NAVA is a 6.3 B-parameter joint audio-video generator that synthesizes synchronized video and audio from a single prompt — including multi-speaker speech with reference-timbre control and image-conditioned continuations.
Instead of post-hoc-aligned dual towers or fully unified tri-modal stacks, NAVA uses an Align-then-Fuse MMDiT: a dedicated alignment space first establishes audio-video correspondence, then context (text, speaker embeddings) is fused via cross-attention. On Verse-Bench it sets new SOTA on Sync-C / Sync-D / video quality / audio WER while using 2× to 5× fewer parameters than open-source baselines.
Highlights
720p 1-min Fast Generation — 720p synchronized audio-video in ~1 minute via 8-GPU Ulysses sequence parallel.
Dual-Channel Audio — stereo audio (scene + speech) jointly denoised with video, no post-hoc vocoder alignment.
Precise Multi-Timbre Control — reference WAVs bound to <S>...<E> speech spans for per-speaker voice identity.
Language-Described Camera Control — shot composition, motion, and pacing directly from the prompt.
Multi-Resolution — landscape / portrait / square aspect ratios from the same checkpoint.
NAVA instantiates Native Audio-Visual Alignment as an Align-then-Fuse MMDiT stack:
Hierarchical Alignment Layers — 10 double-stream blocks. Video and audio keep separate QKV projections and FFNs but share a joint self-attention over concatenated [video_tokens; audio_tokens], plus dedicated cross-attention to text. This builds an alignment space where AV correspondence is learned without semantic context interference.
Unified Fusion Layers — 20 single-stream blocks. Video and audio share QKV/FFN; a unified joint attention treats all tokens as one stream, with a single text cross-attention path. This is where context-conditioned denoising happens.
Positional encoding. 3D RoPE for video (temporal + height + width), 1D RoPE for audio, applied jointly inside the joint-attention path.
Timbre-in-Context Conditioning. Reference-WAV speaker embeddings (ReDimNet, 192-d) are injected through the context pathway and bound to <S>...<E> speech spans, enabling per-speaker timbre control in multi-speaker scenes.
3D cross-modal CFG. Independent classifier-free guidance scales for video, audio, and the cross-modal alignment direction (video_align_guidance_scale, audio_align_guidance_scale) keep AV synchronization tight at inference.
What's Different from Existing Open-Source AV Models
Design axis
Typical baselines
NAVA
Stream layout
Dual-tower (post-hoc align) or fully unified tri-modal
Align-then-Fuse — alignment space first, context fused after
NAVA achieves the best AV synchronization (Sync-C / Sync-D), video quality, and audio WER, with the smallest parameter budget.
Model
Params
Resolution
Sync-C ↑
Sync-D ↓
IB ↑
Video Quality ↑
WER ↓
PQ ↑
FD ↓
Ovi 1.1
10 B
720p
7.4839
7.9791
0.199
0.636
0.102
5.8432
0.9418
MOVA
A18B (32 B)
720p
7.2888
7.808
0.269
0.603
0.126
7.2331
0.9222
Davinci
15 B
540p
7.1487
7.8158
0.269
0.600
0.151
5.9559
0.9307
LTX 2.3
19 B
512p
7.2476
7.6902
0.337
0.576
0.106
6.9459
0.8287
NAVA (ours)
6.3 B
720p
7.7914
7.5655
0.313
0.659
0.099
6.8609
0.8328
↑ higher is better · ↓ lower is better · bold = best · underline = 2nd best.
Table 2 — Seed-TTS-eval (speech quality)
Among joint AV models, NAVA delivers speech quality close to dedicated audio-only systems. Audio-only rows are listed for reference; they are not directly comparable.
Category
Model
WER ↓
Speaker Similarity ↑
Audio-Only (reference)
CosyVoice
4.29
60.9
Audio-Only (reference)
Qwen2.5-Omni
2.72
63.2
Audio-Video Joint
DreamID-Omni
33.44
34.1
Audio-Video Joint
NAVA (ours)
5.81
62.4
How to Use
TL;DR command. After §1 setup is complete:
bash
1bash scripts/inference.sh # General T2AV2bash scripts/inference_timbre.sh # I2AV + timbre control
Outputs land under eval_results/.
