cnsoluciones/wav2multi repository overview

⁠🎵 wav2multi - Multi-Format Audio Transcoder

Professional multi-format audio transcoder for VoIP telephony codecs

Convert WAV audio files to G.729, μ-law, A-law, and SLIN formats with excellent compression and compatibility. Optimized for VoIP applications, IP telephony, and telecommunications systems.

⁠🚀 Quick Start

# G.729 conversion (8 kbps - high compression)
docker run --rm -v $PWD:/work cnsoluciones/wav2multi:latest input.wav output.g729 --format g729

# μ-law conversion (64 kbps - US standard)
docker run --rm -v $PWD:/work cnsoluciones/wav2multi:latest input.wav output.ulaw --format ulaw

# A-law conversion (64 kbps - European standard)
docker run --rm -v $PWD:/work cnsoluciones/wav2multi:latest input.wav output.alaw --format alaw

# SLIN conversion (128 kbps - raw PCM)
docker run --rm -v $PWD:/work cnsoluciones/wav2multi:latest input.wav output.slin --format slin

⁠📋 Supported Formats

⁠✨ Key Features

• ✅ Multi-format support: G.729, μ-law, A-law, SLIN
• ✅ High-quality codecs: Uses libbcg729 for G.729, native Go for others
• ✅ Ultra-light image: Only ~19MB (Alpine Linux)
• ✅ Multi-architecture: Supports amd64 and arm64
• ✅ Easy to use: Simple command-line interface
• ✅ Automatic validation: Checks WAV format requirements
• ✅ Backward compatible: Legacy format still supported

⁠📦 Image Information

• Base Image: Alpine Linux (multi-stage build)
• Size: ~19MB compressed
• Architectures: linux/amd64, linux/arm64
• Go Version: 1.23
• CGO: Enabled (for G.729 support)

⁠🔧 Requirements

Your WAV files must meet these specifications:

• Format: PCM (AudioFormat = 1)
• Channels: Mono (1 channel)
• Sample Rate: 8000 Hz
• Bits per Sample: 16-bit

⁠💡 Usage Examples

⁠Basic Conversion

# Convert to G.729 (highest compression)
docker run --rm -v $PWD:/work cnsoluciones/wav2multi:latest audio.wav audio.g729 --format g729

# Legacy format (auto-detect from extension)
docker run --rm -v $PWD:/work cnsoluciones/wav2multi:latest audio.wav audio.g729

⁠Batch Processing

# Convert all WAV files in current directory
for file in *.wav; do
    docker run --rm -v $PWD:/work cnsoluciones/wav2multi:latest "$file" "${file%.wav}.g729" --format g729
done

⁠With Custom Path

# Mount specific directory
docker run --rm -v /path/to/audio:/work cnsoluciones/wav2multi:latest input.wav output.g729 --format g729

⁠Get Help

# Show complete help
docker run --rm cnsoluciones/wav2multi:latest --help

# Show version
docker run --rm cnsoluciones/wav2multi:latest --version

⁠✅ Verify Conversions

Convert back to WAV using FFmpeg to verify quality:

# Verify G.729
ffmpeg -f g729 -i output.g729 -ar 8000 -ac 1 -c:a pcm_s16le verify.wav

# Verify μ-law
ffmpeg -f mulaw -i output.ulaw -ar 8000 -ac 1 -c:a pcm_s16le verify.wav

# Verify A-law
ffmpeg -f alaw -i output.alaw -ar 8000 -ac 1 -c:a pcm_s16le verify.wav

# Verify SLIN
ffmpeg -f s16le -ar 8000 -ac 1 -i output.slin -c:a pcm_s16le verify.wav

⁠🔄 Converting Incompatible Files

If your WAV file doesn't meet requirements, convert it with FFmpeg:

# All-in-one conversion to compatible format
ffmpeg -i input.mp3 -ar 8000 -ac 1 -sample_fmt s16 -acodec pcm_s16le output.wav

# Then transcode
docker run --rm -v $PWD:/work cnsoluciones/wav2multi:latest output.wav output.g729 --format g729

⁠📊 Codec Technical Details

⁠G.729 (High Compression)

