Setting overlay parameters on v4l2sink fails

[Andreas Naumann]

Am 22.01.2016 um 20:10 schrieb Nicolas Dufresne:
> The overlay support in v4l2sink was designed by TI
> before V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY was added. Contribution are
> welcome, as long as it's backward compatible.

I see, thanks for the background info. I'll try to come up with 
something compatible.

>
> Nicolas
>
> p.s. isn't those thing deprecated in favour of G_SELECTION now ? what
> does vivid do ?

As far as i can see vivid implements both. The v4l2 API docu still lists 
G_SELECTION as experimental..
Is there any other somewhat mature gst-sink that enables using overlay 
planes?

>
> Le vendredi 22 janvier 2016 à 14:12 +0100, Andreas Naumann a écrit :
>> Hi,
>>
>> i observed positioning of video overlays using the v4l2sink
>> parameters
>> like 'overlay-left' doesnt work. Digging a little I found out the
>> VIDIOC_G_FMT/VIDIOC_S_FMT ioctl's dont reach the overlay-driver due
>> to
>> being filtered in the kernels v4l2 ioctl dispatcher functions because
>> my
>> driver is not a VFL_DIR_RX but TX type.
>>
>> After reading the Linux for Video API docu, it seems that the
>> S/G_FMT
>> function are indeed intended for the Capture/Rx part of the Video
>> Overlay Interface. Somehow I cant image such a device but anyway,
>> the
>> code that checks for RX is in place since 2012.
>>
>> Now, the gstreamer v4l2sink does need a TX device doesnt it? So with
>> current kernels, the video-overlay ioctls cant ever work, or what am
>> I
>> missing?
>>
>> Digging further I came across another type, that is
>> V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY. This is per API doc intended for
>> output and shares the data structures for S/G_FMT ioctls with
>> V4L2_BUF_TYPE_VIDEO_OVERLAY. So I tried telling my driver that he
>> supports such an interface and redirected the existing s/g_fmt
>> function
>> pointers (as I saw in some other implementation, I think omap).
>> On v4l2sink side its a oneliner to change to using that interface (
>> gst_v4l2sink_sync_overlay_fields()).
>>
>> Voila, the positioning works!
>>
>> Now, is this the way to go or what do the experts think?
>>
>>
>> cheers,
>> Andreas
>>
>>
>> _______________________________________________
>> gstreamer-devel mailing list
>> gstreamer-devel at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel