Multimodal Large Language Model-Enabled Video Translation: A Role-Oriented Survey
Organizations: School of Computer Science and Technology, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, Guangdong, China.
Abstract
Recent progress in multimodal large language models (MLLMs) is reshaping video translation from a cascaded pipeline of automatic speech recognition, machine translation, text-to-speech, and lip synchronization into a unified multimodal reasoning and generation problem. High-quality video translation requires not only semantic fidelity, but also temporal alignment, speaker consistency, and emotional expressiveness across visual, acoustic, and linguistic streams. This survey provides a focused review of MLLM-enabled video translation through a role-oriented taxonomy. We organize MLLM-enabled and MLLM-relevant studies into three functional roles: Semantic Reasoner, which grounds translation in video understanding, temporal reasoning, and multimodal fusion; Expressive Performer, which supports controllable and context-aware speech generation; and Visual Synthesizer, which enables lip synchronization and visually coherent speaker rendering. We further summarize representative datasets, benchmarks, and metrics for each role, and discuss how current evaluation protocols fall short of end-to-end video translation requirements. Finally, we identify open challenges in long-form video understanding, temporal modeling, multimodal alignment, multilingual robustness, and responsible deployment, outlining future directions for natural and trustworthy cross-lingual video communication.
Figures & tables
| Survey | Year | Main Scope | SR | EP | VS | Missing Link |
| Shen et al. [ 19 ] | 2024 | Multimodal MT | – | – | Multimodal translation without speech or visual synthesis | |
| Das et al. [ 20 ] | 2025 | Video-guided MT | – | – | Video-guided text translation only | |
| Yin et al. [ 21 ] | 2024 | General MLLMs | Broad MLLM scope; not video-translation-specific | |||
| Tang et al. [ 22 ] | 2025 | Video Understanding | – | – | Video comprehension without cross-lingual generation | |
| Wu et al. [ 23 ] | 2025 | Temporal Grounding | – | – | Temporal localization without translation/generation | |
| Gupta et al. [ 24 ] | 2024 | Speech-to-speech Translation | – | Speech translation with limited visual synchronization |
| Model | MSVD-QA [ 147 ] | MSRVTT-QA [ 147 ] | ActivityNet-QA [ 148 ] | Avg. |
| Audio-visual and omni-modal MLLMs | ||||
| FAVOR [ 149 ] | 67.8 | 59.3 | – | 63.5 |
| Dolphin [ 150 ] | 72.7 | 62.6 | 49.1 | 61.5 |
| Video-SALMONN [ 151 ] | 67.9 | 59.5 | – | 63.7 |
| AV-LLM [ 152 ] | 67.3 | 53.7 | 47.2 | 56.1 |
| OneLLM [ 40 ] | 56.5 | 53.8 | – | 55.1 |
| Method | Category | Zero-shot | Main Control | Key Architecture |
| Speech-token Language Models | ||||
| CosyVoice [ 89 ] | Speech-token LM | Speaker, multilingual style | Semantic tokenizer + text-to-token LLM + flow matching decoder | |
| CosyVoice 2 [ 15 ] | Speech-token LM | Streaming, speaker style | FSQ tokenizer + streamlined LLM + chunk-aware flow matching | |
| Spark-TTS [ 90 ] | Speech-token LM | Speaker, acoustic attributes | Qwen-based LLM + BiCodec tokenizers | |
| VALL-E R [ 88 ] | Speech-token LM | Speaker prompt | Neural codec LM + monotonic alignment | |
| HALL-E [ 92 ] | Speech-token LM | Long-form speech | Hierarchical neural codec LM | |
| Dataset | Language | Scale | Primary Use |
| LibriLight [ 161 ] | English | 60k h | Speech Pretraining |
| LibriTTS [ 162 ] | English | 585 h | Speaker Synthesis |
| LibriSpeech [ 163 ] | English | 1k h | ASR and Intelligibility |
| MLS [ 164 ] | Multilingual | Large-scale | Multilingual Speech |
| Emilia [ 165 ] | Multilingual | Large-scale | Zero-shot TTS |