video-generation

name	video-generation
description	AI video generation via Replicate — 17 models, editing, and production workflows
tier	standard
applyTo	**/*video*,**/*animate*,**/*clip*
$schema	../SKILL-SCHEMA.json

Video Generation Skill

Domain: AI Video Generation
Version: 2.0.0
Last Updated: 2026-04-15
Author: Alex (Master Alex)
Source: Patterns from AlexVideos CLI toolkit
Related: image-handling (images), text-to-speech (audio)

Overview

Generate AI videos using 17 cloud models on Replicate. Supports text-to-video, image-to-video, video editing, and talking-head workflows.

---

Model Catalog (17 Models)

Key	Model	Replicate ID	Duration	Audio	Cost
veo3fast	Veo 3.1 Fast	google/veo-3.1-fast	4/6/8s	✅ Auto	$0.10–0.15/sec
veo3	Veo 3.1	google/veo-3.1	4/6/8s	✅ Auto	$0.20–0.40/sec
grok	Grok Video	xai/grok-imagine-video	1–15s	✅ Lip-sync	$0.05/sec
gen45	Gen-4.5 Runway	runwayml/gen-4.5	5–10s	❌	$0.12/sec
kling	Kling v3	kwaivgi/kling-v3-video	3–15s	Optional	$0.17–0.22/sec
kling26	Kling v2.6	kwaivgi/kling-v2.6	5–10s	✅ Auto	variable
kling3omni	Kling v3 Omni	kwaivgi/kling-v3-omni-video	3–15s	❌	variable
sora	Sora-2	openai/sora-2	4–12s	✅ Auto	$0.10/sec
sora2pro	Sora-2 Pro	openai/sora-2-pro	4/8/12s	✅ Auto	$0.30–0.50/sec
seedance	Seedance Lite	bytedance/seedance-1-lite	2–12s	❌	$0.036/sec
seedpro	Seedance Pro	bytedance/seedance-1-pro	2–12s	❌	$0.15/sec
pixverse	PixVerse v5.6

---

Parameter Support Matrix

Model	prompt	duration	image	aspect	resolution	negative	audio
veo3fast	✅	4/6/8	✅	✅	✅	✅	✅ auto
veo3	✅	4/6/8	✅	✅	✅	✅	✅ auto
grok	✅	1–15	✅	✅	✅	—	✅ auto
gen45	✅	5–10	✅	✅	—	—	—
kling	✅	3–15	✅	✅	✅ (mode)	✅	optional
kling26	✅	5–10	✅	✅	—	✅	✅ auto
kling3omni	✅	3–15	✅	✅	✅ (mode)	—	—
sora	✅	4–12	✅	✅

Notes:

• Fixed values (e.g., 5/9) mean only those exact values accepted
• Ranges (e.g., 3–15) accept any integer in range
• Sora models use "portrait"/"landscape" internally (mapped from 9:16/16:9)

---

Model Selection Guide

Need	Model	Why
Default / Quick preview	veo3fast	Best balance: speed, quality, cost
Talking head / lip-sync	grok, kling26	Grok: best lip-sync; Kling26: best motion
High quality cinematic	sora2pro, veo3	Premium quality, synced audio
Image animation	kling, gen45	Strong image-to-video
Budget production	rayflash, seedance	Cheapest per-second
Longest duration (15s)	grok, kling	Only models supporting 15s
Real-world physics	hailuo, hailuo23	Physics simulation, VFX

---

Talking-Head Video Workflow

Proven pipeline for generating a person speaking to camera with synchronized speech:

# Step 1 — Age-progress reference photo (if needed)
node scripts/generate-image.js "A 26-year-old professional in studio" --model nanapro --image ref.png

# Step 2 — Generate video with Kling v2.6 (best talking-head i2v)
node scripts/generate-video.js "Person looking directly into camera, speaking confidently" --model kling26 --image aged.jpg --duration 10

# Step 3 — Generate speech
node scripts/generate-voice.js "[script]" --model mm28turbo

# Step 4 — Merge video + speech
node scripts/generate-edit-video.js --model avmerge --video clip.mp4 --audio speech.mp3

Model notes:

• kling26 — Best overall motion quality for talking-head i2v
• grok — Best lip sync, but no native audio (requires avmerge)
• veo3fast / sora — May flag real-person reference photos

Prompt pattern:

"A sharp [age]-year-old [description] looking directly into camera, speaking to the audience about [topic]. Calm, confident, broadcast-quality delivery. Professional studio lighting."

