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Image MIME Reference
AVCS

AVC Image Sequence (HEIF Container)

image/avcs
VS

PaintShop Pro Image

image/x-paintshoppro
PaintShop-Pro-PSP

A complete technical comparison of AVC Image Sequence (HEIF Container) and PaintShop Pro Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature AVCS PaintShop-Pro-PSP
Transparency (Alpha) Yes Yes
Animation Support Yes ✕ No
Progressive Loading ✕ No ✕ No
HDR Support Yes Yes
EXIF Metadata Yes Yes
ICC Color Profile Yes Yes
AVC Image Sequence (HEIF Container)
image/avcs
Extension
.avcs.heifs
Container HEIF / ISOBMFF (ISO/IEC 14496-12)
Compression Lossy / Lossless
Algorithm
AVC (Advanced Video Coding / H.264)
Color Depth 8-bit, 10-bit, 12-bit
Developed by Moving Picture Experts Group (MPEG) / ISO/IEC JTC 1
Released 2015
Magic Bytes
XX XX XX XX 66 74 79 70 61 76 63 73
Full AVCS reference →
PaintShop Pro Image
image/x-paintshoppro
Extension
.psp.pspimage.tub.pat
Container PSP Chunk-based Format
Compression Uncompressed / RLE (Run-Length Encoding) / LZ77
Algorithm
RLELZ77
Color Depth 8-bit (Indexed), 16-bit (Grayscale), 24-bit (RGB), 32-bit (RGBA), 48-bit (High Color)
Developed by Jasc Software / Corel Corporation (Alludo)
Released 1990
Magic Bytes
7E 42 4B 00
Full PaintShop-Pro-PSP reference →

Browser Support Comparison

Browser AVCS PaintShop-Pro-PSP
Chrome Chrome
Firefox Firefox
Safari Safari
Edge Edge
IE IE (Legacy)
AVCS

AVCS Strengths

  • Efficiently stores bursts of images or animations utilizing inter-frame compression
  • Leverages the highly compatible and widely hardware-accelerated AVC (H.264) codec
  • Robust HEIF container supports extensive metadata, alpha channels, and depth maps
Limitations
  • Zero native support in web browsers
  • Largely superseded in efficiency by newer sequence formats like HEICS (HEVC) or Animated AVIF (AV1)
  • Complicated container structure requires specialized parsing libraries
PaintShop-Pro-PSP

PaintShop-Pro-PSP Strengths

  • Provides robust, non-destructive editing capabilities with full support for vector layers, adjustment layers, and layer blend modes
  • Historically offered a highly capable and affordable alternative to Adobe Photoshop's PSD format for Windows users
  • Features proprietary support for 'Picture Tubes' (.tub), a unique brush technology that paints sequential or random raster objects along a path
Limitations
  • Deeply proprietary format tied exclusively to the Corel/Alludo ecosystem
  • Third-party software support (like GIMP or ImageMagick) is often limited to parsing older .psp files, frequently failing to render complex layers in modern .pspimage files
  • No support in modern web browsers; must be exported to a flattened web format (JPEG/PNG) for online viewing

When to choose which format

AVCS
Use AVCS when…
  • Burst Photography
  • Short Animations
  • Camera Capture
  • Archival Storage
PaintShop-Pro-PSP
Use PaintShop-Pro-PSP when…
  • PaintShop Pro Multi-layer Project Archival
  • Digital Art and Photo Retouching
  • Picture Tubes (.tub) and Custom Patterns (.pat)
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