Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> escreveu:
On Monday 17 December 2012 18:12:19 William Swanson wrote:
If the remote video sensor reports an interlaced video mode, the CCDC block
should configure itself appropriately.
What will the CCDC do in that case ? Will it capture fields or frames to
memory ? If frames, what's the field layout ? You will most likely need to
modify ispvideo.c as well, to support interlacing in the V4L2 API, and
possibly add interlaced formats support to the media bus API.
Sorry for the delay in responding; today is my first day back at the
office. I do not know the answers to these questions, and the
documentation doesn't discuss interlacing much. Our application has the
following pipeline:
composite video -> TVP5146 decoder
-> CCDC parallel interface -> memory -> application
One of the wires in the parallel interface, cam_fld, indicates the
current field, and this patch simply enables that wire. Without the
patch, every other line in our memory buffer is garbage; with the patch,
the image comes out correctly.
As a matter of fact, an earlier version of the ISP driver actually
contained code for dealing with this flag; it was removed in
cf7a3d91ade6c56bfd860b377f84bd58132f7a81 along with a bunch of other
cleanup work. This patch simply adds the code back, but in a way that is
compatible with the new media pipeline stuff.
I believe that the CCDC simply captures image data a line at a time and
writes it directly to memory, at least in our use case. The CCDC_SDOFST
register controls the layout, and the default value (which is what the
driver uses now) is basically correct. I am not familiar enough with the
V4L2 architecture to tell you how the driver decides that it now has a
complete frame, or what that even means in an interlaced case.
On 12/27/2012 12:27 PM, Mauro Carvalho Chehab wrote:
> Btw, you missed to add a Signed-off-by: line on it.
Oops, this was a problem with my git setup. Both email addresses are
mine; I can re-send the patch with them both set to the same address if
you would prefer that.
-William
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