AVIF Won't Open? Convert to SUN Instantly
Fast, instant AVIF to SUN conversion. No signup required. Just drop your .avif file and get .sun in seconds.
Batch Settings
AVIF形式の画像をSUN形式へ変換する作業は、ファイルの互換性や特定のシステムでの表示最適化を図る上で、時に不可欠となります。特に、高画質な画像データを扱うクリエイティブな現場や、特定のレガシーシステムとの連携が必要なビジネスシーンにおいては、適切なフォーマット変換がワークフローの効率を大きく左右します。このページでは、お手持ちのAVIFファイルをSUN形式に、簡単かつ迅速に変換する方法をご紹介。画質を損なうことなく、変換プロセスをスムーズに進めるためのヒントも併せて解説いたします。煩雑な手順は一切不要。どなたでも直感的に操作できるよう設計されていますので、ご安心ください。
- 漫画・アニメ制作における素材連携
- ビジネス文書への画像埋め込み
- 旧システムでの画像表示対応
日本では、特定の産業や研究機関においてSUN形式の画像が今も利用されることがあり、AVIFのような新しい高圧縮フォーマットとの橋渡しが求められる場面があります。特に縦書きの文書や、特定のフォントを多用するデザインでは、変換後の文字表現に注意を払うことが重要です。
About AVIF to SUN Conversion
Dealing with a AVIF file that won't open on your device? You're not alone — AVIF compatibility issues are one of the most common reasons people search for a file converter. AVIF is the newest image format based on AV1 video codec, delivering exceptional compression — up to 50% smaller than JPEG at the same quality.
The fix is simple: convert your AVIF to SUN. SUN is a widely used file format. This conversion lets you convert between formats quickly, solving the problem in seconds rather than hours of troubleshooting.
Converting AVIF to SUN maintains high quality with CocoConvert's optimised encoder settings.
CocoConvert processes your AVIF file on secure servers in Germany — upload, convert, download. Your files are encrypted via TLS and automatically deleted within 24 hours. No account needed, no software to install, and it works on any device with a browser.
This conversion is ideal when you When you need a SUN file.
The conversion engine behind CocoConvert uses FFmpeg, Sharp, and qpdf — the same open-source libraries trusted by Netflix, YouTube, and enterprise platforms. Pro users can batch convert up to 100 files at once.
How to Convert AVIF to SUN
- 1
Add your AVIF file
Drag and drop your .avif file into the converter, or tap "Browse" to pick it from your device. Multiple files are supported for batch processing.
- 2
Pick SUN output
Select .sun as the target format. CocoConvert automatically applies the best quality settings for this conversion.
- 3
Start conversion
Hit the Convert button. The image engine processes your file server-side — no CPU drain on your device.
- 4
Save your file
Once done, download your .sun file. For batch jobs, download all at once as a zip.
What Happens When You Convert AVIF to SUN
Your AVIF file is decoded and re-encoded as SUN.
Your AVIF file is uploaded and validated
The file is decoded (parsed into its raw data)
The data is re-encoded in SUN format
The converted file is ready for download
Format Comparison
AVIF
.avif file
| Extension | .avif |
| MIME Type | image/avif |
| Category | Image |
SUN
.sun file
| Extension | .sun |
| MIME Type | image/x-sun-raster |
| Category | Image |
Should You Convert AVIF to SUN?
When to Convert
- ✓When you need a SUN file
Frequently Asked Questions
Why won't my AVIF file open?
AVIF files may not open if your device lacks the right codec or application. Converting to SUN — a more widely supported format — usually resolves this. SUN is a widely used file format.
Is it safe to convert AVIF to SUN online?
Yes. CocoConvert encrypts your file via TLS, processes it on isolated servers in Germany, and permanently deletes it within 24 hours. Your files are never shared or analysed.
Will I lose quality converting AVIF to SUN?
Converting AVIF to SUN maintains high quality with CocoConvert's optimised encoder settings. CocoConvert uses high-quality encoder defaults to preserve as much fidelity as possible.
How large can my AVIF file be?
Free users can convert files up to 250 MB each. Pro users get a 5 GB limit per file, and Business API users have custom limits.
Can I convert AVIF to SUN on my phone?
Absolutely. CocoConvert works in any modern browser — iOS Safari, Android Chrome, and all desktop browsers. No app required.
Versions are pinned in our worker Dockerfile and re-built via CI on every change.