The television broadcast market is rapidly shifting from analog to digital video production and delivery, and in particular, to high-definition television (HDTV), the highest quality video available for television. The feature-rich architecture of the Stratix™ GX device family provides an ideal solution for creating and transmitting HDTV video signals. Built on Altera's new Stratix architecture, Stratix GX devices include up to 20 full duplex transceiver channels capable of operating at up to 3.125 gigabits per second (Gbps) per channel.
System Overview of HDTV Video Production Environment
An HDTV video production environment must support a network of various equipment sets, such as video switchers and routers, storage servers, professional cameras and monitors, as well as recording, editing, encoding, and decoding equipment. Video and embedded audio is transported between equipment over coaxial cable using the video serial digital interface (SDI) transmission standard at the HD-SDI rate of 1.485 Gbps. (See Figure 1.)
Figure 1. Typical HDTV Video Production Studio
Stratix GX Transceivers for HD-SDI
The Stratix GX family supports the 1.485 Gbps serial data speeds of HD-SDI on 4 to 20 full-duplex transceiver channels. The transceiver circuitry integrates clock-data recovery (CDR) and serializer-deserializer (SERDES) capabilities. Stratix GX logic elements (LEs) can be used to perform SDI input and output signal-processing functions such as framing, scrambling/descrambling, and synchronization of multiple SDI signals to the same clock edge.
Figures 2 and 3 show a typical hardware flow for processing SDI signals when received or transmitted from video production equipment. SDI signals can be routed over up to 100 meters of coaxial cable. Due to the long distance that SDI must be carried, each SDI channel requires an external cable equalizer device at the receiver to improve the signal quality, and a cable driver device at the transmitter to boost the signal strength.
Figure 2. SDI Input Processing Flow
Figure 3. SDI Output Processing Flow
Performing Video Processing in DSP Blocks
The DSP blocks in Stratix GX devices provide a powerful solution for implementing high-performance digital signal processing (DSP) applications. The DSP blocks are dedicated circuitry that provide predictable and very high signal performance without congesting the FPGA interconnect routing. Each DSP block is capable of running at up to 250 MHz, providing ample performance to process a 10-bit HD video signal or two 20-bit HD video signals, plus overhead data. These blocks provide fast and efficient processing for functions such as multiplication, filtering, color--space conversion, error detection and correction, or JPEG and MPEG encoding and decoding. For more information on the Stratix GX DSP Blocks, visit the DSP Blocks in Stratix GX Devices page.
TriMatrix Memory for HD Video
The Stratix GX devices feature the TriMatrix™ memory structure, which is composed of three sizes of embedded RAM blocks, and provides more than 3.4 megabits (Mbits) of RAM. TriMatrix memory includes 512-bit M512 blocks, 4-Kbit M4K blocks, and 512-Kbit M-RAM blocks, each of which can be configured to support a wide range of features. The M512, M4K, and M-RAM blocks can operate at over 300MHz, providing ample performance to process 10- or 20-bit HD video signals plus overhead. TriMatrix memory provides an optimal solution for storing multiple horizontal video lines, or the active portion of HD video lines. For more information on TriMatrix memory, visit the TriMatrix Memory in Stratix GX Devices page.
