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), T42 (Teletext packet stream), and MPEG-TS (Transport Stream) files, with SMPTE timecode and Teletext caption support.

Features

• Multi-format support: MXF, extracted data streams, VBI, T42, and MPEG-TS file parsing
• Format conversion: Automatic VBI ↔ T42 conversion, plus RCWT and EBU STL output
• MPEG-TS teletext extraction: Automatic PAT/PMT parsing with DVB teletext support
• 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

# Filter MPEG-TS teletext (auto-detects PIDs)
opx filter input.ts

# Filter MPEG-TS with specific PID
opx filter --pid 70 input.ts

# Convert between formats (auto-detected from extension)
opx convert input.vbi output.t42

# Convert MPEG-TS to T42
opx convert --pid 70 input.ts output.t42

# Convert to EBU STL subtitle format
opx convert -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 from VBI
using var vbi = new VBI("input.vbi");
foreach (var line in vbi.Parse(magazine: 8, rows: new[] { 20, 22 }))
{
    Console.WriteLine(line);
}

// Parse and filter teletext from MPEG-TS (auto-detects PIDs)
using var ts = new TS("input.ts");
foreach (var line in ts.Parse(magazine: 8))
{
    Console.WriteLine(line);
}

// Parse MPEG-TS with specific PID
using var ts2 = new TS("input.ts") { PIDs = new[] { 70 } };
foreach (var line in ts2.Parse())
{
    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, TS)
│   ├── 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.