heartmula

---
name: heartmula
description: Set up and run HeartMuLa, the open-source music generation model family (Suno-like). Generates full songs from lyrics + tags with multilingual support.
version: 1.0.0
metadata:
  hermes:
    tags: [music, audio, generation, ai, heartmula, heartcodec, lyrics, songs]
    related_skills: [audiocraft]
---

# HeartMuLa - Open-Source Music Generation

## Overview
HeartMuLa is a family of open-source music foundation models (Apache-2.0) that generates music conditioned on lyrics and tags. Comparable to Suno for open-source. Includes:
- **HeartMuLa** - Music language model (3B/7B) for generation from lyrics + tags
- **HeartCodec** - 12.5Hz music codec for high-fidelity audio reconstruction
- **HeartTranscriptor** - Whisper-based lyrics transcription
- **HeartCLAP** - Audio-text alignment model

## When to Use
- User wants to generate music/songs from text descriptions
- User wants an open-source Suno alternative
- User wants local/offline music generation
- User asks about HeartMuLa, heartlib, or AI music generation

## Hardware Requirements
- **Minimum**: 8GB VRAM with `--lazy_load true` (loads/unloads models sequentially)
- **Recommended**: 16GB+ VRAM for comfortable single-GPU usage
- **Multi-GPU**: Use `--mula_device cuda:0 --codec_device cuda:1` to split across GPUs
- 3B model with lazy_load peaks at ~6.2GB VRAM

## Installation Steps

### 1. Clone Repository
```bash
cd ~/  # or desired directory
git clone https://github.com/HeartMuLa/heartlib.git
cd heartlib
```

### 2. Create Virtual Environment (Python 3.10 required)
```bash
uv venv --python 3.10 .venv
. .venv/bin/activate
uv pip install -e .
```

### 3. Fix Dependency Compatibility Issues

**IMPORTANT**: As of Feb 2026, the pinned dependencies have conflicts with newer packages. Apply these fixes:

```bash
# Upgrade datasets (old version incompatible with current pyarrow)
uv pip install --upgrade datasets

# Upgrade transformers (needed for huggingface-hub 1.x compatibility)
uv pip install --upgrade transformers
```

### 4. Patch Source Code (Required for transformers 5.x)

**Patch 1 - RoPE cache fix** in `src/heartlib/heartmula/modeling_heartmula.py`:

In the `setup_caches` method of the `HeartMuLa` class, add RoPE reinitialization after the `reset_caches` try/except block and before the `with device:` block:

```python
# Re-initialize RoPE caches that were skipped during meta-device loading
from torchtune.models.llama3_1._position_embeddings import Llama3ScaledRoPE
for module in self.modules():
    if isinstance(module, Llama3ScaledRoPE) and not module.is_cache_built:
        module.rope_init()
        module.to(device)
```

**Why**: `from_pretrained` creates model on meta device first; `Llama3ScaledRoPE.rope_init()` skips cache building on meta tensors, then never rebuilds after weights are loaded to real device.

**Patch 2 - HeartCodec loading fix** in `src/heartlib/pipelines/music_generation.py`:

Add `ignore_mismatched_sizes=True` to ALL `HeartCodec.from_pretrained()` calls (there are 2: the eager load in `__init__` and the lazy load in the `codec` property).

**Why**: VQ codebook `initted` buffers have shape `[1]` in checkpoint vs `[]` in model. Same data, just scalar vs 0-d tensor. Safe to ignore.

### 5. Download Model Checkpoints
```bash
cd heartlib  # project root
hf download --local-dir './ckpt' 'HeartMuLa/HeartMuLaGen'
hf download --local-dir './ckpt/HeartMuLa-oss-3B' 'HeartMuLa/HeartMuLa-oss-3B-happy-new-year'
hf download --local-dir './ckpt/HeartCodec-oss' 'HeartMuLa/HeartCodec-oss-20260123'
```

All 3 can be downloaded in parallel. Total size is several GB.

