Opened 16 years ago

Closed 15 years ago

Last modified 15 years ago

#1094 closed defect (outdated)

MI2 (MAC): Tones of infinite length

Reported by: SF/superqult Owned by: SF/jamieson630
Priority: normal Component: Engine: SCUMM
Keywords: Cc:
Game: Monkey Island 2


This is probably another bug coming from the use (or
rather ScummVM's non-use) of the MAC sound data in the
mac version of MI2. Anyway, I experience a lot of
glitches in the music, where a tone can stretch out
forever. Usually, a sound rings until I leave the
current area. This occurs in almost every (if not
every) area I enter. I didn't find it very annoying at
first, but the more I play the more it disturbs me :)

I'm using the latest CVS version (July 31, 18:55).

Ticket imported from: #781025. Ticket imported from: bugs/1094.

Change History (12)

comment:1 Changed 16 years ago by fingolfin

Owner: set to SF/jamieson630

comment:2 Changed 16 years ago by SF/superqult

This also appears in Indiana Jones: FOA. I have a feeling
that there is a connection there, maybe the iMuse system?
I'll check other games too.

comment:3 Changed 16 years ago by SF/jamieson630

Summary: MI2: Tones of infinite lengthMI2 (MAC): Tones of infinite length

comment:4 Changed 16 years ago by SF/jamieson630

When testing the Mac MI2 files for bug 780675, I didn't notice
any hanging notes. Consequently, it could be one of two
things: (1) some endian-unsafe code in the MidiParser, or (2)
a quirk specific to the platform sound system.

The former is highly unlikely because event delays are
measured with VLQs, and that code is definitely endian safe.
Furthermore, the SMF format used by MI2 specifies explicit
Note Off events (as opposed to specifying durations for the
Note On events like XMIDI does). Explicit Note Off events
make it much harder to lose track of when to turn a note off.

The second alternative, a quirk in the sound system, is
something we've run into before. We had hanging note
problems specific to the Windows Software Synth, and I
continue to refine the MidiParser's output to deal with such

A more specific description of WHERE notes start hanging
would be useful. For instance, do hanging notes tend to
appear around the time that the music interactively
transitions from one passage to another (e.g. when moving in
and out of buildings in Woodtick)? If it occurs within a single
passage (i.e. no transitions), does it happen consistently at
one particular point in the music? Also, does it happen only
for the native MIDI driver, or for Adlib mode as well?

A recording of what you're hearing would be especially useful -
- I can get a lot more clues from a recording since I can listen
for very specific patterns. Are you able to whip up an MP3 or

comment:5 Changed 16 years ago by SF/superqult

I've tested it with a few drivers, and it's always the same
result. Though, the glitches appear in different places with
different drivers; but in the same places with the same
driver. Here's a couple of samples, and explanations:
In the beginning one of the tones plays a G in the third
octave forever, while an F-sharp in the fourth octave plays
a few notes. After a while, two other tones forms a chord
with the first one with an E in the third octave and an
F-sharp in the fourth octave. This appears when I walk out
of the bar (titled "hatch" in the game) in Woodtick. This
one uses the QT driver.
An E-flat in the second octave is playing forever. This
appears in the intro, after the first pause in the music
(when Guybrush chases away the two monkeys for the second
time). This one uses the Core Driver.

comment:6 Changed 16 years ago by SF/jamieson630

Hmm, the notes that are hanging don't even sound like notes
that should have been played in the first place, or like notes
that are supposed to be percussion. The latter is theoretically
plausible because percussion instruments don't necessarily
need a Note Off event -- a smart sound synth will
automatically free up synth resources once a percussion
instrument has faded to zero or near-zero volume. In reality,
the only reason to send percussion instruments over
something other than the percussion channel is because they
use custom instrumentation. Since I don't know anything
about the custom instrumentation capabilities of the Mac, I
don't know if custom instruments can specify something
(an "auto-off" or skipped Sustain phase of the ADSR cycle)
that the sound synth would use to automatically recycle
synth resources.

My hunch is that if custom percussion is being used, it may
be be in the 10-15 (zero-based) MIDI channel range. Try
inserting a check before line 213 of imuse_player.cpp (right
after "chan" has been init'd):

if (chan > 9) return;

If that doesn't work, try changing it to:

if (chan != [chan]) return;

...and vary [chan] from 0 to 15. This will filter out all but one
channel, allowing you to isolate on what channel(s)
extraneous notes are triggering.

The other possibility is the Smart Jump logic, which has been
the culprit of numerous issues since its revamp. The Woodtick
music, at least, does seem to pick up extraneous notes about
the time of a transition. (Actually, most the MP3 clip involved
transitions. Does the Woodtick music have extraneous notes
when you first walk into town, after the Largo theme, if you
don't actually walk in and out of buildings?) Try disabling
Smart Jump by changing line 185 of imuse_player.cpp to set
property mpSmartJump to 0 instead of 1.

Let me know the results of these tests, and we'll take it from

comment:7 Changed 16 years ago by Kirben

Just adding first suggestion of 'if (chan > 9) return;' to
imuse_player.cpp fixes the problem.

comment:8 Changed 16 years ago by Kirben

To be exact, channel 11 is causing the ringing noise.
Channel 10 is been used for another instrument, so best to
restrict fix to that particular channel.

comment:9 Changed 15 years ago by fingolfin

Running MI2 mac intro on my G4/400, with latest ScummVM CVS.
I run the MI2 intro with the CoreAudio driver 2 times, and got no
hanging notes.

Markus, is the problem *always* reproducible, or just sometimes?
Does it still happen with latest CVS?

comment:10 Changed 15 years ago by SF/superqult

This bug seems to have disappeared somewhere between July 31
and January 29 (today). You can probably close this one now.

comment:11 Changed 15 years ago by SF/jamieson630

Closing as out-of-date. I'm still not sure this was actually
fixed, or just a fluke to begin with. At any rate, I'm glad you
don't have to put up with annoying hanging notes anymore,
Markus. :)

comment:12 Changed 15 years ago by SF/jamieson630

Resolution: outdated
Status: newclosed
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