audio-filter-mlir

Audio processing utility with MLIR optimization support.

Quick Start

# Setup and build
make setup
make build

# Run tests
make test

# Install utility
make install

# Use the utility
audio-util --input audio.wav --filter hpf --freq 100 --output audio-clean.wav

Future Optimizations to Try

• -march=native equivalent - Explicitly enable AVX-512/FMA
• Polyhedral optimizations - Better loop tiling for cache
• Vectorization hints - Force SIMD on the loop
• Inlining - Inline the biquad equation directly into the loop body
• Fast-math flags - Relaxed FP semantics for speed

Features

• WAV File I/O: Read/write 8/16/24/32-bit PCM audio files
• High-Pass Filter: Butterworth 2nd-order filter for removing low frequencies
• Command-Line Tool: audio-util for batch processing
• Comprehensive Tests: 100% test pass rate with 12 test cases

Make Targets

make help       # Show available targets
make setup      # Initial project setup
make build      # Build all libraries and executables
make test       # Run all tests
make install    # Install audio-util to /usr/local/bin
make uninstall  # Remove audio-util
make clean      # Remove build artifacts

Requirements

• CMake 3.10+
• C99-compatible compiler
• Math library (libm)

Project Structure

audio-filter-mlir/
├── include/          # Public headers
│   ├── audio_io.h
│   ├── biquad.h
│   └── hpf.h
├── src/              # Implementation
│   ├── audio_io.c
│   ├── biquad.c
│   ├── hpf.c
│   └── audio_util.c
├── tests/            # Test suites
│   ├── test_audio_io.c
│   ├── test_biquad.c
│   └── test_hpf.c
└── docs/             # Documentation

Example Usage

Remove Low-Frequency Rumble

audio-util --input recording.wav --filter hpf --freq 80 --output clean.wav

Remove DC Offset

audio-util --input audio.wav --filter hpf --freq 5 --output audio-clean.wav

Batch Processing

for file in *.wav; do
    audio-util --input "$file" --filter hpf --freq 100 \
               --output "processed/${file%.wav}_clean.wav"
done

Development

Build System

• CMake: Primary build system
• Makefile: Convenience wrapper
• clangd: LSP support via compile_commands.json

Code Statistics

• Total Lines: 2,443 (implementation + tests)
• Libraries: 3 static libraries
• Executables: 1 utility + 3 test suites
• Test Coverage: 12 test cases, 100% pass rate

Running Tests

# All tests via CTest
make test

# Individual test suites
./build/test_audio_io
./build/test_biquad
./build/test_hpf

Technology Stack

• Language: C99
• Build: CMake, Make
• Testing: CTest, custom test harness
• Audio Format: WAV (RIFF/WAVE) with PCM
• DSP: Butterworth filters via biquad implementation
• Future: MLIR optimization framework

License

See LICENSE file.

Contributing

This is a personal learning project focused on MLIR optimization. The current implementation serves as a baseline for MLIR performance comparisons.

See Also

• MLIR Documentation: https://mlir.llvm.org/
• WAV Format Spec: http://soundfile.sapp.org/doc/WaveFormat/
• Butterworth Filter Theory: Digital Signal Processing texts