Subtitle
SubRip Subtitle is a subtitle format commonly identified by .srt. Use the listed signatures, MIME types, and structure notes to validate files beyond the extension.
31 0A 30 30 3A 30 30 1.00:00SIGNATURE = bytes.fromhex("310a30303a3030")
OFFSET = 0
def is_srt(path: str) -> bool:
with open(path, "rb") as f:
f.seek(OFFSET)
head = f.read(len(SIGNATURE))
return head == SIGNATUREconst SIGNATURE = [0x31, 0x0a, 0x30, 0x30, 0x3a, 0x30, 0x30];
const OFFSET = 0;
// bytes: a Uint8Array / Buffer holding the start of the file
export function isSrt(bytes) {
return SIGNATURE.every((byte, i) => bytes[OFFSET + i] === byte);
}package fileid
import "bytes"
var issrtSignature = []byte{0x31, 0x0a, 0x30, 0x30, 0x3a, 0x30, 0x30}
const issrtOffset = 0
func IsSrt(b []byte) bool {
end := issrtOffset + len(issrtSignature)
if len(b) < end {
return false
}
return bytes.Equal(b[issrtOffset:end], issrtSignature)
}const SIGNATURE: &[u8] = &[0x31, 0x0a, 0x30, 0x30, 0x3a, 0x30, 0x30];
const OFFSET: usize = 0;
fn is_srt(bytes: &[u8]) -> bool {
bytes.get(OFFSET..OFFSET + SIGNATURE.len()) == Some(SIGNATURE)
}<?php
$signature = "\x31\x0a\x30\x30\x3a\x30\x30";
$offset = 0;
function is_srt(string $bytes): bool {
global $signature, $offset;
return substr($bytes, $offset, strlen($signature)) === $signature;
}SubRip Subtitle is used for data exchange, imports, exports, parser testing, and validation workflows. Encoding, delimiters, versions, and container structure often change implementation behavior.
Untrusted input is not safe just because the format was detected. Account for parser exceptions, large files, unexpected encodings, and external references.
11 samples help test leading-byte detection, parser errors, upload limits, and download behavior.
Blue Sky SRT is a SubRip Subtitle sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
01-blue-sky.srtdf98bfdbc94f9a020161538cf6d26234861f300a7c090158735eba993762e5a4Flower Garden SRT is a SubRip Subtitle sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
02-flower-garden.srt0cfd87b4517ffe51778c7f0d6387d4e83cecf7ff950226f897f6f9a7dfae4956Navy Blue Sky SRT is a SubRip Subtitle sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
03-navy-blue-sky.srt494bd539264047912fa02785b36a80474c8b5b0b6e079967ef4bf236568fdcdeNature of the Sky SRT is a SubRip Subtitle sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
04-nature-sky.srt466d40a2e987a462611e234655d5020ed9c3a0c78971311828dfbc8ef8df68d3Sky Landscape SRT is a SubRip Subtitle sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
05-sky-landscape.srt82aef437534e82862820628e3868d631672f56ea21f808814b4c4e867e16f13dStarry Sky SRT is a SubRip Subtitle sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
06-starry-sky.srte0a400c54266cf8af4940679e89e29d510baaf45fba5766cbff603bb45667ff6Blue Night Sky SRT is a SubRip Subtitle sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
07-blue-night-sky.srta13e8e06c9db6cbdb6b97d17948bb5c39ccedcd441ee5d25e3a64a4e83b939a0Hibiscus Flower SRT is a SubRip Subtitle sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
08-hibiscus-flower.srtf618dc19ae2bebe46ca4defe0db51f596b9209c4c8cd2ddbe6988dd672c85fb7Arctic Sky SRT is a SubRip Subtitle sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
09-arctic-sky.srtb40fc412ab14f1ccc272c96b890f8bf7f5b6fe4ad134f5cb14cde3e8423677beSunset Rays SRT is a SubRip Subtitle sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
10-sunset-rays.srt7419b45bc6adcb4b91eb64665474d99716f835bdc50b771e45d9c19b61b70807NASA Blue Marble SRT is a SubRip Subtitle sample based on NASA Image and Video Library. It can be used to test downloads, parsers, previews, and file type detection.
nasa-blue-marble-2012-east.srt4d5b3cd6f6de5de54a34fdceb6fa30f7cf6e88bc695b78311164b2aaa621439fSubRip Subtitle files begin with the byte signature 31 0A 30 30 3A 30 30 ("1.00:00"). Detect the format by reading these leading bytes rather than trusting the file extension alone.
The MIME type for SubRip Subtitle is application/x-subrip, text/plain.
SubRip Subtitle files use the .srt extension. The extension is a convention only and does not guarantee the file contents, so combine it with signature and structure checks.