Orin nano: clarification on the number of supported concurrent stream

Autonomous Machines Jetson & Embedded Systems Jetson Orin Nano
1

Hi,

The official summary for the Orin Nano (published at: Jetson Orin for Next-Gen Robotics | NVIDIA) under “CSI Camera” mentions:

Up to 4 cameras (8 via virtual channels***)
8 lanes MIPI CSI-2
D-PHY 2.1 (up to 20Gbps)

However, in the Jetson / Orin Nano Series / Data sheet / DS-11105-001_v1.1 document :

  • the section 1.5.1 MIPI Camera Serial Interface (CSI) mentions:

Orin Nano can support up to 16 virtual channels (VC) and supports data type interleaving.

  • the section 1.5.2 Video Input (VI) mentions:

These models include single and multi-camera systems, which may have up to six active streams

We plan to use the Orin Nano 4GB in the 4x 2-lane MIPI D-PHY configuration with the following breakdown:

  • 2x MIPI CSI with a single virtual channel on each port
  • 2x MIPI CSI with up to 4 virtual channels on each port. The total bandwidth would always be far below the 2.5Gbps/pair supported by the interface.
  • every virtual channel would carry RAW10 data.

While capturing concurrently on the 4 different ports seems feasible, we are much more confused about the exact capabilities when it comes to the maximum number of virtual channels which can be used concurrently.

Could you please clarify what is expected to be supported?

In case ISP processing would impact the numbers, please let us know.

Best regards

3

Suppose the HW able connect to 16 but only support 8 cameras launch simultaneously.

Thanks

4

Hi @ShaneCCC,

Thanks for the very fast feedback.

only support 8 cameras launch simultaneously.

By cameras here, do you mean not a physical camera, but also a virtual channel? So should I read you reply as:the HW supports up to 16 virtual channels, among which 8 can operate concurrently

Please let me know if you think there is any misunderstanding.

Would you know what the document DS-11105-001_v1.1 means by the restriction about the 6 active stream? Is this an errata, or are there some scenario which bring more restrictions on the number of concurrently active streams?

Best regards

5

From software point of view support to 8 cameras due to bandwidth concern.
But if from HW design by virtual channel suppose able support to 16 cameras.
For your case looks like would like to use 10 cameras. I would suggest to use AGX Orin instead or AGX Xavier instead of Orin Nano

7

Hi @ShaneCCC,

Thank you for the fast follow up.

Ok, I think I understand. For cost reason, only the Orin Nano is an option in our design.

We could bring down the number of concurrent virtual channels in used from 10 to 6, but this would not impact the bandwidth.
We checked the peak bandwidth for the MIPI CSI bus, and we are in specs for the Orin Nano. Our only concern was about the number of max concurrently supported virtual channels.

My new understanding is that actually, even on the Orin Nano, up to 16 channels may be concurrently supported, but the bandwidth is the main concern from Nvidia side.

By software, do you refer to a particular layer of the stack? Is there a software limit defined explicitly somewhere?

Best regards

8

Not only the MIPI CSI bandwidth also the ISP and CPU bandwidth due to need lots of software stack like 3A …

Thanks

9

Hi @ShaneCCC,

Thanks for highlighting this point. The datasheet mentions:

The ISP in the Jetson Orin Nano supports a maximum frequency of 704 MHz, with two pixels/clock is equivalent to approximately 1408 MPixels

We would also be quite far below this number in our use case. But we will keep this in mind.

We will run more tests once we have the HW, and post more specific queries if needed.

Thank you for your prompt support today.

Best regards.

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