Even as they headline tech conferences, AI video tools struggle with continuity and sound, a key limitation separating demos from production-ready output. Keeping characters, lighting, and audio consistent across frames taxes even today’s advanced models, but a new wave of platforms is starting to close the gap.
The continuity puzzle
AI video tools struggle with continuity because most models generate each frame or short clip independently, lacking a persistent ‘memory’ of object positions, lighting, or character appearance. This leads to cascading probabilistic errors over time, causing props to vanish, costumes to change, or camera angles to drift unexpectedly.
While generators can create polished short clips, longer sequences often suffer from continuity errors. This occurs because prompts rarely specify every detail, and without persistent memory, small rendering variations compound over time. To combat this, newer engines use advanced techniques. Runway Gen-3 employs cross-frame attention to stabilize scenes, while OpenAI’s Sora uses physics-aware transformers to ensure objects behave realistically. These upgraded diffusion models are key to solving the puzzle.
Sound still lags visuals
Audio generation has historically lagged behind visual advancements in AI video. Early tools provided only generic soundtracks, forcing extensive post-production work. However, newer platforms are integrating audio more effectively. For example, Veo 3 now generates synchronized ambient sound and dialogue within its pipeline, reducing the need for external edits on shorter clips. Similarly, Synthesia offers precise lip-syncing in over 40 languages for corporate use. Despite this progress, most professional studios still refine AI-generated audio using dedicated software to ensure broadcast-quality results.
Emerging long-form workflows
Previously, short clip lengths hindered long-form storytelling. Now, tools like Sora 2 can generate 60-second 4K segments, and Runway Gen-4 enables timeline stitching of shorter shots. This has led to powerful hybrid workflows where creators can:
– Draft cohesive narratives in Sora.
– Inject high-impact, stylized shots from Runway.
– Test different visual styles using integrated platforms like Freepik.
Because these tools are connected via APIs, producers can seamlessly move assets into editing software like Premiere for final color grading without cumbersome transcoding.
Cost and adoption in 2025
As competition intensifies, the cost of AI video generation is decreasing. Sora 2 offers a free tier for 720p drafts, while premium 4K generation from Veo costs around $0.15 per second. This accessibility is driving rapid market growth, with analysts projecting the sector to expand from $0.53 billion in 2024 to $2.5 billion by 2032. Growth is primarily fueled by short-form advertising and multilingual content. While agencies widely use AI for ideation and B-roll, flagship campaigns are typically reserved for human cinematographers to ensure brand consistency and quality.
What creators watch next
The next frontier for AI video generation centers on three key milestones: extended scene memory beyond five minutes, automated emotional analysis for performance, and fine-grained control over digital avatars. Achieving these breakthroughs will significantly blur the line between AI-generated prototypes and final, publishable content, making today’s continuity challenges a distant memory.
Why does Flow’s scene builder work well, yet longer stories still feel disjointed?
Flow can craft a single 8-second clip that looks polished, but the moment you string clips together, characters jump position, lighting shifts and props vanish. The underlying diffusion process recreates every frame from scratch, so the model has no memory of what the previous clip contained. Creators routinely spend extra hours in traditional editors patching these gaps, an unexpected step that doubles production time for anything longer than a social-media teaser.
Is generated sound really “completely useless” in 2025?
Inside Flow, yes – the platform still outputs generic beeps or muddy ambience that rarely matches on-screen action. Across the wider 2025 market, however, Veo 3 and Synthesia now ship native stereo tracks, automated lip-sync and multilingual voice-overs that sync within milliseconds. The catch: most of those features sit behind enterprise paywalls, so low-budget creators who rely on Flow must export visuals, then marry them to separately generated audio in tools like Descript or Adobe Premiere.
How long can today’s AI tools actually run before hitting a wall?
Flow caps usable output at roughly eight seconds. Looking at the current field, Sora 2 stretches to 60 seconds, Google Veo 3 offers 30 seconds, and only paid tiers unlock 4K resolution. Even the most advanced models still force creators to storyboard in chunks, render each segment, then stitch results in post – a multistep workflow that mirrors traditional filmmaking more than the one-click promise marketing suggests.
Do professionals really juggle five or six apps just to finish one video?
Yes, and data from 2025 support the anecdote. A FastCompany survey found that 78% of agencies combine at least four AI tools on a typical spot: one for initial visuals, another for style transfer, a third for audio, plus conventional editing and color software. The upside is speed for first cuts; the downside is asset-version chaos, with teams tracking dozens of watermarked previews before they reach final approval.
Will these continuity and sound issues still matter in late 2025?
They already dictate where AI video gets deployed. Short-form ads and social loops – segments under 15 seconds – account for 63% of commercially released AI footage because flaws are less noticeable. Studios reserve full-length promos, narrative shorts and brand stories for hybrid pipelines where AI speeds pre-visualization yet humans finish continuity, color and mix. Until memory-aware architectures become standard, “generate-edit-polish” remains the norm, and creators budget extra time for hand-off steps rather than expecting a single platform to deliver broadcast-ready scenes.
