Capture a single pixel row from each frame of video and compile them together

Question

I'm working on a project where I need to take a single horizontal or vertical pixel row (or column, I guess) from each frame of a supplied video file and create an image out of it, basically appending the pixel row onto the image throughout the video. The video file I plan to supply isn't a regular video, it's actually just a capture of a panning camera from a video game (Halo: Reach) looking straight down (or as far as the game will let me, which is -85.5°). I'll look down, pan the camera forward over the landscape very slowly, then take a single pixel row from each frame the captured video file (30fps) and compile the rows into an image that will effectively (hopefully) reconstruct the landscape into a single image.

I thought about doing this the quick and dirty way, using a AxWindowsMediaPlayer control and locking the form so that it couldn't be moved or resized, then just using a Graphics object to capture the screen, but that wouldn't be fast enough, there would be way too many problems, I need direct access to the frames.

I've heard about FFLib, and DirectShow.NET, I actually just installed the Windows SDK but haven't had a chance to mess with and of the DirectX stuff yet (I remember it being very confusing for me a while back when I messed with it). Hopefully someone can give me a pointer in the right direction.

If anyone has any information they think might help, I'd be super grateful for it. Thank you!

Answer 1

You could use a video rendered in renderless mode (Eg VMR9, EVR), which allows you to process every frame yourself. By using frame stepping playback you can step one frame each time and process the frame.

DirectShow.NET can help you to use managed code where possible, and I can recommend it. It is however only a wrapper to DirectShow, so it might be worthwhile to look for more advanced libraries as well.

A few sidenotes: wouldn't you experience issues with lighting which differs from angle to angle? Perhaps it's easier to capture some screenshots and use existing stitching algorithms ?