Write portion of frame buffer

[Altera_Forum]

Hi i would like, when i receive a new frame, to select the central part of it (clip) and store it in memory. The position where i save this piece of frame should depend on the frame number like this: 

 | 1 | 2 | 3 | 4 |   where 1 2 3 4 are the frame number.  i would do:  CVI --> CLIP --> Frame Buffer --> CVO  How can i control the memory address where i want to write data?

[Altera_Forum]

You must specify what you are talking about. 

What kind of frames? Ehternet or whatever?  Where do frames come from? What IP or module are you using? How are you supposed to write into memory?

[Altera_Forum]

What kind of frames? Ehternet or whatever?  

 DVI Video Frames   Where do frames come from?   From a Camera   What IP or module are you using?   Altera VIP , DDR2 Memory Controller   How are you supposed to write into memory?    Now i write all the frames into a frame buffer    i would in future:  Get Video Frame 1 --> Take a small portion of it--> write in position 1  Get Video Frame 2 --> Take a small portion of it --> write in position 2   and so on...    Then i would read a video frame composed of those pieces:   | 1 | 2 | 3 | 4 |     Every time i get for example frame 1, i refresh the portion of video in position 1

[Altera_Forum]

Maybe using a SGDMA at the clipper output?

[Altera_Forum]

If you already can transfer the frame to memory, you should be able to change the address. 

Infact you said you now write to a frame buffer, so you defined somewhere a buffer address and address. I guess you only need to conditionate it with the frame number.

[Altera_Forum]

Thanks for your reply. 

I understand what you say but how can i conditionate this address?

[Altera_Forum]

I'm afraid, I don't know your VIP module, neither how you operate it, so I can't help you much. 

If you have the HDL source code (but I suppose you have not), you could find and modify the lines involved in the frame transfer. If it's provided as a black box with no configurable parameters for this, I think you can do little or nothing. A solution could be starting a memory to memory dma just after the VIP core has completed the frame transfer, and copy it to the right section. But this is somewhat inefficient and maybe inapplicable in your case.

[Altera_Forum]

Thanks for your reply! 

 i think i need an interface between the video streaming(Avalon ST interface) coming from the clipper, and the memory controller (Avalon MM interface).   es. Frame 1 --> Clipper --> write this data at location 1 in memory --> Frame Reader   Maybe using a dma or i need a custom component?