1 · Setup (once)
bash
1git clone https://github.com/ernie-research/NAVA &&cd NAVA
23# Python deps4pip install torch torchvision torchaudio
5pip install diffusers transformers accelerate safetensors einops scipy PyYAML tqdm sentencepiece
6pip install flash-attn --no-build-isolation
78# All weights in one shot — main checkpoint + Wan2.2 VAE + T5 + LTX audio VAE9huggingface-cli download <NAVA-repo-id> --local-dir .
The LTX audio-VAE Python code is vendored under nava_src/vendor/ltx_core/ (see its NOTICE.md), so no separate clone of the LTX-Video repo is needed. ReDimNet is fetched via torch.hub on first run.
2 · One-command inference (recommended, 8 GPU SP)
The repo ships two end-to-end scripts that build a JSONL inline and launch SP=8 inference:
bash
1# General T2AV (text-only)2bash scripts/inference.sh
34# I2AV + Timbre Control (first-frame image + reference voice)5bash scripts/inference_timbre.sh
Outputs land at outputs/{save_path}-{gen_turn}_av.mp4. For timbre-controlled samples, also pass --timbre_cfg --timbre_align_guidance_scale 3.0.
Mode cheatsheet
Goal
JSONL fields
Extra flags
Text → AV
prompt
—
Image → AV
prompt + image_path
(auto-detected)
Timbre-controlled speech
prompt + spk_wavs
--timbre_cfg --timbre_align_guidance_scale 3.0
9-second video
any
--frames 55
Single-GPU (slower)
any
omit --use_sp
4 · Prompt rewriting (recommended for short / English inputs)
NAVA is trained on Chinese dense captions; short or English prompts benefit substantially from rewriting before inference. Three pathways are provided, all sharing the same system prompt and sampling profile (so output style stays consistent), with <S>...<E> speech spans preserved verbatim.
Pathway
Backend
Speed
Best for
vLLM batch server (pe_src/)
Qwen3-4B-Thinking-2507 served via vLLM, async HTTP
< 2 s / prompt
Offline batches
Local transformers, single (gradio_demo/rewrite_single.py)
Same model, in-process
40–80 s / prompt
One-off CLI
Gradio "Rewrite" button
Same as above, hosted in Gradio
40–80 s / prompt
Interactive UI
bash
1# Batch path: start vLLM server, then rewrite a txt of prompts2bash pe_src/start_server.sh --gpu 0 --low-footprint
3python pe_src/rewrite.py -i prompts.txt -o prompts_rewritten.txt
5 · Gradio Web UI
Interactive demo with click-to-rewrite (Qwen3-4B), image upload, and reference-WAV upload:
NAVA can synthesize video and speech conditioned on a reference image (image_path) and reference voice (spk_wavs). Using it to depict real persons without consent — including face-likeness or voice-likeness reproduction — is prohibited by the license and may also be illegal in your jurisdiction. We recommend:
Only use consent-approved reference media.
Label generated content as synthetic.
Apply provenance / watermarking before redistribution.
Citation
bibtex
1@article{nava2026,
2 title = {NAVA: Native Audio-Visual Alignment for Joint Audio-Video Generation},
3 author = {ERNIE Team},
4 journal = {arXiv preprint},
5 year = {2026},
6}
Acknowledgements
NAVA builds on excellent upstream work: Wan2.2-TI2V-5B (video backbone & VAE), LTX 2.3 (audio VAE + built-in vocoder), umt5-xxl (text encoder), and ReDimNet (speaker embedding). We also thank the open-source AV-generation community — Ovi, MOVA, Davinci, LTX — for releasing strong baselines that made fair benchmarking possible.
License & Contact
Released under Apache-2.0. For research / commercial inquiries, contact the ERNIE team at Baidu Inc.