Fill black frames with interpolations,...

[Selur]

Hi, I wrote two small functions:

• ReplaceBlackFrames: replace a black frames with interpolations of the surrounding frames.
• FillBlackFrames: replace a black frames with interpolations of the surrounding frames.

ReplaceBlackFrames works as expected.
Problem is FillBlackFrames, where I suspect that I messed up indices somewhere:

# replace the frames 'firstFrametoReplace' to 'firstGoodFrame-1' with interpolations between 'firstFrametoReplace - 1' and 'firstGoodFrame'
def fillMultipleWithSVP(clip, firstFrametoReplace=None, firstGoodFrame=None, gpu=False):
  clip1 = core.std.AssumeFPS(clip, fpsnum=1, fpsden=1)
  start = core.std.Trim(clip1, first=firstFrametoReplace-1, length=1) # last good frame before black frames
  end = core.std.Trim(clip1, first=firstGoodFrame, length=1) # first good frame after black frames
  startend = start + end
  if gpu:
    super  = core.svp1.Super(startend,"{gpu:1}")
  else:
    super  = core.svp1.Super(startend,"{gpu:0}")
  vectors= core.svp1.Analyse(super["clip"],super["data"],startend,"{}")

  # interpolate
  r = core.svp2.SmoothFps(startend,super["clip"],super["data"],vectors["clip"],vectors["data"],"{rate:{num:"+str(firstGoodFrame-firstFrametoReplace+1)+",den:1,abs:false}}")
  a = core.std.Trim(clip1, first=0, last=firstFrametoReplace-2) # last good frame before is part of r
  b = core.std.Trim(clip1, first=firstGoodFrame+1) # first good frame, ist part of r
  # join
  join = a + r + b
  if (join.num_frames != clip.num_frames): # did I messup with the join
    raise vs.Error(f"fillMultipleWithSVP: frame count issue join '{join.num_frames}' vs clip '{clip.num_frames}'")
  return core.std.AssumeFPS(join, src=clip)
  

# replace a black frames with interpolations of the surrounding frames.
# threshold average frame threshold
def FillBlackFrames(clip, thresh=0.1, debug=False):
    if not isinstance(clip, vs.VideoNode):
        raise ValueError('This is not a clip')
    
    def selectFunc(n, f):
        nonlocal clip
        firstGoodFrame = f.props['FirstGoodFrame']
        if n == 0:
          clip = core.std.SetFrameProp(clip, prop="FirstGoodFrame", intval=firstGoodFrame)
          return clip
        if firstGoodFrame >= n: # this frame, we already dealt with
            return clip

        if f.props['PlaneStatsAverage'] > thresh or n == 0:
            if debug:
                return core.text.Text(clip=clip, text="Org, avg: " + str(f.props['PlaneStatsAverage']), alignment=8)
            clip = core.std.SetFrameProp(clip, prop="FirstGoodFrame", intval=n)
            return clip
        firstFrametoReplace = n
        firstGoodFrame = n + 1
        for i in range(n, clip.num_frames-1):
            if clip.get_frame(i).props['PlaneStatsAverage'] <= thresh:
                continue
            firstGoodFrame = i
            break
        clip = core.std.SetFrameProp(clip, prop="FirstGoodFrame", intval=firstGoodFrame)
        replaced = fillMultipleWithSVP(clip, firstFrametoReplace, firstGoodFrame, gpu=True)
        if debug:
            return core.text.Text(clip=replaced, text="Replaced from " + str(firstFrametoReplace) + " to " + str(firstGoodFrame-1))
        return replaced
    clip = core.std.SetFrameProp(clip, prop="FirstGoodFrame", intval=0)
    clip = core.std.PlaneStats(clip)
    fixed = core.std.FrameEval(clip, selectFunc, prop_src=clip)
    return fixed

When I have a clip where:
Frame 19 is fine
Frame 20&21 are black
Frame 22 is fine
and I apply FillBlackFrames to it, both frame 20&21 get replaced, but frame 21 is the same as 22.

Does someone spot where I went wrong?
(Or is this caused by Vapoursynth not really supporting linear processing in script?)

Cu Selur

Latest version:on GitHub