Technical Report

OmniScript

Towards Audio-Visual Script Generation for Long-Form Cinematic Video

Junfu Pu* Yuxin Chen* Teng Wang* Ying Shan

ARC Lab, Tencent  ·  *Equal Contribution

Abstract

TL;DR — An 8B omni-modal model that converts long cinematic videos into structured, temporally-grounded scripts.

Current multimodal large language models (MLLMs) have demonstrated remarkable capabilities in short-form video understanding, yet translating long-form cinematic videos into detailed, temporally grounded scripts remains a significant challenge. This paper introduces the novel Video-to-Script (V2S) task, aiming to generate hierarchical, scene-by-scene scripts encompassing character actions, dialogues, expressions, and audio cues. To facilitate this, we construct a first-of-its-kind human-annotated benchmark and propose a temporally-aware hierarchical evaluation framework. Furthermore, we present OmniScript, an 8B-parameter omni-modal (audio-visual) language model tailored for long-form narrative comprehension. OmniScript is trained via a progressive pipeline that leverages chain-of-thought supervised fine-tuning for plot and character reasoning, followed by reinforcement learning using temporally segmented rewards.

Extensive experiments demonstrate that despite its parameter efficiency, OmniScript significantly outperforms larger open-source models and achieves performance comparable to state-of-the-art proprietary models, including Gemini 3-Pro, in both temporal localization and multi-field semantic accuracy.

Video Script Transcription Video Understanding Multimodal LLM Audio-Visual Long-Form Video Reinforcement Learning
8B
Parameters
45K
Training Videos
16.8K
Benchmark Events
19.9h
Benchmark Duration

The Video-to-Script Task

Generating hierarchical, temporally-grounded scripts from long-form cinematic videos.

Fig 1: Overview of the Video-to-Script (V2S) framework

Figure 1: Overview of our Video-to-Script (V2S) framework. Given a long-form cinematic video, the pipeline performs temporally grounded scene-event parsing and generates a structured script with multimodal fields (dialogue, action, expression, and audio cues).

Given an untrimmed cinematic video containing complex narrative transitions, recurring characters, and multimodal cues, the model produces a structured output organized into three hierarchical levels:

Meta-Level

Global attributes including title, total duration, and a comprehensive character list for the entire video.

Scene-Level

A sequence of scenes, each with location, environment description, time attribute (day/night), and mood.

Event-Level

Ordered events within each scene, with timestamps, character identity, dialogue, action, expression, and audio cues.

Key Challenges Addressed

  • Data scarcity: Annotating long-form videos with fine-grained, multi-scene structure is exceptionally labor-intensive.
  • Evaluation difficulty: Traditional metrics (BLEU, ROUGE) fail to capture hierarchical dependencies and open-vocabulary descriptions.
  • Task definition: We formalize Video-to-Script (V2S) — converting cinematic videos into structured, temporally-grounded scripts with hierarchical scene-event decomposition covering characters, dialogues, actions, expressions, and audio cues.

Architecture

OmniScript: an omni-modal (audio + visual + language) model built on Qwen3-VL with AV-DeepStack injection.

Fig 3: OmniScript Architecture Overview

Figure 3: Overview of the proposed architecture. Instruction, video, and audio are encoded into multimodal tokens and fused in the LLM via AV-DeepStack across multiple layers. The model first performs multimodal plot and character-relationship reasoning and then generates structured script outputs.

Multimodal Temporal Alignment

Strict timestamp-level alignment between visual frames and Whisper-encoded audio features, preserving cross-modal synchrony for dialogues, narration, environmental sounds, and BGM.

AV-DeepStack Injection

Audio tokens are paired with visual tokens and jointly injected across stacked transformer layers via residual multimodal adapters, enabling repeated cross-modal interaction during deep semantic inference.

Reasoning-Guided Decoding

Chain-of-Thought paradigm: the model first generates a plot summary and character-relationship state, then uses this as a scaffold for coarse-to-fine structured script generation.

Progressive Training Pipeline

A four-stage training recipe followed by reinforcement learning refinement.

1

Modality Alignment

Train audio projector on 1M bilingual ASR samples. Freeze ViT, Whisper, LLM. Random frame masking.

