10 KB WebM sample
A WebM file of exactly 10,240 bytes. It is a valid WebM video file, generated by this site. Compare its checksum and test it with the parser used by your application. Use it wherever you need a 10 KB sample, test or dummy WebM file.
Download
sample-webm-10kb.webm
10 KB10,240 bytes
Download 10 KB WebMCreated in your browser in a few seconds, then checked against the SHA-256 checksum. The file is not uploaded anywhere. No sign-up.
- Type
- video/webm
- SHA-256
1e43e72219eaa17fbb0ef77456e51f60326f943bb48eba2b8c15cc1c1fcfd126- Delivery
- Created in your browser from static generator assets (how it works).
What is in this file
1 frames (0.0 s) of a synthetic test pattern with a frame counter, looping every six seconds, in one VP9 video track. The index of key frames comes before the picture data, so a player can seek without reading the whole file. 282 bytes of an EBML Void element bring the file to the exact size.
| Dimensions | 640 × 360 px |
|---|---|
| Duration | 0.0 s |
| Frame rate | 30 fps |
| Video codec | VP9 |
| Audio | No audio track |
| Document type | webm |
| Clusters | 1, one for each key frame |
| Seek index | Cues element before the first cluster |
First bytes of the file
The first 64 bytes of sample-webm-10kb.webm as a hex dump: offset, bytes, then the same bytes as text. The WebM signature is 1A 45 DF A3.
00000000 1a 45 df a3 9f 42 86 81 01 42 f7 81 01 42 f2 81 |.E...B...B...B..|
00000010 04 42 f3 81 08 42 82 84 77 65 62 6d 42 87 81 04 |.B...B..webmB...|
00000020 42 85 81 02 18 53 80 67 01 00 00 00 00 00 27 d0 |B....S.g......'.|
00000030 11 4d 9b 74 b3 4d bb 8e 53 ab 84 15 49 a9 66 53 |.M.t.M..S...I.fS|Preview
Creates the file in your browser and shows it here.
Where 10 KB matters
A 10,240-byte file that still arrives in the first round trip of a new connection. These are the default limits a file of this size is useful for testing:
| System | Limit | Note |
|---|---|---|
| TCP initial congestion window | About 14.6 KB (10 segments) | A 10 KB response fits in the first flight of packets; the 25 KB sample does not. |
| nginx and Apache request headers | 8 KB per header line by default | Data this large must go in the request body. |
| webpack asset modules | 8 KB by default | Assets over the threshold are emitted as files instead of data URIs. |
Use this file for
- Checking email size handling
- Checking uploads of browser-recorded video
- Verifying type detection between WebM and MKV
Testing notes for WebM
- H.264 and AAC are not allowed in WebM. A file with those codecs and a .webm extension is really Matroska, and browsers may refuse it.
- Recordings made in the browser usually lack a duration and an index, because both are only known when recording stops. Players show no length and cannot seek until the file is remuxed.
Technical details
| File name | sample-webm-10kb.webm |
|---|---|
| Format | WebM (WebM video) |
| Extension | .webm |
| MIME type | video/webm |
| Size | 10,240 bytes (10 KB) |
| Kind | Binary |
| Signature | 1A 45 DF A3 |
| SHA-256 | 1e43e72219eaa17fbb0ef77456e51f60326f943bb48eba2b8c15cc1c1fcfd126 |
| Created | 2026-10-23 |
| Validation | See the listed size and SHA-256. Small downloads are checked in the browser; verify streamed downloads manually. A hash match does not prove parser compatibility. |
| Preview | Available on this page |
| Source | Generated in your browser by this site's generator; not copied from elsewhere |
| Licence | Free to use, modify and redistribute (terms) |
| Category | Video |
Check the stated structure and checksum against your application requirements. As with any download, scan the file with your own security tools before opening it. How files are made and checked
Verify your copy
This file is created in your browser, so it has no direct URL for curl or wget. The generator is designed to produce reproducible bytes. After saving, compare the checksum with the SHA-256 value above.
sha256sum sample-webm-10kb.webm # Linux
shasum -a 256 sample-webm-10kb.webm # macOSOn Windows, run Get-FileHash sample-webm-10kb.webm -Algorithm SHA256 in PowerShell. For scripts and pipelines, save the file once and keep your own copy.
Related files
Questions about this file
- Is this file exactly 10 KB?
- Yes. It is 10,240 bytes, which is 10 KB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
- What is inside the 10 KB WebM file?
- 1 frames (0.0 s) of a synthetic test pattern with a frame counter, looping every six seconds, in one VP9 video track. The index of key frames comes before the picture data, so a player can seek without reading the whole file. 282 bytes of an EBML Void element bring the file to the exact size.
- Can the WebM samples be seeked?
- Yes. They declare their duration and carry an index of key frames ahead of the picture data, unlike a raw browser recording.