Free webp to jpg
EN
Image MIME Reference
APNG

Animated Portable Network Graphics

image/vnd.mozilla.apng
VS

JPEG XS Image Sequence (HEIF Container)

image/jxss
JPEG-XS-Sequence

A complete technical comparison of Animated Portable Network Graphics and JPEG XS Image Sequence (HEIF Container) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

APNG wins on browser support

Feature Support

Feature APNG JPEG-XS-Sequence
Transparency (Alpha) Yes Yes
Animation Support Yes Yes
Progressive Loading Yes ✕ No
HDR Support ✕ No Yes
EXIF Metadata Yes Yes
ICC Color Profile Yes Yes
Animated Portable Network Graphics
image/vnd.mozilla.apng
Extension
.apng.png
Container PNG Chunk Stream
Compression Deflate (Lossless)
Algorithm
Deflate (zlib)
Color Depth 8-bit (Indexed), 24-bit (TrueColor), 32-bit (RGBA)
Developed by Mozilla Corporation (Stuart Parmenter & Vladimir Vukićević)
Released 2004
Magic Bytes
89 50 4E 47 0D 0A 1A 0A
Full APNG reference →
JPEG XS Image Sequence (HEIF Container)
image/jxss
Extension
.jxss.jxs
Container HEIF / ISOBMFF (ISO/IEC 23008-12)
Compression Lossy (Visually Lossless) / Mathematically Lossless
Algorithm
JPEG XS (ISO/IEC 21122-1)
Color Depth 8-bit, 10-bit, 12-bit, 14-bit, 16-bit
Developed by Joint Photographic Experts Group (JPEG)
Released 2019
Magic Bytes
XX XX XX XX 66 74 79 70 6A 78 73 73
Full JPEG-XS-Sequence reference →

Browser Support Comparison

Browser APNG JPEG-XS-Sequence
Chrome Chrome
✓ 59
 ✕
Firefox Firefox
✓ 3
 ✕
Safari Safari
✓ 8
 ✕
Edge Edge
✓ 79
 ✕
IE IE (Legacy)
✕ ✕
APNG

APNG Strengths

  • Supports 8-bit alpha transparency, completely solving the ugly 'white halo' problem inherent to GIFs
  • Gracefully degrades; viewers that do not support APNG will render a perfectly valid, static PNG of the first frame
  • Provides lossless compression that retains absolute pixel-perfect quality for UI elements and line art
Limitations
  • Because it relies on lossless Deflate compression, file sizes for complex, video-like animations can be massive compared to lossy formats like WebP or AVIF
  • Was initially rejected by the official PNG group, delaying its adoption for nearly a decade
  • Lacks native hardware decoding acceleration, unlike video-based animated formats (like MP4 or WebM)
JPEG-XS-Sequence

JPEG-XS-Sequence Strengths

  • Provides sub-millisecond encoding and decoding latency across a video sequence while retaining visually lossless quality
  • Leverages the robust ISOBMFF track structures for accurate frame timing, audio synchronization, and metadata handling
  • Optimized for professional video production and IP broadcasting workflows
Limitations
  • Zero web browser compatibility, limiting its use entirely to professional and industrial hardware workflows
  • Compression ratios are significantly lower than consumer video codecs like HEVC or AV1
  • Extremely niche format that requires highly specialized broadcast hardware or custom software libraries to process

When to choose which format

APNG
Use APNG when…
  • High-Quality Web Animations
  • Stickers (Apple iMessage, LINE, Discord)
  • UI Loaders with Alpha Transparency
  • GIF Replacement
JPEG-XS-Sequence
Use JPEG-XS-Sequence when…
  • Live Broadcast Video Snippets
  • Medical Imaging Sequences
  • HDR Burst Photography Archiving
  • Automotive & Drone Video Storage

More comparisons

APNG vs ACES → JPEG-XS-Sequence vs ACES → APNG vs AVCI → JPEG-XS-Sequence vs AVCI → APNG vs AVCS → JPEG-XS-Sequence vs AVCS → APNG vs AVIF → JPEG-XS-Sequence vs AVIF → All comparisons →
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