Newsroom editing low-rez: Why bother?
David Schleifer
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10/30/97
Broadcast Engineering
Copyright (c) 1997 Intertec Publishing Corporation. All rights reserved.
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Low-resolution is an answer for broadcasters looking to increase shared access capabilities. With the number of vendors offering low-resolution browsing systems and improving low-resolution quality, broadcasters can now begin to seriously look at low-resolution as a viable newsroom solution.
Quality vs. quantity Broadcasters have always struggled with two opposing requirements: the need to work with the highest-quality images, a necessity that leads to higher-bandwidth requirements, and the need to lower the cost of storage (on tape or disk), thereby lowering the data threshold requirements for transmission (allowing transmission at lower data rates from the field, for example). Until fairly lossless compression is feasible, these two opposing requirements cannot be satisfied in one product without a compromise of one for the other.
Non-linear systems, which began as off-line systems, have worked their way from being fast and feature-rich editors that lacked the ability to output broadcast-quality pictures, to systems that can now output high-quality images that are ready for air. The ability to "finish" stories on non-linear systems has gained acceptance with technology able to handle higher bandwidth, resulting in higher-resolution images. At the point where the pictures became good enough to go on-air, many broadcasters decided that the benefits of non-linear editing were too compelling to ignore.
While non-linear editing products continue to take advantage of improved technology to provide better pictures, acceptable, editable compression algorithms have not changed appreciably. The result is that non-linear systems are delivering on-air quality by increasing the bandwidth that they are capable of handling. The result is improved picture quality, but at a cost of increased storage and bandwidth requirements.
Non-linear advantages Non-linear editors are gaining acceptance because they offer a better way to edit. They allow last-minute changes, are more flexible in the creative process and ultimately produce a better on-air product. As stand-alone systems, they have proved their ability to deliver flexible feature-rich editing tools at a cost-effective price.
Non-linear newsrooms also offer more collaborative operations, which require the sharing of information between edit locations. (Information can arrive simultaneously from several sources - text on the newsroom computer system, video from a satellite or microwave feed or background information over the phone. Often, several people will be working on a story at once. Additionally, several versions of a story may be edited from the same source material. These additional requirements have pushed vendors toward the development of several shared storage solutions.
One distributed solution is to push the video around, duplicating it wherever it is needed. This model imitates the traditional tape-based environment where a tape must be copied to be used in a second location or in order to be viewable at a second location while editing continues. The benefits of using disk-based, non-linear systems with this workflow are that unlike tape, quality does not degrade when copied, and as technology allows, copies could be made at faster than real-time. The drawbacks are the extra time it takes to make copies and the need to track and manage multiple versions of every file across your system. No matter how quick the system, editors pay enormous costs for storing files in several locations.
A second server-centric solution for sharing stories between editors is to place all of the stories in a central location, allowing all of the editors to use the same media at the same time. The advantages of this type of solution are no transfer time for re-use of media, no additional cost of storage (other than the original) and simpler media management. The disadvantages are that bandwidth issues constrain the system to a specific number of simultaneous users. If requirements are below the system's top-end, bandwidth is not an issue, but unlimited scalability becomes difficult.
Making media accessible Today, neither of the solutions described are cost-effective for sharing media to every desktop in a newsroom. If the goal is to make video and audio available to every desktop, the cost of doing it in high-resolution becomes prohibitive. Even so, there are good reasons why a facility would want to get the media to the desktop. The primary reason is because it is at this point where broadcasters can start to change workflow to realize the benefits of disk-based computing.
Systems that require copying of files or that limit access to your media to less than the number of users in a newsroom lend themselves to improving existing workflow processes. For example, a system where video and audio are stored on disk instead of tape, then copied to an editor for editing, then moved to an on-air buffer for playback may take advantage of disk, networking and computers to get the job done, but will ultimately use this technology to deliver incremental improvements in transfer time, flexibility and accessibility of the media. A system that restricts the number of users to a total lower than newsroom requirements will also leave the need to develop work- arounds to manage workflow requirements.
A solution that could increase the accessibility of media available with a server-centric system could solve these issues. The only way to solve the problems posed by a distributed solution is to speed transfer time to the point where it is of negligible consequence, and to reduce the cost of storage to the point where the cost of keeping multiple copies is no longer a disadvantage.
Low-resolution versions of media can offer solutions to many of these problems. Smaller, lower-resolution pictures can be moved faster and take up less space to store than broadcast-quality images.
