Laurent Pinchart wrote:
Hi Sakari,
On Monday 13 August 2012 17:18:20 Sakari Ailus wrote:
Laurent Pinchart wrote:
On Saturday 28 July 2012 00:27:23 Sakari Ailus wrote:
On Fri, Jul 27, 2012 at 01:02:04AM +0200, Laurent Pinchart wrote:
On Thursday 26 July 2012 23:54:01 Sakari Ailus wrote:
On Tue, Jul 24, 2012 at 01:10:42AM +0200, Laurent Pinchart wrote:
Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---
drivers/media/video/mt9v032.c | 36
++++++++++++++++++++++++++++---
1 files changed, 33 insertions(+), 3 deletions(-)
Changes since v1:
- Make sure the total horizontal time will not go below 660 when
setting the horizontal blanking control
- Restrict the vertical blanking value to 3000 as documented in the
datasheet. Increasing the exposure time actually extends vertical
blanking, as long as the user doesn't forget to turn auto-exposure
off...
Does binning either horizontally or vertically affect the blanking
limits? If the process is analogue then the answer is typically "yes".
The datasheet doesn't specify whether binning and blanking can influence
each other.
Vertical binning is often analogue since digital binning would require as
much temporary memory as the row holds pixels. This means the hardware
already does binning before a/d conversion and there's only need to
actually read half the number of rows, hence the effect on frame length.
That will affect the frame length, but why would it affect vertical
blanking ?
Frame length == image height + vertical blanking.
The SMIA++ driver (at least) associates the blanking controls to the
pixel array subdev. They might be more naturally placed to the source
(either binner or scaler) but the width and height (to calculate the
frame and line length) are related to the dimensions of the pixel array
crop rectangle.
So when the binning configuration changes, that changes the limits for
blanking and thus possibly also blanking itself.
Do the blanking controls expose blanking after binning or before binning ? In
the later case I don't see how binning would influence them.
Some sensors control the blanking in pixel array directly whereas some,
like the SMIA++, control the frame length in the source (scaler or
binner) source instead.
So it is up to the sensor hardware --- I think it's still better to keep
all the controls in a single subdev. Otherwise it'd be quite difficult
for the user to figure out how to calculate the frame rate.
Kind regards,
--
Sakari Ailus
sakari.ailus@xxxxxx
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