カットごとに最適な AI 動画モデルを選ぶ方法

英語ナレーションの文字起こしです。

0:04There is no best video model. There's the best model for a given shot on a given day. Models change every few months. So in this lecture, you'll learn a method that outlives them. The criteria that matter, a quick test to compare models, and a strategy to keep your costs under control.

0:23Here are the criteria. First, consistency. Does the model respect your reference sheets, shot after shot? Second, motion. Are bodies, hands, and objects physically believable? Third, faces. Some models refuse photorealistic faces as references. Fourth, sound. Some generate dialogue and ambiance, others don't. Fifth, duration and resolution limits. And sixth, cost and speed. Rank these for your film before you look at a single demo reel.

0:56Then, test. The same way every time. Take one representative shot with the same references and the same prompt and run it on two or three models. Put the results side by side and score each one on your criteria. Write the scores down. After a few films, that notebook will be worth more than any ranking you'll find online.

1:17Here's what a test can look like for the close -up that ends the photo. Model A keeps her face, but the tears look painted. Model B gets the emotion, but changes her scoff. Model C nails both, but costs twice as much. For the one close -up that carries the whole ending, Model C wins. For a simple establishing shot, it probably wouldn't be worth it.

1:42Here's what you'll find in Screenweaver at the time of this recording. Seedance 2 .5, the default, references, start and end frames, sound, and clips from 4 to 15 seconds, longer in some modes. Veo 3 .1, up to 4K and shorter clips. Cling 3 .0, in standard and pro versions, plus a motion control variant. Minimax H3, then Grok Imagine Video, both with sound always on, and Seedance 2 .0. My recommendation for narrative scenes today is Seedance 2 .5. But run your own test. That's the whole point of this lecture.

2:20Now the money strategy. Draft first, finish later. Seedance 2 .5 has a draft mode, at 480p, for quick and cheaper previews. You generate your takes as drafts, pick the winner, and then finish that one draft to 1080p. For even higher resolution, you can upscale a finished video with topaz, up to 4K. You pay full price only for the shots that made the cut.

2:49And check the limits before you plan. Some models cap the length of a clip, some only offer their highest resolution in short clips, and some always generate sound. Read the options of the video node before you write your shot list, not after.

3:06Next decision. One clip per shot, or one clip per scene. Some models, like Seedance 2 .5, can generate several shots in a single clip, with real cuts between them. The four shots of the photo were generated that way, as one continuous clip, so the light, the rain, and the actors stay identical across the cuts. Generating shot by shot gives you more control over each one, but more chances for things to drift between them. For short, intimate scenes, one clip per scene is often the safest choice.

3:43A practical rule, if a scene has only a few shots, one location, and the same characters throughout, try one clip for the whole scene first. If it has many shots, several locations, or complex action, generate shot by shot, or in small groups of shots.

4:00And think about sound before you click generate. When a model generates audio, it can deliver the dialogue and the ambience in the same take. In the photo, Thomas' line and the rain on the glass were generated with the picture. But if you plan to design the sound yourself, switch the audio off and you'll get a clean picture to build on. Decide shot by shot, and write it down in your shot list.

4:26One last tip. Match the model to the shot, not to the film. A dialogue scene, a wide establishing shot, and a fast action beat don't have the same needs. It's perfectly fine to use one model for most of your film, and a second one for the two shots where it struggles. Just keep your references and your art direction identical across both, so the audience never feels the switch.

4:51Your exercise, list your six criteria in order of importance for your film. Pick one representative shot, test it on three models with the same references and prompt, and score the results. Then decide your default model and your draft and finish strategy. In the next lecture, we'll write the prompt itself, the way a director briefs a crew.