Hi Sakari, On Tuesday 10 January 2012 10:42:58 Sakari Ailus wrote: > Laurent Pinchart wrote: > > On Tuesday 10 January 2012 00:26:46 Sakari Ailus wrote: > >> Laurent Pinchart wrote: > >>> On Monday 09 January 2012 23:32:06 Sakari Ailus wrote: > >>>> Laurent Pinchart wrote: > >>>>> On Monday 09 January 2012 18:38:25 Sakari Ailus wrote: > >> ... > >> > >>>>>> A fourth section may be required as well: at this level the frame > >>>>>> rate (or frame time) range makes more sense than the low-level > >>>>>> blanking values. The blanking values can be calculated from the > >>>>>> frame time and a flag which tells whether either horizontal or > >>>>>> vertical blanking should be preferred. > >>>>> > >>>>> How does one typically select between horizontal and vertical > >>>>> blanking ? Do mixed modes make sense ? > >>>> > >>>> There are minimums and maximums for both. You can increase the frame > >>>> time by increasing value for either or both of them --- to achieve > >>>> very long frame times you may have to use both, but that's not very > >>>> common in practice. I think we should have a flag to tell which one > >>>> should be increased first --- the effect would be to have the minimum > >>>> possible value on the other. > >>> > >>> But how do you decide in practice which one to increase when you're an > >>> application (or middleware) developer ? > >> > >> I think it's the responsibility of this library to do that, unless the > >> user wants really, really precise control in which case they have to > >> deal with the blanking values directly. In general it should be the > >> library. > > > > And how does the library decide ? :-) > > frame_time = pixel_rate / ((width + hblank) * (height + vblank)) > > The user gives you frame time and the configuration contains the > information which one to prefer. Let's say the user prefers hblank (from > the above): That was my question, how does the user decide whether hblank or vblank is preferred ? > (width + hblank) * frame_time = pixel_rate / (height + vblank_min) > > hblank = pixel_rate / (height + vblank_min) / frame_time - width > > width, height, pixel_rate and blankings are as in the pixel array. > Elsewhere these values may depend on the link frequency and other > factors so the pixel array is the only reliable place to do this. -- 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
