RGB to OTB Converter

Change RGB format to OTB with our free tool

Drop files here. 1 GB maximum file size or Sign Up
to
Facebook Amazon Microsoft Tesla Nestle Walmart L'Oreal

Server-Side Processing

Conversion happens entirely on Convertio's servers. Your device stays responsive while RGB data is transformed into OTB in the cloud.

Zero Install

Run the entire RGB to OTB conversion in your web browser. No downloads, plugins, or system requirements beyond an internet connection.

Rapid Conversion

Processing RGB to OTB is swift — most conversions finish in moments, so you spend less time waiting and more time working.

How to convert RGB to OTB

1

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

2

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

3

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

About formats

RGB is a raw (headerless) image format that stores pixel data as a flat sequence of red, green, and blue sample values with no container structure, compression, or metadata. Each pixel is represented by three consecutive bytes (in 8-bit mode) — one for red intensity, one for green, and one for blue — written in scanline order from the top-left corner of the image to the bottom-right. Because there is no header, the image dimensions and bit depth must be specified externally when reading the file. The format supports multiple bit depths: 8-bit (0-255 per channel), 16-bit (0-65535 per channel), and floating-point variants, with 8-bit being the most common. The RGB color model itself reflects how display hardware produces color — by mixing red, green, and blue light at varying intensities — and raw RGB files represent this model in its most direct digital form. With 8-bit channels, three bytes per pixel yield a 24-bit color palette capable of representing 16,777,216 distinct colors. One advantage is zero-overhead processing: without headers or compression to parse, raw RGB data can be memory-mapped, fed directly into GPU textures, or piped between processing stages with minimal latency — valuable in real-time imaging, scientific instrumentation, and computer vision pipelines where every millisecond matters. The format's universal simplicity provides another practical strength — any programming language can read or write raw pixel data with just basic file I/O, making it a reliable interchange format between custom software that may not share support for structured image containers. Raw RGB files are handled by ImageMagick, FFmpeg, and various scientific and graphics tools.
Initial release: 1990
OTB (Over-the-Air Bitmap) is a monochrome image format developed by Nokia as part of their Smart Messaging specification in 1997, designed for transmitting small graphics — operator logos, group graphics, and picture messages — to Nokia mobile phones via SMS. OTB files contain 1-bit (black and white) images at small fixed resolutions, typically 72x14 pixels for operator logos and 72x28 pixels for group graphics, encoded in a compact binary format suitable for embedding within the payload of SMS text messages. The format uses a simple structure: a header byte indicating whether the image is an operator logo or group graphic, width and height values, and the raw bitmap data where each bit represents one pixel packed eight per byte. The extremely tight format — designed to fit within a single SMS message (140 bytes maximum payload, shared with addressing overhead) — reflects the severe constraints of mobile communication in the late 1990s. Nokia's Smart Messaging system was one of the first commercial implementations of rich content delivery to mobile phones, and OTB images represented the entire visual content capability of Nokia handsets before MMS and mobile data browsing arrived. One advantage is the format's historical role as a pioneer of mobile visual messaging: OTB images were among the first graphics that ordinary consumers could send to each other's phones, predating MMS, camera phones, and smartphones by nearly a decade. The format's minimal footprint is another characteristic — entire images fit in a few dozen bytes, reflecting an era of extreme bandwidth constraints. OTB files are supported by ImageMagick, various Nokia phone management tools, and specialty mobile format utilities.
Developer: Nokia
Initial release: 1997

Frequently Asked Questions

Why convert RGB to OTB?

RGB contains raw pixel data with no metadata or structure — converting to OTB adds proper formatting so any application can display and share the image.

What programs open OTB files?

OTB files can be opened in Nokia phone tools, XnView, and legacy mobile device management applications.

What makes OTB a good target format?

OTB offers mobile bitmap, Nokia operator logo, monochrome. It gives your raw RGB data a proper structure that any image viewer or editor can handle.

What platforms support this converter?

Convertio runs in any modern web browser — Chrome, Firefox, Safari, Edge — on Windows, macOS, Linux, Android, and iOS devices.

Is RGB to OTB conversion free?

Standard conversions are free on Convertio. Premium plans unlock larger uploads, faster processing, and higher-volume batch conversions.

Is the conversion process fast?

Yes — RGB to OTB conversion on Convertio usually completes in seconds. Cloud-based processing handles the work without taxing your device.