On Sat, Jul 25, 2009 at 04:39:18PM +0200, ext Hans Verkuil wrote: > On Saturday 25 July 2009 15:25:21 Eduardo Valentin wrote: > > On Sat, Jul 25, 2009 at 03:33:55PM +0200, ext Hans Verkuil wrote: > > > On Saturday 25 July 2009 15:29:38 ext-eero.nurkk...@nokia.com wrote: > > > > > > > > > I'm surprised at these MAX string lengths. Looking at the RDS > > > > > standard it > > > > > seems that the max length for the PS_NAME is 8 and for RADIO_TEXT it > > > > > is > > > > > either 32 (2A group) or 64 (2B group). I don't know which group the > > > > > si4713 > > > > > uses. > > > > > > > > > > Can you clarify how this is used? > > > > > > > > > > Regards, > > > > > > > > > > Hans > > > > > > > > Well, PS_NAME can be 8 x n, but only 8 bytes are shown at once... > > > > so it keeps 'scrolling', or changes periodically. There's even > > > > commercial > > > > radio stations that do so. > > > > > > And I'm assuming that the same is true for radio text. However, this > > > behavior > > > contradicts the control description in the spec, so that should be > > > clarified. > > > > Yes, I'll add a comment explaining this for those defines. > > Another question: what happens if I give a string that's e.g. 10 characters > long? What will happen then?
I believe receiver will still scroll, but may get confused. This case, it is better to pad with spaces. > > If the string must be exactly 8 x n long, then I think that it is a good idea > to start using the 'step' value of v4l2_queryctrl: this can be used to tell > the application that string lengths should be a multiple of the step value. > I've toyed with that idea before but I couldn't think of a good use case, > but this might be it. I think that would be good. It is a way to report to user land what can be done in these cases which strings can be chopped in small pieces. Of course, documenting this part it is appreciated. > > Regards, > > Hans > > -- > Hans Verkuil - video4linux developer - sponsored by TANDBERG Telecom -- Eduardo Valentin -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
