How can I acomplish this? Make a prank. thanks

[caminando]

Hello. I need some small help with a big problem (for me). I hope you can help me out with this.
I want to make a prank to someone and convince that person that the person to whom I talked on yahoo messenger had a certain image as avatar. I know how to make a print screen and after that replace the avatar image from the yahoo messenger window. But it won't look so real like a video. So I want to capture the desktop while I talk with that person and after that insert in that video an image over the avatar image of that person from the yahoo window.
How can I make this look very real, I mean to not be obvious that was inserted an image there, difference of colours or luminosity or I don't know. I am using camstudio for desktop capture. Please advise me also If I should use something else for a better compatibility with the editing software.
How can I do this?
Thanks

[dwero]

That's creative, but camstuidio is the most good editing software Iv ever used. And I am also wondering how you can do that. If you find any ways, please let me know.

[fitch.j]

Simply make the image that will blend will into the video first. Then drag the image into the clip bin in camtasia, from there drag it down to the timeline (it will come up as a callout). You can then move it around on the preview pane to make it line up with the video.

[caminando]

thx a lot fitch.j
it worked

the only problem I am having now is that when I am installing a losless codec from camstudio site that codec is not appearing in the program
could you recomand me a high quality codec for desktop capture?

[poisondeathray]

e.g. huffyuv is an example of lossless codec commonly used for capture . I think camrec included with camstudio is lossless too

what os are you using ? if it's 64-bit you need 64-bit version of the codec