Vid
1s Color WebM
1s Color WebM is a WebM sample generated for file format testing. It can be used to test downloads, parsers, previews, and file type detection.
color-1s.webmType Sample
1.1 KB DownloadVideo
WEBM WebM
WebM is a video format commonly identified by .webm. Use the listed signatures, MIME types, and structure notes to validate files beyond the extension.
Extensions .webm
MIME video/webm, audio/webm
Magic numbers
Analyze your fileoffset 0 WebM leading signature
1A 45 DF A3 .E..Structure
- EBML header
- Segment
- Tracks
- Clusters
Caveats
- Do not trust the extension alone. Check the MIME type, the first bytes such as 1A 45 DF A3, and format-specific structure when possible.
- Container formats and damaged files can share the same opening bytes, so deeper validation may be required for production upload, preview, or conversion flows.
Detection example
SIGNATURE = bytes.fromhex("1a45dfa3")
OFFSET = 0
def is_webm(path: str) -> bool:
with open(path, "rb") as f:
f.seek(OFFSET)
head = f.read(len(SIGNATURE))
return head == SIGNATUREconst SIGNATURE = [0x1a, 0x45, 0xdf, 0xa3];
const OFFSET = 0;
// bytes: a Uint8Array / Buffer holding the start of the file
export function isWebm(bytes) {
return SIGNATURE.every((byte, i) => bytes[OFFSET + i] === byte);
}package fileid
import "bytes"
var iswebmSignature = []byte{0x1a, 0x45, 0xdf, 0xa3}
const iswebmOffset = 0
func IsWebm(b []byte) bool {
end := iswebmOffset + len(iswebmSignature)
if len(b) < end {
return false
}
return bytes.Equal(b[iswebmOffset:end], iswebmSignature)
}const SIGNATURE: &[u8] = &[0x1a, 0x45, 0xdf, 0xa3];
const OFFSET: usize = 0;
fn is_webm(bytes: &[u8]) -> bool {
bytes.get(OFFSET..OFFSET + SIGNATURE.len()) == Some(SIGNATURE)
}<?php
$signature = "\x1a\x45\xdf\xa3";
$offset = 0;
function is_webm(string $bytes): bool {
global $signature, $offset;
return substr($bytes, $offset, strlen($signature)) === $signature;
}Practical usage
Use cases
WebM is used for video previews, encoding checks, responsive UI testing, and upload flows. Container format and codecs are separate concerns, so leading bytes alone do not prove playability.
Common detection mistakes
- The .webm extension alone does not prove the file contents. Upload and conversion flows should combine extension, MIME type, leading bytes, and format-specific structure checks.
- WebM can start with signatures such as 1A 45 DF A3, but related containers and damaged files may require additional validation.
Security notes
Media files can still stress decoders through corrupt metadata, extreme dimensions, long durations, or unusual chunks. Read size, dimensions, and duration before processing.
Using samples
11 samples help test duration handling, playback startup, metadata reads, and download behavior.
Sample files
11 / 11 filesVid
Cloud Flight WEBM 0.5s
Cloud Flight WEBM 0.5s is a WebM sample based on Wikimedia Commons, 160 x 284, 0.5s. It can be used to test downloads, parsers, previews, and file type detection.
01-flight-over-clouds.webmResolution 160 x 284 45 Kpx
15 KB SHA-256
4f8795ff434b987b64523f6aba51be11e304da71d8396ce78ba83dd2bfb098b6Vid
Cloud Flight WEBM 1s
Cloud Flight WEBM 1s is a WebM sample based on Wikimedia Commons, 240 x 426, 1s. It can be used to test downloads, parsers, previews, and file type detection.
02-flight-over-clouds.webmResolution 240 x 426 102 Kpx
30 KB SHA-256
dd5b30623c6daa77d60c793b86d973a799140e836c92c4d96610e43e9bc53bd5Vid
Cloud Flight WEBM 1.5s
Cloud Flight WEBM 1.5s is a WebM sample based on Wikimedia Commons, 320 x 568, 1.5s. It can be used to test downloads, parsers, previews, and file type detection.
03-flight-over-clouds.webmResolution 320 x 568 182 Kpx
41 KB SHA-256
0cbdf422385dc969242f6b7b9205c52f3b1f53e1b2aaeb739c2f0ef787b12c2cVid
Cloud Flight WEBM 2s
Cloud Flight WEBM 2s is a WebM sample based on Wikimedia Commons, 480 x 854, 2s. It can be used to test downloads, parsers, previews, and file type detection.
04-flight-over-clouds.webmResolution 480 x 854 410 Kpx
51 KB SHA-256
22e8050151f15b8bd26b6d5330f7d78330cf47c989d035599fa09722b2faa84bVid
Cloud Flight WEBM 3s
Cloud Flight WEBM 3s is a WebM sample based on Wikimedia Commons, 640 x 1138, 3s. It can be used to test downloads, parsers, previews, and file type detection.
05-flight-over-clouds.webmResolution 640 x 1138 728 Kpx
82 KB SHA-256
c3c94f61d6af9ccc72bceedcbc7211fbc0360e6c2210630d65279e9e8af7168dVid
Cloud Flight WEBM 4s
Cloud Flight WEBM 4s is a WebM sample based on Wikimedia Commons, 720 x 1280, 4s. It can be used to test downloads, parsers, previews, and file type detection.
06-flight-over-clouds.webmResolution 720 x 1280 922 Kpx
109 KB SHA-256
e820dd77bbe9618d9d3d3f6fe2813027911e1932faf50363ba5c8f37399cecb8Vid
Cloud Flight WEBM 5s
Cloud Flight WEBM 5s is a WebM sample based on Wikimedia Commons, 854 x 1518, 5s. It can be used to test downloads, parsers, previews, and file type detection.
07-flight-over-clouds.webmResolution 854 x 1518 1.3 MP
131 KB SHA-256
77c5c24769695148b130924796d6438f2aa6475560a265950ca6304256180a83Vid
Cloud Flight WEBM 6s
Cloud Flight WEBM 6s is a WebM sample based on Wikimedia Commons, 960 x 1706, 6s. It can be used to test downloads, parsers, previews, and file type detection.
08-flight-over-clouds.webmResolution 960 x 1706 1.6 MP
173 KB SHA-256
94c9fd21e74b0fb6a76654629230bb884486973f356452f39fa4b541bcb7947fVid
Cloud Flight WEBM 8s
Cloud Flight WEBM 8s is a WebM sample based on Wikimedia Commons, 1080 x 1920, 8s. It can be used to test downloads, parsers, previews, and file type detection.
09-flight-over-clouds.webmResolution 1080 x 1920 2.1 MP
217 KB SHA-256
f6ec21e5f4c03c5c14bf6eba1b6e398261a3217d4e35614034bbdc633029c611Vid
NASA Clouds WEBM
NASA Clouds WEBM is a WebM sample based on NASA Image and Video Library, 480 x 270, 2s. It can be used to test downloads, parsers, previews, and file type detection.
nasa-clouds-orbit.webmResolution 480 x 270 130 Kpx
80 KB SHA-256
ea9f8789a512641c556a43e75a6e1e59324f2e5eddd656dfd047e6ea25f9b063Frequently asked questions
What is the magic number (file signature) of WebM?
WebM files begin with the byte signature 1A 45 DF A3 (".E.."). Detect the format by reading these leading bytes rather than trusting the file extension alone.
What is the MIME type of WebM?
The MIME type for WebM is video/webm, audio/webm.
What file extension does WebM use?
WebM files use the .webm extension. The extension is a convention only and does not guarantee the file contents, so combine it with signature and structure checks.