25 KB MP4 sample
An MP4 file of exactly 25,600 bytes. It is a valid MPEG-4 Part 14 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 25 KB sample, test or dummy MP4 file.
Download
sample-mp4-25kb.mp4
25 KB25,600 bytes
Download 25 KB MP4Created 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/mp4
- SHA-256
00936294965a7f462d4953e6c76e41b693f0df2d91210ddfa9f2940d7276ead8- Delivery
- Created in your browser from static generator assets (how it works).
What is in this file
16 frames (0.5 s) of a synthetic test pattern with a frame counter, looping every six seconds, in one H.264 video track. 673 bytes of a trailing "free" box bring the file to the exact size.
| Dimensions | 640 × 360 px |
|---|---|
| Duration | 0.5 s |
| Frame rate | 30 fps |
| Video codec | H.264 (AVC), Main profile |
| Audio | No audio track |
| Fast start | Yes (moov before mdat) |
First bytes of the file
The first 64 bytes of sample-mp4-25kb.mp4 as a hex dump: offset, bytes, then the same bytes as text. The MP4 signature is 66 74 79 70 at offset 4.
00000000 00 00 00 20 66 74 79 70 69 73 6f 6d 00 00 02 00 |... ftypisom....|
00000010 69 73 6f 6d 69 73 6f 32 61 76 63 31 6d 70 34 31 |isomiso2avc1mp41|
00000020 00 00 02 bb 6d 6f 6f 76 00 00 00 6c 6d 76 68 64 |....moov...lmvhd|
00000030 00 00 00 00 e5 7b 69 80 e5 7b 69 80 00 00 03 e8 |.....{i..{i.....|Preview
Creates the file in your browser and shows it here.
Where 25 KB matters
A 25,600-byte file: the size of a small web image or a short document. 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) | 25 KB needs at least two flights of packets on a new connection. |
| Base64 encoding | Adds 33 percent | A 25 KB file becomes about 34 KB inside JSON or an email. |
Use this file for
- Checking email size handling
- Checking HTML video playback and seeking
- Testing range-request support on servers and CDNs
Testing notes for MP4
- Uploads are large and slow, so they expose timeout, retry and progress-reporting bugs that small files never reach.
- Seeking in a browser needs HTTP range requests. A server that ignores the Range header makes video appear to work until someone drags the progress bar.
Technical details
| File name | sample-mp4-25kb.mp4 |
|---|---|
| Format | MP4 (MPEG-4 Part 14 video) |
| Extension | .mp4 |
| MIME type | video/mp4 |
| Size | 25,600 bytes (25 KB) |
| Kind | Binary |
| Signature | 66 74 79 70 at offset 4 |
| SHA-256 | 00936294965a7f462d4953e6c76e41b693f0df2d91210ddfa9f2940d7276ead8 |
| 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-mp4-25kb.mp4 # Linux
shasum -a 256 sample-mp4-25kb.mp4 # macOSOn Windows, run Get-FileHash sample-mp4-25kb.mp4 -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 25 KB?
- Yes. It is 25,600 bytes, which is 25 KB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
- What is inside the 25 KB MP4 file?
- 16 frames (0.5 s) of a synthetic test pattern with a frame counter, looping every six seconds, in one H.264 video track. 673 bytes of a trailing "free" box bring the file to the exact size.
- Will they play in a browser before fully downloading?
- Yes. The index is at the start of the file, so playback can begin immediately.