# LTX-2 Pro Text-to-Video Implementation - Complete ✅

## Summary

Successfully implemented Lightricks LTX-2 Pro text-to-video generation following the same modular architecture pattern as HunyuanVideo-1.5.

## Implementation Details

### 1. Service Structure ✅

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

- **`LTX2ProService`**: Complete implementation
  - Model-specific validation (duration: 6, 8, or 10 seconds)
  - Fixed 1080p resolution (no resolution parameter needed)
  - `generate_audio` parameter support (boolean, default: True)
  - Cost calculation (placeholder - update with actual pricing)
  - Full API integration (submit → poll → download)
  - Progress callback support
  - Comprehensive error handling

### 2. Key Differences from HunyuanVideo-1.5

| Feature | HunyuanVideo-1.5 | LTX-2 Pro |
|---------|------------------|-----------|
| **Duration** | 5, 8, 10 seconds | 6, 8, 10 seconds |
| **Resolution** | 480p, 720p (selectable) | 1080p (fixed) |
| **Audio** | Not supported | `generate_audio` parameter (boolean) |
| **Negative Prompt** | Supported | Not supported |
| **Seed** | Supported | Not supported |
| **Size Format** | width*height (selectable) | Fixed 1080p |

### 3. API Integration ✅

**Model**: `lightricks/ltx-2-pro/text-to-video`

**Parameters Supported**:
- ✅ `prompt` (required)
- ✅ `duration` (6, 8, or 10 seconds)
- ✅ `generate_audio` (boolean, default: True)
- ❌ `negative_prompt` (not supported - ignored with warning)
- ❌ `seed` (not supported - ignored with warning)
- ❌ `audio_base64` (not supported - ignored with warning)
- ❌ `enable_prompt_expansion` (not supported - ignored with warning)
- ❌ `resolution` (ignored - fixed at 1080p)

**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**: Placeholder pricing (update with actual pricing)
- ✅ **Metadata return**: Full metadata including dimensions (1920x1080), cost, prediction_id
- ✅ **Audio generation**: Optional synchronized audio via `generate_audio` parameter

### 5. Validation ✅

**LTX-2 Pro Specific**:
- Duration: Must be 6, 8, or 10 seconds
- Resolution: Fixed at 1080p (parameter ignored)
- Prompt: Required and cannot be empty
- Generate Audio: Boolean (default: True)

### 6. Factory Function ✅

**Updated**: `get_wavespeed_text_to_video_service()`

**Model Mappings**:
- `"ltx-2-pro"` → `LTX2ProService`
- `"lightricks/ltx-2-pro"` → `LTX2ProService`
- `"lightricks/ltx-2-pro/text-to-video"` → `LTX2ProService`

## Usage Example

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

result = await ai_video_generate(
    prompt="A cinematic scene with synchronized audio",
    operation_type="text-to-video",
    provider="wavespeed",
    model="ltx-2-pro",
    duration=6,
    generate_audio=True,  # LTX-2 Pro specific parameter
    user_id="user123",
    progress_callback=lambda progress, msg: print(f"{progress}%: {msg}")
)

video_bytes = result["video_bytes"]
cost = result["cost"]
resolution = result["resolution"]  # Always "1080p"
```

## Testing Checklist

- [ ] Test with valid prompt
- [ ] Test with 6-second duration
- [ ] Test with 8-second duration
- [ ] Test with 10-second duration
- [ ] Test with `generate_audio=True`
- [ ] Test with `generate_audio=False`
- [ ] Test progress callbacks
- [ ] Test error handling (invalid duration)
- [ ] Test cost calculation
- [ ] Test metadata return
- [ ] Test that unsupported parameters are ignored with warnings

## Next Steps

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

## Notes

- **Fixed Resolution**: LTX-2 Pro always generates 1080p videos (1920x1080)
- **Audio Generation**: Unique feature - can generate synchronized audio with video
- **Pricing**: Placeholder cost calculation - update with actual pricing from WaveSpeed docs
- **Unsupported Parameters**: `negative_prompt`, `seed`, `audio_base64`, `enable_prompt_expansion` are ignored with warnings
- **Polling interval**: 0.5 seconds (same as HunyuanVideo-1.5)
- **Timeout**: 10 minutes maximum

## Official Documentation

- **API Docs**: https://wavespeed.ai/docs/docs-api/lightricks/ltx-2-pro/text-to-video
- **Model Playground**: https://wavespeed.ai/models/lightricks/ltx-2-pro/text-to-video

## Ready for Testing ✅

The implementation is complete and ready for testing. All features are implemented following the modular architecture with separation of concerns, matching the pattern established by HunyuanVideo-1.5.
