) seems like a safe bet
and I'll be able to get a lot out of it.
Cheers,
James.
On 4/4/2009, "Luis Garrido" <luisgarrido(a)users.sourceforge.net> wrote:
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
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6 Apr
6 Apr
10:44 a.m.
New subject: 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:
On Fri, Apr 3, 2009 at 6:13 PM, james morris
<james(a)jwm-art.net> wrote:
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.
i wasn't suggesting JACK. just ladspa.
11 a.m.
New subject: SDL_mixer+LADSPA was:basic in-game audio synthesis api?
On Mon, Apr 6, 2009 at 8:44 AM, james morris <james(a)jwm-art.net> wrote:
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:
If I understand correctly, what you are talking about is the buffer
size. The tradeoffs with buffer size are that with a short buffer size
sonic events happen with a shorter latency (ie. if a "pew pew" sound
goes with the laser, a shorter buffer reduces the delay between the
user pushing the "fire" button and hearing the "pew pew" sound). If
the buffer is too short, your CPU usage will become too large, and
eventually you will probably get underruns in your output buffers,
creating skipping sounds or gaps in your audio. If the buffer size is
too large, you will have a sluggish feeling to the game and for faster
sequences of events the sounds won't quite go with the key presses and
images. Typically you want buffer sizes to be some power of two, or a
small multiple of a power of two.
On Fri, Apr 3, 2009 at 6:13 PM, james morris
<james(a)jwm-art.net> wrote:
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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.
i wasn't suggesting JACK. just ladspa.
11:50 a.m.
New subject: SDL_mixer+LADSPA was:basic in-game audio synthesis api?
On 6/4/2009, "Justin Smith" <noisesmith(a)gmail.com> wrote:
If I understand correctly, what you are talking about
is the buffer
size.
Not exactly. I set the buffer size to 4096 with the call to
Mix_OpenAudio. The figure I'm talking about is the length of the stream
passed by SDL_mixer to my sfx processing callback. 1880 samples at
sample rate 44100 (halved for 22050). I'm trying to understand how this
figure is arrived at, and if I can rely on it (before any audio
processing starts) when I create the buffers the LADSPA plugins will
use. Changing the size of the buffers makes no difference to this
figure, but changing the sample rate does. Hmmm, that kinda half answers
it.
james.
12:20 p.m.
New subject: SDL_mixer+LADSPA was:basic in-game audio synthesis api?
passed by SDL_mixer to my sfx processing callback.
1880 samples at
sample rate 44100 (halved for 22050). I'm trying to understand how this
figure is arrived at, and if I can rely on it (before any audio
The buffer size you get from an audio backend is normally difficult to
predict, and I wouldn't advice you to do so. Sometimes it may even
depend on the hardware you are using, so it is not guaranteed that it
will be the same on another machine. I don't know whether SDL
encapsulates that for you, that would be more a question for SDL
support.
Most audio processing apps use ring buffers to account for that variability.
Just use any value you think provides you with a reasonable latency.
If you get more from the backend, just make several calls to the
LADSPA, it shouldn't mean much overhead. If you get less, just process
that bit or save it for the next iteration.
L
1:19 p.m.
New subject: SDL_mixer+LADSPA was:basic in-game audio synthesis api?
On Mon, Apr 6, 2009 at 9:20 AM, Luis Garrido
<luisgarrido(a)users.sourceforge.net> wrote:
The output buffer is not your only audio buffer, what we are dealing
with here is the size of the LADSPA processing buffer. This is a
simple matter of sending data from one buffer to another, as suggested
above, using a ring buffer is you most likely solution.
passed by
SDL_mixer to my sfx processing callback. 1880 samples at
sample rate 44100 (halved for 22050). I'm trying to understand how this
figure is arrived at, and if I can rely on it (before any audio
The buffer size you get from an audio backend is normally difficult to
predict, and I wouldn't advice you to do so. Sometimes it may even
depend on the hardware you are using, so it is not guaranteed that it
will be the same on another machine. I don't know whether SDL
encapsulates that for you, that would be more a question for SDL
support.
Most audio processing apps use ring buffers to account for that variability.
Just use any value you think provides you with a reasonable latency.
If you get more from the backend, just make several calls to the
LADSPA, it shouldn't mean much overhead. If you get less, just process
that bit or save it for the next iteration.
L
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4 Apr
4 Apr
7:27 a.m.
Hi james,
Have a look on FxEngine framework, ladspa and openAL.
S
----- Original Message -----
From: "james morris" <james(a)jwm-art.net>
To: <linux-audio-dev(a)lists.linuxaudio.org>
Sent: Friday, April 03, 2009 9:50 PM
Subject: [LAD] basic in-game audio synthesis api?
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.
Cheers,
James
_______________________________________________
Linux-audio-dev mailing list
Linux-audio-dev(a)lists.linuxaudio.org
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
6 Apr
6 Apr
11:40 a.m.
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.
The main disadvantage of course is having to distribute source files
for the audio that aren't compiled into the main executable. Not sure
if that's really a disadvantage though, it depends on your intentions.
(For instances many games have tons of extra data files anyways.)
Another idea: if you really want to do this in C, and already using
SDL to deal with sound output, but are still looking for a
higher-level solution, you could use FAUST to generate C++ code which
is actually not too hard to convert to C. (FAUST mostly just
generates a single C++ class with a single audio routine that
manipulates some arrays and floating-point numbers.)
Steve
On Fri, Apr 3, 2009 at 3:50 PM, james morris <james(a)jwm-art.net> wrote:
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.
Cheers,
James
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Linux-audio-dev(a)lists.linuxaudio.org
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
12:56 p.m.
Hallo,
Stephen Sinclair hat gesagt: // Stephen Sinclair wrote:
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.
Or you embed Pd: It's done like that in "Spore", which runs a Pd engine
inside,
or in RjDj, which is something in between a game and a music software and also
runs Pd embedded.
Advertisment: Here you can find hours and hours of RjDj-user-generated music:
http://rjdj.me Recorded on iPod or iPhone, but many of the RjDj scenes used
there have been made on Linux.
Ciao
--
Frank
7 Apr
7 Apr
12:32 p.m.
"james morris" <james(a)jwm-art.net> writes:
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.
It depends on what game you're developing.
If you're developing a 3d action game, like first person shooters,
then that's a whole chapter for itself if you want to do it right, but
if you're making a pin ball game, tetris or some game where you
generally don't move through corridors, etc, I would definitely use
supercollider.
You can load samples into supercollider or you can model your
synthesis from scratch or a combination of both, then just send
timestamped OSC messages to trigger or control them.
--
Esben Stien is b0ef@e s a
http://www. s t n m
irc://irc. b - i . e/%23contact
sip:b0ef@ e e
jid:b0ef@ n n
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days inactive
5508
days old
linux-audio-dev@lists.linuxaudio.org
16 comments
8 participants
participants (8)
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Esben Stien -
Frank Barknecht -
james morris -
Justin Smith -
Luis Garrido -
Paul Davis -
smprocess -
Stephen Sinclair