2

Multimodal Pretraining

Full fine-tuning on 2.4M videos. Multi-task: ASR, captioning, summarization, temporal grounding.

3

CoT SFT

45K curated videos. Chain-of-Thought traces with plot reasoning and character relationship mapping.

4

RL (GRPO)

Temporally segmented rewards. Event-level one-to-one matching for fine-grained error penalization.

Fig 2: Memory-Augmented Annotation Pipeline

Figure 2: Overview of the memory-augmented progressive annotation pipeline. The character profile manager injects historical profiles to guide plot reasoning and dynamically updates character memory. The generated plot description and raw audio-visuals are then fed into a Gemini-based annotator to produce a fine-grained video script.

Memory-Augmented Annotation

A Character Profile Manager (CPM) maintains cross-segment character memory, enabling consistent identity resolution and coherent plot descriptions across long videos. Uses lazy naming strategy for entity resolution.

Thinking Data Construction

CoT trajectories driven by plot and character dynamics. A strong LLM retroactively distills intermediate thinking from generated scripts, creating structured Video → Thinking → Script training data.

V2S Benchmark

A meticulously curated benchmark with hierarchical evaluation metrics.

10
Movies
1.4K
Distinct Scenes
14.1
Events / Minute
445
Test Clips

Hierarchical Evaluation Framework

  • Text-Content-Guided Event Alignment: Dynamic programming for optimal, order-preserving assignment under temporal proximity and non-overlap constraints.
  • LLM-Assisted Character Resolution: Optimal bipartite mapping to disambiguate open-vocabulary character identities with strict semantic constraints.
  • Multi-dimensional Field Evaluation: Semantic similarity for actions/mood, Levenshtein distance for dialogues, exact matching for characters.
  • Temporal Boundary Evaluation: tIoU hit rate at multiple strictness thresholds (0.1, 0.3, 0.5, 0.7, 0.9).

Experimental Results

OmniScript (8B) outperforms much larger open-source models and rivals proprietary systems.

Event-Level Comparison on 5-Minute Videos

Model Params Omni Char. Dia. Act. Exp. Aud. Overall tIoU@0.1
Proprietary Models
Gemini-3-flash 28.850.328.225.511.228.844.3
Gemini-3-pro 39.868.837.435.413.338.964.4
Gemini-2.5-flash 40.175.542.836.522.843.674.3
Gemini-2.5-pro 41.775.041.939.017.042.973.4
Seed-1.8 × 40.954.435.129.612.434.550.7
Seed-2.0-pro × 47.468.142.935.710.340.967.1
Open-Source Models
Qwen3VL 8B × 30.449.626.925.36.627.747.6
Qwen3-Omni 30/3B 4.93.45.57.34.45.112.8
Qwen3VL 32B × 37.157.131.328.77.232.352.5
Qwen3VL 235/22B × 38.158.633.029.16.033.062.0
Ours
OmniScript 8B 39.272.233.731.911.637.769.3

Scene-Level Comparison on 5-Minute Videos

Model Params Omni Loc. Type Env. Time Mood Overall tIoU@0.1
Proprietary Models
Gemini-3-flash 54.659.842.754.950.452.570.3
Gemini-3-pro 58.863.146.961.654.857.075.3
Seed-2.0-pro × 57.762.249.262.754.357.275.5
Open-Source Models
Qwen3VL 8B × 41.349.731.839.841.740.960.6
Qwen3VL 32B × 50.458.742.755.447.951.071.1
Qwen3VL 235/22B × 52.660.245.457.950.953.472.8
Ours
OmniScript 8B 54.058.441.958.149.552.474.6

Ablation Study: Training Strategy

Model CoT Reward Char. Dia. Act. Exp. Aud. Overall tIoU@0.1
SFT × 35.668.230.531.211.135.366.6
SFT 37.871.033.531.211.537.068.9
SFT+RL Global 39.269.032.431.812.337.068.7
SFT+RL Segmented 39.272.233.731.911.637.769.3

Ablation Study: Subtitle Removal

Vision-only models rely heavily on burned-in subtitles for dialogue recognition. Removing subtitles reveals whether a model truly understands speech.

