TDA4VM: DSS M2M writeback mode (M2M) in linux SDK

Munan Xu

Part Number: TDA4VM
Other Parts Discussed in Thread: AM5718,

Hello,

I see from the SDK documentation that writeback (M2M) mode on the DSS is available for the processor SDK RTOS, but it isn't enabled for the Linux SDK. Is there a way to enable this functionality within Linux? I have a customer using AM5718 today using the VPE to process one video stream and scale it and colorspace correct the video data before sending it out across either Ethernet or USB interfaces. It seems like the only way to do this on TDA4VM would be if there was a way to leverage the writeback mode to send the converted frame back to memory so that it could be accessed by different interfaces other than the display output.s

Would there be another way to accomplish this functionality?

Munan

over 3 years ago

0 Manisha Agrawal over 3 years ago

TI__Mastermind 22946 points

What's the scaling and colorspace format requirement? TDA4VM has Multi-Scaler (MSC) hardware accelerator for downscaling, and DSP based streamer plugin for color space format conversion.

0 Munan Xu over 3 years ago in reply to Manisha Agrawal

TI__Expert 5440 points

Hi Manisha,

Source is currently in YUY2 format, I see that all the documentation on the tiovxmultiscaler uses NV12, so would the pipeline have to look something like this?

I think the only question would be how to get the NV12 format back into YUY2 for raw USB video output.

Munan

0 Gang Hua over 3 years ago in reply to Munan Xu

TI__Guru 63690 points

There is no H/W in TDA4VM-VPAC that can do NV12 to YUYV conversion.

So, you may have to do that in DSP.

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TDA4VM: DSS M2M writeback mode (M2M) in linux SDK