Re: Creating Video Software
Re: Creating Video Software
- Subject: Re: Creating Video Software
- From: Scott Anguish <email@hidden>
- Date: Tue, 19 Aug 2003 02:03:48 -0400
Have a good look at the bMovie example code at
/Developer/Examples/AppKit
It has some useful items to deal with some of this.
On Tuesday, August 19, 2003, at 1:31 AM, email@hidden wrote:
I'm about to start development on a new special effects program. It's
a very basic program that basically takes images with alpha channels
and composites them over a video fame. So, it might take a picture of
a lightsaber and composite it on a video frame using alpha channels in
the lightsaber image. The user will need to be able to drag the image
around on the screen, resize it, etc. The software will create the
effects on a frame by frame basis.
I'm not sure how to approach creating this software. I've looked into
a couple different options:
1) Video frame to NSImage using Quicktime API: One way to create the
program would be to convert every frame of the video to an NSImage
when the movie was loaded. Then, I could just use NSComposite to
composite the effects image over the frame. To handle scrolling
through the frames, the software could just update the NSImageView
with the correct image for the frame selected. When the user is ready
to export it just creates a movie file by combining all the different
NSImages using the quicktime API. This route seems to take a lot of
overhead in terms of memory, especially if its a large movie.
Yep, but not as much as painting it on each frame by hand! :-)
2) Use quicktime API: I haven't looked into using the quicktime API
that extensively yet. I suppose there are functions that would let me
composite the image over a video frame without first converting the
video frame to an NSImage. I'm not sure how I would display this on
the screen through, especially since the user needs to be able to drag
the image around over the video frame.
Consider that the overlay may not move from frame to frame, so allow
them to leave it in place for a number of frames.
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