[Feature] feat: add video frame interpolation postprocess (#2555)

Signed-off-by: David Chen <530634352@qq.com>

docs/user_guide/diffusion_features.md

@@ -14,7 +14,7 @@ vLLM-Omni supports various advanced features for diffusion models:
 
 - Acceleration: **cache methods**, **parallelism methods**, **startup optimizations**
 - Memory optimization: **cpu offloading**, **quantization**
-- Extensions: **LoRA inference**
+- Extensions: **LoRA inference**, **frame interpolation**
 - Execution modes: **step execution**
 
 ## Supported Features
@@ -69,6 +69,7 @@ Extension methods add specialized capabilities to diffusion models beyond standa
 | Method | Description | Best For |
 |--------|-------------|----------|
 | **[LoRA Inference](diffusion/lora.md)** | Enables inference with Low-Rank Adaptation (LoRA) adapters weights | Reinforcement learning extensions |
+| **[Frame Interpolation](diffusion/frame_interpolation.md)** | Inserts intermediate video frames after generation for smoother motion | Video generation pipelines that need higher temporal smoothness |
 
 
 ### Execution Modes
@@ -143,6 +144,11 @@ The following tables show which models support each feature:
 | **HunyuanVideo-1.5 T2V I2V** | ❌ | ✅ | ❌ | ✅ | ✅ | ✅ | ✅ | ✅ (decode) | ✅ | ❌ |
 | **DreamID-Omni** | ❌ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ |
 
+**Frame Interpolation Support**
+
+- **Supported**: Wan2.2 text-to-video, image-to-video, and TI2V pipelines
+- **Not supported**: Wan2.1-VACE, LTX-2, Helios, HunyuanVideo-1.5, DreamID-Omni
+
 ### AudioGen
 
 | Model | ⚡TeaCache | ⚡Cache-DiT | 🔀SP (Ulysses & Ring) | 🔀CFG-Parallel | 🔀Tensor-Parallel | 🔀HSDP | 💾CPU Offload (Layerwise) | 💾VAE-Patch-Parallel | 💾Quantization | 🔄Step Execution |
@@ -258,6 +264,7 @@ Measured on NVIDIA H800:
 **Extensions:**
 
 - **[LoRA Inference Guide](diffusion/lora.md)** - Low-Rank Adaptation for style customization and fine-tuning
+- **[Frame Interpolation Guide](diffusion/frame_interpolation.md)** - Worker-side post-generation video frame interpolation for smoother motion
 
 **Execution Modes:**