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MMM (.mmm)

.mmm file signature | application/octet-stream

MacroMind Multimedia Movie or Microsoft Multimedia Movie

Safe

Magic Bytes

Offset 0
52 49 46 46 52 4D 4D 50

Sources: Wikipedia

Extension

.mmm

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .mmm files in Python

Python 
def is_mmm(file_path: str) -> bool:
    """Check if file is a valid MMM by magic bytes."""
    signature = bytes([0x52, 0x49, 0x46, 0x46, 0x52, 0x4D, 0x4D, 0x50])
    with open(file_path, "rb") as f:
        return f.read(8) == signature

How to validate .mmm files in Node.js

Node.js 
function isMMM(buffer: Buffer): boolean {
  const signature = Buffer.from([0x52, 0x49, 0x46, 0x46, 0x52, 0x4D, 0x4D, 0x50]);
  return buffer.subarray(0, 8).equals(signature);
}

How to validate .mmm files in Go

Go 
func IsMMM(data []byte) bool {
    signature := []byte{0x52, 0x49, 0x46, 0x46, 0x52, 0x4D, 0x4D, 0x50}
    if len(data) < 8 {
        return false
    }
    return bytes.Equal(data[:8], signature)
}

API Endpoint

GET /api/v1/mmm
curl https://filesignature.org/api/v1/mmm

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .mmm file?

A .mmm file is a MMM file. MacroMind Multimedia Movie or Microsoft Multimedia Movie

What are the magic bytes for .mmm files?

The magic bytes for MMM files are 52 49 46 46 52 4D 4D 50 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .mmm file?

To validate a .mmm file, read the first bytes of the file and compare them against the known magic bytes (52 49 46 46 52 4D 4D 50) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .mmm files?

There is no officially registered MIME type for .mmm files. Systems typically use application/octet-stream as a generic fallback when handling this format.

Is it safe to open .mmm files?

MMM (.mmm) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.