1 KB VTT sample file

A VTT file of exactly 1,024 bytes. It is a valid WebVTT subtitles file, generated for this site and checked with an independent parser.

sample-vtt-1kb.vtt

1 KB1,024 bytes

Download 1 KB VTT

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Type: text/vtt
SHA-256: 531b57336718c4509c1d2715f99f9a12a906abf582378a48619941e93b641c8a
Direct URL: https://sampletestfiles.com/downloads/vtt/sample-vtt-1kb.vtt

What is in this file

The WEBVTT header and 8 cues with identifiers. A closing NOTE comment block brings the file to the exact size.

Cues	8
Cue length	3 seconds, one every 4 seconds
Running time	00:00:32
Encoding	UTF-8 (ASCII characters only)
Line endings	LF

How the file begins

The opening lines of sample-vtt-1kb.vtt, exactly as they appear in the file.

WEBVTT

NOTE SampleTestFiles sample WebVTT file (1 KB)

1
00:00:00.000 --> 00:00:03.000
This sample file exists so that software
can be tested with realistic input.

2
00:00:04.000 --> 00:00:07.000
Every line in this document was generated
by a script and describes nothing
confidential.

Preview

Shows the file contents.

Where 1 KB matters

The smallest practical test file: 1,024 bytes, small enough to travel in a single network packet. These are the default limits a file of this size is useful for testing:

System	Limit	Note
Ethernet	1,500 bytes (typical MTU)	A 1 KB payload fits in one packet with its headers.
Browser cookies	4,096 bytes per cookie	1 KB is well inside the limit; the 5 KB sample is over it.

All 1 KB sample files

Use this file for

Smoke tests in CI that must run in milliseconds
Testing HTML video captions
Checking subtitle conversion

Testing notes for VTT

Browsers load caption tracks under the same cross-origin rules as scripts, so a .vtt file on another domain needs CORS headers.
Servers that send WebVTT as text/plain may see tracks ignored; the correct type is text/vtt.

VTT format reference

Technical details

File name	sample-vtt-1kb.vtt
Format	VTT (WebVTT subtitles)
Extension	.vtt
MIME type	text/vtt
Size	1,024 bytes (1 KB)
Kind	Text
Signature	57 45 42 56 54 54
SHA-256	531b57336718c4509c1d2715f99f9a12a906abf582378a48619941e93b641c8a
Created	2026-10-10
Validation	Exact size, signature bytes and structure checked when the file was generated
Preview	Available on this page
Source	Generated for this site; not copied from elsewhere
Licence	Free to use, modify and redistribute (terms)
Category	Subtitles

Validated for expected format and integrity. As with any download, scan the file with your own security tools before opening it. How files are made and checked

Download from the command line and verify

Fetch the file with curl, then compare its checksum with the SHA-256 value above.

curl -o sample-vtt-1kb.vtt 'https://sampletestfiles.com/downloads/vtt/sample-vtt-1kb.vtt'
sha256sum sample-vtt-1kb.vtt     # Linux
shasum -a 256 sample-vtt-1kb.vtt # macOS

On Windows, run Get-FileHash sample-vtt-1kb.vtt -Algorithm SHA256 in PowerShell. A matching value proves that the download is complete and unaltered.

Related files

Questions about this file

Is this file exactly 1 KB?: Yes. It is 1,024 bytes, which is 1 KB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
What is inside the 1 KB VTT file?: The WEBVTT header and 8 cues with identifiers. A closing NOTE comment block brings the file to the exact size.
Can I use these with the MP4 samples?: Yes. Add the file with a <track> element to check that captions appear, though the text is unrelated to the picture.

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