MIDI Note Zero Velocity Semantic Normalizer

Description

Normalize MIDI note-on with zero velocity to an explicit note-off with zero release velocity; other channel records are preserved.

MIDI 1.0 channel messages use a status byte identifying a message type and a channel, followed by one or two seven-bit data bytes. This family uses channel indexes 0–15 and raw program values 0–127. Raw message bytes do not include musical timing, instrument state or a MIDI file container.^[1]

Normalize MIDI note-on with zero velocity to an explicit note-off with zero release velocity; other channel records are preserved.

When to use this tool

Use this tool to normalize MIDI note-on with zero velocity to an explicit note-off with zero release velocity; other channel records are preserved.

How to use the tool and how it works

Enter messagesJson using the field definitions below. For JSON text, serialize the explicit records in the shown shape.
Run the operation. Correct input errors before interpreting an output.
Read result.messages. Use the ordering, boundary rules and absence conditions described below.

For note-on records with velocity zero, replace the status with note-off on the same channel and retain note plus zero velocity. Preserve other records.^[2]

Input field	Meaning and units	Accepted input
messagesJson	JSON text encoding array of {status: number, data: array of number}. Keep the record keys and value types shown in the decoded example below.	Text, at most 8,192 UTF-16 code units; the operation’s grammar also applies.

These are the decoded structures used in the example’s JSON text fields. Supply the corresponding serialized JSON strings as input.

json

{
  "messagesJson": [
    {
      "status": 146,
      "data": [
        60,
        0
      ]
    }
  ]
}

Output field	Interpretation
result	Object containing the named fields below.
result.messages	Explicit validated or transformed {status, data} records in source order.

json

{
  "input": {
    "messagesJson": "[{\"status\":146,\"data\":[60,0]}]"
  },
  "output": {
    "result": {
      "messages": [
        {
          "status": 130,
          "data": [
            60,
            0
          ]
        }
      ]
    }
  }
}

Limitations and assumptions

This rewrites explicit MIDI 1.0 channel records; it does not track active notes or release-velocity behavior.
Message data bytes must be integers 0–127 and channel statuses 128–239. Channels are zero-based; this family does not implement MIDI 2.0 UMP, audio synthesis or a complete timed MIDI file.
Every declared top-level input field is required and unexpected fields are rejected. Ordinary strings are limited to 8,192 UTF-16 code units and lists to 128 entries, with tighter operation-specific bounds where stated. JSON text has bounded nesting and node counts.
Numeric outputs must be finite and no larger in absolute magnitude than the safe-integer limit; operations returning exact large integers use decimal text. Positions are zero-based and spans end exclusively unless the operation explicitly states a different convention.

Alternative or Complementary methods

Separate channel-message encoding from timing, running status and device interpretation. Use a MIDI sequencer or full file/stream parser when those additional layers matter.

References

Summary of MIDI 1.0 Messages — The MIDI Association
Tool behavior and example: MIDI Note Zero Velocity Semantic Normalizer — tool.io

Similar or alternative tools

MIDI Channel Message Note Transposer
Transpose MIDI note-on/off and polyphonic key-pressure note fields only, rejecting out-of-range pitches rather than clipping; other records remain unchanged.
MIDI Channel Message Byte Count
Return required MIDI 1.0 channel-message byte counts from an explicit status, excluding running-status omission and system messages.