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Running out of channels (on GBA)
Posted: Mon Jun 10, 2013 10:36 am
by sverx
It looks like when I play an XM (though it doesn't happen with every XM), it eats up all the available 'channels' and none is left for sound effects... even if the XM is using 8 channels only and MaxMod has been initialized with 12 channels.
Code: Select all
mmInitDefault((mm_addr)soundbank_bin, 12);
Is there a MaxMod function that checks how many channels are currently used, as in the demo?
Thanks!
Re: Running out of channels (on GBA)
Posted: Tue Jun 11, 2013 9:59 am
by sverx
... there's something I really don't get
Why is an 8 channels XM using more than 8 'MaxMod' channels?
AFAIK MaxMod on GBA doesn't feature "volume ramping" so I'm really puzzled.
Anyone?
Re: Running out of channels (on GBA)
Posted: Wed Jun 12, 2013 10:05 am
by sverx
I tried increasing channels from 12 to 16, but the problem persists.
It really sounds like some channels get 'stuck' busy -even if not playing anything- and they never get back to the 'free' state.
The XM causing this uses volume envelopes and key-off commands... I'll try remove those and see if something changes.
Re: Running out of channels (on GBA)
Posted: Thu Jun 13, 2013 10:29 am
by sverx
I am using the
Code: Select all
mmMixerChannelActive(channel_number)
function now to see the state of the channel(s).
Let's see if I can sort out the problem...
Re: Running out of channels (on GBA)
Posted: Thu Jun 13, 2013 12:46 pm
by sverx
Quite curious: in mm_mixer_gba.s there's this:
Code: Select all
@ MIXER CHANNEL FORMAT
.equ CHN_SIZE, 24
.equ CHN_SRC,0
.equ CHN_READ,4
.equ CHN_VOL,8
.equ CHN_PAN,9
// 10
// 11
.equ CHN_FREQ,12
.equ CHN_SIZE,16
if I'm right, the last line redefines CHN_SIZE to value 16.
But then in MaxMod.h there's
which should be wrong, then.
BTW I yet don't know if this is causing the problem I'm having.
(Oh wait, MaxMod on sourceforge.net is 1.0.8, in the dev kit package is 1.0.7, but the compiled files have the same datestamps...
)
Re: Running out of channels (on GBA)
Posted: Thu Jun 13, 2013 1:41 pm
by elhobbs
are you sure this is referring to the number of channels and not the size of an internal data structure?
Re: Running out of channels (on GBA)
Posted: Thu Jun 13, 2013 2:28 pm
by sverx
Indeed it's the size of the internal data structure...
Re: Running out of channels (on GBA)
Posted: Thu Jun 13, 2013 7:35 pm
by sverx
Looks like it's a problem that arises when I stop a module and start another... am I not supposed to start a module immediately after stopping another?
I'm trying to reproduce it in a test program...
Re: Running out of channels (on GBA)
Posted: Fri Jun 14, 2013 10:49 am
by sverx
It seems that the problem may be caused by a vblank happening while I'm stopping the old module/starting the new one, so I solved adding this:
before stop/start.
I hope that's enough, and that this info would be useful to others
Re: Running out of channels (on GBA)
Posted: Sat Jun 15, 2013 4:21 pm
by sverx
mmm... I spoke too soon
