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FLIC Animation file (.fli)

.fli file signature | video/x-fli

FLIC animation (FLI) is a legacy animation file format developed by Autodesk for its Animator and Animator Pro software. It was used to store short, looping raster animations for early personal computers and DOS-based multimedia applications. The format is largely obsolete, and files are generally safe to open, though modern support is limited and older converters or viewers may not handle malformed or nonstandard files reliably.

Safe

Magic Bytes

Offset 0
00 11 AF

Sources: Gary Kessler

Extension

.fli

MIME Type

video/x-fli

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .fli files in Python

Python 
def is_fli(file_path: str) -> bool:
    """Check if file is a valid FLI by magic bytes."""
    signature = bytes([0x00, 0x11, 0xAF])
    with open(file_path, "rb") as f:
        return f.read(3) == signature

How to validate .fli files in Node.js

Node.js 
function isFLI(buffer: Buffer): boolean {
  const signature = Buffer.from([0x00, 0x11, 0xAF]);
  return buffer.subarray(0, 3).equals(signature);
}

How to validate .fli files in Go

Go 
func IsFLI(data []byte) bool {
    signature := []byte{0x00, 0x11, 0xAF}
    if len(data) < 3 {
        return false
    }
    return bytes.Equal(data[:3], signature)
}

API Endpoint

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

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .fli file?

A .fli file is a FLIC Animation file file. FLIC animation (FLI) is a legacy animation file format developed by Autodesk for its Animator and Animator Pro software. It was used to store short, looping raster animations for early personal computers and DOS-based multimedia applications. The format is largely obsolete, and files are generally safe to open, though modern support is limited and older converters or viewers may not handle malformed or nonstandard files reliably.

What are the magic bytes for .fli files?

The magic bytes for FLIC Animation file files are 00 11 AF at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .fli file?

To validate a .fli file, read the first bytes of the file and compare them against the known magic bytes (00 11 AF) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .fli files?

The primary MIME type for .fli files is video/x-fli.

Is it safe to open .fli files?

FLIC Animation file (.fli) 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.