Root Delta Codec

RDC is a lossy media codec framework designed to significantly reduce file sizes while maintaining high perceptual quality. It uses efficient compression algorithms and a unified approach to support various types of content.

The framework defines a family of formats including:

• RDI – Root Delta Image
• RDA – Root Delta Audio
• RDV – Root Delta Video
• RDAI – Root Delta Animated Image

Warning

This project is under active development and not ready for general use.

Installation & Build Instructions

You can build RDC from source or download prebuilt binaries from the latest GitHub Releases.

To build RDC from source, ensure you have the .NET 9 SDK installed.

Run the following commands from the root of the repository to restore dependencies and publish the project:

Windows

dotnet restore
dotnet publish ./RootDeltaCodec.sln -c Release -r win-x64 --self-contained true /p:PublishAot=true /p:PublishTrimmed=true /p:TrimMode=link

Linux

dotnet restore
dotnet publish ./RootDeltaCodec.sln -c Release -r linux-x64 --self-contained true /p:PublishAot=true /p:PublishTrimmed=true /p:TrimMode=link

Output

After publishing, the executable will be located at:

• ./bin/Release/net9.0/win-x64/publish/rdc.exe (Windows)
• ./bin/Release/net9.0/linux-x64/publish/rdc (Linux)

Usage

RDC is available both as a CLI tool and as a .NET library for programmatic use.

Command-Line Interface

rdc encode input.bmp output.rdi
rdc decode input.rdi output.bmp

rdc encode -w -f bmp:rdi input output
rdc decode -w -f :bmp input.rdi output

Options:

• -f, --format: Input and output media formats as FROM:TO
• -m, --mode: Set encoding mode
• -w, --overwrite: Allow overwriting the output file if it exists
• -h, --help: Show help and usage information
• -v, --version: Show tool version

.NET Library

The core encoding/decoding logic lives in RdcEngine, while the CLI front-end uses RdcCli.

using RdcEngine.Image;

{
    using var inputBmp = File.OpenRead("input.bmp");
    using var outputRdi = File.Create("output.rdi");
    ImageCodec.EncodeBmp(inputBmp, outputRdi);
}

{
    using var inputRdi = File.OpenRead("input.rdi");
    using var outputBmp = File.Create("output.bmp");
    ImageCodec.DecodeBmp(inputRdi, outputBmp);
}

Supported Formats

From	To	Status
BMP	RDI	Supported
RDI	BMP	Supported
PNG, JPEG	RDI	Not Yet
RDI	PNG, JPEG	Not Yet
Video/Audio/GIF	RDV, RDA, RDAI	Planned

Tip

You can use tools like ffmpeg or other image converters to transform unsupported file types (e.g., PNG to BMP) before encoding, or back again (BMP to PNG) after decoding.

License

Copyright © 2025 Anar Bastanov
Distributed under the MIT License.