[ scummvm-Feature Requests-806641 ] Increase MIDI performance by omitting redundancies

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Feature Requests item #806641, was opened at 2003-09-15 18:42
Message generated for change (Comment added) made by logicdeluxe
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Category: None
Group: None
Status: Closed
Resolution: Fixed
Priority: 5
Submitted By: Marek Roth (logicdeluxe)
Assigned to: Jamieson Christian (jamieson630)
Summary: Increase MIDI performance by omitting redundancies

Initial Comment:
In all LEC-Adventures supporting MIDI (original or

converted from MT-32 doesn't matter) send the drum bank

change command with every single note, which cause some

tone generators like the Terratec Wavetable

Professional (which is a SC55 clone, and it can not be

that bad as it worked fine for all my MIDI games so

far) to terrible lagging notes, since it doesn't like

it at all. If ScummVM could filter the bank change

command on channel 10, the performance for MPU401

devices could increase the prformance a lot. This

command is useless anyway, since General MIDI has not

defined bank changes at all, and it IS General MIDI

after all. Also the bank switch never ever selects

another bank then 0 as far as I could find out. However

the standard bank should be selected then when native

MIDI is initialized to ensure the correct drum set is

selected throughout the game on GS or XG devices.



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>Comment By: Marek Roth (logicdeluxe)
Date: 2003-09-16 12:21

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I will verify this, as soon as there is a daily build uploaded.

I though a bit about it some more: Those bank changes might

be useful for native MT-32. I have to check this, but I

don't have my MT-32 right now. Assuming it is ment for MT-32

usage, it might be a good idea omitting the bank change only

when General MIDI is used, but actually send them when using

a real MT-32. At least it won't hurt, I guess.

And in deed, the problem is not the bandwidth of the MIDI

interface but the lot of time the bank change takes on some

devices. I also heard of people having such problems even

with software wavetables. If you wanna check some

wavetables, the MI2 title score drives MPU401 interfaces to

the limit.

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Comment By: Jamieson Christian (jamieson630)
Date: 2003-09-15 23:40

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Changed in CVS. There is a warning in case a non-zero bank 

select is attempted. That logic was supposedly in the original 

distro, after all, and may have been there for a good reason. 

If that warning manifests itself, we'll have to put bank select 

back in.



logicdeluxe, please verify that this even fixes your problem. 

The bandwidth chewed up by the bank selects is not 

prohibitive given spec MIDI transfer rates, so it sounds to me 

like poor handling of the program change messages by the 

Terratec card.

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You can respond by visiting: 
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