USB 3.0 throughput on Apalis iMX8

Technical Support
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1

We are interested in your Apalis iMX8 module and we would like to know about operability / compatibility between USB 3.0 cameras, gstreamer and USB 3.0 interface.
What kind of throughput can we achieve with your module regarding video capture over USB3.0? Can we do 1080p60 in YUY2 (16bit/px) ?

In summary, what is the achievable bitrate?

We know we had bandwidth issue on iMX6 chipset using a xHCI to USB 3.0 bridge. Wondering if we will have the same bottleneck in USB 3.0 with iMX8.

Thank you.
Regards,
Jérôme

2

HI @jbolduc01

iMX6 does not feature any USB 3.0 Port but iMX8 does. From hardware point, the throughput is defined by USB 3.0. However we never tested capturing a high video resolution using a USB 3.0 with gstreamer.

You would need to try this out on your own.

Best regards,
Jaski

3

We used a iMX6 with a xHCI to USB 3.0 bridge (PCIe).
So you have no result on throughput with USB 3.0?

4

As I said from Hardware side the throughput on USB 3.0 Port should work but we never tried using this in the combination with video capturing software.

Best regards,
Jaski

5

Is it possible to test this on your side using a USB 3.0 camera and tell me the frame rate you are able to achieve using gstreamer?

Thanks,
Jérôme

6

Hi @jbolduc01

We will check if we can get a USB 3.0 Camera and come back to you next week.

Best regards,
Jaski

7

Hi @jbolduc01

Meanwhile we got a USB 3.0 Camera and we are checking if it is possible to use it with Apalis iMX8.

We will let you know once we know more.

Which USB 3.0 camera are you using?

Best regards,
Jaski

8

Hi,
We are using INOGENI devices to capture video to USB 3.0. It is uncompressed video and you can capture up to 1080p60 or 4K30
https://inogeni.com/product/4k-to-usb-3
Maybe you can buy one?

Regards,
Jérôme

9

Hi @jbolduc01

Finally we did some testing and therefore we can share some results with you.

We tested this USB 3.0 camera with Apalis iMX8QM which has a resolution of 1280x1024, but we had only a throughput of 3.7MB/s.
Further we have done read tests using USB 3.0 Harddisk (not SSD), which gave us the following results:

root@apalis-imx8:~# hdparm -t /dev/sda1

/dev/sda1:
 Timing buffered disk reads: 280 MB in  3.01 seconds =  93.00 MB/sec

This throughput is near to the speed marked in the specification of the disc. With this throughput, it should be possible to send 23.5 Frames per second from your Camera with Full HD resolution with YUV2 (16bit/px).

I know this is not the final answer you were looking for, but it gives you some idea about the USB3.0 speed of Apalis iMX8QM.

Best regards,
Jaski

10

Hi Jaski,

I really appreciate your answer to this question!
Which app have you tried to capture video from this camera? gstreamer?
A total speed of 3.7MB/s is way below achievable USB3.0 speed. I was able to do more over USB 2.0 using iMX6.

Regards,
Jérôme

11

Hi,
no, we used a proprietary software given by the USB 3.0 Camera provider. The video was also monochrome so not really similar use-case as yours.

Best regards,
Jaski

12

Hi Jérôme

I wanted to add that with the newest Bsp changes the USB speed was increased from 165MB/s to 220MB/s. This speed should be enough for you to USB 3.0 Camera with the asked resolution.

Best regards,
Jaski