Open-Qwen-Music: An Auditable Framework for LLM-Based Music Composition and Diffusion Rendering
Organizations: Work done at Tencent.
Abstract
We present Open-Qwen-Music, an open reconstruction of Qwen-Music and a fully specified research system for text-to-music generation that couples LLM-based semantic composition with diffusion-based acoustic rendering. The system comprises a 25 Hz single-codebook music tokenizer, a 3B-parameter autoregressive Music LLM, and a diffusion renderer producing 48 kHz stereo audio, following the cross-module interfaces reported by Qwen-Music. The strongest systems of this design remain closed, and prominent open music-generation projects release weights and inference code without their training corpora or end-to-end training implementations. This limits independent and controlled study of how information loss and prediction errors propagate from semantic representation through autoregressive planning to acoustic rendering. To our knowledge, Open-Qwen-Music is the first fully open release of an LLM-composition-plus-diffusion-rendering text-to-music system. Beyond model weights and inference code, the release includes the training datasets and provenance manifests, complete data-processing, annotation, training, inference, and evaluation pipelines, configurations, and pretrained weights for every learned module. Artifact manifests bind the identities of these artifacts across the complete workflow. Together, these artifacts establish a reproducible implementation of the modular architecture and provide an empirical basis for component-level analysis and future evaluation. We present the system as a transparent, executable research baseline and a starting point for the community, not as evidence of quality parity with Qwen-Music. Open-Qwen-Music is an ongoing effort, and we will continue to improve its generation quality, controllability, and robustness. All release artifacts are available at https://github.com/biang15343100-source/Open-Qwen-Music.
Figures & tables
| Dataset | Audio records | Audio hours | Definition and main use |
|---|---|---|---|
| Dataset-Inventory | 1,481,301 | 63,170.407 | Broad 26-source inventory for tokenizer and Spec-VAE training. |
| Dataset-Annotated | 240,325 | 9,506.162 | Source-capped, annotated subset of Dataset-Inventory. |
| Dataset-Annotation-Filtered | 44,355 | 2,155.176 | Strict annotation-filtered subset of Dataset-Annotated: 35,484 vocal and 8,871 instrumental records. |
| MiniMax | 25,606 | 1,103.057 | Independent synthetic augmentation: 10,197 Chinese, 9,955 English, and 5,454 instrumental records. |
| Research package | 62,417 | 2,958.571 | Access-screened Dataset-Annotation-Filtered audio plus MiniMax audio; 631 additional metadata-only records are not included in the audio count. |
| Representation | Rate | Specification | Downstream role |
|---|---|---|---|
| Semantic Tokens | 25 Hz | one codebook, 32,768 | Music LLM and DiT |
| Melody Tokens | 6.25 Hz | 256; unvoiced | Melody-CoT |
| Spectral latent | 25 Hz | 128 dimensions | Spec Decoder |
| Waveform | 48 kHz | stereo | playback and evaluation |
| Phase | Objective | Main reconstruction choice |
|---|---|---|
| Pretraining | Bidirectional BestRQ | Broad pretraining with waveform masking and four-frame targets. |
| Domain adaptation | BestRQ | Fresh optimizer and sampler-matched feature statistics. |
| Causal adaptation | Causal BestRQ | Strictly causal attention; unchanged targets. |
| Semantic supervision | Multi-task prediction | 4096-unit multilingual CTC, Mel, and Chroma losses with weights . |
| Discretization | Vector quantization | 16-dimensional cosine VQ, data-dependent initialization, exact all-rank usage statistics, and no dead-code revival. |
| Setting | Music LLM |
|---|---|
| Initialization | Qwen2.5-Omni thinker |
| Learning rate / schedule | / constant |
| Parallelism | 64 H20 GPUs, DDP, BF16 |
| Context | 4,096 tokens; 30 s / 750 Semantic frames |
| Component | Objective | Main reconstruction choice |
|---|---|---|
| Spec-VAE | Reconstruction | Full VAE on 48 kHz stereo; global batch 256. |
| Spec-VAE | Decoder fine-tuning | Encoder frozen; STFT-domain adversarial training at batch 64. |
| DiT | Conditional flow matching | 24-block, width-1536 backbone; exponential-moving-average weights. |
| Refiner | Band-aware residual correction | Frozen VAE with fresh optimizers; mid-band magnitude and phase correction. |
| Signal | Result | Note |
|---|---|---|
| Lyric LCS recall | 0.889 | precision 0.879; CI |
| Vocal gender | 88.3% | CI |
| Genre | 75.2% | GTZAN subset |
| Mood | 76.9% | arousal after dead-zone mapping |
| Confidence–error correlation | Spearman | two-transcription confidence |
| Evaluation panel | Examples | PER (pp) | Mel | Chroma |
|---|---|---|---|---|
| Common music holdout | 2,372 | 2.352 | — | 0.00124 |
| Exposure panel | 256 | 2.153 | 0.0306 | 0.00159 |
| Real-recording panel | 101 | 2.879 | 0.0267 | 0.00143 |
Appendix figures & tables8 assets
Supplementary material from the paper’s appendix.
