Memory array to pio using DMA (Video)

Yes a DMA can do what you are looking for. But I don't recommend using a PIO to send video offchip. You can't predict the rate at which the DMA will write pixels to the PIO. Instead have the DMA write pixels into a FIFO that has the read port sampled at a fixed rate so that the DAC will see a constant stream of pixels.

I think if you ripped the stuff out of this design at the end of the pixel pipeline, exported a FIFO interface, and connected that exported FIFO interface to your ADC it should work. Just change the C code for whatever buffer size you use in your design. If you use Qsys then exporting a FIFO is easy, you just click the export as column. In SOPC Builder you would need to create a custom FIFO, with one side connected to the DMA and the other side exported through a conduit.