ACCESS: Martian Memorandum - MT-32 channel mapping (original game bug)

[spiffythedog]

When running the original DOS release of Martian Memorandum with MT-32 music, the game does not remap its MIDI output to the nonstandard MT-32 channel configuration of 1-8 and 10 (as opposed to the default standard MT-32 channel configuration of 2-10). Naturally, the default arrangement renders channel 1 completely silent, resulting in missing notes and instruments. For the original DOS version at least, this issue can be remedied by manually setting the MT-32's channel mapping to the nonstandard 1-8 and 10 configuration before starting the game. Unfortunately, this does not seem to work for the ScummVM implementation.

This issue can best be demonstrated by comparing the music for the first narration sequence after the intro credits using both standard and nonstandard MT-32 channel mapping. Notice the absence of the Doctor Solo instrument on channel 1 with the standard mapping. Additionally, when looking through the window with the camera in Tex's office, you can also notice the absence of the Electric Organ 2 instrument on channel 1 (about 8 seconds in) with the standard mapping.

I've attached some brief sample recordings from MUNT to this ticket to better demonstrate the issue, as well as MIDI files for closer comparison.

[spiffythedog]

MIDI file - 'narration 1'

[spiffythedog]

MIDI file - 'camera look'

[spiffythedog]

OGG File - 'narration 1' (standard channels 2-10)

[spiffythedog]

OGG File - 'narration 1' (nonstandard channels 1-8 and 10)

[spiffythedog]

OGG File - 'camera look' (standard channels 2-10)

[spiffythedog]

OGG File - 'camera look' (nonstandard channels 1-8 and 10)