riffy 0.1.2

A pure Python library for parsing and managing RIFF format files

riffy

Riffy provides a pure Python implementation for working with RIFF format files, with initial support for WAV audio files. The library is designed to have zero external dependencies while providing robust parsing capabilities for managing RIFF chunks.

Features

• Zero Dependencies: Pure Python implementation with no external dependencies
• WAV File Support: Complete WAV file parsing with format validation
• RIFF Chunk Management: Access and inspect individual RIFF chunks
• Audio Metadata Extraction: Extract sample rate, channels, bit depth, and duration
• Format Validation: Automatic validation of file format and integrity
• Type Safety: Full type hints for better IDE support and code quality
• Lightweight: Minimal footprint, perfect for embedded systems or restricted environments

Installation

From PyPI

pip install riffy

From Source

# Clone the repository
git clone https://github.com/jmcmeen/riffy.git
cd riffy

# Install in development mode
pip install -e .

# Or build and install
pip install build
python -m build
pip install dist/riffy-*.whl

For Development

# Install with development dependencies
pip install -e ".[dev]"

Quick Start

Basic WAV File Parsing

from riffy import WAVParser

# Parse a WAV file (parsing happens automatically on initialization)
parser = WAVParser("audio.wav")

# Access format information
info = parser.get_info()
print(f"Sample Rate: {info['format']['sample_rate']} Hz")
print(f"Channels: {info['format']['channels']}")
print(f"Bit Depth: {info['format']['bits_per_sample']} bits")
print(f"Duration: {info['duration_seconds']:.2f} seconds")

Accessing RIFF Chunks

from riffy import WAVParser

# Parsing happens automatically on initialization
parser = WAVParser("audio.wav")

# Access all chunks
for chunk_id, chunk in parser.chunks.items():
    print(f"Chunk: {chunk_id}, Size: {chunk.size} bytes, Offset: {chunk.offset}")

# Access specific chunk
if 'fmt ' in parser.chunks:
    fmt_chunk = parser.chunks['fmt ']
    print(f"Format chunk size: {fmt_chunk.size}")

Working with Audio Data

from riffy import WAVParser

# Parsing happens automatically on initialization
parser = WAVParser("audio.wav")

# Access raw audio data
audio_data = parser.audio_data
print(f"Audio data size: {len(audio_data)} bytes")

# Get sample count
info = parser.get_info()
print(f"Total samples: {info['sample_count']}")

Exporting Chunks to Binary Files

from riffy import WAVParser

# Parsing happens automatically on initialization
parser = WAVParser("audio.wav")

# Export raw audio data (most common use case)
bytes_written = parser.export_audio_data("raw_audio.bin")
print(f"Exported {bytes_written} bytes of audio data")

# Export specific chunks
parser.export_chunk('fmt ', "format_chunk.bin")
parser.export_chunk('data', "data_chunk.bin")

# List all available chunks before exporting
chunks = parser.list_chunks()
for chunk_id, info in chunks.items():
    print(f"Chunk '{chunk_id}': {info['size']} bytes at offset {info['offset']}")

# Export all chunks
for chunk_id in chunks.keys():
    filename = f"{chunk_id.strip()}_chunk.bin"
    parser.export_chunk(chunk_id, filename)

Getting Detailed File Information

from riffy import WAVParser
import json

# Parsing happens automatically on initialization
parser = WAVParser("audio.wav")
info = parser.get_info()

# Pretty print all information
print(json.dumps(info, indent=2))

Output example:

{
  "file_path": "/path/to/audio.wav",
  "file_size": 1234567,
  "format": {
    "audio_format": 1,
    "channels": 2,
    "sample_rate": 44100,
    "byte_rate": 176400,
    "block_align": 4,
    "bits_per_sample": 16,
    "is_pcm": true
  },
  "duration_seconds": 3.5,
  "audio_data_size": 617400,
  "sample_count": 154350,
  "chunks": {
    "fmt ": 16,
    "data": 617400
  }
}

API Reference

WAVParser

The main class for parsing WAV files.

