TDA4VM: How to replicate display node.

Hi Lee,

Display node cannot be replicated, as each instance of display node can support only video pipeline. If you want to create two displays, please create two display nodes instances and assign different display pipe line to each of them.. You could redirect the 4 camera output ie object array to display node and then can select the channel/camera output to be displayed in each display node using control command.

Regards,

Brijesh

Hi

I have two question. 

Q.1 TIVX_KERNEL_DISPLAY_ZERO_BUFFER_COPY_MODE / TIVX_KERNEL_DISPLAY_BUFFER_COPY_MODE difference and usage

Q.2 

Brijesh Jadav said:

If you want to create two displays, please create two display nodes instances and assign different display pipe line to each of them

-> What is mean pipe line? pipeId or TIVX_TARGET_DISPLAY1 ?

I think that TIVX_TARGET_DISPLAY1 selects physical image data output path and pipeIds select image data path in one physical path (ex TIVX_TARGET_DISPLAY1) as abstractly.

-> Does variable of tivx_display_select_channel_params_t change pipeID for selecting input soruce? 

Thank you for quick reply.

Hi Lee,

youngwoo lee said:

Q.1 TIVX_KERNEL_DISPLAY_ZERO_BUFFER_COPY_MODE / TIVX_KERNEL_DISPLAY_BUFFER_COPY_MODE difference and usage

Please use only zero copy mode, as there is a memory copy involved in the Buffer_Copy_Mode.

youngwoo lee said:

-> What is mean pipe line? pipeId or TIVX_TARGET_DISPLAY1 ?

pipeline here means pipe id. It is used to select the display pipeline.. Whereas TIVX_TARGET_DISPLAY1 is used to select the target in Openvx, under which display would run. You could consider target as a task in which display pipeline would be running on R5F core.

youngwoo lee said:

-> Does variable of tivx_display_select_channel_params_t change pipeID for selecting input soruce? 

No, pipeid is used to select the display pipe. There are 4 display pipeline supported in the DSS. This variable is used to select the pipeid. There is a separate control command for selecting input channel. I think it is named as *_SELECT_CHANNEL in the display node. Using this control command, you could select the camera to be displayed in this display, selected by pipeld. Please refer to the capture->display test case in the tiovx/kernels_j7/hwa/test folder. It shows how SELECT_CHANNEL command can be used.

Regards,

Brijesh

Hi,

Actually I can display video of which I select camera but I don't understand principle exactly.

Brijesh Jadav said:

Whereas TIVX_TARGET_DISPLAY1 is used to select the target in Openvx, under which display would run

-> What does "target" mean?

I want to display one of videos to two display devices.  I'm refer to app_dss_dual_display_defaults.c in dss 

Thank you.