Re: Displaying a stream of images using GTK



On Thu, 28 Jul 2005 20:00:05 -0000, alok nagdev said:
> I'm writing an application for displaying a sequence of images. The sequence 
> of images is actually converted from a 30 frames/sec. video and are stored 
> as a single binary file containing 3 channels (RGB). Can someone give me any 
> idea on how to do it or give me a pointer to some tutorial? What is the 
> fastest way of displaying images/frames just as in a video?

The single biggest question is "Do you have enough memory or a small enough
video clip that it fits in RAM easily?".  If not, you'll need to do some sort
of pre-buffering and/or readahead from disk (think threads here....)

The second question is "Do you need to be able to start displaying the instant
Frame 1 shows up, or are you allowed some amount of pre-buffering"?  (If you're
allowed to run 5-6 frames behind, your timing constraints get a *lot* easier.. ;)

The third question is "How do you define 'fastest way'?".  I've had to deal
with applications that had inbound data at around 30fps, but had to actually
output 96fps (stereo 48fps for a VR system), and handling the stereo, the 3D
imaging, interpolating from 30 to 48fps, and a lot of really messy mathematical
modelling, and suddenly the time budget gets *really* tight.  I've had to deal
with applications where "30fps is good enough, but we need a minimum-CPU-usage
solution because other things are going on".  And then there's always the
question of "how much trouble are you in if you drop a frame on the floor" (a
fatal error for broadcast TV, a nuisance if you're just playing a DVD for
yourself...).

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