50 KB MP4 sample

An MP4 file of exactly 51,200 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 50 KB sample, test or dummy MP4 file.

sample-mp4-50kb.mp4

50 KB51,200 bytes

Download 50 KB MP4

Created 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: a4166d2ec129f1d881bd5f207de6f10e975b4f24660e862959f1c5048fab05ea
Delivery: Created in your browser from static generator assets (how it works).

What is in this file

30 frames (1.0 s) of a synthetic test pattern with a frame counter, looping every six seconds, in one H.264 video track. 2,078 bytes of a trailing "free" box bring the file to the exact size.

Dimensions	640 × 360 px
Duration	1.0 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-mp4-50kb.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 f3 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 50 KB matters

A 51,200-byte file, half of the default body limit in several web frameworks. These are the default limits a file of this size is useful for testing:

System	Limit	Note
Express body parsers	100 KB by default	50 KB is accepted; 500 KB is rejected with 413 unless the limit is raised.
Base64 encoding	Adds 33 percent	50 KB becomes about 67 KB when embedded in JSON.

All 50 KB sample files

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.

MP4 format reference

Technical details

File name	sample-mp4-50kb.mp4
Format	MP4 (MPEG-4 Part 14 video)
Extension	.mp4
MIME type	video/mp4
Size	51,200 bytes (50 KB)
Kind	Binary
Signature	66 74 79 70 at offset 4
SHA-256	a4166d2ec129f1d881bd5f207de6f10e975b4f24660e862959f1c5048fab05ea
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-mp4-50kb.mp4     # Linux
shasum -a 256 sample-mp4-50kb.mp4 # macOS

On Windows, run Get-FileHash sample-mp4-50kb.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 50 KB?: Yes. It is 51,200 bytes, which is 50 KB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
What is inside the 50 KB MP4 file?: 30 frames (1.0 s) of a synthetic test pattern with a frame counter, looping every six seconds, in one H.264 video track. 2,078 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.

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