Transcribe Audio
Local audio transcription using whisper-cpp — a C++ port of OpenAI's Whisper.
Quick Start
# Transcribe with a small model (fast, ~75MB)
nix run nixpkgs#whisper-cpp -- -m models/ggml-tiny.en.bin -f audio.mp3
Available Models
| Model | Size | Speed | Quality |
| -------------------- | ------ | ---------- | ------- |
| ggml-tiny.en.bin | 75 MB | ⚡ Fastest | Basic |
| ggml-base.en.bin | 142 MB | ⚡ Fast | Good |
| ggml-small.en.bin | 468 MB | 🐌 Medium | Better |
| ggml-medium.en.bin | 1.4 GB | 🐌 Slower | Good |
| ggml-large-v3.bin | 3.1 GB | 🐌🐌 Slow | Best |
Download a Model
# Example: download base model
curl -L https://huggingface.co/ggerganov/whisper.cpp/resolve/main/ggml-base.en.bin -o ggml-base.en.bin
Common Options
| Option | Description |
| -------------------- | ------------------------------------ |
| -m MODEL | Model path |
| -f FILE | Input audio file |
| -t N | Threads (default: 4) |
| -l LANG | Language (en, auto, etc.) |
| -otxt | Output to .txt file |
| -osrt | Output to .srt subtitle file |
| -ovtt | Output to .vtt file |
| -oj | Output to JSON |
| -of PATH | Output file path (without extension) |
| -nt | No timestamps in output |
| -np | No prints (results only) |
| --print-confidence | Show confidence scores |
Examples
Transcribe with Timestamps (Default)
nix run nixpkgs#whisper-cpp -- -m ggml-base.en.bin -f recording.mp3
Save to Text File
nix run nixpkgs#whisper-cpp -- -m ggml-base.en.bin -f recording.mp3 -otxt -of transcript
Generate Subtitles
nix run nixpkgs#whisper-cpp -- -m ggml-base.en.bin -f video.mp4 -osrt -of captions
JSON Output with Confidence
nix run nixpkgs#whisper-cpp -- -m ggml-base.en.bin -f audio.wav -oj -of result --print-confidence
Auto-Detect Language
nix run nixpkgs#whisper-cpp -- -m ggml-base.bin -f audio.mp3 -l auto
Process Multiple Files
nix run nixpkgs#whisper-cpp -- -m ggml-base.en.bin -f file1.mp3 file2.mp3 file3.mp3
Offset and Duration
# Start at 30s, process 60 seconds
nix run nixpkgs#whisper-cpp -- -m ggml-base.en.bin -f audio.mp3 -ot 30000 -d 60000
Supported Formats
flac, mp3, ogg, wav
GPU Acceleration
For GPU support, use whisper-cpp-vulkan:
nix run nixpkgs#whisper-cpp-vulkan -- -m ggml-base.en.bin -f audio.mp3