On Friday 09 October 2009 07:07:32 Jun Nie wrote:
> 2009/9/23 Jun Nie <niej0001@xxxxxxxxx>:
> > Hi,
> > I re-send this email for the last one is rejected by system. I am
> > sorry if you guys received both.
> >
> > I am optimizing video playback with overlay with V4L2 driver. The
> > video content is a sub-region of codec output. Thus a memory copy is
> > necessary.
> > Is there plan to support for stride and discrete YUV planer in
> > kernel? Such as below changes can help much for my usage case.
> >
> > --- a/include/linux/videodev2.h
> > +++ b/include/linux/videodev2.h
> > @@ -529,7 +529,20 @@ struct v4l2_buffer {
> > __u32 offset;
> > unsigned long userptr;
> > } m;
> > + /* UV/GB location is valid only in planer case */
> > + union {
> > + __u32 offset_ug;
> > + unsigned long userptr_ug;
> > + } m_ug;
> > + union {
> > + __u32 offset_vb;
> > + unsigned long userptr_vb;
> > + } m_vb;
> > __u32 length;
> > + /* stride of YUV or RGB */
> > + __u32 stride_yr;
> > + __u32 stride_ug;
> > + __u32 stride_vb;
> > __u32 input;
> > __u32 reserved;
> > };
> >
> > If such change is acceptable for everyone, I may help on the implementation.
> > Any comments are welcome.
> >
> > Jun
> >
>
> Hi, Hans/Guennadi
>
> What do you think of supporting this feature?
>
> Jun
>
>
Well, it is definitely not possible to do it in this manner since changing
the size of struct v4l2_buffer will break the API. Furthermore, something like
this will only work if the DMA engine can handle strides. Is that the case
for your hardware? I don't think you mentioned what the hardware is you use.
Regards,
Hans
--
Hans Verkuil - video4linux developer - sponsored by TANDBERG Telecom
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