Matrox Matrox Radient eV-CXP, Установка и справочник по оборудованию, Страница: 41 / 70

Host interface 41
The equations for the YUV16 conversion are described in the following table.
Host interface
The Matrox Radient eV-CXP PCIe 2.0 Host interface is capable of high-speed
DMA transfers to Host memory, or other memory mapped onto the PCIe bus.
The DMA write engine of the Host interface is capable of performing the transfers
without the help of the Host CPU.
Matrox Radient eV-CXP uses PCIe 2.0 technology to communicate with the
Host. Under optimum conditions, Matrox Radient eV-CXP can send data to the
Host at a peak transfer rate of up to 4 Gbytes/sec. Optimum conditions include
using the board in a PCIe 2.x slot with 8 active lanes, using a 256-byte payload.
DMA write performance is chipset and computer dependent, and is slightly
affected by the image size and alignment in Host memory.
The Matrox Radient eV-CXP Host interface has four DMA write contexts, which
act independently, simulating four DMA write engines running in parallel. The
presence of multiple DMA contexts does not change the maximum bandwidth,
but can help reduce latency.
Color space conversion Equations
RGB-to-YUV • Y = 0.299 R + 0.587 G + 0.114 B
• U = -0.169 R - 0.331 G +0.500 B + 128
• V = 0.500 R - 0.419 G - 0.081 B +128
BGR-to-YUV • Y = 0.114B + 0.587G +0.0229R
• U = 0.500B - 0.331G - 0.169R + 2
(res-1)
• V = -0.081B - 0.419G + 0.500R + 2
(res-1)