gemma-tuner-multimodal
Gemma Multimodal Fine-Tuner
Skill by ara.so — Daily 2026 Skills collection.
Fine-tune Gemma 4 and Gemma 3n models on text, images, and audio data entirely on Apple Silicon (MPS), with support for streaming large datasets from GCS/BigQuery without filling local storage.
What It Does
- Text LoRA: instruction-tuning or completion fine-tuning from local CSV
- Image + Text LoRA: captioning and VQA from local CSV
- Audio + Text LoRA: the only Apple-Silicon-native path for this modality
- Cloud streaming: train on terabytes from GCS/BigQuery without local copy
- MPS-native: no NVIDIA GPU required — runs on MacBook Pro/Air/Mac Studio
Installation
Prerequisites
- macOS 12.3+ with Apple Silicon (arm64)
- Python 3.10+ (native arm64, not Rosetta)
- Hugging Face account with Gemma access
# Install Python 3.12 if needed
brew install python@3.12
# Create venv
python3.12 -m venv .venv
source .venv/bin/activate
# Verify arm64 (must show arm64, not x86_64)
python -c "import platform; print(platform.machine())"
# Install PyTorch
pip install torch torchaudio
# Clone and install
git clone https://github.com/mattmireles/gemma-tuner-multimodal
cd gemma-tuner-multimodal
pip install -e .
# For Gemma 4 support (separate venv recommended)
pip install -r requirements/requirements-gemma4.txt
Authenticate with Hugging Face
huggingface-cli login
# Or set environment variable:
export HF_TOKEN=your_token_here
CLI Commands
# Check system is ready
gemma-macos-tuner system-check
# Guided setup wizard (recommended for first run)
gemma-macos-tuner wizard
# Prepare dataset
gemma-macos-tuner prepare <dataset-profile>
# Fine-tune a model
gemma-macos-tuner finetune <profile> --json-logging
# Evaluate a run
gemma-macos-tuner evaluate <profile-or-run>
# Export merged HF/SafeTensors (merges LoRA when adapter_config.json present)
gemma-macos-tuner export <run-dir-or-profile>
# Blacklist bad samples from errors
gemma-macos-tuner blacklist <profile>
# List training runs
gemma-macos-tuner runs list
Configuration (config/config.ini)
The config is hierarchical INI: defaults → groups → models → datasets → profiles.
[defaults]
output_dir = output
batch_size = 2
gradient_accumulation_steps = 8
learning_rate = 2e-4
num_train_epochs = 3
[model:gemma-3n-e2b-it]
group = gemma
base_model = google/gemma-3n-E2B-it
[model:gemma-4-e2b-it]
group = gemma
base_model = google/gemma-4-E2B-it
[dataset:my-audio-dataset]
data_dir = data/datasets/my-audio-dataset
audio_column = audio_path
text_column = transcript
[profile:my-audio-profile]
model = gemma-3n-e2b-it
dataset = my-audio-dataset
modality = audio
lora_r = 16
lora_alpha = 32
lora_dropout = 0.05
max_seq_length = 512
Use GEMMA_TUNER_CONFIG env var to point to config outside repo root:
export GEMMA_TUNER_CONFIG=/path/to/my/config.ini
Modality Configuration
Text-Only Fine-Tuning
Instruction tuning (user/assistant pairs):
[profile:text-instruction]
model = gemma-3n-e2b-it
dataset = my-text-dataset
modality = text
text_sub_mode = instruction
prompt_column = prompt
text_column = response
max_seq_length = 2048
lora_r = 16
lora_alpha = 32
Completion tuning (full sequence trained):
[profile:text-completion]
model = gemma-3n-e2b-it
dataset = my-text-dataset
modality = text
text_sub_mode = completion
text_column = text
max_seq_length = 2048
CSV format for instruction tuning (data/datasets/my-text-dataset/train.csv):
prompt,response
"What is photosynthesis?","Photosynthesis is the process by which plants..."
"Explain LoRA fine-tuning","LoRA (Low-Rank Adaptation) is a parameter-efficient..."
Image Fine-Tuning
[profile:image-caption]
model = gemma-3n-e2b-it
dataset = my-image-dataset
modality = image
image_sub_mode = captioning
image_token_budget = 256
prompt_column = prompt
text_column = caption
max_seq_length = 512
CSV format (data/datasets/my-image-dataset/train.csv):
image_path,prompt,caption
/data/images/img1.jpg,Describe this image,A dog sitting on a green lawn...
/data/images/img2.jpg,What is shown here,A bar chart showing quarterly revenue...
Audio Fine-Tuning
[profile:audio-asr]
model = gemma-3n-e2b-it
dataset = my-audio-dataset
modality = audio
audio_column = audio_path
text_column = transcript
max_seq_length = 512
lora_r = 16
lora_alpha = 32
lora_dropout = 0.05
CSV format (data/datasets/my-audio-dataset/train.csv):
audio_path,transcript
/data/audio/recording1.wav,The patient presents with acute respiratory symptoms
/data/audio/recording2.wav,Counsel objects to the characterization of the evidence
Supported Models
| Model Key | Hugging Face ID | Notes |
|---|---|---|
gemma-3n-e2b-it |
google/gemma-3n-E2B-it |
Default, ~2B instruct |
gemma-3n-e4b-it |
google/gemma-3n-E4B-it |
~4B instruct |
gemma-4-e2b-it |
google/gemma-4-E2B-it |
Needs requirements-gemma4.txt |
gemma-4-e4b-it |
google/gemma-4-E4B-it |
Needs requirements-gemma4.txt |
gemma-4-e2b |
google/gemma-4-E2B |
Base, needs Gemma 4 stack |
gemma-4-e4b |
google/gemma-4-E4B |
Base, needs Gemma 4 stack |
Add custom models with a [model:your-name] section using group = gemma.
