DM8168 - V4l2 Capture driver dual output support

Hi,

By default V4L2 framework doesnt support dual output, thats why we have not supported that. There is not plan to support it as of now.

Regards,

Hardik Shah

Hi Hardik,

Is this lack of support because it has not been implemented in software or is it a case that the media controller binary does not support dual output?

Thanks,
Ralph

Hi,

Media controller binary supports dual output. But there is not way in V4L2 to configure two independent streams using same /dev/videox node. Thats why we are not supporting it in V4L2.

Regards,

Hardik shah

Okay, thanks. Sounds like I might be able to modify the driver to allow dual output then.

Ralph

Hi,

Is it possible? Because according to Hardik its V4L2 which does not support this kind of feature.

It is very important for us to achieve this. Can you please help us to understand how is this possible? I would like to work in that direction and get dual output out of V4L2.

Regards,

Krunal

I think Hardik meant the specific TI816x video ouput driver.

V4L2 seems to support multiple outputs. See: http://v4l2spec.bytesex.org/spec-single/v4l2.html#VIDEO

I would need to look deep into the driver to get this working. I'm working on H264 capture at the moment, then onto dual H264 capture.............

Hi,

The V4L2 can support multiple video channels (i.e. through /dev/video0 and /dev/video5) and I am able to do that using two different HDMI ports.

Here we are talking about two separate streams from a single channel (single HDMI port, i.e. The driver should provide two separate buffers to application from a single video channel)

Regards,

Krunal

Hi,

Thats what I am taling about. Can you please suggest us a way of doing it. Like S_FMT, G_FMT S_CROP etc doing differently for each streams on same node. And again same for Queue, Dequeue etc.

Regards,

Hardik Shah

Can we add a new configuration parameter named (outputStreamId) for this (not sure if anything like this is already available in V4L2 framework)?

Based on the outputStreamId can't we separate format, cropping related operations?

Regards,

Krunal

Hi,

Please go through V4L2 framework and create a RFC on how to support two streams. You can start implementing if you get some good ideas and start posting on V4L2 community. But its not simple like adding new variable.

Regards,

Hardik Shah

Hi,

      I'm also interested in the dual capture, is there some place with a guide about how to start on this? As far as I know this was not possible with the VFCC provided in OMX, but it seems to be possible using V4L2 in the DM816x, if that is the case, do you have some suggestion about how to start on this?

Thanks,

-David

Hi All,

I got the dual capture working with the DM8168 EVM. You can find a patch with the changes that I did in the following link:

https://www.ridgerun.com/developer/wiki/index.php/Getting_Started_Guide_for_DM8168_EVM#Dual_Capture_Support

Regards,

-David