• Bitrate: 8 kbps
• Frame size: 10ms (80 samples @ 8kHz)
• Usage: VoIP, IP telephony, videoconferencing
• Implementation: libbcg729 library (CGO)

⁠μ-law (Standard Telephony)

• Bitrate: 64 kbps
• Usage: US telephony, legacy systems
• Implementation: Native Go algorithm

⁠A-law (European Standard)

• Bitrate: 64 kbps
• Usage: European telephony, international
• Implementation: Native Go algorithm

⁠SLIN (Raw PCM)

• Bitrate: 128 kbps
• Usage: Raw audio, debugging, high quality
• Implementation: Direct PCM extraction

⁠🐛 Troubleshooting

⁠Error: "WAV is not PCM"

ffmpeg -i file.wav -acodec pcm_s16le output.wav

⁠Error: "mono required (1 channel)"

ffmpeg -i file.wav -ac 1 output.wav

⁠Error: "8000 Hz required"

ffmpeg -i file.wav -ar 8000 output.wav

⁠All-in-one fix

ffmpeg -i input.mp3 -ar 8000 -ac 1 -sample_fmt s16 -acodec pcm_s16le output.wav

⁠🎯 Use Cases

• VoIP Systems: Prepare audio files for Asterisk, FreeSWITCH
• IP Telephony: Convert hold music, announcements, IVR prompts
• Telecommunications: Standard format conversion for telecom systems
• Audio Optimization: Reduce file sizes for bandwidth-constrained applications
• Testing: Generate test files in different codec formats

⁠🏗️ Technical Architecture

This Docker image uses a multi-stage build for optimal size:

1. Build Stage: Compiles bcg729 library and Go binary
2. Runtime Stage: Only includes binary and essential libraries
3. Result: Ultra-light ~19MB image

⁠What's Inside

• Alpine Linux (minimal base)
• Go 1.23 compiled binary
• libbcg729.so (G.729 codec library)
• Minimal dependencies (ca-certificates, libc6-compat)

⁠📚 Documentation

• GitHub Repository: github.com/lordbasex/wav2multi⁠
• Complete Documentation: README.md⁠
• Spanish Documentation: README.es.md⁠
• Raspberry Pi Guide: README-RASPBERRYPI.md⁠
• Installation Guide: INSTALL.md⁠

⁠🔗 Links

• Docker Hub: hub.docker.com/r/cnsoluciones/wav2multi⁠
• GitHub: github.com/lordbasex/wav2multi⁠
• bcg729 Library: github.com/BelledonneCommunications/bcg729⁠
• G.729 Specification: ITU-T G.729⁠

⁠👨‍💻 Author

Federico Pereira - [email protected]⁠

⁠🏢 CNSoluciones

This project is part of CNSoluciones, specialized in telecommunications and VoIP solutions.

⁠📄 License

wav2multi is licensed under the Apache License 2.0.

Copyright © 2025 Federico Pereira [email protected]⁠

⁠Quick Summary

✅ You CAN: Use commercially, modify, distribute, sublicense
⚠️ You MUST: Include copyright, provide attribution, state changes
❌ You CANNOT: Hold author liable, remove copyright notices

⁠Third-Party Components

• bcg729 (GPLv3) - G.729 codec library
• go-wav (MIT) - WAV file parsing
• go-audio (Apache 2.0) - Audio processing

⁠Patent Information

G.729 codec patents expired in 2017. Free to use worldwide without royalties.

⁠Commercial Licensing

Need different terms? Commercial licenses available:

• No attribution requirements
• Priority support
• Custom development
• Contact: [email protected]⁠

For complete terms, see LICENSE⁠

⁠🤝 Contributing

Contributions are welcome! Please visit our GitHub repository⁠ to:

• Report issues
• Submit pull requests
• Request features
• Improve documentation

⁠🌟 Show Your Support

If you find this project useful, please:

• ⭐ Star the GitHub repository⁠
• 🐳 Pull and use the Docker image
• 📢 Share with your team
• 🤝 Contribute improvements

Questions or issues? Open an issue on GitHub⁠

Made with ❤️ by CNSoluciones | Telecommunications & VoIP Solutions