CTranslate2 Go Bindings

Go bindings for CTranslate2 using libffi (no CGo required).

Features

• Whisper: Speech recognition and transcription
• Translator: Sequence-to-sequence translation
• Generator: Language model text generation

Requirements

Runtime

• The CTranslate2 shared library (libctranslate2.so, libctranslate2.dylib, or ctranslate2.dll)
• libffi runtime:
  • Linux: apt install libffi8 or dnf install libffi
  • macOS: Bundled with the system
  • Windows: Bundled with the ffi package

Installation

go get github.com/ardanlabs/ctranslate2ffi

Usage

Load the Library

Before using any functions, load the CTranslate2 shared library:

package main

import "github.com/ardanlabs/ctranslate2ffi"

func main() {
    // Provide the directory containing libctranslate2.so/dylib/dll
    if err := ctranslate2ffi.Load("/usr/local/lib"); err != nil {
        panic(err)
    }
    
    // Check version
    fmt.Println("CTranslate2 version:", ctranslate2.Version())
}

Whisper (Speech Recognition)

// Load a Whisper model
config := ctranslate2.DefaultModelConfig()
config.Device = ctranslate2.DeviceCPU
config.ComputeType = ctranslate2.ComputeFloat32

whisper, err := ctranslate2.NewWhisper("/path/to/whisper-model", config)
if err != nil {
    panic(err)
}
defer whisper.Close()

// Check model properties
fmt.Println("Multilingual:", whisper.IsMultilingual())
fmt.Println("Num mels:", whisper.NumMels())

// Create audio features (mel spectrogram)
// Shape should be [batch_size, n_mels, time_frames]
features, err := ctranslate2.NewStorageViewFloat(melData, []int64{1, 80, 3000}, ctranslate2.DeviceCPU)
if err != nil {
    panic(err)
}
defer features.Close()

// Transcribe
opts := ctranslate2.DefaultWhisperOptions()
result, err := whisper.Generate(features, []string{"<|startoftranscript|>", "<|en|>"}, opts)
if err != nil {
    panic(err)
}

Translator

// Load a translation model
translator, err := ctranslate2.NewTranslator("/path/to/model", config)
if err != nil {
    panic(err)
}
defer translator.Close()

// Translate tokenized input
opts := ctranslate2.DefaultTranslationOptions()
result, err := translator.Translate([]string{"Hello", "world"}, opts)
if err != nil {
    panic(err)
}

Generator (Language Model)

// Load a language model
generator, err := ctranslate2.NewGenerator("/path/to/model", config)
if err != nil {
    panic(err)
}
defer generator.Close()

// Generate text
opts := ctranslate2.DefaultGenerationOptions()
opts.MaxLength = 100
result, err := generator.Generate([]string{"Once", "upon", "a", "time"}, opts)
if err != nil {
    panic(err)
}

Building CTranslate2 with C API

The C API wrapper must be compiled with CTranslate2:

1. Copy ctranslate2_c.h to CTranslate2/include/
2. Copy ctranslate2_c.cc to CTranslate2/src/
3. Add the source file to CMakeLists.txt
4. Build CTranslate2:

cd CTranslate2
mkdir build && cd build
cmake -DBUILD_SHARED_LIBS=ON ..
make -j$(nproc)

API Reference

Types

• Device - CPU or CUDA
• ComputeType - Computation precision (float32, int8, float16, etc.)
• ModelConfig - Model loading configuration
• WhisperOptions - Whisper generation options
• TranslationOptions - Translation options
• GenerationOptions - Text generation options

Functions

• Load(path string) - Load the CTranslate2 shared library
• Version() - Get library version
• CUDAAvailable() - Check if CUDA is available
• CUDADeviceCount() - Get number of CUDA devices

Error Handling

• GetLastError() - Get the last error message
• ClearError() - Clear the error state

License

Apache 2.0