On Sunday 22 February 2009, Hans de Goede wrote: > We want to be able to differentiate between a cam which has its sensor > mounted upside down, and a cam which can be pivotted and happens to be > upside down at the moment, in case of any upside down mounted sensor, we > will always want to compentsate, in case of a pivotting camera wether we > compensate or not could be a user preference. If we take Olivier Lorin's gl-860 case though, how do we define what is the normal orientation and what is pivoted, it is likely we'd just decide the direction where the sensor output is the right way up is normal and the other is pivoted and then what info have you got from having multiple flags. In order to explain what I mean it is probably best to refer to rotations in terms of pitch, yaw and roll (as per the definitions at http://en.wikipedia.org/wiki/Flight_dynamics) where the forward direction is the shooting direction. When still cameras are fitted with gravity sensors they are normally set up with the intention of measuring roll and will often get confused by 90 degrees of pitch. If a laptop is fitted with a camera that can either record the user or the view looking away from the user then the camera needs to be able to either pitch or yaw but not roll. If the camera yaws then no correction is needed but if it pitches then the resulting image needs rotating to be the correct way up (and in that scenario it is improbable that the user doesn't want the correction applied). Other than the fact that one needs correcting and the other doesn't these options appear identical to the user and so manufacturers provide one or the other but not both. If a video camera had a roll sensor (or even, as a believe some specialist tripods can manage, a full set of roll, pitch and yaw measurements) then a substantially different mechanism is needed to provide access to that data but in the absence of anyone having access to such equipment I don't think we can design the interface now. Adam -- 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
