[ IMX8M - Max. number of cameras can the SoC support ]

[davidtrinh]

Dear, 

We are considering to use the IMX8 SoC for our next project in which the SoC is required to input 6 720p HD cameras simultaneously.  The IMX8M datasheet tells me that the SoC has 2 MIPI-CSI ports with virtual channel support for each port, which theoretically can input 8 cameras streams simultaneously. In case of the IMX6Q, the camera peripheral is handled by the IPUs subsystem which can input 4 camera streams (max.) via its MIPI-CSI because each IPU core can handle only 2 streams. However, neither the datasheet nor reference manual have detail descriptions about how MIPI-CSI camera streams are read into the IMX8M. As a result, I can not be sure if more than 4 cameras can be read simultaneously by the SoC. 

I would like to ask if it is possible to input 8 720p HD video streams into the SoC using its 2 MIPI-CSI ports in virtual channel input mode!? If not, what is the max. number of cameras that this SoC can support?!

Thank you.

[jamesbone]

Hello David,

In the case of the i.MX8M there is no IPU,  but there is a module DCSS ( Display Controller Subsytem),

The iMX8M video data path is followed:

MIPI CSI2 -> MIPI CSI to CSI Bridge -> CSI (CMOS Sensor Interface)

The CSI hardware module is reused from iMX7, and this CSI module is also used on iMX6S, iMX6UL, it is not IPU based. There are no resizing, CSC, rotation features on the capture path. You can do these in post processing with DCSS and GPU hardware.

Best Regards,

Jaime

[davidtrinh]

Dear Jaime,

Thank you for your response.

Can you please let me know how many camera inputs can the SoC handle simultaneously, please?!

I would like to connect 2 DS90UB964-Q1 chips to the SoC's 2 MIPI ports so that I can stream 8 cameras into the SoC. Will that be possible for the SoC to receive all the streams?! 

Thank you!

David

[bernhardfink · Accepted solution]

Even if the virtual channel support is mentioned in the 8M reference manual, it does not exist.

For i.MX 8M MIPI-CSI2 virtual channel is not supported in hardware, so the driver cannot automatically split the input from each virtual channel. The software can just receive a combined stream into memory, then split it by using the CPU.

So natively the 8M can support 2 cameras connected to the 2 MIPI-CSI2 ports.

Regards,

Bernhard.

[davidtrinh]

Hi Bernhard,

Thank you for your reply. 

Cheers,

David