🚀 MIDI 2.0 / UMP — Deep Dive¶

Referência técnica completa sobre MIDI 2.0, Universal MIDI Packets (UMP) e a implementação em ESP32_Host_MIDI.

O Que é MIDI 2.0¶

O MIDI 2.0 é o sucessor do MIDI 1.0 (1983), publicado pela MIDI Manufacturers Association (MMA) em 2020. Mantém total retrocompatibilidade com MIDI 1.0 enquanto adiciona:

Velocidade 16-bit (0–65535 vs 0–127)
Control Change 32-bit (0–4.294.967.295 vs 0–127)
Pitch Bend 32-bit (maior precisão de afinação)
Pressure polirítmica 32-bit por nota
Per-note controllers (pitch bend por nota individualmente)
Profile Negotiation — dispositivos negociam capacidades
Property Exchange — metadados em JSON

Universal MIDI Packet (UMP)¶

O MIDI 2.0 usa um novo formato de pacote — o Universal MIDI Packet — em vez dos bytes simples do MIDI 1.0:

graph LR
    subgraph MIDI1["MIDI 1.0"]
        B1["Byte 0\nStatus"]
        B2["Byte 1\nData"]
        B3["Byte 2\nData"]
    end

    subgraph UMP32["UMP 32-bit (MIDI 1.0 em UMP)"]
        W1["Word 0\n32 bits\n[MT][Group][Status][Channel][Note][Vel7]"]
    end

    subgraph UMP64["UMP 64-bit (MIDI 2.0)"]
        W2["Word 0\n32 bits\n[MT][Group][Opcode][Channel][Note][Attr]"]
        W3["Word 1\n32 bits\n[Velocity16][Attribute Data]"]
    end

    MIDI1 -.->|"encapsular"| UMP32
    UMP32 -.->|"upgrade"| UMP64

Tipos de Mensagem UMP¶

Código	Tipo	Tamanho
`0x0`	Utility	32-bit
`0x1`	System Real-Time / Common	32-bit
`0x2`	MIDI 1.0 Channel Voice	32-bit
`0x3`	Data Messages (SysEx7)	64-bit
`0x4`	MIDI 2.0 Channel Voice	64-bit
`0x5`	Data Messages (SysEx8)	128-bit

Opcodes MIDI 2.0 Channel Voice (MT=0x4)¶

Opcode	Mensagem	Dados Word 1
`0x9`	Note On	Velocity 16-bit
`0x8`	Note Off	Velocity 16-bit
`0xB`	Control Change	Value 32-bit
`0xE`	Pitch Bend	Value 32-bit
`0xC`	Program Change	—
`0xD`	Channel Pressure	Value 32-bit
`0xA`	Poly Pressure	Value 32-bit
`0x6`	Per-Note Pitch Bend	Value 32-bit
`0xF`	Per-Note Management	—

Escalamento MIDI 1.0 ↔ MIDI 2.0¶

flowchart LR
    subgraph M1["MIDI 1.0"]
        V7["Vel: 7-bit\n0–127"]
        CC7["CC: 7-bit\n0–127"]
        PB14["PitchBend: 14-bit\n0–16383"]
    end

    subgraph M2["MIDI 2.0"]
        V16["Vel: 16-bit\n0–65535"]
        CC32["CC: 32-bit\n0–4.29B"]
        PB32["PitchBend: 32-bit"]
    end

    V7 <-->|"×512.00\n(scale7to16)"| V16
    CC7 <-->|"×33.825.421"| CC32
    PB14 <-->|"×65536\n÷16384"| PB32

    style M1 fill:#37474F,color:#fff
    style M2 fill:#3F51B5,color:#fff

Fórmulas de Escalamento¶

// MIDI 1.0 → MIDI 2.0 (upscale)
uint16_t vel16 = ((uint32_t)vel7 * 0xFFFF) / 0x7F;
uint32_t cc32  = ((uint64_t)cc7  * 0xFFFFFFFF) / 0x7F;
uint32_t pb32  = ((uint64_t)pb14 * 0xFFFFFFFF) / 0x3FFF;

// MIDI 2.0 → MIDI 1.0 (downscale)
uint8_t  vel7  = (vel16 * 0x7F + 0x8000) / 0xFFFF;
uint8_t  cc7   = (cc32  * 0x7F + 0x80000000) / 0xFFFFFFFF;
uint16_t pb14  = (pb32  * 0x3FFF + 0x80000000) / 0xFFFFFFFF;

Implementação em ESP32_Host_MIDI¶

MIDI2Support.h¶

#include "src/MIDI2Support.h"

