SIXEL to HEIF Converter

Export terminal images to compressed HEIF online

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Fast Conversion

SIXEL to HEIF processing completes in seconds for typical image sizes. Cloud infrastructure keeps turnaround times consistently short.

Server-Side Speed

Heavy lifting happens in the cloud — your device resources are untouched while SIXEL images are processed into HEIF format.

Terminal Image Export

SIXEL graphics from modern terminals become portable when converted to HEIF — share terminal art beyond the command line.

How to convert SIXEL to HEIF

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose heif or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your heif file right afterwards

About formats

SIXEL (Six Pixel) is a bitmap graphics encoding format created by Digital Equipment Corporation (DEC) in 1983 for rendering images on character-cell printers and video terminals. The name derives from the encoding's fundamental unit: a column of six pixels represented by a single ASCII character. Each printable character in the sixel data stream (ASCII 63-126) encodes a 6-pixel vertical column, with the character's binary value determining which pixels are on or off. Color is specified through register-based palette control: a Select Color Sequence assigns an HLS or RGB color value to a numbered register, and subsequent sixel characters use that color until another register is selected. The encoding supports raster attributes for specifying pixel aspect ratio and image dimensions, repeat sequences (! followed by a count and character) for run-length compression of identical columns, and $ (carriage return) and - (new line) for navigating the sixel grid. DEC implemented SIXEL support in their VT240, VT241, VT330, and VT340 terminals, as well as multiple printer models. One advantage of the SIXEL encoding is its ASCII-clean nature: the data stream consists entirely of printable characters and standard control sequences, meaning SIXEL graphics can be transmitted through any text-based communication channel — serial terminals, SSH sessions, telnet connections — without requiring binary-safe transport or protocol modifications. The format's modern renaissance provides another remarkable dimension: after decades of obscurity, SIXEL support has been implemented in numerous contemporary terminal emulators, enabling inline image display in command-line workflows. SIXEL output can be generated by ImageMagick, libsixel, chafa, and various plotting libraries.
Initial release: 1983
HEIF (High Efficiency Image File Format) is a container format for images and image sequences standardized by the Moving Picture Experts Group as ISO/IEC 23008-12, first published in 2015. HEIF is built on the ISO Base Media File Format (ISOBMFF, the same container used for MP4 video), providing a flexible structure that can hold single images, image collections, image sequences (like animations or bursts), and derived images with non-destructive editing operations. The container is codec-agnostic — while the most common implementation pairs HEIF with HEVC/H.265 compression (branded as HEIC by Apple), the standard also accommodates AV1 compression (creating the AVIF variant), H.266/VVC, and other future codecs. HEIF supports features that JPEG lacks: 10-bit and 12-bit color depth, wide color gamuts (Display P3, BT.2020), lossless compression, alpha transparency, depth maps, thumbnail images, and Exif/XMP metadata — all within a single file. Auxiliary image items can store computational photography data like depth maps, HDR gain maps, and semantic segmentation masks. One advantage is the format's future-proof architecture: by separating the container from the codec, HEIF can adopt newer, more efficient compression technologies without changing the file structure, metadata handling, or application-level APIs. The substantial compression improvement over JPEG is another core strength — HEVC-based HEIF typically achieves 40-50% file size reduction compared to JPEG at the same visual quality, beneficial for storage and bandwidth. HEIF is supported by Apple's ecosystem (iOS, macOS), Windows 10/11, Android 10+, GIMP, ImageMagick, and Adobe products.
Initial release: 2015

Frequently Asked Questions

Why convert SIXEL to HEIF?

SIXEL graphics are designed for terminal display, not general use. Converting to HEIF produces a portable image for sharing or editing.

What programs can open HEIF?

Apple Photos, Windows Photos (with codec), Adobe Lightroom, Photoshop, GIMP, and most modern mobile gallery apps support HEIF.

How accurate is SIXEL to HEIF conversion?

Some compression artifacts are possible since HEIF is a lossy format. Choosing maximum quality preserves visual fidelity as closely as possible.

How quickly can I convert SIXEL to HEIF?

The process is fast — cloud-based processing handles SIXEL to HEIF conversion in seconds for standard-sized images, even on slower connections.

Can I queue several SIXEL files for conversion?

Absolutely. Add several SIXEL images at once, set HEIF as the output, and the converter processes them all in parallel for maximum efficiency.