---

Video Editing (10 Models)

Key	Model	Purpose	Cost
modify	Luma Modify	AI video style transfer	variable
reframe	Luma Reframe	AI crop to new aspect ratio	$0.06/sec
trim	Trim Video	Extract segment by time	<$0.001
merge	Video Merge	Concatenate videos	variable
avmerge	ffmpeg-static	Combine audio + video	free (local)
extract	Extract Audio	Strip audio from video	variable
frames	Frame Extractor	Export frames as images	<$0.001
upscale	Real-ESRGAN	AI upscale to 4K	~$0.46
caption	AutoCaption	Auto subtitles	~$0.07
utils	Video Utils	Convert, misc ops	<$0.002

---

Generation Workflows

Text-to-Video

import Replicate from "replicate";

const replicate = new Replicate();

const output = await replicate.run("google/veo-3.1-fast", {
  input: {
    prompt: "A person walking through a futuristic city at sunset, cinematic lighting",
    duration: 5, // seconds
  },
});

console.log("Video URL:", output);

Image-to-Video (Animation)

import { readFileSync } from "fs";

const output = await replicate.run("kwaivgi/kling-v3-video", {
  input: {
    prompt: "Gentle wind blowing through hair, subtle movement",
    image: readFileSync("source-image.png"), // or URL
    duration: 5,
  },
});

Talking Head with Lip-Sync

const output = await replicate.run("xai/grok-imagine-video", {
  input: {
    prompt: "Person speaking to camera with natural expressions",
    audio: readFileSync("narration.mp3"), // Voice audio
    duration: 10,
  },
});

---

Quality Guidelines

Prompt Engineering

Element	Good Example	Avoid
Camera motion	"slow dolly forward", "tracking shot"	"camera moves"
Lighting	"golden hour", "dramatic side lighting"	"good lighting"
Style	"cinematic 4K", "documentary style"	"nice video"
Subject	"a person with short brown hair"	"someone"
Action	"walking slowly through", "gesturing while talking"	"doing something"

Duration Selection

Duration	Use Case	Model Recommendation
2-4s	Loop, GIF replacement	veo-3.1-fast
5-8s	Short clip, social media	veo-3.1-fast, kling-v3
10-15s	Story segment, talking head	grok-video, sora-2

Resolution

• Most models default to 720p or 1080p
• Kling v3 supports explicit 1080p
• Higher resolution = longer generation time

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Audio Handling

Models with Built-in Audio

Model	Audio Type	Notes
veo-3.1-fast	Auto-generated	Ambient sounds from scene
grok-video	Lip-sync	Syncs mouth to provided audio
sora-2	Synced	High-quality scene audio

Adding Audio Post-Generation

For models without audio, combine with TTS:

// 1. Generate video (no audio)
const video = await replicate.run("kwaivgi/kling-v3-video", {
  input: { prompt: "...", duration: 5 },
});

// 2. Generate narration via TTS
const audio = await replicate.run("minimax/speech-2.8-turbo", {
  input: { text: "Narration text", voice: "Wise_Woman" },
});

// 3. Combine with ffmpeg
// ffmpeg -i video.mp4 -i audio.mp3 -c:v copy -c:a aac output.mp4

---

Cost Estimation

Model	5s clip	10s clip	15s clip
veo-3.1-fast	~$0.15	~$0.30	N/A (8s max)
grok-video	~$0.25	~$0.50	~$0.75
minimax-video	~$0.25	~$0.50	N/A (6s max)
kling-v3	varies	varies	varies
sora-2	premium	premium	premium

---

Output Handling

Download Video

import { writeFileSync } from "fs";

const response = await fetch(output);
const buffer = await response.arrayBuffer();
writeFileSync("output.mp4", Buffer.from(buffer));

Verify Quality

# Check video properties with ffprobe
ffprobe -v quiet -print_format json -show_format -show_streams output.mp4

---

Error Handling

Error	Cause	Solution
Generation timeout	Complex prompt	Simplify, reduce duration
NSFW rejection	Content policy	Adjust prompt
Low quality output	Vague prompt	Add specific details
Audio desync	Wrong model	Use lip-sync model

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Integration with Studio Agents

• Image Studio: Generates source images for image-to-video
• Audio Studio: Creates narration for post-hoc audio
• Visual Memory: Stores reference images/videos