Video servers are rapidly kicking out tape in studio production.
One small revolution in studio production has been the replacement of videotape with the video server. The first generation of video servers supported the modest data rates required for playout applications, but advances in disk technology means that record rates now exceed that of most tape formats. This has opened up the use of video servers for acquisition.
The first department to adopt servers for production was the newsroom. By moving away from tape to file servers, it could accelerate workflows. Previously, when a story broke, there was a wait while multiple copies of a source tape were dubbed. That wait is now gone. Instead, servers now allow journalists to browse incoming feeds within a few seconds of the record starting. With the server architecture, the problem of journalists and editors wanting simultaneous access to the same clips is no longer an issue. The multiple-read access to files inherently supports collaboration and parallel workflows.
Many studio operations, including multi-camera shoots and live shows, are finding they can also benefit when they free themselves from the constraints imposed by tape. Studio productions have been made in three basic forms: a finished show from the production switcher; with minor edits to the switcher mix using iso camera recordings; or a full multicam edit using the iso recordings from each camera. (See Figure 1.)
Producers are always looking for new, innovative show formats. The current vogue is a fast turnaround show, with interaction from the local audience and viewers via social media. These productions demand fluid workflows supported by server production and cannot be made under the constraints imposed by the linear nature of tape.
Producers look to accelerate the speed of production. If post production becomes during production, the show can be turned around faster. If highlights can be cut while a live show is on-air, the show closing can be enriched with reviews of key moments from earlier in the show. A further benefit to shortened production cycles should be cost savings.
Many of these techniques have been borrowed from live sports production, where rapid package production is performed in parallel with live events.
Television still retains many advantages over more recent delivery formats, especially for live events. The first run of a show is a special draw for viewers who want catch up with the latest stories, or the latest embarrassments in a reality show. The social media around popular shows is of the moment; it's no good tweeting about events of a week ago. This imposed time compression of viewers' interactions with a show is affecting production techniques.
Studio shows must be turned around faster, and a live show may need highlight packages prepared while the show is on-air. Shows may need “mobisodes” to be viewed on smartphones, and support websites with backstage stories have become essential for bonding with viewers. All these extras need rapid turnaround to retain topicality.
This more flexible, free-flowing, yet accelerated production was not possible with videotape. A live mix on the production switcher offered the primary version, with edited versions available much later.
The techniques of server-based news production are being leveraged by producers who are looking for fast turnaround studio productions that can retain television's advantages over OTT, VOD and other formats that compete for their viewers.
The news systems generally used low bit-rate codecs and simple, cuts-only editing. Shared storage systems can handle much higher bandwidths now, and it is perfectly possible to toss lightly compressed HD files around edit workstations so that studio production can gain the immediacy of news production while retaining the picture quality and polish of a conventional studio production.
The stock in trade of many production companies is episodic programming. These production factories stand to benefit if process efficiency can be improved. Some shows are aired daily, others two or three days a week. Any improvement in productivity is going to benefit the bottom line. The flexible workflows that servers offer present opportunities for the producer to streamline operations.
Videotape imposed many constraints on studio recording. First, there was the straight operational cost if many iso feeds were to be recorded. Second, for rapid turnaround shows, a tape cannot be accessed while it is recording, and ingest to the editing system adds further delay. Workarounds were to use short duration tapes, but it all adds to the complexity of the workflow.
Recording directly to a disk array delivers many benefits over a straight replacement for VTR. The use of a shared storage array means the entire production team can access camera feeds as they are shot. Shot logging can start within seconds, with an editor able to access fully logged shots within minutes.
Servers can easily sync camera recordings so that multicam shoots can be viewed on suitable browse workstations as synchronized shots. (Try doing that on tape without using an NLE.) Although multiple VTRs can be controlled from one station, the nature of servers allows full control, as well as proxy browsing, asset management and logging all from networked workstations.
A server-based production can use the three basic formats of the tape studio: live to tape, minor edit of mix and full multicam edit. But, it can also supplant it with all manners of parallel package productions for insert to a live feed or multiformat delivery of show versions to different devices like smartphones and tablets. (See Figure 2.)
Aside from operational flexibility servers offer other advantages.
Standard-definition tape workflows stood up to multi-generation dubbing, partly due to the high quality of the Digital Betacam codec. In HD, artifacts are more visible, and many broadcasters are striving to deliver a high video quality to match the definition. This has led to a move to design workflows that avoid concatenation of codecs: for example, 50Mb/s MPEG-2 from acquisition to air for SD.
Recording directly to disk means that if the storage system supports it, then you can choose the codec to best match your workflow. For example, DNxHD can be used for capture if you use Avid for craft editing. This avoids the encode-record-decode, then ingest and re-encode that makes up the usual videotape capture process. As many broadcasters are striving to increase HD picture quality by avoiding the concatenation of codecs in their workflows, disk recording offers a solution.
The nature of the server means it is possible to build an SD system for later upgrade to HD without major replacement of equipment — another advantage for the large number of broadcasters still operating SD looking to move away from videotape.
Most production systems will be integrated with an NLE, and here the options are to edit-in-place or to transfer files to the editor for cutting. Edit-in-place avoids transfer delays, but can require high bandwidths across the infrastructure for multi-layer editing at DNxHD or ProRes data rates (circa 220Mb/s per stream) in HD. It is the usual price/performance trade-offs.
As producers looked to lower costs, they also searched for ways to continue improving production values and quality. However, the linear nature of videotape was an obstacle to progress. Advances in server technologies have reached the point where 100Mb/s codecs are now routinely supported, and high-performance systems can handle DNxHD files at 220Mb/s.
This allows engineers to build a platform that integrates live ingest, logging, “offline” and rough-cut editing, as well as craft editing and finishing. Another advantage is the simultaneous availability of browse copies of the broadcast material, which is essential for all of the production applications that need material as it is shot.
The server brings many other additional advantages as well:
It provides a genuine replacement for the VTR.
It is file-based and integrates simply with popular NLEs.
Acquisition, production and post-production, become integrated, leading to quicker and more efficient production processes.
Faster than real-time file exchange with post-production reduces shoot-to-air time.
These advantages stem from features of the servers:
Play while record for instant access.
Multiple read access for collaboration across the production team.
Lower operating costs than VTRs.
Inbuilt support for proxy workflows.
Integrated control during production.
Choice of codec.
This platform has been proven under the rigors of the newsroom and sports production, so the use in studio production is just a new application of existing, well-proven technology — not a leap in the dark. With videotape disappearing from camcorders, and servers ousting the VTR in studio production, it looks as if the VTR is destined for the science and technology museum.