JPEG-XS-Codestream

JPEG XS Codestream

image/jxsc Released 2019 · by Joint Photographic Experts Group (JPEG) / intoPIX

The image/jxsc MIME type represents a raw JPEG XS (Extra Speed) codestream. Unlike the image/jxs format, which typically encapsulates the image data within an ISOBMFF container (providing metadata and box structures), a JXSC file contains only the bare JPEG XS compressed data. This structure is optimized for ultra-low latency hardware decoding, real-time live broadcasting, and embedded systems that require zero container parsing overhead.

Professional & Video Production Transparency ✦ HDR Production Ready

Technical Specifications

MIME Type

image/jxsc

Extensions

.jxsc.jxs

Container

None (Raw Codestream)

Compression

Lossy (Visually Lossless) & Mathematically Lossless

Algorithms

JPEG XS (ISO/IEC 21122-1)

Color Depth

8-bit, 10-bit, 12-bit, 14-bit, 16-bit

Metadata

None

Capabilities

Transparency

Animation

Progressive Loading

Alpha Channel

HDR Support

Official Specification

Aliases: image/x-jxsc

Magic Bytes & HTTP Headers

File Signature (Magic Bytes)

FF 10

ASCII: ..

HTTP Headers

Content-Type: image/jxsc

HTML Accept Attribute

accept="image/jxsc, .jxsc"

Browser Support Matrix

Browser	Status	Min Version
Chrome	Not Supported	—
Firefox	Not Supported	—
Safari	Not Supported	—
Edge	Not Supported	—
Internet Explorer	Not Supported	Legacy

Advantages & Limitations

Advantages

Eliminates container overhead, maximizing parsing speed and minimizing latency to fractions of a millisecond
Highly optimized for direct hardware implementation in FPGAs and ASICs
Perfect for continuous data streaming over IP networks without needing to establish file headers

Limitations

Lacks standard container metadata (EXIF, XMP, ICC profiles), meaning color space and orientation data must be handled externally or out-of-band
Zero support in web browsers or standard consumer operating systems
Often requires specialized broadcast hardware or custom software libraries to decode

Developer Code Snippets

import magic
print(magic.from_file('stream.jxsc', mime=True)) # May default to generic 'application/octet-stream' depending on library rules

const FileType = require('file-type');
const type = await FileType.fromFile('stream.jxsc');
console.log(type?.mime); // Standard libraries will likely not detect this format natively

import "net/http"
// Custom codestream parsing is required to read the FF 10 SOC marker.

$mime = mime_content_type('stream.jxsc');
echo $mime; // Standard systems will map this to application/octet-stream

File Detection Steps

How to programmatically detect a image/jxsc file by reading its raw bytes:

1 Check the first 2 bytes for the raw JPEG XS Start of Codestream (SOC) signature (FF 10)
2 Parse the Picture Header (PIH) starting at byte 2 to verify codestream dimensions, color profiles, and wavelet configurations

Software Support

F

FFmpeg (with external libraries)

i

intoPIX FastTICO-XS

Conversion Tools

Share & Embed

Markdown Badge

[![JPEG-XS-Codestream Format](https://freewebptojpg.com/mime/image/jpeg-xs-codestream/badge.svg)](https://freewebptojpg.com/mime/image/jpeg-xs-codestream)

Interactive iframe Widget

<iframe src="https://freewebptojpg.com/mime/image/jpeg-xs-codestream/embed" width="100%" height="280" style="border:1px solid #cbd5e1;border-radius:8px;" title="JPEG-XS-Codestream Specs"></iframe>

JSON API

All data on this page is available as a free, open JSON API. Use it in your project, documentation, or tooling.

GET https://freewebptojpg.com/mime/image/jpeg-xs-codestream.json Open JSON

Free to use

No auth required

CORS enabled

Use from any domain

Cached 24h

Cache-Control headers set

Frequently Asked Questions

What is the difference between image/jxs and image/jxsc?

image/jxs represents a JPEG XS image that is usually encapsulated within a standard ISOBMFF container (complete with metadata, color profiles, and headers). image/jxsc represents the raw, stripped-down JPEG XS codestream without any surrounding container structure.

What is the magic byte for a JPEG XS codestream?

A raw JPEG XS codestream always begins with the Start of Codestream (SOC) marker, which is represented by the 2-byte hex sequence FF 10.

Can I view image/jxsc files in a web browser?

No. Modern web browsers do not support JPEG XS codestreams. They are utilized almost exclusively in backend video pipelines, embedded hardware (FPGA/ASIC), and professional broadcast infrastructure (such as SMPTE ST 2110 workflows).