But there are challenges. First, the low-resolution images are by definition non-broadcast quality. Second, the most popular and open compression codec for low-resolution ( MPEG ) is not easily editable. This means that low-resolution can not replace high-resolution versions, but can be used to supplement or extend the reach of the high-resolution media. Interestingly, it can offer advantages to server-based, stand-alone or even tape-based facilities.
Overall benefits By pairing editable high-resolution pictures with low-resolution images that can be made accessible simultaneously to a number of users, systems can be designed that allow users to access media almost anywhere in the newsroom. The low-resolution system needs to give simultaneous multi-user access to a clip or story and it also needs to allow the decision-making process to start.
Because the low-resolution images are not broadcast quality, there is no real need to edit them. What is needed is the ability to make decisions, preview them and then create a broadcast-quality version as quickly as possible. With a server-centric solution, broadcasters can reduce the need for more clients by off-loading the previewing, pre-editing or simple editing processes to the low-resolution system. A site may be able to manage with two channels that go to air, four high-resolution editing systems and a low-resolution media system that allows an additional 10 or 20 users to preview and perform the equivalent of cuts-only edit decisions at their workstations.
Pairing low-resolution with a system designed to move video around between multiple small servers raises some tough technical issues. First, the issue of media management is more complex and needs to be resolved if broadcasters ultimately want to conform the decisions made against the low-resolution images with the high-resolution images. Broadcasters need to know that pictures will be available, and that they are, in fact, thesame clips.
Additionally, for the quickest turnaround between low- and high-resolution systems, broadcasters need a system that can take an edit decision list created with low-resolution images and play back the high-resolution version on the fly. Systems that create edited stories by playing out video in real time and re-encoding a new complete story will always introduce a delay between making a decision in low-resolution and playing back to air.
Some of the more interesting benefits that innovative use of low-resolution video can offer come with the ability to pair these systems with tape. Video coming into a facility can be dual digitized to tape and to a low-cost PC-based MPEG video-browsing system. The low-resolution images can be available with the incoming feed to allow editors to start making decisions, pulling clips and building stories or lists of selections.
Several users can now have access to the material that was previously locked up onto a single tape. They can even edit pieces using that material at the same time. Because all the users are using low-resolution images, they still need to build broadcast-quality versions to go to air. The easiest way to do this is to use a stand-alone, non-linear editor that should be capable of taking the EDL generated from the low-resolution sessions and then batch digitizing the relevant clips, creating the edited piece in the process. In its simplest implementation, a low-resolution system paired with tape would allow a producer to walk into an edit room with a printed list of tape IDs with accurate time-code markers for every clip needed.
Workflow changes With a system that allows a number of users simultaneous video access, broadcasters can begin to work in different ways. They have the ability to make low-resolution video available to many users and the ability to be productive with that video earlier in the process.
Traditional tape-based systems create linear workflow processes. Video arrives and is recorded. After recording is complete, video can be edited. Then, the source tape can be handed to someone else to start editing another project with the same material. Broadcasters have developed workarounds to make this process more efficient, such as double-recording important feeds and logging material as it comes in to speed the clip selection process.
By using low-resolution video properly, broadcasters can begin to create non-serial, non-linear workflow. They can begin several processes in parallel. Video can come into the facility and editing can begin simultaneously at several locations. New approval processes can be set up based on the system's ability to make material available over the network, without disrupting ongoing processes. A workstation can also access video and text in the same workspace.
Price/performance Systems that are efficient at pairing high- and low-resolution images will deliver more functionality and access to media with today's technology. Because the process of storing and distributing high- and low-resolution images and sound rely on the same base technologies, the spread in cost between the two will always be about the same. As high-resolution systems become cheaper and faster, so will low-resolution systems by about the same factor. No matter how cheap disk storage gets, it will always be much cheaper to store low-res images. With many users desiring systems that will keep many years of material on-line, low-resolution-based systems will offer a more cost-effective solution.
Working with low-resolution images will offer new possibilities with wide-area networking, possibilities that will always benefit from systems that require lower-bandwidth requirements.
Systems that make use of low-resolution images are about to arrive in force. Properly implemented, these systems will be compelling solutions to many of the workflow issues faced in newsrooms. They will also offer benefits that will not be canceled or replaced as technology makes video on disk cheaper. |
