G4 to AVIF Converter

Transform fax documents to AVIF format online free

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Document Recovery

Extract visual content from G4 files and save as AVIF — ideal for archiving important fax correspondence.

Any Device Works

Access the G4 to AVIF converter from desktops, laptops, tablets, and phones — fully browser-based.

Data Protection

Your G4 files are removed immediately after processing. Converted AVIF output is purged within 24 hours.

How to convert G4 to AVIF

1

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

2

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

3

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

About formats

G4 is a monochrome image format based on the ITU-T Group 4 facsimile coding standard (Recommendation T.6), ratified by the CCITT in 1984 as an improvement over Group 3 for use on error-free digital networks like ISDN rather than analog telephone lines. G4 files contain 1-bit image data compressed using exclusively two-dimensional Modified Modified READ (MMR) coding, where each scanline is encoded as a set of differences (changing elements) relative to the line above it. By eliminating the one-dimensional coding fallback and the end-of-line synchronization markers required by Group 3, G4 achieves 20-50% better compression ratios on typical document pages while producing a simpler, more regular bitstream. The format is most commonly encountered as a compression method within TIFF files (TIFF compression tag 4), where it became the standard archival format for scanned documents in enterprise document management, government records, and legal imaging systems. G4 compression is specified at 200, 300, or 400 dpi depending on the scanning application, with 300 dpi being the most common for archival-quality document imaging. One advantage is exceptional compression efficiency for document content: G4's two-dimensional prediction exploits the strong vertical correlation in text and line art pages, typically compressing a 300 dpi letter-size page to 30-50 KB — roughly half the size of equivalent Group 3 encoding. The format's entrenchment in document management infrastructure is another strength — G4 TIFF is the mandated format for many government digital records systems, court filing systems, and corporate archives, supported by every enterprise imaging platform.
Developer: ITU-T (CCITT)
Initial release: 1984
AVIF (AV1 Image File Format) is a modern image format derived from the AV1 video codec, developed by the Alliance for Open Media and specified in February 2019. The format leverages the intra-frame coding tools of AV1 — a royalty-free video codec backed by Google, Apple, Microsoft, Amazon, Netflix, and other major technology companies — to compress still images with substantially higher efficiency than JPEG, PNG, or even WebP. AVIF stores images in the HEIF (High Efficiency Image File Format) container, supporting both lossy and lossless compression, HDR (high dynamic range) with wide color gamuts up to 12-bit depth, alpha transparency, and animated sequences. At equivalent visual quality, AVIF files are typically 30-50% smaller than WebP and 50-70% smaller than JPEG, representing the largest compression improvement in mainstream image formats in over a decade. One advantage is exceptional compression efficiency — AVIF delivers visually indistinguishable images at dramatically lower file sizes, directly reducing bandwidth consumption and improving page load times for web content. The royalty-free licensing model provides another key strength: unlike HEIC/HEIF which relies on patent-encumbered HEVC, AVIF's AV1 foundation is free for anyone to implement without licensing fees. Browser support has reached broad adoption, with Chrome, Firefox, Safari, and Edge all rendering AVIF natively. The format is rapidly gaining adoption for web images where quality-to-size ratio is paramount.
Initial release: February 8, 2019

Frequently Asked Questions

Why convert G4 to AVIF?

Digitizing fax files to AVIF format enables easy viewing, sharing, and embedding across modern platforms.

What can open AVIF format?

View AVIF files with modern web browsers (Chrome, Firefox), GIMP, or Paint.NET — all handle this format natively.

Does converting G4 degrade quality?

The AVIF output faithfully reproduces all content from the G4 source — quality is not compromised.

Can I use this converter at no cost?

Free for regular use. Premium plans unlock faster conversion speeds and larger batch processing limits.

Is multi-file G4 conversion supported?

Yes, batch processing works. Upload as many G4 files as needed and each becomes a separate AVIF output.

Can I use this converter on a Mac?

Yes — the converter runs in any browser on macOS, Windows, Linux, Android, and iOS. Fully cross-platform.