High-quality encoding
Jul 1, 2008 12:00 PM, By Stephane Blondin
Sophisticated solutions preserve the quality of your assets.
Mastering and repurposing
Mastering traditional workflows
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In the mastering environment, the integrity of branded assets is paramount. High-end mastering relies on sophisticated picture processing algorithms, and encoders today are chock-full of proven technologies developed for professional broadcast applications. These technologies provide superior-looking pictures in a wide range of professional formats, whether HD masters or mobile media encoded at low bit rates. Content owners must seek out efficient and reliable encoding systems that will allow them to achieve the balance of quality and bandwidth right for each target application. In turn, this will create new opportunities for revenue generation while lowering storage, distribution and transmission costs.
Integrated motion estimation technology is the foundation of key processing tasks, including deinterlacing, frame rate conversion, SD-to-HD upconversion and HD-to-HD conversion. These processing tasks require advanced image conversion capabilities to enable the high-quality, artifact-free output necessary to leverage HD and SD masters successfully.
Phase correlation is the most powerful and accurate motion estimation technique today. It provides the highest level of vector reliability and precision by analyzing incoming images and shifting the pixels in each video field so that they line up perfectly, even for complex scenes where there is fast motion, fine graphics, or mixed film and video material. The accurate shift of pixels enables clean deinterlacing of video to progressive with minimal artifacts. It also provides the high-quality motion portrayal necessary for transparent standards conversion and SD/HD conversions.
Phase correlation technology eliminates issues such as ringing, softness and adaptive mode switching artifacts. With still images, the technology achieves maximum resolution and preserves the fine detail in graphics and sharpness of text. In fast-moving action, phase-correlated motion estimation and motion compensation ensure full resolution and well-defined motion. In complex pictures, a variety of components can be handled without compromise, yielding a crisp overall output.
Sophisticated encoding techniques give content owners the power to create high-quality deliverables from their masters. In the creation of content for low-bit rate applications, advanced encoder capabilities such as automated dynamic reframing and background blurring allow for a significant improvement of sports and entertainment content delivered on small screens. Systems with advanced mobile encoding capability can dynamically distinguish the foreground and the background within the video image, treating each separately in order to concentrate the most energy (or bits) on the parts of the image that are most important to the viewer.
By bringing the most important object, character or athlete into crisp detail, while lessening the detail and prominence of objects or scenery in the background, the encoder can provide a compelling viewing experience regardless of the size of the display. Dynamic reframing of video images and the production of tighter, sharper shots helps to retain the emotional impact of the original content when transcoded for low-bandwidth delivery to portable or bit-starved devices.
The bit rate savings resulting from advanced video processing techniques allow content owners to leverage limited bandwidth to provide more downloads to more customers or to stream additional material on their distribution channels. Companies producing higher quality content can improve the look of their product for the same amount of money or bandwidth, thus maintaining costs while targeting premium customer segments. By establishing a high level of automation in encoding material, a facility owner or manager can reduce operational costs, free up staff for creative work, and improve the throughput and time to market or air.
Automating QC in encoding
Among the greatest advantages of advanced encoders is their ability to perform real-time quality control (QC) during the encoding process, whether at ingest, receipt of external file, or following any subsequent conversion or repurposing operation. Issues with video, audio and metadata often appear at the end of the production chain, long after they first emerge. Until recently, the limited options for controlling the quality of file-based content typically involved having an operator review content on a computer monitor or copy the content to tape or server, and then send it to a dedicated QC suite for checking. A more proactive approach — made possible through the latest encoding systems — allows such problems to be tagged much earlier. This enables the user to identify and resolve issues sooner and consequently minimize the time, resources and money wasted on compromised assets.
While a large visual artifact may be easy to flag, identifying smaller problems that are invisible to the human eye, yet critical to downstream encoders, requires more sophisticated evaluation of content. Inspection of content prior to encoding allows not only for identification of problems with the signal, but also for a before-and-after comparison of QC reports to determine if any new artifacts have been introduced.
Automated QC processes in advanced encoders can measure parameters that eyes and ears don't, such as multichannel audio levels, compression performance, bit rates, metadata and content legality. Data stream can be monitored for closed captions and Dolby metadata. Rather than spending time visually scanning content in a QC suite, staff can use a frame-by-frame QC report to inspect only the exception found by the machine QC stage. This allows the operator to quickly deal with potential problems in content. Easy integration with automation and asset management systems permits seamless checking and encoding of content with little need for human intervention.
Once content is compressed and compared with the original signal, the advanced encoder provides operators with tools for finding the best balance between quality and the desired bit rate. In cases in which content is being captured from a satellite or contribution link, there may be just one chance to make the right decision. The encoder can help operators monitor ingest in real time so that their masters are of the quality they expect and require. With the right system in place, content producers and owners can be assured that they will get it right the first time. This confidence is also particularly valuable in mastering from delicate or deteriorating tape-based archives that might last through just one round of digitizing.
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