Producers and editors are increasingly faced with editing projects that require compositing of multiple layers of video, graphics and text information, which make programs more attractive and more valuable.
Media 100’s 844/X utilizes a proprietary media supercomputer called the GenesisEngine to improve rendering performance on multilayer content.
Because editing has traditionally been a real-time operation while compositing often requires significant rendering time, these workflows have remained separate. Slow rendering time also makes editors reluctant to experiment creatively and last minute changes are often costly or impractical.
Media 100 offers a solution to these problems with 844/X, a new editing system designed specifically for lightning-fast compositing of unlimited layers.
A Media Supercomputer
To solve the issue of rendering performance when compositing layers, Media 100 developed a media supercomputer called the GenesisEngine that provides the bandwidth to precisely manage an avalanche of video, graphic, key and audio data. The GenesisEngine offers real-time image processing that delivers greater than 420MB/s sustained throughput using a signal architecture that is 10 bits throughout. To meet the system’s processing and performance specifications, Media 100 designed three ASICs containing a total of 33 million transistors and used seven times in each 844/X — Foss, Holmes and Hatalsky. Each of the three devices addresses specific needs.
The Foss processor is a 140,000-gate, 0.35-micron device that caches video and key data from the host and distributes the data to the processing pipelines. Controlling 128MB of high-speed SDRAM, this cache is required to make the high-data-rate GenesisEngine immune to host latency issues.
The Hatalsky processor is a 750,000-gate, 0.25-micron device that handles real-time effects processing. The device simultaneously performs de-interlacing, scaling, color correction, chroma/luma keying, repositioning, rotations and output filtering. DVE calculations are processed in real time with sub-pixel precision. There are five Hatalsky processors within each system, one per stream and one dedicated to the graphics buffer.
The Holmes processor is a 450,000-gate, 0.25-micron device that performs real-time compositing, border generation, blend mode processing, re-interlacing and subsampling. This device also routes data to and from the GenesisConnect Expansion port.
Compositing unlimited layers introduces potential quality issues including banding errors endemic to eight-bit systems. The 844/X was developed to uphold picture quality through millions of recursive operations. 10-bit, 4:2:2:4, uncompressed video data and keys enter the processing pipeline and are de-interlaced and upsampled so that the processing pipeline operates on progressive 4:4:4:4 RGB and alpha data at 60 fps. This is important to avoid temporal artifacts when processing interlaced video data.
The Hatalsky processor uses bicubic-subpixel interpolation and maintains up to 31-bit precision through its internal processing pipeline, again important to maintain processing quality. And at the Hatalsky output, Quantel’s Dynamic Rounding, licensed from Quantel, has been implemented to bring the data back to 10 bits.
After the compositing stage, the data is re-interlaced and stored to disk as 10-bit 4:2:2:4, 30 fps data.
Facility Integration
844/X provides full SMPTE 259M compliance for integration within a facility. There is an active loopthrough on the input and there are two SDI outputs. Audio support includes four channel pairs of digital audio I/O that can be acquired from, or played out as, embedded data in the serial digital video stream or as 24-bit AES/EBU. The GenesisEngine also includes V-LAN and Genlock that is so strictly compliant with television requirements that the system can operate as the master reference for a studio, post-production or television broadcasting facility.
The system was designed to be adaptable to the evolving needs of the industry. Major functional circuits were developed to be replaceable subsystems, simplifying the path to future upgrades. The facilities integration subsystem, the Studio card, and the in-stream effects subsystem (the IFX card), are examples. In each case, the system can be adapted to future equipment or effects requirements. Similarly, the host interface card (the CFX card) can be replaced if necessary to adapt to changing CPU requirements.
Along with the capability to change, further functionality can also be added to the system via an expansion connector. The GenesisConnect component enables additional subsystems to be added into the system’s 4:4:4:4, progressive-processing pipeline.
An embedded operating system distributes 32,000 VLIW commands per field. This, coupled with the data caching technologies built into the ASICs, greatly reduces communication over-head with the host. The application is unhindered by the processing requirements of the platform, resulting in a fast and responsive user interface.
Application Software
Tightly integrated application software enables the processing power of the GenesisEngine supercomputer; together they enable a new way of processing layer-intensive designs. The software’s Intelligent Layering Architecture (ILA) enables efficient processing of any number of composite layers, recursively processing data when the layer count moves beyond eight. The ILA applies intelligence in the automated management of intermediate (rendered) media, optimizing the speed of the recursive layering process. As an example, a 10-second segment consisting of 10 video and 10 key layers will take just 20 seconds to process, and the layers can contain any or all of the system’s in-stream effects.
A useful tool in the ILA is Visual Voicing, which lets the user select any four of the composited layers (or subcomps) to be previewed in real time. With this feature, users can easily check layer relationships when working with complex composites that consist of high layer counts.
Workflow
The capabilities described above exist within an environment that brings together editing and compositing in one application.
The system’s editorial features were built around the standard source/ record model and, with a customizable keyboard, the system should feel familiar to the user. Editing capabilities include resizable subsamplers, vari-speed jog and shuttle, drag-and-drop editing, and advanced trim editing with roll and slip-and-slide functions. The Sync Grouping feature supports “grouping” and synchronization of user-defined sets of audio and video clips, allowing the user to sidestep problems with rippling changes and sync loss.
Users can access real-time compositing features such as 13 transfer modes with unlimited keyframes, and keying capabilities that include alpha keying, luma keying and chroma keying with control for individual color channels (RGB). There are also several refinement tools, including tolerance, transparency, opacity, spill suppression and softness.
Today’s editors need to quickly turn around high-quality video content that consists of highly complex and compute-intensive imagery. The challenge then is to maintain high levels of creativity, while minimizing render downtimes and breaks in the creative flow.
844/X addresses this problem by using technological innovations to enable an integrated workflow that combines editing and incredibly fast, unlimited-layer compositing with 10-bit image quality throughout – all integrated into an industry-standard PC platform.
Dan Holmes is the director of hardware engineering at Media 100.
