[BUG]: SDK MidiMessageConverter seems to lose group index

Reported by Jared from MOTU on Discord:

I did actually just find and confirm the bug, it looks like MidiMessageConverter::ConvertMidi1Message is losing the MIDI group

I confirmed it with this quick and dirty code snippet pasted into one of the sample projects - as I understand it these two messages should be identical:

int msg0 = 0xB0;
int status = 0x0B;
int channel = 0x0;
int msg1 = 0x3C;
int msg2 = 01;

auto msg = MidiMessageBuilder::BuildMidi1ChannelVoiceMessage(0, MidiGroup(2), Midi1ChannelVoiceMessageStatus(status), MidiChannel(channel), msg1, msg2);
std::cout << "Good message - Word 0:            0x" << std::hex << msg.Word0() << std::endl;
auto badmsg = MidiMessageConverter::ConvertMidi1Message(0, MidiGroup(2), msg0, msg1, msg2);
std::cout << "Bad message - Word 0:            0x" << std::hex << badmsg.Word0() << std::endl;

Found the bug here. Thank you

Changed

inline void SetGroupIndexInFirstWord(_Inout_ std::uint32_t firstWord, _In_ std::uint8_t groupIndex) noexcept

to this

// this is only called from SDK code, so doesn't need CFR wrapping
inline void SetGroupIndexInFirstWord(_Inout_ std::uint32_t& firstWord, _In_ std::uint8_t groupIndex) noexcept

The reference operator was missing in the old definition, so the changes were discarded.

Pete
Microsoft

Fix lost group in MidiMessageConverter

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[BUG]: SDK MidiMessageConverter seems to lose group index #947

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[BUG]: SDK MidiMessageConverter seems to lose group index #947

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Psychlist1972 commented on Mar 28, 2026

Psychlist1972 commented on Apr 12, 2026

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