Automatically remove "black frames" - Printable Version

Automatically remove "black frames" - Printable Version

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Automatically remove "black frames" - Bartoloni - 18.05.2023

right now after processing a footage with Hybrid .. i need to use a Linux script (FFMPEG + blackdetect filter) to cut in pieces the clip removing the black frames interruptions (i use a blackmagic intensity PRO that generate BLACK frames when the signal is too much "noised" ) and after that i need to merge all these parts to create an output without any BLACK frame..

is possible to used the "blackdetect" filter or something similar on Hybrid to AUTOMATICALLY remove all black frames from footage? (or maybe <5% black frames)

thank you!

RE: Automatically remove "black frames" - Selur - 18.05.2023

No, Hybrid has no filter which would:
a. remove black frames
and
b. cut the audio to keep the source sync

Cu Selur

RE: Automatically remove "black frames" - Bartoloni - 18.05.2023

thank you Cu Selur Smile

Smile

RE: Automatically remove "black frames" - Selur - 18.05.2023

Cu = see you
Selur <- the Name Smile

Smile

RE: Automatically remove "black frames" - Selur - 18.05.2023

Can you share a small sample of such a clip (with the black frames)?
I suspect that one could use something like:

def replace_low_luma_frames(clip, threshold):
    # Calculate average luma for each frame
    luma = core.std.ShufflePlanes(clip, planes=0, colorfamily=vs.GRAY)
    avg_luma = core.std.PlaneStats(luma)

    # Create a mask of frames with luma below the threshold
    low_luma_mask = core.std.Expr(avg_luma, f'x {threshold} <')

    # Get frame before for replacement
    frame_before = core.std.Trim(clip, 0, clip.num_frames - 1)

    # Replace frames with low luma using frame_before
    replaced = core.std.MaskedMerge(clip, frame_before, low_luma_mask)

    return replaced

clip = replace_low_luma_frames(clip, 30)

(code is untested, not totally sure whether it works Wink

Wink

)
to replace each frame which luma is below 30 (or lower) with the frame before it.
Assuming there are only single black frames in the soure and thus singe duplicates that one could use 'FillDrops' to replace the inserted duplicates with interpolated frames.

Cu Selur

RE: Automatically remove "black frames" - humanoid86 - 19.05.2023

try it - pulldown="telecine" or "interpolation"

+ tune: Grain or PSNR or SSIM

RE: Automatically remove "black frames" - Bartoloni - 27.05.2023

OMG very thank you helping me!
here a small interlaced sample: www.wcn.it/black.avi

i have a lot of old footages with these black frames (generated by the blackmagic intensity pro card) (there are more than 1 black consecutive frames BTW.. in the sample maybe not.. but there are)

here there are a lot of black "zones" : www.wcn.it/black2.avi

RE: Automatically remove "black frames" - Selur - 28.05.2023

Okay, here's what you can do.

Start Hybrid
load clip
set 'Filtering->(De-)Interlace/Telecine->Overwrite input scan type to' to 'top field first'
optional: enable 'Filtering->(De-)Interlace/Telecine->QTGMC Vapoursynth->Bob'.
go to 'Filtering->Vapoursynth->Custom->Insert Before' set it to 'FillDrops', enable the text box below it.
in this custom section you now enter:

# replace a black frames with last frame that was not black def ReplaceBlackFrames(clip, thresh=0.1, debug=False): core = vs.core if not isinstance(clip, vs.VideoNode): raise ValueError('This is not a clip') def selectFunc(n, f): 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) return clip toReplace = n for i in range(n)[::-1]: if clip.get_frame(i).props['PlaneStatsAverage'] <= thresh: continue # remove current replace with frame before start = core.std.Trim(clip, first=0, last=n-1) r = core.std.Trim(clip, first=i, last=i) end = core.std.Trim(clip, first=n+1) replaced = start + r + end break if debug: return core.text.Text(clip=replaced,text="Replaced, avg: "+str(f.props['PlaneStatsAverage']),alignment=8) return replaced clip = core.std.PlaneStats(clip) fixed = core.std.FrameEval(clip, selectFunc, prop_src=clip) return fixed clip = ReplaceBlackFrames(clip, thresh=0.1, debug=False)
If you now look at the Vapoursynth Preview all black frames should be replaced with the last non-black frame.
optional: if there were no multiple black frames in a row, enable 'Filtering->Vapoursynth->Misc->FillDrops', this will then replace the duplicate with an interpolated version.

Cu Selur

RE: Automatically remove "black frames" - Bartoloni - 28.05.2023

OMG!!! very very very thank you!!!

RE: Automatically remove "black frames" - Selur - 29.05.2023

Happy that helped, note that this will only work on clips that do not start with black frames.

Cu Selur