Dataset Directory Layout
data/
└── datasets/
└── <dataset-name>/
├── train.csv # required
├── validation.csv # optional
└── test.csv # optional
Output Layout
output/
└── {run-id}-{profile}/
├── metadata.json
├── metrics.json
├── checkpoint-*/
└── adapter_model/ # LoRA artifacts
Python API Examples
Running Fine-Tuning Programmatically
from gemma_tuner.core.config import load_config
from gemma_tuner.core.ops import run_finetune
# Load config
config = load_config("config/config.ini")
# Run fine-tuning for a profile
run_finetune(profile="my-audio-profile", config=config, json_logging=True)
Using Device Utilities
from gemma_tuner.utils.device import get_device, memory_hint
device = get_device() # Returns "mps", "cuda", or "cpu"
print(f"Training on: {device}")
hint = memory_hint(model_key="gemma-3n-e2b-it")
print(hint)
Loading and Inspecting Datasets
from gemma_tuner.utils.dataset_utils import load_csv_dataset
train_df, val_df = load_csv_dataset(
data_dir="data/datasets/my-text-dataset",
text_column="response",
prompt_column="prompt"
)
print(f"Train samples: {len(train_df)}, Val samples: {len(val_df)}")
Custom LoRA Config
from peft import LoraConfig, get_peft_model
from transformers import AutoModelForCausalLM
model = AutoModelForCausalLM.from_pretrained(
"google/gemma-3n-E2B-it",
torch_dtype="auto",
device_map="mps"
)
lora_config = LoraConfig(
r=16,
lora_alpha=32,
lora_dropout=0.05,
target_modules=["q_proj", "v_proj", "k_proj", "o_proj"],
task_type="CAUSAL_LM"
)
model = get_peft_model(model, lora_config)
model.print_trainable_parameters()
Common Patterns
Full Workflow: Text Instruction Tuning
# 1. Prepare your data
mkdir -p data/datasets/my-dataset
cp train.csv data/datasets/my-dataset/
cp validation.csv data/datasets/my-dataset/
# 2. Add profile to config/config.ini
cat >> config/config.ini << 'EOF'
[dataset:my-dataset]
data_dir = data/datasets/my-dataset
[profile:my-text-run]
model = gemma-3n-e2b-it
dataset = my-dataset
modality = text
text_sub_mode = instruction
prompt_column = prompt
text_column = response
max_seq_length = 2048
lora_r = 16
lora_alpha = 32
EOF
# 3. Prepare dataset
gemma-macos-tuner prepare my-dataset
# 4. Fine-tune
gemma-macos-tuner finetune my-text-run --json-logging
# 5. Export merged weights
gemma-macos-tuner export my-text-run
GCS Streaming for Large Datasets
[dataset:large-audio-gcs]
source = gcs
gcs_bucket = my-bucket
gcs_prefix = audio-training-data/
audio_column = audio_path
text_column = transcript
[profile:large-audio-run]
model = gemma-3n-e4b-it
dataset = large-audio-gcs
modality = audio
lora_r = 32
lora_alpha = 64
Set credentials:
export GOOGLE_APPLICATION_CREDENTIALS=/path/to/service-account.json
gemma-macos-tuner finetune large-audio-run
Add a Custom Gemma Checkpoint
[model:my-custom-gemma]
group = gemma
base_model = my-org/my-gemma-checkpoint
[profile:custom-run]
model = my-custom-gemma
dataset = my-dataset
modality = text
text_sub_mode = instruction
Troubleshooting
Wrong architecture (x86_64 instead of arm64)
python -c "import platform; print(platform.machine())"
# Must be arm64 — if x86_64, reinstall Python natively:
brew install python@3.12
python3.12 -m venv .venv && source .venv/bin/activate
MPS out of memory
- Reduce
batch_size(try 1) - Increase
gradient_accumulation_stepsto compensate - Use a smaller model (
e2binstead ofe4b) - Reduce
max_seq_length
Gemma 4 model not loading
# Gemma 4 requires the updated Transformers stack
pip install -r requirements/requirements-gemma4.txt
# Use a separate venv if you also need Gemma 3n
Config not found outside repo root
export GEMMA_TUNER_CONFIG=/absolute/path/to/config/config.ini
gemma-macos-tuner finetune my-profile
Hugging Face auth errors
huggingface-cli login
# Or:
export HF_TOKEN=your_hf_token
# Accept Gemma license at: https://huggingface.co/google/gemma-3n-E2B-it
System check before debugging anything else
gemma-macos-tuner system-check
Audio tower loaded even for text-only runs
This is a known v1 issue — USM audio tower weights stay in memory even for modality = text. See README/KNOWN_ISSUES.md. Workaround: use a smaller model variant to stay within RAM budget.
Architecture Reference
| File | Role |
|---|---|
gemma_tuner/cli_typer.py |
Main CLI entrypoint (gemma-macos-tuner) |
gemma_tuner/core/ops.py |
Dispatches prepare/finetune/evaluate/export |
gemma_tuner/scripts/finetune.py |
Router: Gemma models → models/gemma/finetune.py |
gemma_tuner/models/gemma/finetune.py |
Core training loop with LoRA |
gemma_tuner/scripts/export.py |
Merges LoRA → HF/SafeTensors tree |
gemma_tuner/utils/device.py |
MPS/CUDA/CPU selection and memory hints |
gemma_tuner/utils/dataset_utils.py |
CSV loading, blacklist/protection semantics |
gemma_tuner/wizard/ |
Interactive CLI wizard (questionary + Rich) |
config/config.ini |
Hierarchical INI configuration |