# HunyuanVideo-1.5 Text-to-Video Implementation - Complete ✅

## Summary

Successfully implemented HunyuanVideo-1.5 text-to-video generation with modular architecture, following separation of concerns principles.

## Implementation Details

### 1. Service Structure ✅

**File**: `backend/services/llm_providers/video_generation/wavespeed_provider.py`

- **`HunyuanVideoService`**: Complete implementation
  - Model-specific validation (duration: 5, 8, or 10 seconds, resolution: 480p or 720p)
  - Based on official API docs: https://wavespeed.ai/docs/docs-api/wavespeed-ai/hunyuan-video-1.5-text-to-video
  - Size format conversion (resolution + aspect_ratio → "width*height")
  - Cost calculation ($0.02/s for 480p, $0.04/s for 720p)
  - Full API integration (submit → poll → download)
  - Progress callback support
  - Comprehensive error handling

### 2. Unified Entry Point Integration ✅

**File**: `backend/services/llm_providers/main_video_generation.py`

- **`_generate_text_to_video_wavespeed()`**: New async function
  - Routes to appropriate service based on model
  - Handles all parameters
  - Returns standardized metadata dict

- **`ai_video_generate()`**: Updated
  - Now supports WaveSpeed text-to-video
  - Default model: `hunyuan-video-1.5`
  - Async/await properly handled

### 3. API Integration ✅

**Model**: `wavespeed-ai/hunyuan-video-1.5/text-to-video`

**Parameters Supported**:
- ✅ `prompt` (required)
- ✅ `negative_prompt` (optional)
- ✅ `size` (auto-calculated from resolution + aspect_ratio)
- ✅ `duration` (5, 8, or 10 seconds)
- ✅ `seed` (optional, default: -1)

**Workflow**:
1. ✅ Submit request to WaveSpeed API
2. ✅ Get prediction ID
3. ✅ Poll `/api/v3/predictions/{id}/result` with progress callbacks
4. ✅ Download video from `outputs[0]`
5. ✅ Return metadata dict

### 4. Features ✅

- ✅ **Pre-flight validation**: Subscription limits checked before API calls
- ✅ **Usage tracking**: Integrated with existing tracking system
- ✅ **Progress callbacks**: Real-time progress updates (10% → 20-80% → 90% → 100%)
- ✅ **Error handling**: Comprehensive error messages with prediction_id for resume
- ✅ **Cost calculation**: Accurate pricing ($0.02/s 480p, $0.04/s 720p)
- ✅ **Metadata return**: Full metadata including dimensions, cost, prediction_id

### 5. Size Format Mapping ✅

**Resolution → Size Format**:
- `480p` + `16:9` → `"832*480"` (landscape)
- `480p` + `9:16` → `"480*832"` (portrait)
- `720p` + `16:9` → `"1280*720"` (landscape)
- `720p` + `9:16` → `"720*1280"` (portrait)

### 6. Validation ✅

**HunyuanVideo-1.5 Specific**:
- Duration: Must be 5, 8, or 10 seconds (per official API docs)
- Resolution: Must be 480p or 720p (not 1080p)
- Prompt: Required and cannot be empty

## Code Structure

```
backend/services/llm_providers/
├── main_video_generation.py          # Unified entry point
│   ├── ai_video_generate()          # Main function (async)
│   └── _generate_text_to_video_wavespeed()  # WaveSpeed router
│
└── video_generation/                # Modular services
    ├── base.py                       # Base classes
    └── wavespeed_provider.py         # WaveSpeed services
        ├── BaseWaveSpeedTextToVideoService  # Base class
        ├── HunyuanVideoService      # ✅ Implemented
        └── get_wavespeed_text_to_video_service()  # Factory
```

## Usage Example

```python
from services.llm_providers.main_video_generation import ai_video_generate

result = await ai_video_generate(
    prompt="A tiny robot hiking across a kitchen table",
    operation_type="text-to-video",
    provider="wavespeed",
    model="hunyuan-video-1.5",
    duration=5,
    resolution="720p",
    user_id="user123",
    progress_callback=lambda progress, msg: print(f"{progress}%: {msg}")
)

video_bytes = result["video_bytes"]
cost = result["cost"]  # $0.20 for 5s @ 720p
```

## Testing Checklist

- [ ] Test with valid prompt
- [ ] Test with 5-second duration
- [ ] Test with 8-second duration
- [ ] Test with 10-second duration
- [ ] Test with 480p resolution
- [ ] Test with 720p resolution
- [ ] Test with negative_prompt
- [ ] Test with seed
- [ ] Test progress callbacks
- [ ] Test error handling (invalid duration)
- [ ] Test error handling (invalid resolution)
- [ ] Test cost calculation
- [ ] Test metadata return

## Next Steps

1. ✅ **HunyuanVideo-1.5**: Complete
2. ⏳ **LTX-2 Pro**: Pending documentation
3. ⏳ **LTX-2 Fast**: Pending documentation
4. ⏳ **LTX-2 Retake**: Pending documentation

## Notes

- **Audio support**: Not supported by HunyuanVideo-1.5 (ignored with warning)
- **Prompt expansion**: Not supported by HunyuanVideo-1.5 (ignored with warning)
- **Aspect ratio**: Used for size calculation (landscape vs portrait)
- **Polling interval**: 0.5 seconds (as per example code)
- **Timeout**: 10 minutes maximum

## Ready for Testing ✅

The implementation is complete and ready for testing. All features are implemented following the modular architecture with separation of concerns.
