Re: [Q] Interleaved formats on the media bus

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sakari,

On Saturday 04 February 2012 13:22:21 Sakari Ailus wrote:
> Sylwester Nawrocki wrote:
> > On 02/01/2012 11:00 AM, Sakari Ailus wrote:
> >> I'd guess that all the ISP would do to such formats is to write them to
> >> memory since I don't see much use for either in ISPs --- both typically
> >> are
> >> output of the ISP.
> > 
> > Yep, correct. In fact in those cases the sensor has complicated ISP built
> > in, so everything a bridge have to do is to pass data over to user space.
> > 
> > Also non-image data might need to be passed to user space as well.
> 
> How does one know in the user space which part of the video buffer
> contains jpeg data and which part is yuv? Does the data contain some
> kind of header, or how is this done currently?
> 
> I'd be much in favour or using a separate channel ID as Guennadi asked;
> that way you could quite probably save one memory copy as well. But if
> the hardware already exists and behaves badly there's usually not much
> you can do about it.

If I'm not mistaken, the sensor doesn't send data in separate channels but 
interleaves them in a single channel (possibly with headers or fixed-size 
packets - Sylwester, could you comment on that ?). That makes it pretty 
difficult to do anything else than pass-through capture.

-- 
Regards,

Laurent Pinchart