Video Capture Synchronization using DM6446

Bob Yiu said:

I'm using two DM6446 chip connecting camera separately.

To try to understand better, you have two cameras and two DM6446 processors that you want to be frame synchronized?

Bob Yiu said:

So how to dely the other camera 16ms,and let them capture synchronously?

From a capture standpoint this would not be possible without additional hardware, you would need some buffer logic (like an FPGA) to hold the incoming frames and send them out to the DM6446s at the same time.

On the other hand you could do this in software within the DM6446 devices, if the only problem is that you want the processing/displaying to happen at the same time. In software you could have the two DM6446s communicate over some medium, such as GPIO, such that each device can inform the other when the frame has been received and to begin processing/displaying at the same time. This could be as simple as having two GPIOs across between the two devices such that each device asserts the GPIO as soon as it has a frame and than waits on the other device to assert its GPIO before beginning processing, so they both process in sync.

Hey,Bernie 

Thanks for your reply.

Bernie Thompson said:

To try to understand better, you have two cameras and two DM6446 processors that you want to be frame synchronized?

Yes,I have and two cameras, and two DM6446 processors,and each DM6446 processor connects a camera.

And I want them to be  frame synchronized.

Unfortunately,I need them capture synchronously,so I need some buffer logic. Is there any solution using TI products?

Thanks!

Bob

Bob Yiu said:

Unfortunately,I need them capture synchronously,so I need some buffer logic. Is there any solution using TI products?

TI does not provide anything for this specific operation, this is something you would normally be able to do with a relatively simple CPLD/FPGA with some RAM to buffer the frames.

You could do this synchronization/buffering operation with another processor that has two inputs and two outputs like a TMS320DM648 however that would be overkill and expensive.

Would like to give a different perspecitve:

Not sure of the stringent requirement of sync'ng 2 video sources. 2 sources have different clock sources making it even more difficult. Further, from s/w perspective as well, it's not a good idea of processing synced' sources; The reason being the Peak Cycles. If the video content is staggered, the Peak cycles requirement gets averaged out.

I decide to turn to DM648 and DM6467

I've bought a DM6467.Can it capture video synchronously(two cameras input)?

Bob Yiu said:

I've bought a DM6467.Can it capture video synchronously(two cameras input)?

The DM6467 itself could capture video and synchronize it internally in software with double buffering, synchronization at the time of capture is dependent on the sources being in sync already so it is outside the control of the DM6467.