BackChange plugin

phil_the

Has anyone had any success using the BackChange VirtualDub plugin?

I have managed to get it to work using his supplied tutorial files, but am struggling to get it working with my own files.

The first issue was that I was initially getting repeated messages popping up saying that it couldn't find the files, but I fixed this by replacing the filenames in the script file with full paths instead of relative paths.

The second issue was that it seemed to be doing something but wasn't looking quite right, and I realized that somehow the image was being flipped vertically. I added a Flip Effect before the BackChange effect and this fixed it.

As soon as I try to use my own video clip and my own background images, it just seems to crash VP every time 😞 I upgraded to latest version of VP yesterday. I assume the error is being generated by the plugin, but it would be nice if VP could trap the error rather than just dying.

He says that the background image files need to be 24bpp uncompressed .tga files, and match the resolution of the clip. I couldn't find a program online to convert png or jpg files to this format (there are some online converters but none of them seem to give the option to chose whether or not you want compression or allow you to specify the pixel format). I had a go yesterday at writing my own program to do the conversion, and I have something which I think is working but it is still crashing VP.

It is possible my converter isn't working quite right, so I'll do some more testing on that. Meanwhile I wondered if anyone else had managed to get this working or has discovered another way to remove the background from a video?

Phil.

[deleted]

Are we looking at a full length video or just a few frames? If the latter you might try the mask effect.?????

Nat

phil_the

This is for a reasonable length of video with multiple overlapping clips, so I can appear on the screen multiple times, in front, behind and beside myself. I did one a few weeks ago using the mask effect in combination with multiple green screens, but it took me many hours of editing and the result was far from perfect.

https://www.youtube.com/watch?v=FLeHVoteW8o

I didn't make it easy for myself by having a very busy background and I was filming in strong sunlight over the course of a day so was getting varying lengths of shadows and changes in brightness as clouds went overhead etc. I'd like to do more of these, but even if I can find a better location and better lighting, having the ability to remove a static background from a whole clip would be extremely useful.

[deleted]

Bravo! ... and yes, it must have taken some time to do! VP don't guarantee that Virtualdub plugins will all work being third party apps, just that the facility to incorporate them into the program is available. The principle one being Deshaker for stabilization. A few years ago you could run your clip with the plugin on the virtualdub website and download the result. (Or something similar) I don't think that can be done now.

Nat

phil_the

Thanks. I ended up using other effects to obscure parts of the video where I didn't have time to keep fine tuning the masks. I had quite a bit of extra footage that I didn't end up using.

Yes, I realise that individual plugins aren't supported, that's why I posted here asking if anyone else has had any success or otherwise with this one.

It is really frustrating when you see programs like Zoom and Skype, that can detect and replace a background really easily. If they can do it with a live stream, it is surprising that NCH can't come up with a way of doing this in the editor.

I have done a bit more experimenting and I have managed to get it to replace the background of the tutorial animation with my own image, but I've still not been able to do anything with my own video clips. I wondered if it might be something to do with the format of the video file. I tried converting my mp4 to avi but that didn't seem to fix it either. I even tried reducing the resolution right down to 320x240, but again no joy yet.

I could keep experimenting, but it might be easier to see if I can write my own program to remove a background or write my own plugin. I had a quick glance at the virtualdub plugin api yesterday, but it is such old technology that the project files are no longer compatible with more recent versions of the C++ compiler!