Hi Guennadi,
Guennadi Liakhovetski wrote:
Hi Sakari,
On Tue, 19 Jan 2016, Sakari Ailus wrote:
Hi Guennadi,
Guennadi Liakhovetski wrote:
Add documentation for 3 formats, used by RealSense cameras like R200.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
---
[snip]
+ <para>This is a 16-bit format, representing depth data. Each pixel is a
+distance to the respective point in the image coordinates. Distance unit can
+vary and has to be negotiated with the device separately. Each pixel is stored
+in a 16-bit word in the little endian byte order.
I think we really need a way to convey the unit (and prefix) information
to the user. Considering the same should be done to controls, it'd be
logical to do that at the same time with the controls.
Do I understand you correctly, that you'd like to add a control to specify
distance units for this format? If yes - I don't think you want a separate
control just for this format, right? And you mention, you also want to be
Considering there are no other depth formats defined, it should be
generic I think, but so far with a single user.
able to specify units for other controls. But I would've thought, that
controls themselves should define, what unit they are using. E.g.
V4L2_CID_EXPOSURE_ABSOLUTE specifies, that it's unit is 100us. I would
expect the same from other controls too. "Legacy" controls like
V4L2_CID_EXPOSURE don't specify units, so, I would expect, that their use
should be discouraged.
Would you create a new control whenever someone needs a new unit for a
control? That's the very problem I think --- currently applications have
no means to know what's the unit for the control.
I've always wondered why we had V4L2_CID_EXPOSURE_ABSOLUTE as
V4L2_CID_EXPOSURE already existed. :-)
The smiapp driver, for instance, uses V4L2_CID_EXPOSURE, and the unit is
lines. There's a fine exposure control as well implemented by many
sensors but the driver currently does not expose that capability.
Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
I'd like to have Hans's and/or Laurent's ack on this as well.
Unless the original patch requires changes, it could be re-applied if no
changes are requested to it. My understanding is that the issue mainly
was the missing documentation, i.e. this patch.
Yes, I'll repost both patches as a series, maybe let's try to get some
understanding on the units question first.
--
Regards,
Sakari Ailus
sakari.ailus@xxxxxxxxxxxxxxx
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