Running out of channels (on GBA)

[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.

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mmInitDefault((mm_addr)soundbank_bin, 12);

Is there a MaxMod function that checks how many channels are currently used, as in the demo?
Thanks!

[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?

[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.

[sverx]

I am using the

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mmMixerChannelActive(channel_number)

function now to see the state of the channel(s).
Let's see if I can sort out the problem...

[sverx]

Quite curious: in mm_mixer_gba.s there's this:

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@ 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

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#define MM_SIZEOF_MIXCH		24

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... )

[elhobbs]

are you sure this is referring to the number of channels and not the size of an internal data structure?

[sverx]

Indeed it's the size of the internal data structure...

[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...

[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:

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mmFrame();
VBlankIntrWait();

before stop/start.
I hope that's enough, and that this info would be useful to others

[sverx]

mmm... I spoke too soon