AXI VDMA configuration for accessing full DDR address space

[bhavinlapasia]

Hi,

I am reading AXI video stream input from camera and using VDMA (S2MM) storing it to DDR. With the same VDMA (MM2S), I am reading the data back from DDR and displaying it on monitor using HDMI. I am using the board ZC706. The VDMA is set to maximum 32 frame buffers. My image size is 640x480 (300Kb, gray image) at 60fps. VDMA stores data in cyclic buffer method. My VDMA address range I have set to 1GB.

I want to capture / write incoming video data for e.g. say 10 seconds i.e. 600 frames and then once captured, display it back on HDMI as a 10 second video. In short I want to capture a video and store it. VDMA however works in cyclic buffer format and overwrites the new frame buffer once it fills the last one. 

So can VDMA only be used for real time video processing or it can be configured to store data in entire memory range by changing the configuration on the go (setting new start location) after its buffers are full?

Regards,

Bhavin Lapasia

[samk · Accepted solution]

Hi @bhavinlapasia,

The VDMA was not developed with the intention of writing a full video to continuous memory space. I think that what you are trying to do would theoretically work, but it will be hard to know for sure without testing.

It will be important to update the new start location so that no frames are overwritten or skipped.

Regards,

Sam

[florentw]

Hi @samk 

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