I’m addicted to Blender’s VSE, so I pretty much use it for all of my projects.
I would like to apply a motion blur onto my video, but after enabling the “Sampled Motion Blur” option, it doesn’t seem to work. Is there any way to make this work, or on a strip by strip basis?
I’m using Blender 2.61 on Ubuntu (Blender’s official Linux build).
Motion blur is caused by a subject moving faster than the camera shutter increments per frame. So the subject might not be entirely captured per frame, which results in a blurry subject. This effect is created in camera when shooting. As such, it is not reproducible in the VSE if you’re using footage shot with a video camera. AFAIK, there are no VSE-related filters (i.e. plugins) which can be used to produce this effect. Don’t really know what you wish to blur or how, but in theory you could use the video as a texture in the 3d viewport and animate the camera (pan, tilt etc). Haven’t tried that myself though so it might be suboptimal or unfeasible.
On the other hand, if you have CG-related footage, it’s fairly simple to add blur to the motion of an object but you need to turn to the compositor for that.
If you look at VLC, it is able to create a motion blur effect on screen. Some other software (expensive software) can also add such an effect too. I think what it does is it takes N number of frames, adjusts the opacity, and layers them on top of each other.
For testing, I’m going to create a plane with the movie texture, and play around with it to see if it will work.
Could you (or anyone else) suggest free software (preferably on Linux) that can perform such a blur?
Avidemux (Linux/Windoze) has lots of postpro filters and the same holds for VirtualDub (Windoze) if you’re interested in other apps. Both free and open source.
I’ve looked at VLC’s blur filter. If that’s what you mean by '‘motion blur’ that’s easily doable in the compositor if you want to do it in Blender. However, normally you’d either have movement of a subject within a frame (i.e. static background and rapid foreground movement which would make the fg subject to appear blurry) or rapid frame movement and relatively static subject (i.e. moving -hence blurry- background but moving and sharp foreground focus). From what I saw the filter just produces an overall blur which might somewhat work for certain types of shots but that’s way too fake to be realistic.
I’m not sure if or how it can be done in the VSE but there’s no filter directly available for that. Worth exploring though.
I’ve looked at Avidemux, but there are no blur filters. Google says to use the delogo filter… which I’m certain isn’t a motion blur filter. 
Avidemux also messes up the ratio/size of the video, so that’s out of the list.
As for VirtualDub, I haven’t looked at it yet. I’m on a Windows computer at the moment, sans my files, so I’ll run a test with a sample vid.
I’m not exactly aiming for a realistic blur - more of those action movie, fake ones.
The video I’m trying to blur is getting the “dizzy” effect - basically, it’s the dizzy person’s perspective. Therefore, an obsurd, heavy motion blur is a must! 
The initial experiment in Blender didn’t work - apparently, you must have object/camera movement, and I don’t want to wobble my camera around just for this effect…
My next attempt is to use the compositor, as you’ve mentioned. I don’t mind working in the compositor, since I can (technically) connect it back to the sequencer. I’m rendering with the same plane with the movie texture, but this time using a vector blur node to do some motion blur… if it works. (Still rendering!) My preference is a regular video input, but…
Assuming that the above will fail miserably, how would I do it correctly (with your method) via the Blender compositor?
EDIT: Yeah, no dice. The blur is barely there, even with the settings on max.
By dizzy, do you mean radially blurred? That is a blur in a rotational direction, instead of horizontally? You could fake that in VSE by stacking versions of a clip with reducing opacity ontop of each other and applying a transform effrct to rotate the image. But it would not be a very smooth operation. As each step would have to have a small angle change, you would recursively stack up 1 per degree for example. So 90 deg rotation may require 90 layers. Each would also need to have a soft matte in the middle to allow the base image through.
In the compositor there is a zoom type blur that iterativley zooms and blurs an image in a similar manner.
You’re seriously underestimating Avidemux. That little app never ceases to amaze me. Not to mention of course the fact that you could also load external filters through plugins.
I’m not sure what exactly you’re trying to do but from the looks of it any kind of blur would be good. The kind of dizzy effect can be accomplished in many different ways, such as distortions, color shifts, chromatic aberration or any combo thereof. You can do miracles with the compositor in that regard. I don’t know what noodle you created for your experiment but could you give the setup in the attachment a shot?
Might not work with your footage per se but focus on the general principle of how to approach it.
Like I said in my earlier response, it’s more than doable in Blender.
