MPEG-4 video|QuickTime file (.m4v)
.m4v file signature | video/mp4
ISO Media, MPEG v4 system, or iTunes AVC-LC file
Magic Bytes
Offset 4
66 74 79 70 4D 34 56 20
Sources: Apache Tika, Gary Kessler
All Known Signatures
5 signature variants are documented for .m4v files across multiple sources.
| Hex Signature | Offset | Sources |
|---|---|---|
| 66 74 79 70 4D 34 56 20 | 4 | Apache Tika, Gary Kessler |
| 66 74 79 70 4D 34 56 48 | 4 | Apache Tika |
| 66 74 79 70 4D 34 56 50 | 4 | Apache Tika |
| 66 74 79 70 6D 70 34 32 | 4 | Gary Kessler |
| 4D 34 56 20 | 0 | Neil Harvey FileSignatures |
Extension
.m4v
MIME Type
video/mp4, video/x-m4v
Byte Offset
4
Risk Level
Safe
Validation Code
How to validate .m4v files in Python
def is_m4v(file_path: str) -> bool:
"""Check if file is a valid M4V by magic bytes."""
signature = bytes([0x66, 0x74, 0x79, 0x70, 0x4D, 0x34, 0x56, 0x20])
with open(file_path, "rb") as f:
return f.read(8) == signatureHow to validate .m4v files in Node.js
function isM4V(buffer: Buffer): boolean {
const signature = Buffer.from([0x66, 0x74, 0x79, 0x70, 0x4D, 0x34, 0x56, 0x20]);
return buffer.subarray(0, 8).equals(signature);
}How to validate .m4v files in Go
func IsM4V(data []byte) bool {
signature := []byte{0x66, 0x74, 0x79, 0x70, 0x4D, 0x34, 0x56, 0x20}
if len(data) < 8 {
return false
}
return bytes.Equal(data[:8], signature)
}API Endpoint
/api/v1/m4v
curl https://filesignature.org/api/v1/m4v
See the full API documentation for all endpoints and parameters.
Frequently Asked Questions
What is a .m4v file?
A .m4v file is a MPEG-4 video|QuickTime file file. ISO Media, MPEG v4 system, or iTunes AVC-LC file
What are the magic bytes for .m4v files?
The magic bytes for MPEG-4 video|QuickTime file files are 66 74 79 70 4D 34 56 20 at byte offset 4. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .m4v file?
To validate a .m4v file, read the first bytes of the file and compare them against the known magic bytes (66 74 79 70 4D 34 56 20) at offset 4. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .m4v files?
The primary MIME type for .m4v files is video/mp4. Additional MIME types include: video/mp4, video/x-m4v.
Is it safe to open .m4v files?
MPEG-4 video|QuickTime file (.m4v) 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.