View Full Version : compositing video
04-23-2006, 08:01 PM
I have been using blender for around a year now, and I love the software. Just recently I have been getting into the more advanced features, and have hit a snag. I am trying to integrate "real life' video with CG objects. It seems no matter what I try, I cannot get it to work. The error I keep getting is "unknown fileformat" in the console window. It should be noted that I am running blender on a windows XP machine.
I have found several tutorials on the internet that lead me to believe that this is possible, but so far, I cannot get past the "unknown fileformat" message.
I have even worked tried the video file (in.avi) referenced in this tutorial
and still get the dreaded "unknown fileformat" message. I thought I remembered reading somewhere that uncompressed AVI files would always load, but so far, no luck. I also remember reading somewhere that as long as you had the codec installed on your machine, then blender could read the video file. I can play the video files I am trying to composite with in Media Player, so I doubt a missing codec is the problem.
My question is, does anyone have any idea what could possibly be wrong? Is this just a limitation with the windows version of blender? Any help would be appreciated.
This is my first post, so please be patient with me.
04-24-2006, 04:11 AM
are you using the official build or a testing build?
have you tried .mov or another video format? (to narrow down the problem).
when you press shift a to add the movie to the sequence editor, are you selecting the correct object type?
04-24-2006, 12:56 PM
I am using blender 2.41. It is the one that you get from the website. I am not into building test builds, although I have downloaded the source code to take a peek at.
I have tried different formats, and none seem to load, but maybe the problem is how I am trying to load and use this video. Let me explain the way I was trying to integrate video with my CG objects.
1) I would load blender and delete the cube, and then create a plane.
2) I would position the plane so that it would fill the TV safe area when viewed from the viewpoint of the camera (NUMPAD 0)
3) I would assign a material and a texture to the plane.
4) for the texture type I would select image, and then load the .avi file. This is when I would see the "unknown fileformat" message in the console window.
Something interesting though is that I was able to successfully load a video into the sequence editor that would give me the "unknown fileformat" when loaded in the way described above.
So with that stated, my question is, how do I get the video from the sequence editor to my scene so I can add my objects to it?
Thanks so much for your help already.
04-24-2006, 05:34 PM
okay. so you want to use a movie as a texture.
i was able to get this to work in my test using a quicktime animation i rendered out using the default settings. i haven't tested other encodings.
make sure you click on the button labelled 'movie' before you load up your video file in the texture settings. otherwise the video won't show up in the render.
next, in the tab labelled 'Anim and Movie' there are some options to set regarding which frames of the movie to use. my video was 41 frames long, so i entered 41 in the text box labelled 'frames'. if you don't set this option, blender will simply use the first frame of the movie as a texture - you won't see any movement.
i can't seem to make blender reproduce the 'unknown file format' error with my video file. i would suggest rendering out a test .mov with the default settings and using that as a texture. if you still get the error it's probably to do with your system or copy of blender.
04-24-2006, 05:36 PM
Disregard the previous post. The sequence editor was the missing piece to the puzzle. I got it working now, and learned something new about Blender.
Thanks again TroutMaskReplica!
04-24-2006, 05:39 PM
That works too. Boy I feel like an idiot for not seeing the movie button there before.
Thanks for your help.
04-24-2006, 05:49 PM
glad i could help. :)
04-24-2006, 09:20 PM
I have successfulyl merged CG video with Live video in the sequence editor, but have hit another snag. The video that contains the CG objects is semi tranparent allowing what is visible in the live video to be seen through the objects. I will describe the steps I am taking and hopefully someone out there will be able to help me find out why I am having the transparency problem.
First I bring the video with the CG objects into the sequence editor by pressing shift-a and then selecting video, and then choosing the video.
Second I bring in the live action video via the same process.
Then I select both videos and press shift-a and then ADD.
Then I set the End Frame number to match, and then the animate button.
The resulting video has the CG objects in it, but they are semi transparent. I have messed with the alpha settings when I create the video that has the CG objects in it, but to no avail. It doesn't seem to matter what I change in that video, the objects are still transparent in the final video, even though they are not transparent in the original video.
I was thinking it was a property of the Sequence strip, but I have changed the settings for each one (by selecting the strip and pressing the n-key), but nothing seems to affect the transparency.
Does anyone have any idea why this is happening?
04-24-2006, 09:56 PM
the add effect adds (go figure) the pixel values of the 2 strips together and that will give you the transparent effect. What you want to use is alpha over but you will need to render your cg sequence as a series of rgba .png images so that you have an alpha channel to work with- avi's do not have alpha information.
04-24-2006, 09:56 PM
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