--- description: Anima Avatar - Interactive Video Generation Engine. Generates 16:9 videos with dynamic character sprites (Shutiao), synced audio (Fish Audio), and text overlay. ---

Anima Avatar (Project Anima)

Generates high-quality interactive videos where Shutiao speaks the text with appropriate expressions, gestures, and voice.

Capabilities

• True Voice: Uses Fish Audio API for realistic speech synthesis.
• Dynamic Sprites: Auto-selects from a library of 30+ sprites (Happy, Angry, Shy, Think, Action) based on emotion tags.
• Smart Director: Handles parallel rendering, audio-sync, and video composition (FFmpeg).
• Pro Delivery: Uploads as native stream to Feishu for direct playback (with correct duration).

Structure

• src/director.js: The core engine. Generates frames (sharp + SVG), audio (Fish Audio), and video (FFmpeg).
• src/send_video_pro.js: Delivery script. Handles transcoding, duration calculation, and Feishu upload.
• src/batch_generator.js: Batch sprite generator. Uses Gemini image generation to produce sprite variants.
• assets/sprites/: The sprite library (1920x1080 PNG files).
• assets/production_plan.csv: The asset registry (25 sprites).
• assets/manifest.json: Sprite metadata for reference.
• output/: Generated videos.

IMPORTANT: Sprites Not Included

ClawHub only distributes text files. The sprite PNG images are not included in the published package.

After installing, follow the steps below in order to prepare your sprites before first use.

All image generation steps use Gemini API (Nano Banana) as the AI image generator. It works by "reference image + text prompt" — you give it an existing image and a text description of what to change, and it returns a new image with the changes applied. This is how both the base sprite (character + background fusion) and all expression variants are created.

Step 1: Prepare your character image

You need a standalone character illustration (transparent background PNG recommended).

• This is your character's "identity" — it defines the look for all sprites.
• Resolution: at least 1920x1080. Full-body is best.
• Example: a full-body anime character PNG with transparent background.

Save it somewhere accessible (e.g. avatars/my_character.png).

Step 2: Prepare your background image

You need a background scene for the character to stand in.

• This is the environment that appears behind the character in every video frame.
• Resolution: at least 1920x1080.
• Example: a cherry blossom garden, a classroom, a city street.

Save it at: assets/backgrounds/ (e.g. assets/backgrounds/cherry_blossom_bg.png).

Step 3: Fuse character + background into base sprite

This step uses Gemini (Nano Banana) image generation to merge your character onto the background. The AI sees both images and creates a natural-looking composite — this is NOT a simple overlay/paste, but an AI-generated fusion that handles lighting, shadows, and blending.

How to do it:

Method A: Use Gemini directly (recommended) Use any Gemini-compatible image generation tool (like Nano Banana, Google AI Studio, or the Gemini API) with:

• Input image: Your background image
• Reference/overlay: Your character image
• Prompt: e.g. "Place this character naturally in the center of this background scene, full body visible, gentle smile"

Save the output as: assets/sprites/shutiao_base.png

Method B: Use the built-in compose script (simple overlay) If you just want a quick mechanical overlay (no AI blending), src/compose_base.js can paste your character onto the background using sharp:

1. Edit src/compose_base.js — update BG_PATH and AVATAR_PATH to point to your files.
2. Run: node src/compose_base.js
3. Output: assets/sprites/shutiao_base.png

Note: Method B is a plain image composite. Method A (Gemini) produces much better results because it handles lighting and integration naturally.

Step 4: Plan your sprite variants

Now that you have a base sprite, plan what expression/pose variants you want.

Open assets/production_plan.csv and customize it:

ID,Emotion,Variant,Description,Filename,Prompt,Status
001,Base,v1,Standard,shutiao_base.png,gentle smile looking at viewer,Done
003,Happy,v1,Smile,shutiao_happy.png,big happy smile eyes closed,Pending
007,Angry,v1,Pout,shutiao_angry.png,angry face pouting,Pending
...

Column meanings:

• Emotion: Category used by the video director to pick sprites (Happy, Angry, Shy, Think, Sad, Action, Base).
• Filename: Output filename. Must follow shutiao__.png format.
• Prompt: Describes how this variant differs from the base. The generator sends the base image + this prompt to Gemini, asking it to change only the expression/pose while keeping everything else the same.
• Status: Pending = will be generated. Done = already exists, skip.

The default CSV has 25 entries. You can add, remove, or modify rows freely.

Step 5: Generate sprite variants

This step uses Gemini (Nano Banana) image generation again. For each Pending row, the batch generator sends your base sprite + the prompt to Gemini, asking: "Same image, change facial expression to [prompt]. Keep clothes and background exactly same."

1. Set your Gemini API key in skills/anima/.env:

GEMINI_API_KEY=your_key_here

1. Make sure assets/sprites/shutiao_base.png (or shutiao_base_1k.png) exists from Step 3.

1. Run the batch generator:

node skills/anima/src/batch_generator.js

What happens:

• Reads production_plan.csv
• Finds all rows with Status=Pending
• For each: sends the base sprite + prompt to Gemini API
• Saves the generated image as a PNG in assets/sprites/
• Updates the CSV row to Status=Done
• Waits 10 seconds between generations (API rate limit cooldown)

Step 6: Verify

Check that assets/sprites/ now has a PNG file for every row in production_plan.csv:

ls assets/sprites/*.png | wc -l

Then do a quick test run:

node skills/anima/run.js --preview --script '[{"text":"Test","emotion":"Happy"}]'

Check the generated frame at temp/frame_0.png — you should see your character with the text overlay.

If a sprite is missing at runtime, the director will fall back to a white background with a warning in the console.

Setup & Requirements

1. System Dependencies

• ffmpeg (required for video processing):

- macOS: brew install ffmpeg - Linux: sudo apt install ffmpeg - Windows: Download/Install FFmpeg and add to PATH.

2. Node Dependencies

Install inside the skill folder:

cd skills/anima
npm install

The only native dependency is sharp, which ships prebuilt binaries for all major platforms via N-API. It does not need recompilation when Node versions change — install once, run everywhere.

3. External Services (API Keys Required)

This skill depends on two external services. You need to provide your own API keys.

Fish Audio (TTS - Text to Speech)

• What: Generates realistic voice audio from text.
• Used by: src/director.js (the generateAudio() function).
• Get a key: https://fish.audio/dashboard/api
• Env vars needed:

- FISH_AUDIO_KEY — Your API key (starts with sk-... or a hex string). - FISH_AUDIO_REF_ID — The voice model reference ID. You can use Fish Audio's default models or clone your own voice.

Gemini API (Image Generation - Optional)

• What: Generates sprite variants using Google Gemini image generation.
• Used by: src/batch_generator.js (only needed if you want to create new sprite variants).
• Self-contained: No external skills needed. batch_generator.js calls the Gemini API directly via curl.
• Get a key: https://aistudio.google.com/apikey
• Env var needed: GEMINI_API_KEY
• Not needed for normal video generation — only for creating new character sprites.

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