Detect missing frames in video with AviSynth

[MartinBB]

I need a list of missing frames from a video. I tried:


WriteFileIf(last, "D:\list.txt", "YDifferenceFromPrevious>3", "current_frame" )


It works, but not very well. I found a better functiom here, thanks to johnmeyer:


function ShowMetrics (clip c)
{
fixed=source.ScriptClip("Subtitle(String(
\ (( (YDifferenceFromPrevious(selectevery(source, 1, 2)) < 0.3 ?
\ YDifferenceFromPrevious(selectevery(source, 1, 3)) :
\ YDifferenceFromPrevious(selectevery(source, 1, 2)) )
\ +
\ (YDifferenceFromPrevious(selectevery(source, 1, 1)) < 0.3 ?
\ YDifferenceFromPrevious(selectevery(source, 1, 2)) :
\ YDifferenceFromPrevious(selectevery(source, 1, 1)) )
\ +
\ (YDifferenceFromPrevious(selectevery(source, 1, -1)) < 0.3 ?
\ YDifferenceFromPrevious(selectevery(source, 1, -2)) :
\ YDifferenceFromPrevious(selectevery(source, 1, -1)) )
\ +
\ (YDifferenceFromPrevious(selectevery(source, 1, -2)) < 0.3 ?
\ YDifferenceFromPrevious(selectevery(source, 1, -3)) :
\ YDifferenceFromPrevious(selectevery(source, 1, -2)) )
\ )/4) /
\ (YDifferenceFromPrevious(source) + 0.01)
\ ))")
return fixed
}

global source=AVISource("E:\fs.avi").ConvertToYV12.killau dio()


How can I modify it to output to a text file instead of subtitles?

[johnmeyer]

Here is a link to the script I wrote:

Script for reliably detecting dropped frames

If you prefer writing your own script, you may find some additional ideas in this similar script:

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

This one shows you how to save the frame numbers to a text file.

[MartinBB]

Thank you johnmeyer for everything you wrote over the years on the forums.
I have read many of your excellent posts, thank you very much.

I would love a motion estimation detection method for missing frames.
I expect some professional software is using something like that,
I just did not find it yet.

I tried to modify the ShowMetrics function:


WriteFileIf(source, "D:\list.txt", "(
\ (( (YDifferenceFromPrevious(selectevery(source, 1, 2)) < 0.3 ?
\ YDifferenceFromPrevious(selectevery(source, 1, 3)) :
\ YDifferenceFromPrevious(selectevery(source, 1, 2)) )
\ +
\ (YDifferenceFromPrevious(selectevery(source, 1, 1)) < 0.3 ?
\ YDifferenceFromPrevious(selectevery(source, 1, 2)) :
\ YDifferenceFromPrevious(selectevery(source, 1, 1)) )
\ +
\ (YDifferenceFromPrevious(selectevery(source, 1, -1)) < 0.3 ?
\ YDifferenceFromPrevious(selectevery(source, 1, -2)) :
\ YDifferenceFromPrevious(selectevery(source, 1, -1)) )
\ +
\ (YDifferenceFromPrevious(selectevery(source, 1, -2)) < 0.3 ?
\ YDifferenceFromPrevious(selectevery(source, 1, -3)) :
\ YDifferenceFromPrevious(selectevery(source, 1, -2)) )
\ )/4) /
\ (YDifferenceFromPrevious(source) + 0.01)
\ )", "current_frame" )


But it is not good, it writes every frame number to file.

Sadly, I am not a programmer and I am out of ideas.
Any help vould be greatly appreciated.