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Image MIME Reference
AVCS

AVC Image Sequence (HEIF Container)

image/avcs
VS

Macromedia FreeHand Document

image/x-freehand
FreeHand

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

Equal browser support

Feature Support

Feature AVCS FreeHand
Transparency (Alpha) Yes Yes
Animation Support Yes Yes
Progressive Loading ✕ No ✕ No
HDR Support Yes ✕ No
EXIF Metadata Yes ✕ No
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 →
Macromedia FreeHand Document
image/x-freehand
Extension
.fh.fh4.fh5.fh7.fh8.fh9.fh10.fh11.ft11
Container Proprietary Binary (Aldus Graphic Document)
Compression Uncompressed / Deflate (in later versions)
Algorithm
NoneDeflate (Optional in later versions)
Color Depth Vector Data (RGB/CMYK)
Developed by Altsys / Aldus / Macromedia
Released 1988
Magic Bytes
41 47 44 31 to 41 47 44 34
Full FreeHand reference →

Browser Support Comparison

Browser AVCS FreeHand
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  • Largely superseded in efficiency by newer sequence formats like HEICS (HEVC) or Animated AVIF (AV1)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
FreeHand

FreeHand Strengths

  • Historically one of the most powerful and intuitive vector editors on the market, praised for multi-page support long before Adobe Illustrator implemented it
  • Files are generally compact and self-contained
Limitations
  • Completely abandoned proprietary format; Adobe actively blocked native import in modern versions of Illustrator
  • No support in modern web browsers; must be converted to SVG
  • Versioning fragmentation means parsers must account for wildly different binary structures depending on the specific .fhX extension used

When to choose which format

AVCS
Use AVCS when…
  • Burst Photography
  • Short Animations
  • Camera Capture
  • Archival Storage
FreeHand
Use FreeHand when…
  • Legacy Graphic Design Portfolios
  • Historical Desktop Publishing Archival
  • Old Corporate Logo Vectors

More comparisons

AVCS vs ACES → FreeHand vs ACES → AVCS vs APNG → FreeHand vs APNG → AVCS vs AVCI → FreeHand vs AVCI → AVCS vs AVIF → FreeHand vs AVIF → All comparisons →
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