MMM (.mmm)

.mmm file signature | application/octet-stream

MMM is a legacy multimedia movie file format developed by MacroMind and later associated with Microsoft multimedia software. It was used for storing animated presentations and simple video or audio sequences in early desktop publishing and authoring applications. The format is largely obsolete, but files are generally safe to inspect; as with any legacy media file, playback should be limited to trusted software.

Safe

Magic Bytes

Offset 0


              52 49 46 46 52 4D 4D 50

Sources: Wikipedia

Extension

.mmm

MIME Type

application/octet-stream

Byte Offset

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

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.

Related Formats

.ani .cda .cdr .cmx .ds4 .qcp

Frequently Asked Questions

What is a .mmm file?

A .mmm file is identified by the magic bytes 52 49 46 46 52 4D 4D 50 at byte offset 0. MMM is a legacy multimedia movie file format developed by MacroMind and later associated with Microsoft multimedia software. It was used for storing animated presentations and simple video or audio sequences in early desktop publishing and authoring applications. The format is largely obsolete, but files are generally safe to inspect; as with any legacy media file, playback should be limited to trusted software.

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.