video-generator（视频生成器）

Video Generator

Generate professional short-form videos using Google VEO 3.1 (with native audio) or OpenAI Sora (high visual quality, up to 12s).

Prerequisites & Setup

API Keys

You need at least one. Both gives you maximum flexibility.

VEO (Google):

1. Go to Google AI Studio
2. Sign in with your Google account
3. Click "Create API Key"
4. Copy the generated key

export GEMINI_API_KEY=your_gemini_key_here

Sora (OpenAI):

1. Go to OpenAI Platform
2. Create a new API key
3. Copy the generated key

export OPENAI_API_KEY=your_openai_key_here

Install Dependencies

pip install google-genai requests

Available Models

When to Use Which

Video Parameters

Approximate Cost

Latency

Video generation is async - expect 11 seconds to 6 minutes depending on server load and provider. The script polls automatically and saves when ready.

Workflow Overview

1. Define the Concept - What story does the video tell in 4-12 seconds?
2. Storyboard the Shot - Camera, motion, subject, environment
3. Add Audio Direction - Dialogue, sound effects, ambient sound (VEO only)
4. Generate Video - Run via API
5. Iterate - Adjust prompt based on results

Prompt Rules

1. 150-300 characters is the sweet spot. Under 100 = generic. Over 400 = the model drops elements unpredictably.
2. One shot = one action. Don't pack multiple scene changes or style shifts into one prompt. One camera move + one subject action.
3. Describe what you want, not what you don't want. Use the --negative flag for exclusions (VEO only), not the main prompt.
4. Treat audio as a separate layer. Write audio cues in their own sentences, not mixed into visual descriptions. (VEO only - Sora has no audio.)
5. Use colon syntax for dialogue. A man says: "Hello!" prevents subtitle artifacts. (VEO only.)
6. Keep dialogue under 7 words per line. Longer speech causes lip-sync drift. (VEO only.)
7. Start simple, then layer. Begin with a basic prompt, evaluate, then add one variable at a time.
8. Slow camera movements win. Fast pans and spins break output. Use tight framing for perceived speed.

Storyboarding the Shot

Structure your prompt with cinematic language. Both VEO and Sora respond well to film terminology:

Camera Language

Motion Description

Be explicit about what moves and how:

Lighting & Atmosphere

Audio Direction (VEO Only)

VEO 3.1 generates synchronized audio natively. This is a major differentiator.

Three Types of Audio Cues

1. Dialogue - Use colon syntax before quotes:

A barista says: "Here you go!" as she slides a latte across the counter.

Keep lines under 7 words for clean lip-sync. One sentence max per 8-second clip.

2. Sound Effects - Describe specific sounds:

The sound of a match striking, then a candle flame flickering to life.

3. Ambient Sound - Set the sonic environment:

Birds chirping in the background, distant traffic hum, morning atmosphere.

Prompt Structure (5-Element Priority)

Structure prompts in this order - you don't need all five every time:

1. Shot Specification - camera work, framing, movement
2. Setting & Atmosphere - location, time, weather, lighting
3. Subject & Action - who/what, described in beats
4. Audio Layer - dialogue, SFX, ambient (VEO only)
5. Style/Grade - artistic treatment, lens, color

[Shot type + camera movement]. [Setting and lighting]. [Subject doing action].
[Audio: what you hear]. [Style/grade].

Example Prompts

Podcast promo (VEO, 16:9):

A close-up tracking shot of a vintage microphone in a warmly lit podcast studio.
Steam rises slowly from a coffee mug beside it. Morning sunlight filters through
blinds, casting soft stripes across the desk. The sound of a quiet room - a clock
ticking, the faint hum of equipment. Cinematic, intimate, inviting.

Social teaser - vertical (Sora, 9:16):

A hand reaches into frame and opens a leather-bound journal on a wooden desk.
The pages flutter briefly before settling on a page covered in handwritten notes.
A pen is set down beside the book. Warm overhead lighting, shallow depth of field.
Shot on 16mm film, natural grain.

Product reveal (either provider, 16:9):

Camera slowly orbits a pair of wireless headphones placed on a dark marble surface.
Dramatic studio lighting with a single warm key light from the left. The headphones
cast a sharp shadow. Premium, minimal, modern.

