On 29 Jan 2001, Gerd Knorr wrote:
> > > > For a bt848, when are the risc program(s) generated? When REQBUFS is called,
> > > > or when VIDIOC_QBUF is called?
> > >
> > > QBUF.
> >
> > Isn't that inefficient? Last time I checked, risc program generation takes
> > a significant length of time.
>
> Depends. Generating the risc code at REQBUFS time means that you'll limited
> to a fixed set of buffers. Depending on your application it might save you
> a memcopy() if you can put it _anywhere_ and not only to one of the predefined
> buffers.
Maybe I misunderstood, I thought you had to call REQBUFS before you could use
the buffers for DMA?
> BTW: This is how bttv works today. It will write new risc code for every
> single frame you are capturing. So it can't be that slow as you can capture
> full frame rate and have (on fast boxen) still enouth spare CPU time to
> compress the video in real time...
Ah, well, I can't capture and compress video in real time. I'd rather improve
the software instead of buying a faster computer.
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