2009. 04. 16, 오후 9:59, Guennadi Liakhovetski 작성:
On Thu, 16 Apr 2009, Dongsoo, Nathaniel Kim wrote:
Hello Guennadi,
On Thu, Apr 16, 2009 at 9:06 PM, Guennadi Liakhovetski
<g.liakhovetski@xxxxxx> wrote:
3. you open videoX, one "default" camera gets activated
immediately - not
all applications issue S_INPUT, so, there has to be a default.
4. if an S_INPUT is issued, you have to verify, whether any camera
is
currently active / capturing, if none - switch to the requested
one, if
one is active - return -EBUSY.
5. reference-counting and guaranteeing consistency is more
difficult, as
well as handling camera driver loading / unloading.
Oops I forgot to say that we need to enforce legacy v4l2 applications
to use VIDIOC_S_INPUT after opening device.
And every S_INPUT issuing should come after G_INPUT like every "set"
API in v4l2.
Hm? Does the API require it? If not, I don't think we should inforce
it.
No I don't think so, but we can use that to be sure.
And what do you mean "legacy v4l2 applications" - which applications
are
not "legacy"?
I mean upcoming applications in the future, like LiMo based platform
from several mobile phone vendors.
And we can also expect for 3rd party applications if the camera APIs
are well made and standardized.
So, I would say, your approach adds complexity and asymmetry. Can
it be
that one camera client has several inputs itself? E.g., a decoder?
In any
case, I wouldn't do this now, if we do decide in favour of your
approach,
then only after the v4l2-device transition, please.
Of course. I didn't mean to disturb your transition job. Please do
your priority job first.
And about camera client with several inputs question, I will say that
almost every 3G UMTS phone has dual camera on it. And we can consider
every 3G UMTS smart phones have dual camera on it with soc camera
solution.
No, sorry, this wasn't my question. By "client" I meant one camera or
decoder or whatever chip connects to a camera host. I.e., if we have a
single chip with several inputs, that should logically be handled with
S_INPUT ioctl, this would further add to the confusion of using
different
inputs on one video device to switch between chips or inputs /
functions
on one chip.
Yes exactly. It was "single chip with several inputs." that I
intended to tell. but still don't get what the confusion you mean.
Sorry ;-()
Cheers,
Nate
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
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