Hi Sakari, On Sunday 06 May 2012 21:14:02 Sakari Ailus wrote: > Laurent Pinchart wrote: > > On Saturday 05 May 2012 16:09:33 Sakari Ailus wrote: > ... > > >> The pixel format and the image size at the pad are clearly format > >> (VIDIOC_SUBDEV_S_FMT) but the other things are related to pads but not > >> format. > >> > >> I see them different kinds of properties of pads. That suggests we might > >> be better renaming the option (-f) to something else as well. > > > > You like breaking interfaces, don't you ? :-D > > I thought you said we have no stable release yet. :-D > > The selection interface on subdevs is currently used to change format > related things (cropping and scaling, for example) but it was one of > Sylwester's patches ("V4L: Add auto focus targets to the selections > API") that adds a focus window target to the V4L2 selection interface. I > don't see why it couldn't be present on subdevs, too. That's got nothing > to do with the image format. > > I've been pondering a bit using another option to configure things > related to selections. Conveniently "-s" is free. We could leave the > crop things to -f but remove the documentation related to them. It would then become much more complex to setup a complete pipeline in a single command line, unless we completely modify the way the command line is parsed. What would you think about renaming -f to -V (long option --video or --v4l2) ? media-ctl will hopefully be used for non-V4L2 devices in the future, so subsystem-specific options will likely be needed. > I'm fine with keeping the things as they are for now, too, but in that > case we should recognise that -f will not be for formats only. Or we > split handling selections into separate options, but I don't like that > idea either. > > >>> I find the '/' a bit confusing compared to the ' ' (but I think you find > >>> the space confusing compared to '/' :-)). I also wonder whether we > >>> shouldn't just drop 'fmt:', as there can be a single format only. > >> > >> You can set it multiple times, or you may not set it at all. That's why I > >> think we should explicitly say it's the format. > > > > Not at all makes sense, but why would you set it multiple times ? > > I guess that's not a very practical use case, albeit there may be > dependencies between the two: Guennadi had a piece of hardware where the > hardware cropping or scaling capabilities depended on the format. We don't have a way to handle that cleanly in the V4L2 API, do we ? > But not setting it at all definitely is a valid use case. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html