[libcamera-devel] [PATCH v4 2/6] libcamera: stream: add initial StreamConfiguration structure

[Niklas Söderlund]

Hi Kieran,

Thanks for your feedback.

On 2019-01-29 09:47:43 +0000, Kieran Bingham wrote:
> Hi Niklas,
> 
> On 29/01/2019 02:00, Niklas Söderlund wrote:
> > Add an initial StreamConfiguration implementation to hold configuration
> > data for a single stream of a Camera. In its current form not many
> > configuration parameters are supported but it's expected the number of
> > options will grow over time.
> > 
> > At this stage the pixel format is represented as an unsigned int to
> > allow for easy mapping to the V4L2 API. This might be subject to change
> > in the future as we finalize how libcamera shall represent pixel
> > formats.
> > 
> > Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> > ---
> >  include/libcamera/stream.h |  6 ++++++
> >  src/libcamera/stream.cpp   | 26 ++++++++++++++++++++++++++
> >  2 files changed, 32 insertions(+)
> > 
> > diff --git a/include/libcamera/stream.h b/include/libcamera/stream.h
> > index 4f47d85ed6382b36..4b24dd841dd64b64 100644
> > --- a/include/libcamera/stream.h
> > +++ b/include/libcamera/stream.h
> > @@ -13,6 +13,12 @@ class Stream final
> >  {
> >  };
> >  
> > +struct StreamConfiguration {
> > +	unsigned int width;
> > +	unsigned int height;
> > +	unsigned int pixelFormat;
> > +};
> > +
> 
> 
> Should we consider a single global 'Format Configuration' structure or
> object as Jacopo has been looking at ? or would that be too generic? (or
> even too specific if it has planar information etc)

I'm not sure I follow you. The idea for StreamConfiguration is to hold 
all configuration parameters that can act on a stream before stream on.  
Once the stream is running I think we will need a different object to 
handle parameters that can change in runtime, such as controls. I think 
we need to tackle this once we start working with queuing requests 
instead of buffers :-)

> 
> 
> 
> >  } /* namespace libcamera */
> >  
> >  #endif /* __LIBCAMERA_STREAM_H__ */
> > diff --git a/src/libcamera/stream.cpp b/src/libcamera/stream.cpp
> > index 01f4e5008af8ac46..ef55f947574e241c 100644
> > --- a/src/libcamera/stream.cpp
> > +++ b/src/libcamera/stream.cpp
> > @@ -48,4 +48,30 @@ namespace libcamera {
> >   * optimal stream for the task.
> >   */
> >  
> > +/**
> > + * \struct StreamConfiguration
> > + * \brief Configuration parameters for a stream
> > + *
> > + * The StreamConfiguration structure models all information which can be
> > + * configured for a single video stream.
> > + */
> > +
> > +/**
> > + * \var StreamConfiguration::width
> > + * \brief Stream width in pixels
> > + */
> > +
> > +/**
> > + * \var StreamConfiguration::height
> > + * \brief Stream height in pixels
> > + */
> > +
> > +/**
> > + * \var StreamConfiguration::pixelFormat
> > + * \brief Stream pixel format
> > + *
> > + * This is a little endian four character code representation of the pixel
> > + * format described in V4L2 using the V4L2_PIX_FMT_* definitions.
> > + */
> > +
> >  } /* namespace libcamera */
> > 
> 
> -- 
> Regards
> --
> Kieran

-- 
Regards,
Niklas Söderlund