libopx 2.0.0

libopx

A .NET 9 C# library for parsing and extracting data from MXF (Material Exchange Format) files and extracted data streams, VBI (Vertical Blanking Interval), and T42 (Teletext packet stream) files, with SMPTE timecode and Teletext caption support.

Features

• Multi-format support: MXF, extracted data streams, VBI, and T42 file parsing
• Format conversion: Automatic VBI ↔ T42 conversion, plus RCWT and EBU STL output
• Teletext filtering: Magazine and row-based filtering with Unicode mapping
• SMPTE timecode: Full timecode calculations with various frame rates
• MXF processing: Stream extraction and demuxing capabilities
• CLI tool: Unified opx command-line interface
• Subtitle formats: RCWT (Raw Captions With Time) and EBU STL (EBU-Tech 3264) export

Format conversions: Convert between HD and SD T42 and VBI formats or vice versa. You can even pipe that data to other applications like ffmpeg or mpv.

ANSI Escaped Teletext: Supports parsing and filtering of teletext data with ANSI escape sequences:

Quick Start

Installation

Add the package reference to your project file from NuGet.org.

dotnet add package libopx

Or download the latest release from GitHub Releases.

Using the CLI Tool

# Filter teletext data by magazine and rows
opx filter -m 8 -r 20,22 input.vbi

# Convert between formats (use -of / --output-format)
opx convert -of t42 input.vbi

# Convert to EBU STL subtitle format
opx convert -of stl -c input.mxf output.stl

# Extract streams from MXF files
opx extract -k d,v input.mxf

Using the Library

using nathanbutlerDEV.libopx.Formats;

// Parse and filter teletext data
using var vbi = new VBI("input.vbi");
foreach (var line in vbi.Parse(magazine: 8, rows: new[] { 20, 22 }))
{
    Console.WriteLine(line);
}

Documentation

• Library Documentation - Detailed API reference and usage examples
• CLI Tool Documentation - Complete command reference and examples

Project Structure

libopx/
├── apps/opx/         # CLI tool
├── lib/              # Main library
│   ├── Formats/      # Format parsers (MXF, MXF data stream, VBI, T42)
│   ├── SMPTE/        # SMPTE metadata system
│   └── Enums/        # Enumeration definitions
├── samples/          # (Deprecated in repo) Obtain sample media from Release
│                       assets (e.g. v1.0.0) and place here if needed
├── scripts/          # Development scripts
└── tests/            # xUnit test suite

Development

# Clone and build
git clone https://github.com/nathanpbutler/libopx
cd libopx
dotnet build

# Run tests
dotnet test

Requirements

• .NET 9 or later
• Supported platforms: Windows, Linux, macOS

Dependencies

• System.CommandLine (v2.0.0-rc.2.25502.107)
• xUnit (testing)
• coverlet (code coverage)

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Ensure all tests pass
6. Submit a pull request

License

MIT - see the LICENSE file for details.

Acknowledgments

• vhs-teletext - Software to recover teletext data from VHS recordings (inspiration for filter command)
• MXFInspect - Tool for displaying the internal structure of MXF files (was super helpful for understanding MXF parsing and the intricacies of SMPTE timecodes)
• bmxtranswrap - BBC's MXF processing library and utilities (inspiration for extract command)
• SubtitleEdit - An incredibly useful C# library and software for subtitle editing and processing
• CCExtractor - Closed caption and subtitle extraction and processing
• ffmpeg - The swiss army knife of multimedia processing

Support

For questions and support, please open an issue.