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RealMedia streaming media file (.rm)

.rm file signature | application/vnd.rn-realmedia

RealMedia (RM) is a multimedia container format created and maintained by RealNetworks for streaming audio and video. It was used for internet media delivery, especially in older web players, broadcasting systems, and downloadable clips distributed through RealPlayer. The format is now largely legacy, and files from untrusted sources should still be handled with standard caution, although the format itself is not typically associated with high security risk.

Safe

Magic Bytes

Offset 0
2E 52 4D 46

Sources: Apache Tika, Gary Kessler

Extension

.rm

MIME Type

application/vnd.rn-realmedia

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .rm files in Python

Python 
def is_rm(file_path: str) -> bool:
    """Check if file is a valid RM by magic bytes."""
    signature = bytes([0x2E, 0x52, 0x4D, 0x46])
    with open(file_path, "rb") as f:
        return f.read(4) == signature

How to validate .rm files in Node.js

Node.js 
function isRM(buffer: Buffer): boolean {
  const signature = Buffer.from([0x2E, 0x52, 0x4D, 0x46]);
  return buffer.subarray(0, 4).equals(signature);
}

How to validate .rm files in Go

Go 
func IsRM(data []byte) bool {
    signature := []byte{0x2E, 0x52, 0x4D, 0x46}
    if len(data) < 4 {
        return false
    }
    return bytes.Equal(data[:4], signature)
}

API Endpoint

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

See the full API documentation for all endpoints and parameters.

Related Formats

.rmvb .asf .mp4 .wmv .3g2 .3gp

Frequently Asked Questions

What is a .rm file?

A .rm file is a RealMedia streaming media file file. RealMedia (RM) is a multimedia container format created and maintained by RealNetworks for streaming audio and video. It was used for internet media delivery, especially in older web players, broadcasting systems, and downloadable clips distributed through RealPlayer. The format is now largely legacy, and files from untrusted sources should still be handled with standard caution, although the format itself is not typically associated with high security risk.

What are the magic bytes for .rm files?

The magic bytes for RealMedia streaming media file files are 2E 52 4D 46 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .rm file?

To validate a .rm file, read the first bytes of the file and compare them against the known magic bytes (2E 52 4D 46) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .rm files?

The primary MIME type for .rm files is application/vnd.rn-realmedia.

Is it safe to open .rm files?

RealMedia streaming media file (.rm) 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.