Appendix
| Source | Records | Hours |
|---|---|---|
| AI-Music Deduplicated ( AI-Music, 2026 ) | 508,557 | 25,141.23 |
| JamendoMaxCaps ( Roy et al., 2025 ) | 261,739 | 13,683.13 |
| Muse ( Jiang et al., 2026 ) | 117,067 | 7,589.09 |
| Udio Dataset ( Blanchon, 2024 ) | 134,329 | 3,914.82 |
| FMA Full ( Defferrard et al., 2017 ) | 65,282 | 3,607.52 |
| GlobalDISCO ( Solak et al., 2025 ) | 73,024 | 3,340.90 |
| Branch | Required evidence | Main numeric rules |
|---|---|---|
| Vocal | Melody-CoT eligible; at least two sections; no under-transcribed, dropped, or hallucinated lyric windows; English, Chinese, or bilingual. | Lyric confidence ; lyric coverage ; genre ; instrument ; binary vocal gender . |
| Instrumental | Non-synthetic; no usable lyrics or vocal tags; fewer than three text units. | Instrumental-gender confidence ; vocal ratio ; vocal-stem-to-mix ratio dB. |
| Stage | Function | |
|---|---|---|
| 1 | Index | Ingest source manifests or file trees, assign stable sample identities, and record source and audio metadata. |
| 2 | Source separation | Extract the vocal stem and vocal-activity evidence used by the lyric and voice-analysis branches. |
| 3 | Structure analysis | Detect musical-section boundaries and normalize predicted section labels to the shared section taxonomy. |
| 4 | Vocal-stem transcription | Produce the primary lyric transcription from the separated vocal stem. |
| 5 | Mixture transcription | Independently transcribe the original mixture for cross-checking the vocal-stem result. |
| 6 | Lyric fusion | Reconcile the two transcription streams with available source text, determine language, and produce the selected lyric sequence with quality measurements. |
| Field group | Contents | Role |
|---|---|---|
| Identity | Schema version, stable sample identifier, and source-dataset label. | Joins annotations to the corresponding corpus item while preserving the record contract. |
| Audio | Audio reference, duration in seconds, sample rate, and channel count. | Defines the media item and its technical properties. |
| Language | Resolved lyric language, when available. | Supports language-aware normalization, filtering, and corpus sampling. |
| Description | Free-form musical description produced by the tagging branch. | Provides text conditioning beyond the controlled tag vocabulary. |
| Musical tags | Genre, mood, instrument, vocal gender, and vocal timbre; low-confidence attributes are omitted. | Supplies independently controllable prompt attributes without treating missing evidence as a negative label. |
| Structured lyrics | Lyrics serialized in section order with section labels. | Provides the text and musical-form representation consumed by downstream sequence construction. |
| Phase | Objective and training unit | Updates | Batch/GPU | Global batch | Peak LR / warmup |
|---|---|---|---|---|---|
| Masked pretraining | Bidirectional BestRQ on deterministic 30-s crops | 100,000 | 2 | 128 | / 10,000 |
| Music-domain adaptation | BestRQ on deterministic 30-s crops from the annotated domain | 20,000 | 4 | 256 | / 500 |
| Causal adaptation | Causal BestRQ with unchanged acoustic targets | 20,000 | 4 | 256 | / 500 |
| Supervised-head warmup | Frozen backbone; CTC head on complete tracks up to 300 s | 2,000 | 1 | 64 | / 100 |
| Joint semantic supervision | CTC, Mel, and Chroma losses with weights | 40,000 | 1 | 64 | / 3,000 |
| Discrete codebook training | CTC/Mel/Chroma/VQ weights | 25,000 | 1 | 64 | / 2,000 |
| Stage | Initialization and data progression | Stage updates | Cumulative updates | Global batch |
|---|---|---|---|---|
| Stage 1 | Qwen2.5-Omni-3B initialization; beginning of the corpus stream | 5,000 | 5,000 | 128 |
| Stage 2 | Stage-1 model initialization; continuation of the corpus stream | 5,000 | 10,000 | 128 |
| Module or stage | Objective | Updates | GPUs | Batch/GPU | Accum. | Global batch | Precision |
|---|---|---|---|---|---|---|---|
| VAE Stage 1 | Full-model reconstruction and KL training | 90,000 | 64 | 4 | 1 | 256 | FP32 |
| VAE Stage 2 | Decoder-only adversarial refinement | 5,000 | 64 | 1 | 1 | 64 | FP32 |
| Renderer | Conditional flow matching | 29,000 | 64 | 1 | 4 | 256 | BF16 |
| Refiner | Band-aware residual correction | 1,250 | 64 | 1 | 1 | 64 | FP32 |
| Setting | Value |
|---|---|
| Music LLM sequence layout | Direct text-to-semantic |
| Sampling | temperature 0.7; top- 0.98; top- 0 |
| Semantic repetition control | penalty 0.1 over a 64-token window |
| Acoustic solver | Euler, 8 steps |
| Classifier-free guidance | 1.0 |
| Loudness condition | LUFS |
Text-to-Music Generation
Text-to-music generation turns natural-language descriptions into audio or symbolic scores, with control over style, instruments, mood, lyrics, and structure.
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