Re: [Workshop-2011] RFC: V4L2 API ambiguities

[Sylwester Nawrocki <sylvester.nawrocki@xxxxxxxxx>]

Hi!

On 08/13/2012 03:13 PM, Hans de Goede wrote:
>> 2) If a driver supports only formats with more than one plane, should
>> V4L2_CAP_VIDEO_CAPTURE still be defined?
> 
> No

Agreed.

>> And if a driver also supports
>> single-plane formats in addition to >1 plane formats, should
>> V4L2_CAP_VIDEO_CAPTURE be compulsary?
> 
> Yes, so that non multi-plane aware apps keep working.

There is the multi-planar API and there are multi-planar formats. Single- 
and multi-planar formats can be handled with the multi-planar API. So if 
a driver supports single- and multi-planar formats by means on multi-planar
APIs, there shouldn't be a need for signalling V4L2_CAP_VIDEO_CAPTURE, 
which normally indicates single-planar API. The driver may choose to not 
support it, in order to handle single-planar formats. Thus, in my opinion 
making V4L2_CAP_VIDEO_CAPTURE compulsory wouldn't make sense. Unless the 
driver supports both types of ioctls (_mplane and regular versions), we 
shouldn't flag V4L2_CAP_VIDEO_CAPTURE. 

Regards,
Sylwester
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