## GPU / CUDA

HeartMuLa uses CUDA by default (`--mula_device cuda --codec_device cuda`). No extra setup needed if the user has an NVIDIA GPU with PyTorch CUDA support installed.

- The installed `torch==2.4.1` includes CUDA 12.1 support out of the box
- `torchtune` may report version `0.4.0+cpu` — this is just package metadata, it still uses CUDA via PyTorch
- To verify GPU is being used, look for "CUDA memory" lines in the output (e.g. "CUDA memory before unloading: 6.20 GB")
- **No GPU?** You can run on CPU with `--mula_device cpu --codec_device cpu`, but expect generation to be **extremely slow** (potentially 30-60+ minutes for a single song vs ~4 minutes on GPU). CPU mode also requires significant RAM (~12GB+ free). If the user has no NVIDIA GPU, recommend using a cloud GPU service (Google Colab free tier with T4, Lambda Labs, etc.) or the online demo at https://heartmula.github.io/ instead.

## Usage

### Basic Generation
```bash
cd heartlib
. .venv/bin/activate
python ./examples/run_music_generation.py \
  --model_path=./ckpt \
  --version="3B" \
  --lyrics="./assets/lyrics.txt" \
  --tags="./assets/tags.txt" \
  --save_path="./assets/output.mp3" \
  --lazy_load true
```

### Input Formatting

**Tags** (comma-separated, no spaces):
```
piano,happy,wedding,synthesizer,romantic
```
or
```
rock,energetic,guitar,drums,male-vocal
```

**Lyrics** (use bracketed structural tags):
```
[Intro]

[Verse]
Your lyrics here...

[Chorus]
Chorus lyrics...

[Bridge]
Bridge lyrics...

[Outro]
```

### Key Parameters
| Parameter | Default | Description |
|-----------|---------|-------------|
| `--max_audio_length_ms` | 240000 | Max length in ms (240s = 4 min) |
| `--topk` | 50 | Top-k sampling |
| `--temperature` | 1.0 | Sampling temperature |
| `--cfg_scale` | 1.5 | Classifier-free guidance scale |
| `--lazy_load` | false | Load/unload models on demand (saves VRAM) |
| `--mula_dtype` | bfloat16 | Dtype for HeartMuLa (bf16 recommended) |
| `--codec_dtype` | float32 | Dtype for HeartCodec (fp32 recommended for quality) |

### Performance
- RTF (Real-Time Factor) ≈ 1.0 — a 4-minute song takes ~4 minutes to generate
- Output: MP3, 48kHz stereo, 128kbps

## Pitfalls
1. **Do NOT use bf16 for HeartCodec** — degrades audio quality. Use fp32 (default).
2. **Tags may be ignored** — known issue (#90). Lyrics tend to dominate; experiment with tag ordering.
3. **Triton not available on macOS** — Linux/CUDA only for GPU acceleration.
4. **RTX 5080 incompatibility** reported in upstream issues.
5. The dependency pin conflicts require the manual upgrades and patches described above.

## Links
- Repo: https://github.com/HeartMuLa/heartlib
- Models: https://huggingface.co/HeartMuLa
- Paper: https://arxiv.org/abs/2601.10547
- License: Apache-2.0

## Activation Keywords

- "heartmula"
- "heartmula"
- "use heartmula"
- "heartmula help"
- "heartmula tool"

## Tools Used

- `Read` - Read existing files and documentation
- `Write` - Create new files and documentation
- `Bash` - Execute commands when needed

## Instructions for Agents

1. Identify user's intent and specific requirements
2. Gather necessary context from files or user input
3. Execute appropriate actions using available tools
4. Provide clear results and suggest next steps

## Examples

### Basic Heartmula usage
```
User: "Help me with heartmula"
→ Understand requirements → Execute actions → Provide results
```

### Advanced usage
```
User: "I need detailed heartmula assistance"
→ Clarify scope → Provide comprehensive solution → Follow up
```