You are here: Home > New Canon HD Codec Ensures Success In File-Based World
 |
New Canon HD Codec Ensures Success In File-Based World Bandwidth-friendly video files start with a robust codec that efficiently conserves digital bits while maintaining high image quality. This helps broadcasters creating and sending content for the local newscast, film/TV production crews share daily footage as manageable digital files, and professional video editors to use less storage space for a particular project. With many of the productions now produced in MPEG-2, and virtually all of the content distribution platforms of media organizations as well as cable, satellite and terrestrial television providers based on it, it's clear that the format is here to stay for many years. Yet there’s also room to grow. Results from the latest-generation MPEG-2 codecs have shown significant improvements (in space conservation and image quality) over previous versions by taking full advantage of the unique toolsets within the SMPTE standardized MPEG-2 specification. With newer MPEG-2 codecs, typical compression ratios between 2:1 and 5:1 can be achieved. The variety of capabilities and features found within the MPEG-2 HD standard help to preserve quality during image processing while providing higher compression ratios, and thus more data storage space, than “lossless” solutions. Its use in a file-based news production workflow, for example, based around a legacy facility infrastructure enables first-generation HD quality to be maintained throughout the production process—from ingest to final distribution and archiving—with no need for more bandwidth (furthermore, images compressed with MPEG-2 codecs look exceptional on an HDTV screen). Recognizing that customers want cost-effective solutions that can be implemented quickly and easily into existing infrastructures, the new Canon XF codec was developed: A next-generation MPEG-2 4:2:2 full HD file-based recording codec that facilitates the reliable capture of the highest quality video imaging and uncompressed audio. This high quality is ensured with the capability to record 1920x1080 and 1280x720 HD images at up to 50 Mbps (constant bit rate).  4:2:2 color sampling allows for greater post-production precision and quality (for compositing, color grading, etc), with double the color resolution of HDV and other 4:2:0 formats. Note: These illustrations represent a color image converted to RGB, after which each component signal is converted to monochrome. Because B-Y and R-Y signals lack a brightness component and only indicate saturation, images produced from them look quite unnatural to the human eye. To avoid confusion, the illustrations are produced by conversion to monochrome and then, for convenience, conversion of saturation to brightness. In addition, because it leverages such an established compression standard, the Canon XF codec is compatible with many video industry-standard editing and processing software applications, including those from Adobe, Apple, Avid and Grass Valley. Long GoP Efficiency Canon’s XF codec features proprietary DIGIC signal processing for the best compression results, employing sophisticated motion estimation prediction techniques to calculate and automatically eliminate redundant data information to get the highest quality images in the smallest amount of storage space. And remember, these networked environments used by broadcasters and professional production studios demand high quality, manageable file-sizes in order to transfer material across multiple workstations and for storage efficiencies in editing, production and archiving.  Inter-frame Compression can significantly reduce the bit rate of a movie with maintaining image quality, and is composed of sequences of I-Frames (Intra-frames), P-Frames (Predictive-coded frames), and B-Frames (Bidirectionally-predictive-coded frames). P-Frames use frame data from earlier in the image sequence with minor changes to create the current frame. B-Frames use data from the video frames before and after to create the current frame in the image sequence. The can be many P- and B-Frames between I-Frames in a sequence. The consecutive inter-frame images is the Group of Pictures (GoP) Length. Note: The above graphic is for illustrative purposes only, and may not indicate the actual GoP length of Canon's new codec. For professionals editors, the maturity of the MPEG-2 Long GoP scheme allows virtually every nonlinear editing system on the market to handle the streams in their native format and in real-time, with modest demands on CPU processing power. Expanded (4:2:2) Color Space Means Greater Color Fidelity While many recording systems on the market today continue to use 4:2:0 color space processing, 4:2:0 suffers from blocky color issues and poor color fidelity resolution. 4:2:0 delivers similar problems with chroma keying and with shooting under solid-color lights (such as shooting on a set dominated with a red or blue wash of light). Processing signals in 4:2:2 delivers twice the color information of 4:2:0, virtually eliminating these issues.  Color sampling refers to selectively extracting information by skipping the color difference signal of some pixels. Applying the principle that the human eye is more sensitive to brightness than hue or saturation, sampling compresses signals by eliminating some pixels from the color difference signals to be read. The color sampling scheme indicates how many pixels out of a four-pixel area (two pixels vertically by two horizontally) are used as brightness and color difference signal information. Note: The above graphic is for illustrative purposes only, and may not indicate the actual color sampling of Canon's new codec. The adoption of MPEG-2 Full HD compression enables the recording of 1920x1080-pixel full HD video. In developing its new MPEG-2 codec, Canon understood that its customers clearly needed higher quality signal processing to produce the best results for on-screen talent against a green screen set, for example. The 4:2:2 specification was chosen because it is the color sampling format used by most professional formats. The immediate benefit is nearly double the color resolution—which leads to much better results when chroma keying—while most natural settings look sharper as well. File-based recording also helps video operations to be much more efficient during the post-production process, making it an ideal format for many genres, such as newsgathering, documentary filmmaking and event videography. Industry-Standard MXF Support Canon’s new codec generates digital files that are fully compatible with the Material eXchange Format (MXF), a widely supported open source file wrapper for the storage of video, audio and metadata. It was developed to suit the latest editing systems and video servers used by broadcasters and professional production and playout facilities. This means that compressed files processed by the Canon XF codec will be immediately recognized and opened by third-party equipment, smoothing and speeding up the various workflow processes. The resulting MXF file from the codec is the data wrapper that includes video, audio, metadata—which describes the material contained within, such as file type other attributes related to that specific file (for example, camera information, time of day, etc.). This MXF wrapper includes full timecode support and is intended as a platform-agnostic way for professionals to store files while ensuring their future usability on a variety of editing and playout systems. The Right Codec At the Right Time The production community continues to migrate to a fully networked, file-based world. It is being accomplished slowly, practically and affordably. Professionals—whether they be a local broadcast station, independent feature DP, or an event videographer capturing a client’s precious moments—clearly understand their workflow better than anyone else and by an overwhelming majority they have chosen to remain working in the MPEG-2 domain. At Canon the goal for all of its production products is to solve problems and make customers more successful in their businesses. Streamlining and improving upon established workflows that have proven to be cost-effective and efficient is always the ultimate goal. With an eye towards the future and its foundation grounded in the universally preferred way of working today, the new Canon MPEG-2 Full HD (4:2:2) file-based recording codec delivers the highest quality video and audio acquisition results in the smallest amount of space. Whatever the application, the new Canon XF codec is the right choice at the right time. |
© 2010 Canon U.S.A., Inc. All Rights Reserved | Reproduction in whole or in part without permission is prohibited. | Privacy Statement | Terms of Use |
No comments:
Post a Comment