// ─── Tipos ─────────────────────────────────────────────────────────────────
struct UMPWord64 {
    uint32_t word0;
    uint32_t word1;
};

struct UMPResult {
    bool valid;
    bool isMIDI2;
    uint8_t msgType;        // Message Type (0x0–0x5)
    uint8_t channel;        // Canal (0–15)
    uint8_t note;           // Nota MIDI (0–127)
    uint16_t velocity16;    // Velocidade 16-bit (MIDI 2.0)
    uint32_t value;         // Valor 32-bit (CC, PB)
    uint8_t midi1[3];       // Equivalente MIDI 1.0 (downscaled)
};

// ─── Escalamento ───────────────────────────────────────────────────────────
class MIDI2Scaler {
public:
    static uint16_t scale7to16(uint8_t v7);
    static uint32_t scale7to32(uint8_t v7);
    static uint32_t scale14to32(uint16_t v14);
    static uint8_t  scale16to7(uint16_t v16);
    static uint8_t  scale32to7(uint32_t v32);
    static uint16_t scale32to14(uint32_t v32);
};

// ─── Builder ───────────────────────────────────────────────────────────────
class UMPBuilder {
public:
    static UMPWord64 noteOn(uint8_t group, uint8_t channel,
                             uint8_t note, uint16_t velocity16);
    static UMPWord64 noteOff(uint8_t group, uint8_t channel,
                              uint8_t note, uint16_t velocity16);
    static UMPWord64 controlChange(uint8_t group, uint8_t channel,
                                    uint8_t index, uint32_t value32);
    static UMPWord64 pitchBend(uint8_t group, uint8_t channel,
                                uint32_t value32);
};

// ─── Parser ────────────────────────────────────────────────────────────────
class UMPParser {
public:
    static UMPResult parseMIDI2(UMPWord64 pkt);
};

Exemplo Completo — Construir e Parsear UMP¶

#include "src/MIDI2Support.h"

void exemploUMP() {
    // 1. Nota com velocidade MIDI 1.0 (7-bit)
    uint8_t vel7 = 100;

    // 2. Escalar para MIDI 2.0 (16-bit)
    uint16_t vel16 = MIDI2Scaler::scale7to16(vel7);
    Serial.printf("vel7=%d → vel16=%u (%.1f%%)\n",
        vel7, vel16, vel16 / 65535.0f * 100.0f);

    // 3. Construir pacote UMP (NoteOn, grupo 0, canal 0, C4=60)
    UMPWord64 pkt = UMPBuilder::noteOn(0, 0, 60, vel16);
    Serial.printf("UMP Word0: 0x%08X\n", pkt.word0);
    Serial.printf("UMP Word1: 0x%08X\n", pkt.word1);

    // 4. Parsear de volta
    UMPResult r = UMPParser::parseMIDI2(pkt);
    Serial.printf("Parse: note=%d vel16=%u vel7=%d\n",
        r.note, r.velocity16, r.midi1[2]);
}

Saída:

vel7=100 → vel16=51380 (78.4%)
UMP Word0: 0x40093C00
UMP Word1: 0xC8B40000
Parse: note=60 vel16=51380 vel7=100

MIDI2UDPConnection — Protocolo¶

Protocolo customizado ESP32→ESP32 de 12 bytes:

┌─────────────────────────────────────────────────────────────────┐
│ 55 4D 50 32  │  Word0 (4 bytes BE)  │  Word1 (4 bytes BE)      │
│  "UMP2"      │  Header UMP          │  Velocidade 16-bit        │
└─────────────────────────────────────────────────────────────────┘

Exemplo NoteOn C4, vel7=100:

55 4D 50 32   ← Magic "UMP2"
40 09 3C 00   ← MT=4, opcode=9 (NoteOn), ch=0, note=60
C8 B4 00 00   ← vel16 = 51380 = 0xC8B4

Status do MIDI 2.0 na Biblioteca¶

Feature	Status
UMP 32-bit (MIDI 1.0 in UMP)	✅ Implementado
UMP 64-bit (MIDI 2.0)	✅ NoteOn, NoteOff, CC, PB
Escalamento 7→16, 7→32, 14→32	✅
MIDI2UDPConnection (ESP32↔ESP32)	✅
Profile Negotiation	🔄 Futuro
Property Exchange	🔄 Futuro
MIDI-CI	🔄 Futuro

Próximos Passos¶

MIDI 2.0 UDP → — usar o transporte
Exemplo MIDI 2.0 → — sketch com display
Roadmap → — MIDI-CI e Profile Negotiation