Running the Script

# VEO: Basic generation (8s, 720p, 16:9)
python scripts/generate_video.py "Your prompt here"

# VEO: Fast draft for iteration
python scripts/generate_video.py "Your prompt here" --model fast

# VEO: High quality vertical video for social
python scripts/generate_video.py "Your prompt" --aspect 9:16 --resolution 1080p

# VEO: Multiple variations to choose from
python scripts/generate_video.py "Your prompt" --count 2 --output ./videos

# VEO: Short clip with specific settings
python scripts/generate_video.py "Your prompt" --duration 4 --resolution 4k --name "hero-clip"

# VEO: Exclude unwanted elements
python scripts/generate_video.py "Your prompt" --negative "text overlays, watermarks, blurry"

# Sora: Basic generation
python scripts/generate_video.py "A cat on a windowsill, warm light" --provider sora

# Sora: 12-second clip (longer than VEO allows)
python scripts/generate_video.py "A dog running through a meadow" --provider sora --duration 12

# Sora: Pro model, vertical
python scripts/generate_video.py "Latte art being poured" --provider sora --model sora-2-pro --aspect 9:16

# Sora: Multiple variations
python scripts/generate_video.py "Ocean waves at sunset" --provider sora --count 2 --output ./videos

Options:

Output: MP4 files with timestamp-based filenames.

Iteration Strategy

1. Start with --model fast (VEO) or --duration 4 (Sora) for quick drafts
2. Refine the prompt through 2-3 fast iterations
3. Switch to full quality/duration for the final take
4. Generate 2 variations of the final prompt and pick the best

After reviewing generated video:

• Motion wrong? Be more explicit about direction, speed, and sequence
• Audio off? (VEO) Add or refine audio cues
• Too much happening? Simplify. One clear action per clip works best
• Style drift? Add a negative prompt (VEO) or adjust style descriptors
• Wrong mood? Adjust lighting and atmosphere descriptors

Negative Prompt Guide (VEO Only)

Use --negative to steer away from common problems:

Prompting Principles

Think in Shots, Not Scenes

8 seconds is one shot. Don't try to cram a narrative arc - describe a single continuous moment.

Be Specific About Motion

Vague motion descriptions produce vague results. Describe *what moves*, *how fast*, and *in which direction*.

Layer Your Audio (VEO)

Don't just describe one sound - create a soundscape:

The crackling of a vinyl record playing soft jazz,
a distant car horn outside the window,
the quiet clink of an ice cube in a glass.

Use Negative Prompts Proactively (VEO)

Always include --negative "text, watermarks" at minimum. The model occasionally generates unwanted text overlays.

Use Cases

Social Media (9:16, 4-8s)

Short, punchy, loop-friendly. Favor close-ups and strong motion.

# VEO with audio
python scripts/generate_video.py "Close-up of coffee being poured into a ceramic mug, steam rising, warm morning light. The sound of liquid pouring and a soft sigh." \
  --aspect 9:16 --duration 4 --resolution 1080p

# Sora for visual quality
python scripts/generate_video.py "Close-up of coffee being poured into a ceramic mug, steam rising, warm morning light. Photorealistic, shallow depth of field." \
  --provider sora --aspect 9:16 --duration 4

Podcast/Newsletter Headers (16:9, 8s)

Ambient, atmospheric. Favor wide shots and subtle motion.

python scripts/generate_video.py "A vintage radio on a wooden shelf, dial slowly turning. Warm tungsten light. Soft static transitioning into faint music." \
  --resolution 1080p --name "podcast-header"

Product/Brand (16:9, 6-8s)

Clean, controlled, premium feel. Studio lighting, slow orbits.

python scripts/generate_video.py "Camera slowly orbits a leather notebook on a dark wood desk. Single warm key light. The sound of pages turning gently." \
  --resolution 4k --duration 6 --negative "text, watermarks, busy background"

Extended Clips (Sora, 12s)

For content that needs more breathing room.

python scripts/generate_video.py "A woman walks through an autumn forest path, leaves falling around her. Golden hour light filters through the canopy. Cinematic, contemplative." \
  --provider sora --duration 12 --name "autumn-walk"

Multi-Clip Consistency

When generating multiple clips for a project:

Lock Your Constants

Create a consistency block and repeat it verbatim across all prompts:

CHARACTER: A woman in her thirties with short silver hair and a black turtleneck
PALETTE: amber, cream, walnut brown, deep olive
LIGHTING: Soft key light from camera right, warm tungsten
STYLE: Cinematic, shallow depth of field, warm film grain
NEGATIVE: no subtitles, no on-screen text, no watermarks

Consistency Checklist

• Same character description, word for word
• Same palette anchors (3-5 named colors)
• Same lighting direction and quality
• Same aspect ratio and resolution
• Same style/grade language
• Same provider for all clips in a sequence