Model Subtitle Char. Dia. Act. Exp. Aud. Overall tIoU@0.1
Qwen3VL-235B 38.158.633.029.16.033.062.0
Qwen3VL-235B × 26.27.729.823.56.018.645.1
Gemini-3-Pro 39.868.837.435.413.338.964.4
Gemini-3-Pro × 40.460.934.733.613.236.660.3
OmniScript (Ours) 39.272.233.731.911.637.769.3
OmniScript (Ours) × 34.163.831.830.611.734.467.0

Key Findings

  • Parameter efficiency: With only 8B parameters, OmniScript outperforms all open-source models (up to 235B) and rivals proprietary systems like Gemini-2.5-Pro.
  • Superior dialogue understanding: Achieves 72.2 Dialogue score, surpassing Gemini-3-Pro (68.8) and Seed-2.0-Pro (68.1) through genuine audio comprehension rather than subtitle reliance.
  • Strong temporal localization: 69.3 tIoU@0.1, outperforming Gemini-3-Pro (64.4) and approaching Gemini-2.5-flash (74.3) at a fraction of the model size.
  • Audio modality is essential: Without subtitles, vision-only Qwen3VL-235B collapses from 58.6 to 7.7 Dialogue F1, while OmniScript retains 63.8 — still surpassing Gemini-3-Pro without subtitles (60.9), proving genuine speech understanding rather than subtitle reading.

OmniScript for Long Video

Extending OmniScript from short clips to full-length cinematic videos (10–45 minutes).

To scale OmniScript from short clips to long videos, we investigate two complementary strategies that trade off between end-to-end global reasoning and modular controllability.

Two strategies for extending OmniScript to long videos

Comparison of two strategies for extending OmniScript to long videos. Left (Strategy 1): Direct long-context extension via pseudo long-video composition. Right (Strategy 2): Two-stage pipeline with plot segmentation followed by clip-level script generation and merging.

Strategy 1: Long Context Extension (LCE)

Directly scales the input context window and trains with long-video supervision. Uses cross-video composition to create pseudo long videos by concatenating thematically coherent short clips. Includes memory-refine labels for correcting historical inconsistencies. Single-stage pipeline with stronger long-range reasoning requirements.

Strategy 2: Two-Stage Generation (TSG)

Decomposes long-video generation into planning and writing. Stage 1: a plot-segmentation model predicts segment timestamps, plots, characters, and relations. Stage 2: each segment is processed independently by OmniScript, conditioned on structural prompts. A lightweight post-processing module merges segment scripts with temporal consistency enforcement.

Multi-dimensional Performance Across Video Durations

Radar charts comparing performance across 10-40 min videos

Performance comparison across video durations (10, 20, 30, 40 min) on multiple metric dimensions including event-level (action, dialogue, character, expression, audio cue, tIoU) and scene-level (location, environment, mood, time, type, tIoU) metrics.

F1 Scores Across Long-Video Durations (10–45 min)

F1 scores across long video durations

(a) Event-level, scene-level, and overall F1 scores across durations from 10 to 45 minutes. (b) Event-level fine-grained F1 scores on character, action, and dialogue. OmniScript-TSG (red) exhibits the strongest long-horizon robustness.

Key Observations

  • Complementary strategies: Both approaches are competitive on shorter inputs (10–20 min), but their behavior diverges as duration increases.
  • LCE strengths: Benefits from end-to-end global context, achieving strong performance at 10–20 minutes, but becomes less stable on 30–40 min videos due to accumulated long-range dependency errors.
  • TSG robustness: Segment-level conditioning provides clearer local constraints, preventing error propagation and maintaining comparatively stable performance across all durations up to 45 minutes.
  • Dialogue resilience: OmniScript-TSG maintains ~65% Dialogue F1 even at 45 minutes, while all Gemini baselines degrade below 30%.
  • Scene-level stability: OmniScript-TSG achieves a near-constant ~50% Scene Avg F1 from 10 to 45 minutes, demonstrating robust scene understanding.

Visualization Examples

Explore OmniScript's structured script generation results on real cinematic videos.

Citation

If you find our work useful, please consider citing our paper.

@inproceedings{omniscript2026,
  title     = {OmniScript: Towards Audio-Visual Script Generation
               for Long-Form Cinematic Video},
  author    = {Pu, Junfu and Chen, Yuxin and Wang, Teng and Shan, Ying},
  journal   = {arXiv preprint},
  year      = {2026}
}