TDA4VE-Q1: Is Simultaneous 4K60 decode and encode possible?

Hi,

The assigned engineer is on a business travel. Please expect a delay of 1~2 days in response.

Regards,
Parth

Hi David,

What's the full resolution for which you want decode functionality? Can you please provide more information? 

I guess ethernet is separate question, your questions are related to only encode & decode, correct?   

Regards,

Brijesh

Hi Brijesh

We have a sensor capable of 4k60 and want to take in the full resolution/frame rate stream from this sensor and process the data using the AI engine.  The result of this will be a processed 4k60 stream.  This stream then needs to be down-converted to at least three other streams, one of which is 1080p, the others would be lower resolution/frame rates.  Additionally, some 4k stills would be required   All four streams and the stills are then distributed out over Ethernet and one of the lower resolution streams stored on a local SD card.  The only reason for mentioning Ethernet is that the processor will be using a lot of its processing power and it was not clear if there were any limitations preventing parallel processing of the conversion to Ethernet.

The customer has a tight specification on latency - would the processing/conversions meet a latency spec of 30ms (ignoring the Ethernet part of course)?

Best regards

Dave

Hi David,

From my tests, I am seeing that the TRM is correct and I am getting approximately 450 MP/s which translates to 4K at 55 FPS. 

None of the use cases you mentioned are supported on the TDA4VE. You are far exceeding the pixel rate that the device is able to support. Its important to keep in mind that the encoder and decoder are the same physical device. So 4K60 encode and decode is not something that is supported simultaneously while also being able to meet timing requirements.

Best,

Brandon

David,

Which HLOS are you using? Linux or QNX? The results I provided were from QNX SDK perspective.

I ran similar tests using the Linux 9.0 SDK and am seeing that 4K 60 FPS decode is supported. Could you please point out to me where in TRM you are seeing that the pixel processing rate for j721s2 is set at 450 MP/s?

Thanks,

Brandon

Hi Brandon

We haven't got as far as deciding what HLOS we would use yet, this is very preliminary investigation to see whether the processor fits our use case.

The document I was looking at is:

SPRUJ28C - J721S2, TDA4AL, TDA4VL, TDA4VE, AM68A TRM.pdf

The 450 MHz/60fps number (based on a 3840 x 2160 frame) is in the performance sub-section 6.2.2.1, page 576 of the Video accelerator section.

Best regards

Dave

Hi David, 

Thank you for showing this to me, I believe what this table is trying to convey is that in order to meet the 4K60 timing requirements, a frequency of 450 MHz is needed - this isn't directly saying that our device only supports 450 MP/s. The important document to reference would be the datasheet for the device. I can see that this was referenced in the linked question you attached. From that document, you can see that the pixel processing rate for both encode and decode is 480 MP/s. As pointed out in other thread, 500 MP/s is more accurate because this correlates to the 4K60 case. 

4K 60FPS encode and decode is supported on TDA4VE. However, it should be understood that encoding and decoding are offloaded to the same piece of physical hardware, hence why a 4K60 FPS encode and decode cannot be done at the same time. 

TDA4VH has two instances of the physical hardware block that does encoding and decoding. Therefore pixel processing will double and make more use cases available to you.

Best,

Brandon