Removing Something from the Background of a Video

[Lightfoot]

I assume the answer to this question is no, but I'll ask anyway.

A family member took a video and now wants to remove or blur a literal banner that appears in the background (the explanation why isn't interesting enough to mention).  There are three problems I see automatically: 1, the camera is almost continuously panning to the right, making the banner's position move.  2, there is an object in the foreground, covering part of the banner.  3, people walk in front of the banner at one point.

My video experience is limited to turning VHS tapes or video to DVDs, or turning video into a kind of file that can be emailed.  Basically conversion using VisualHub or Toast and clipping excess from the beginning and end of video using MPEG Steamclip.  I've messed with the version of iMovie that came with my Mac, but I'm not very experienced with it.

Is there any (nearly) magical way of removing or blurring this item in the background?  Googling this question only brought up how you would do this with a stationary background where nothing moved in front of the object.  I'd almost think the only way to do this is to manually edit the frames (it's a motion JPEG made up of about 1125.541 frames)... if it were worth the trouble to do that.  BUT maybe there's some program I don't know about.  Mac, PC, Linux, I could try anything.

[Palomine]

I assume the answer to this question is no, but I'll ask anyway.

A family member took a video and now wants to remove or blur a literal banner that appears in the background (the explanation why isn't interesting enough to mention).  There are three problems I see automatically: 1, the camera is almost continuously panning to the right, making the banner's position move.  2, there is an object in the foreground, covering part of the banner.  3, people walk in front of the banner at one point.

My video experience is limited to turning VHS tapes or video to DVDs, or turning video into a kind of file that can be emailed.  Basically conversion using VisualHub or Toast and clipping excess from the beginning and end of video using MPEG Steamclip.  I've messed with the version of iMovie that came with my Mac, but I'm not very experienced with it.

Is there any (nearly) magical way of removing or blurring this item in the background?  Googling this question only brought up how you would do this with a stationary background where nothing moved in front of the object.  I'd almost think the only way to do this is to manually edit the frames (it's a motion JPEG made up of about 1125.541 frames)... if it were worth the trouble to do that.  BUT maybe there's some program I don't know about.  Mac, PC, Linux, I could try anything.

Easy peasy more or less, though I won't rely upon specific apps but instead just talk about steps.. you're Mac (I think?) and I've switched to Ubuntu (Linux) some time ago but be that as it may...

Two  (technically, three) steps: you can either manually (or semi/automatically) motion track the banner to be obscured. Basically, it's an animated polygon... a four-sided shape that changes over time due to its relationship to the camera (POV) and/or perspective, etc... AND of course, folks (as they're apt to do) walk in front of it from time to time. So you'll be wanting to rotoscope them out (so that you can subtract them from the matte of the polygon for your composite), That's step two (the rotoscoping) after the motion tracking.

The end result being (if you were to view it over time) a shape roughly equivalent to the banner that magically gets out of the way when someone in the foreground steps between it and the camera. This shape (aka matte) can be used for a variety of nefarious purposes: if you had a 'clean plate' you could simply replace it with something else (i.e.: sans banner) or for logo replacement (you know, some fast food chains don't exist overseas so the corporate parent will insist you swap out that logo for another in the company fold) or in your case, for simply delimiting a blur.

You follow me so far? I hope so, since I'm way too tired to elaborate, though if you PM me later (when I wake up on Friday) I will belabour (sp?) every detail ad nauseum because you are swell, plus, it's only common courtesy!  

OK, step three: so you made a matte channel (file, clip, whatever) which (if viewed by itself in motion) will be a black and white image of an animated shape that conforms to the banner but gets out of the way when someone walks through the foreground (we'll discuss corner pinning, motion tracking, etc... when we PM). The matte file will be used to composite (or delimit) your blur... basically, it contains what will be blurred.... you'll batch process your video file (using whatever application you have that's amenable to such indignities, be it After Effects, some batch plugin for Photoshop, or Nuke or Shake or whatever) so that you apply an X-kernel-diameter blur to each frame *as delimited* by your matte file (filmroll, channel, layer, ad infinitum...).

So (in your case) thanks to your matte, just the banner gets obscured and not anything else, nor anyone who has the temerity to step in front of it. A theree-step process: make the matte (which will perhaps require a bit of human input or not, depending on your software) and then delimit the matte to protect foreground subjects (rotoscoping) and finally, use the resulting matte as you see fit (in your case, to blur a specific background object).

Sorry me and my verbage are so frazzled... it's late and I've been drinking (per my other nearby post). PM me and by the time I reply I'll have sobered up and will respond in detail.



Added later: I've replied to your PM Lightfoot... again, I apologize for the somewhat fragmentary/disjointed explanations (above, when I was a bit sloshed, and in the PM, when I'm a little hung over). -Pal