Adaptive Multi-Rate ACELP (.amr)
.amr file signature | audio/amr
Adaptive Multi-Rate ACELP (Algebraic Code Excited Linear Prediction)Codec, commonly audio format with GSM cell phones. (SeeRFC 4867.)
Magic Bytes
Offset 0
23 21 41 4D 52
Sources: Apache Tika, Wikipedia, Gary Kessler, Neil Harvey FileSignatures
All Known Signatures
2 signature variants are documented for .amr files across multiple sources.
| Hex Signature | Offset | Sources |
|---|---|---|
| 23 21 41 4D 52 | 0 | Apache Tika, Wikipedia, Gary Kessler, Neil Harvey FileSignatures |
| 23 21 41 4D 52 0A | 0 | Apache Tika |
Extension
.amr
MIME Type
audio/amr
Byte Offset
0
Risk Level
Safe
Validation Code
How to validate .amr files in Python
def is_amr(file_path: str) -> bool:
"""Check if file is a valid AMR by magic bytes."""
signature = bytes([0x23, 0x21, 0x41, 0x4D, 0x52])
with open(file_path, "rb") as f:
return f.read(5) == signatureHow to validate .amr files in Node.js
function isAMR(buffer: Buffer): boolean {
const signature = Buffer.from([0x23, 0x21, 0x41, 0x4D, 0x52]);
return buffer.subarray(0, 5).equals(signature);
}How to validate .amr files in Go
func IsAMR(data []byte) bool {
signature := []byte{0x23, 0x21, 0x41, 0x4D, 0x52}
if len(data) < 5 {
return false
}
return bytes.Equal(data[:5], signature)
}API Endpoint
/api/v1/amr
curl https://filesignature.org/api/v1/amr
See the full API documentation for all endpoints and parameters.
Frequently Asked Questions
What is a .amr file?
A .amr file is a Adaptive Multi-Rate ACELP file. Adaptive Multi-Rate ACELP (Algebraic Code Excited Linear Prediction)Codec, commonly audio format with GSM cell phones. (SeeRFC 4867.)
What are the magic bytes for .amr files?
The magic bytes for Adaptive Multi-Rate ACELP files are 23 21 41 4D 52 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .amr file?
To validate a .amr file, read the first bytes of the file and compare them against the known magic bytes (23 21 41 4D 52) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .amr files?
The primary MIME type for .amr files is audio/amr.
Is it safe to open .amr files?
Adaptive Multi-Rate ACELP (.amr) 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.