Constructor

WAVParser(file_path: Union[str, Path])

Parameters:

• file_path: Path to the WAV file (string or pathlib.Path)

Note: The file is automatically parsed during initialization.

Raises (during initialization):

• FileNotFoundError: If the file doesn't exist
• InvalidWAVFormatError: If the file is not a valid WAV file
• CorruptedFileError: If the file is corrupted or incomplete

Methods

get_info() -> Dict

Get comprehensive information about the parsed WAV file.

Returns: Dictionary with file metadata

parse() -> Dict

Re-parse the WAV file and return comprehensive information. This method can be called to refresh the parser state, but is automatically called during initialization.

Returns: Dictionary containing file information, format details, and chunk data

export_chunk(chunk_id: str, output_path: Union[str, Path]) -> int

Export a specific chunk's data to a binary file.

Parameters:

• chunk_id: The ID of the chunk to export (e.g., 'fmt ', 'data')
• output_path: Path where the chunk data will be written

Returns: Number of bytes written

Raises:

• KeyError: If the specified chunk doesn't exist

export_audio_data(output_path: Union[str, Path]) -> int

Export raw audio data to a binary file (convenience method).

Parameters:

• output_path: Path where the audio data will be written

Returns: Number of bytes written

Raises:

• WAVError: If no audio data exists

list_chunks() -> Dict[str, Dict[str, int]]

List all chunks in the WAV file with their sizes and offsets.

Returns: Dictionary mapping chunk IDs to their metadata (size and offset)

Properties

• format_info: WAVFormat object containing format details
• chunks: Dictionary of WAVChunk objects keyed by chunk ID
• audio_data: Raw audio data as bytes

WAVFormat

Dataclass containing WAV format information.

Attributes:

• audio_format: Audio format code (1 = PCM)
• channels: Number of audio channels
• sample_rate: Sample rate in Hz
• byte_rate: Bytes per second
• block_align: Block alignment in bytes
• bits_per_sample: Bits per sample

Properties:

• is_pcm: Boolean indicating if format is PCM (uncompressed)
• duration_seconds: Audio duration in seconds

WAVChunk

Dataclass representing a RIFF chunk.

Attributes:

• id: Chunk identifier (e.g., "fmt ", "data")
• size: Chunk size in bytes
• data: Raw chunk data
• offset: Byte offset in the file

Exception Hierarchy

RiffyError (base exception)
├── WAVError
│   ├── InvalidWAVFormatError
│   ├── CorruptedFileError
│   └── UnsupportedFormatError
└── ChunkError
    ├── InvalidChunkError
    └── MissingChunkError

Exception Handling

from riffy import WAVParser, InvalidWAVFormatError, CorruptedFileError

try:
    parser = WAVParser("audio.wav")
    info = parser.parse()
except InvalidWAVFormatError as e:
    print(f"Invalid WAV format: {e}")
except CorruptedFileError as e:
    print(f"File is corrupted: {e}")
except FileNotFoundError:
    print("File not found")

Supported Formats

Currently, Riffy supports:

• WAV Files: PCM (uncompressed) audio only
• RIFF Chunks: Standard chunk parsing for any RIFF file

Planned Support

• AVI files
• WebP images
• Additional WAV compression formats
• RIFF chunk writing/modification

Requirements

• Python 3.8 or higher
• No external dependencies!

Development

Running Tests

# Install development dependencies
pip install -e ".[dev]"

# Run tests
pytest

# Run tests with coverage
pytest --cov=riffy --cov-report=html

Code Formatting

# Format code with black
black src/

# Lint with ruff
ruff check src/

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Changelog

Version 0.1.0 (Initial Release)

• Pure Python WAV file parser
• RIFF chunk management
• Zero external dependencies
• Full type hints
• Comprehensive error handling

References

• RIFF format specification: Microsoft RIFF Specification
• WAV format specification: WAV Audio File Format

Support

For bugs, feature requests, or questions, please open an issue.