OTB to APNG Converter
Processing entirely on your device — large files may take a moment.
Nokia OTA Bitmap and Animated PNG exist for different jobs: OTB is the Nokia OTA Bitmap — 1-bit monochrome images that old Nokia phones displayed as operator logos and picture messages. Convert an animated GIF to APNG to keep smooth color and clean transparency while staying animated.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How OTB compares to APNG
| OTB | APNG | |
|---|---|---|
| Structure | Nokia OTA Bitmap coder | PNG frames + acTL/fcTL chunks |
| Compatibility | ImageMagick, specialty tools | Chrome, Firefox, Safari (all modern) |
| Best for | Legacy and specialty pipelines | High-quality animation on the web |
How to convert OTB to APNG
- 1
Select your files
Drag & drop your OTB files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to APNG". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted APNG file individually, or grab everything at once as a ZIP archive.
About the OTB format
The Nokia OTA Bitmap coder of the ImageMagick set — the retro-phone format is written natively by the magick.wasm engine, entirely in your browser.
Obscure coder formats like this are exactly what template-driven converters list and never actually convert — here it really works.
+Strengths
- ✓Written natively by ImageMagick
- ✓Runs entirely in your browser
- ✓Free, private, no watermarks
!Limitations
- −Niche format — few modern readers
- −Feature subset varies by coder
- −Keep the original for re-editing
About the APNG format
APNG (Animated PNG) is what GIF should have been: the same PNG file format with an animation extension — every frame in full 24-bit color with 8-bit alpha, no 256-color palette, no binary transparency with jagged edges. All modern browsers render it natively.
GIF has one job APNG does better in every dimension: color fidelity and clean transparency for animation. Converting an animated GIF to APNG keeps every frame but upgrades color depth and kills the halo around transparent edges. The only cost is file size — true color costs bytes.
+Strengths
- ✓Full 24-bit color per frame (no 256-color palette)
- ✓8-bit alpha transparency — no jagged edges
- ✓Native rendering in every modern browser
!Limitations
- −Larger files than GIF for the same animation
- −Legacy tools may show only the first frame
- −Not accepted by some social platforms
Why convert OTB to APNG?
There is a concrete reason this conversion exists: Niche format — few modern readers APNG sidesteps that — Full 24-bit color per frame (no 256-color palette) If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this OTB to APNG converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Will I lose quality converting OTB to APNG?
No — APNG is a lossless format, so every pixel of the converted image matches your original OTB file. You can also adjust the quality/size balance before converting when the target format supports compression.
Will transparent areas survive the conversion to APNG?
Transparency is kept whenever APNG actually supports an alpha channel. If the target format has none (like JPG), transparent areas are flattened onto a white background — that is a property of the format, not of this tool.
Can I convert several OTB files at once?
Yes — drop as many files as you like into the tool and they are converted in one batch. When more than one file comes out, everything is bundled into a ZIP for a single download.