Skill metadata
Reference: full SKILL.md
The following is the complete skill definition that Mibyan loads when this skill is triggered. This is what the agent sees as instructions when the skill is active.
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, with multilingual support. Generates full songs from lyrics + 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:1to split across GPUs - 3B model with lazy_load peaks at ~6.2GB VRAM
Installation Steps
1. Clone Repository
2. Create Virtual Environment (Python 3.10 required)
3. Fix Dependency Compatibility Issues
IMPORTANT: As of Feb 2026, the pinned dependencies have conflicts with newer packages. Apply these fixes:4. Patch Source Code (Required for transformers 5.x)
Patch 1 - RoPE cache fix insrc/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:
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
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==2.4.1includes CUDA 12.1 support out of the box torchtunemay report version0.4.0+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
Input Formatting
Tags (comma-separated, no spaces):Key Parameters
Performance
- RTF (Real-Time Factor) ≈ 1.0 — a 4-minute song takes ~4 minutes to generate
- Output: MP3, 48kHz stereo, 128kbps
Pitfalls
- Do NOT use bf16 for HeartCodec — degrades audio quality. Use fp32 (default).
- Tags may be ignored — known issue (#90). Lyrics tend to dominate; experiment with tag ordering.
- Triton not available on macOS — Linux/CUDA only for GPU acceleration.
- RTX 5080 incompatibility reported in upstream issues.
- 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

