Add support for interpolating more than one frame

Signed-off-by: ArchieMeng <archiemeng@protonmail.com>

Author: ArchieMeng

src/rife_ncnn_vulkan.py

@@ -1,5 +1,5 @@
+from __future__ import annotations
 import sys
-from math import floor
 from pathlib import Path
 
 from PIL import Image
@@ -13,9 +13,21 @@
 
 
 class RIFE:
-    def __init__(self, gpuid: int = -1, model: str = "rife-HD", tta_mode: bool = False, uhd_mode: bool = False, num_threads: int = 1):
+    def __init__(self,
+                 gpuid: int = -1,
+                 model: str = "rife-HD",
+                 scale: int = 2,
+                 tta_mode: bool = False,
+                 uhd_mode: bool = False,
+                 num_threads: int = 1):
         rife_v2 = "rife-v2" in model
         self.model = model
+
+        if (scale & (scale -1)) == 0:
+            self.scale = scale
+        else:
+            raise ValueError("scale should be powers of 2")
+
         self._raw_rife = raw.RIFEWrapper(gpuid, tta_mode, uhd_mode, num_threads, rife_v2)
         self.load()
 
@@ -42,7 +54,24 @@ def load(self, model_dir: str = ""):
         else:
             raise FileNotFoundError(f"{model_dir} not found")
 
-    def process(self, im0: Image, im1: Image) -> Image:
+    def process(self, im0: Image, im1: Image) -> list[Image]:
+        """
+        interpolate frames between im0 and im1
+        :param im0: First frame
+        :param im1: Second frame
+        :return: the interpolation frames between im0 and im1
+        """
+        def _proc(im0: Image, im1: Image, level) -> list[Image]:
+            if level == 1:
+                return []
+            else:
+                im = self._process(im0, im1)
+                level /= 2
+                return _proc(im0, im, level) + [im] + _proc(im, im1, level)
+
+        return _proc(im0, im1, self.scale)
+
+    def _process(self, im0: Image, im1: Image) -> Image:
         in_bytes0, in_bytes1 = bytearray(im0.tobytes()), bytearray(im1.tobytes())
         channels = int(len(in_bytes0) / (im0.width * im0.height))
         out_bytes = bytearray(len(in_bytes0))
@@ -62,6 +91,7 @@ def process(self, im0: Image, im1: Image) -> Image:
     t = time()
     im0, im1 = Image.open("../images/0.png"), Image.open("../images/1.png")
     rife = RIFE(0)
-    im = rife.process(im0, im1)
-    im.save("../images/out_wrapper.png")
+    ims = rife.process(im0, im1)
+    for i, im in enumerate(ims):
+        im.save(f"../images/out_{i}.png")
     print(f"Elapsed time: {time() - t}s")