SDI includes low resolution SD-SDI (SMPTE 259) and HD-SDI (SMPTE 294). SD-SDI is used to transmit low resolution PAL compatible video 720 * 576 @ 25fps and uses a clock rate of 27 MHz. HD-SDI is used to transmit HD video including 720-P and 1080-I using a 10 bit 148.5 MHz, YCbcr, BT656 complian video.
Logic-Fruit SDI IP suppports both SD and HD-SDI mode. The main task of the IP includes
- Recover clock and data from HD-SDI using GTX IP
- Decoder the Video Data using a Xilinx SDI IP
- BT-656 format conversion
For the SD-HDI mode, GTX are run at 11 time oversampling rate at 27*11 = 2.97 Gbps. Then a specially designed 11 time downsampling unit (DRU) is used to recover the data at 27 MHz.