Hi,
On Tuesday 04 March 2014 01:13 PM, Hans Verkuil wrote:
On 03/04/2014 08:38 AM, Archit Taneja wrote:
Hi Hans,
On Monday 03 March 2014 01:20 PM, Hans Verkuil wrote:
Hi Archit!
On 03/03/2014 08:33 AM, Archit Taneja wrote:
Add crop ioctl ops. For VPE, cropping only makes sense with the input to VPE, or
the V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE buffer type.
For the CAPTURE type, a S_CROP ioctl results in setting the crop region as the
whole image itself, hence making crop dimensions same as the pix dimensions.
Setting the crop successfully should result in re-configuration of those
registers which are affected when either source or destination dimensions
change, set_srcdst_params() is called for this purpose.
Some standard crop parameter checks are done in __vpe_try_crop().
Please use the selection ops instead: if you implement cropping with those then you'll
support both the selection API and the old cropping API will be implemented by the v4l2
core using the selection ops. Two for the price of one...
When using selection API, I was finding issues using the older cropping
API. The v4l_s_crop() ioctl func assumes that "crop means compose for
output devices". However, for a m2m device. It probably makes sense to
provide the following configuration:
for V4L2_BUF_TYPE_VIDEO_OUTPUT (input to the mem to mem HW), use CROP
target(to crop the input buffer)
and, for V4L2_BUF_TYPE_VIDEO_CAPTURE(output of the mem to mem HW), use
COMPOSE target(to place the HW output into a larger region)
Don't you think forcing OUTPUT devices to 'COMPOSE' for older cropping
API is a bit limiting?
Yes, and that's why the selection API was created to work around that
limitation :-)
The old cropping API was insufficiently flexible for modern devices, so
we came up with this replacement.
Another reason why you have to implement the selection API: it's the only
way to implement your functionality.
Okay, I'll go ahead with the selection API then :)
Archit
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