# LTX-2 Pro Implementation Review ✅

## Documentation Review

**Official API Documentation**: https://wavespeed.ai/docs/docs-api/lightricks/lightricks-ltx-2-pro-text-to-video

### ✅ Implementation Verification

| Feature | Official Docs | Our Implementation | Status |
|---------|--------------|-------------------|--------|
| **Duration** | 6, 8, 10 seconds | 6, 8, 10 seconds | ✅ Correct |
| **generate_audio** | boolean, default: true | boolean, default: true | ✅ Correct |
| **Resolution** | Fixed 1080p | Fixed 1080p (1920x1080) | ✅ Correct |
| **Pricing** | $0.06/s (1080p) | $0.06/s (1080p) | ✅ Updated |
| **prompt** | Required | Required | ✅ Correct |
| **negative_prompt** | Not supported | Ignored with warning | ✅ Correct |
| **seed** | Not supported | Ignored with warning | ✅ Correct |
| **API Endpoint** | `lightricks/ltx-2-pro/text-to-video` | `lightricks/ltx-2-pro/text-to-video` | ✅ Correct |

### ✅ Polling Implementation Review

**Our Polling Implementation**:
```python
result = await asyncio.to_thread(
    self.client.poll_until_complete,
    prediction_id,
    timeout_seconds=600,  # 10 minutes max
    interval_seconds=0.5,  # Poll every 0.5 seconds
    progress_callback=progress_callback,
)
```

**WaveSpeedClient.poll_until_complete()** Features:
- ✅ **Status Checking**: Checks for "completed" or "failed" status
- ✅ **Timeout Handling**: 10-minute timeout (600 seconds)
- ✅ **Polling Interval**: 0.5 seconds (fast polling)
- ✅ **Progress Callbacks**: Supports real-time progress updates
- ✅ **Error Handling**: 
  - Transient errors (5xx): Retries with exponential backoff
  - Non-transient errors (4xx): Fails after max consecutive errors
  - Timeout: Raises HTTPException with prediction_id for resume
- ✅ **Resume Support**: Returns prediction_id in error details for resume capability

**Polling Flow**:
1. ✅ Submit request → Get prediction_id
2. ✅ Poll `/api/v3/predictions/{id}/result` every 0.5 seconds
3. ✅ Check status: "created", "processing", "completed", or "failed"
4. ✅ Handle errors with backoff and resume support
5. ✅ Download video from `outputs[0]` when completed

**Matches Official API Pattern**:
- ✅ Uses GET `/api/v3/predictions/{id}/result` endpoint
- ✅ Checks `data.status` field
- ✅ Extracts `data.outputs` array for video URL
- ✅ Handles `data.error` field for failures

### ✅ Implementation Status

**All Requirements Met**:
- ✅ Correct API endpoint
- ✅ Correct parameters (prompt, duration, generate_audio)
- ✅ Correct validation (duration: 6, 8, 10)
- ✅ Correct pricing ($0.06/s)
- ✅ Correct polling implementation
- ✅ Progress callbacks supported
- ✅ Error handling with resume support
- ✅ Metadata return (1920x1080, cost, prediction_id)

## Polling Implementation Analysis

### Strengths ✅

1. **Robust Error Handling**:
   - Distinguishes between transient (5xx) and non-transient (4xx) errors
   - Exponential backoff for transient errors
   - Max consecutive error limit for non-transient errors

2. **Resume Support**:
   - Returns `prediction_id` in error details
   - Allows clients to resume polling later
   - Critical for long-running tasks

3. **Progress Tracking**:
   - Supports progress callbacks for real-time updates
   - Updates at key stages (submission, polling, completion)

4. **Timeout Management**:
   - 10-minute timeout prevents indefinite waiting
   - Returns prediction_id for manual resume if needed

5. **Efficient Polling**:
   - 0.5-second interval balances responsiveness and API load
   - Fast enough for good UX, not too aggressive

### Potential Improvements (Optional)

1. **Adaptive Polling**: Could slow down polling interval after initial attempts
2. **Progress Estimation**: Could estimate progress based on elapsed time vs. typical duration
3. **Webhook Support**: Could support webhooks instead of polling (if WaveSpeed supports it)

### Conclusion

✅ **Polling implementation is correct and robust**. It follows WaveSpeed API patterns, handles errors gracefully, and supports resume functionality. No changes needed.

## Next Model Recommendation

Based on the Lightricks family and our implementation pattern, I recommend:

### 🎯 **LTX-2 Fast** (Recommended Next)

**Why**:
1. **Same Family**: Part of Lightricks LTX-2 series (consistent API patterns)
2. **Likely Similar**: Probably similar parameters to LTX-2 Pro (easier implementation)
3. **Use Case**: Fast generation for quick iterations (complements LTX-2 Pro)
4. **Natural Progression**: Fast → Pro → Retake makes logical sense

**Expected Differences**:
- Likely faster generation (lower quality or smaller model)
- Possibly different pricing
- May have different duration options
- May have different resolution options

### Alternative: **LTX-2 Retake**

**Why**:
1. **Same Family**: Part of Lightricks LTX-2 series
2. **Unique Feature**: "Retake" suggests ability to regenerate/refine videos
3. **Production Workflow**: Complements Pro for production pipelines

**Expected Differences**:
- Likely requires input video or prediction_id
- May have different parameters for refinement
- May have different use case (refinement vs. generation)

### Recommendation

**Start with LTX-2 Fast** because:
1. ✅ Likely simpler implementation (similar to Pro)
2. ✅ Natural progression (Fast → Pro → Retake)
3. ✅ Complements existing models (fast iteration + production quality)
4. ✅ Easier to test and validate

**Then implement LTX-2 Retake** for:
1. ✅ Video refinement capabilities
2. ✅ Complete LTX-2 family coverage
3. ✅ Advanced production workflows

## Summary

✅ **LTX-2 Pro implementation is correct** and matches official documentation
✅ **Polling implementation is robust** with proper error handling and resume support
✅ **Pricing updated** to $0.06/s (was placeholder $0.10/s)
✅ **Ready for production use**

**Next Step**: Implement **LTX-2 Fast** following the same pattern.