modifying frames

[tonyalcapon]

Hello, i would like to know how to automatic modify some frames,

my situation is: i recived a video for homework and i have to remove or modify like writing something on the frame. The frames to modify are every 12 frames. And the video is very long so i can't do it one by one.

Does anyone can tell me how to do this, i have no clue.

Thanks!!

[poisondeathray]

Exactly what do you have to modify?

If it's writing, where is it? does it move or animate? does it change over time, or is it always the same? maybe post an example screenshot

How do you want to "modify" it? cover it up with a black patch? try to "remove" it ?

If it's static, you might be able to use an avisynth filter with ApplyEvery() or similar functions to every 12th frame

[tonyalcapon]

Thanks to answer me,

to give you more informations, i have a normal video (avi) which have been modified every 12 frames, the modified frames have a white page with "change this one".

So i simply have to write "done" under "change this one" or change the frames with a picture.

Can you help me?

psoison i saw you are from canada, it would be easier for me to talk in french =)

[poisondeathray]

uhhh my french is rusty, I learned some back in elementary & junior high school...but I forgotten most of it



But you can do this in avisynth, but there is a bit of a learning curve

Here is an example, that shows the framenumber, you can work though the code, and adjust to your video (just change the filenames, instead of "blankclip" you would use AVISource("yourvideo.avi") .

video "1.avi" is the original , "2.avi" has the replaced frames . You can open it up in something like vdub to go frame by frame . It's really not that difficult, but it helps if you can see and example to work though the code

1

BlankClip(length=300, width=640, height=480)
AssumeFPS(30000,1001)
ShowFrameNumber()
ConvertToYV12()

2

BlankClip(length=300, width=640, height=480)
AssumeFPS(30000,1001)
ShowFrameNumber()
ConvertToYV12()
a=last


a
SelectEvery(12,0)
Subtitle("change this one")
replaced=last


a
DeleteEvery(12,0)
InterleaveEvery(replaced, 12,0)

I chose, 0,12,24,.... but you can change the offset of selectevery . e.g. you might want 1,13,25,....
http://avisynth.org/mediawiki/SelectEvery

I used simple subtitle("change this one"), but you can change the x,y position, font, color etc... to place wherever you want . The default is x=0,y=0, so you will see in the example it's in the top left corner
http://avisynth.org/mediawiki/Subtitle

You need stickboy's applyevery.dll for DeleteEvery(), and InterleaveEvery() - the other filters are internal avisynth filters that come with standard install
http://avisynth.org/stickboy/

[manono]

Yeah, this is simple using AviSynth. I wonder if the instructor knows about it, or is expecting the students to use some NLE for the job.

[poisondeathray]

Yeah, this is simple using AviSynth. I wonder if the instructor knows about it, or is expecting the students to use some NLE for the job.

It might seem like a "simple task" for avisynth, but it's actually quite difficult to do in a NLE

[smrpix]

What kind of class is this?

[tonyalcapon]

hello poison, i tried your script and it worked perfect! =)

now i'm working on it thanks!

[poisondeathray]

Cheers , glad you got it working. Avisynth can be confusing at first

Now what kind of "mean" teacher would give you homework over the Holidays!

[budwzr]

Whew! That sounds like a bunch of work.

Why not make a 12-frame loop, set to repeat, stretch it out as needed, and composite it against the original? Of course frames 1-11 would be all white.

The 12th would be a still.

[tonyalcapon]

i was also trying to place a picture (just for fun/curiosity) but can't found the solution, do you have any idea?

[poisondeathray]

i was also trying to place a picture (just for fun/curiosity) but can't found the solution, do you have any idea?

it's the same method / same idea , just use ImageSource() instead of subtitle
http://avisynth.org/mediawiki/ImageSource

using the example above

BlankClip(length=300, width=640, height=480)
AssumeFPS(30000,1001)
ShowFrameNumber()
ConvertToYV12()
a=last


ImageSource("image.jpg", 0,300, fps=29.97)
ConvertToYV12()
LanczosResize(640,480)
AssumeFPS(30000,1001)
SelectEvery(12,0)
replaced=last


a
DeleteEvery(12,0)
InterleaveEvery(replaced, 12,0)

The "trick" is that the image has to be the same format in terms of colorspace, fps, dimensions etc...
That's what the ConvertToYV12, LanczosResize, AssumeFPS etc... are for . You just change the parameters to match whatever your source video is

[tonyalcapon]

awsome