Automatically remove black frames?

[nexus_013]

Recorded VHS a lot of black frames
any "easy" way to cut the black frames automatically?
thanks

[jagabo]

Why is your sample 23.976 fps and poorly deinteralced? Any VHS recording should be 29.97 fps interlaced. You should capture again.

[nexus_013]

the quality is irrelevant in this topic
thanks anyway

[netmask56]

If the file is a MPEG2 you could use a function in Womble aka MPEG Video Wizard called blank fades in the bookmark menu http://www.womble.com/support/help.dvd5/chap4b-2.html

[manono]

the quality is irrelevant in this topic

Hardly. It looks to me like you already screwed it up beyond redemption by giving it a film framerate by blending to get it to 23.976fps when it wasn't shot on film. And it isn't just a case of good video/black frames. If you study it you can see they fade out and in, probably also a result of you not knowing what you were doing. There are plenty of 'half-black' frames. It's a godawful mess.

Is the original tape like this? If so, there's no hope unless you want to fix it manually using frame interpolation. Otherwise do as jagabo suggests and start over again.

[nexus_013]

thanks netmask56

original footage is not 23 fps

[johnmeyer]

The footage is in bad shape, for sure.

I have written many blank frame removal scripts. In some of them I use motion estimation to create a new frame to replace the black/blank frame. In others, I simple decimate the frame.

Of all the scripts I have posted, you may find this one the most useful:

Finding individual "bad" frames in video; save frame number; or repair

[jagabo]

Here's a simple AviSynth command that will replace isolated black frames (ie, black frames with non-black frames before and after them) with a copy of the frame before it:

ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", 25)

If there are several black frames in a row you can repeat the line a number times. Ie, to cover a sequence of 5 black frames you need to use the command 5 times. The last variable in the call, "25" is a threshold value. Larger values will cause dark, but not completely black, frames being replaced.

Even after removing the black frames from the OP's video it flickers a lot because there are many dark frames in addition to the black ones. If you raise the threshold it will flicker less but then it will lock up more often and for longer stretches.

[jagabo]

Here's the video with the darkest frames replaced (with the above replacement technique) and flicker reduction. If there was audio it could be retained and remain in sync. Original video (reencoded) on the left, filtered on the right.

[nexus_013]

thanks johnmeyer & jagabo
I'm new to scripts but I'll try

[nexus_013]

Here's a simple AviSynth command that will replace isolated black frames (ie, black frames with non-black frames before and after them) with a copy of the frame before it:

ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", 25)

If there are several black frames in a row you can repeat the line a number times. Ie, to cover a sequence of 5 black frames you need to use the command 5 times. The last variable in the call, "25" is a threshold value. Larger values will cause dark, but not completely black, frames being replaced.

Even after removing the black frames from the OP's video it flickers a lot because there are many dark frames in addition to the black ones. If you raise the threshold it will flicker less but then it will lock up more often and for longer stretches.

invalid arguments to function ConditionalFilter
Can you explain how to use it a bit more?
completely new to avisynth

[jagabo]

Your script should look something like:

LSmashVideoSource("Untitled.mp4")  # open the video

Trim(1,0) # first frame is black, get rid of it
Crop(8,0,-8,-0) # removing black borders improves autogain later

THRESHOLD = "50" # lower values will replace fewer frames, higher values will replace more frames

# 14 calls to ConditionalFilter will remove as many as 14 black frames in a row
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)
ConditionalFilter(last, Loop(2,0,0), last, "AverageLuma()", "lessthan", THRESHOLD)

ColorYUV(autogain=true) # even out the brightness of the remaining frames

[nexus_013]

it worked thanksssss