There have been huge changes in the technologies that deliver TV content to air in recent years. Most obviously tape is replaced by discs for media storage, but there has also been a succession of developments in the many activities associated with playout. The services offered by broadcasters and other providers may now include new video formats and outputs that can be the traditional broadcast ‘push’ type or on-demand ‘pull’. At the same time the range of providers now span from start-up channels running on minute budgets, to international broadcasters running multiple channels.
TV channel-in-a-box solutions can meet the needs of many channels and broadcasters. For most, the compact size is not the overriding attraction, but the much lower price points are. All the same, these must meet all customer requirements with reliable replay, automation, graphics and on-air presentation, as well as the flexibility to fit with project-specific needs. Going a step beyond, solutions are now helping to open up new transmission workflows, lowering capital expenditure, completing tapeless operations and using low cost distribution.
Playout is always live and broadcasters will always do all they can to ensure their playout constantly runs smoothly. The playout hardware and software must first sustain continuous playout day-in and day-out. Then further measures ensure that any failure does not stop the playout by providing full redundancy with a duplicate playout system running in sync with the main ‘on-air’ unit, complete with an automatic switchover. A power supply fault would stop operation so a redundant supply with automatic switchover is often included with relay bypass as a final solution should all power be lost
The media storage uses hard disc drives. Although drive manufacturers quote phenomenal mean-time-between-failure rates of over a million hours (114 years), that is only a statistical average and does not mean it will run that long before failing! The failure of an unprotected disc loses vital data for playout. One way to avoid disruption or loss of data is to use a RAID (Redundant Array of Independent Discs). There are several types particularly suitable for supporting continuous video. RAID1 doubles up the disks and so everything is stored twice. A popular version is RAID 5 that adds one extra ‘parity’ disc drive to the array, enabling continuous operation if any one drive fails. The broken drive can be replaced and its data automatically re-built.
Ins, outs and formats
The progression from SD to HD means there are currently both formats in use. Handling both at once in the playout system, by re-sizing video to fit the required output standard and outputting clean cuts between all clips, is a real bonus. Other image sizes are used for applications such as internet video (correct term for things like BBC iPlayer, U-tube, etc.). Support for Full HD (1080p) provides future proofing.
Television production is rapidly adopting file-based workflows that result in file-based edited masters. Although SDI connections are in wide use, the direct acceptance of media files into the playout store, typically Network Attached Storage (NAS), is much more efficient. This involves accepting the media file either by plugging in removable storage or over a network. Either way this avoids VTR replays, ingesting the material in real-time, storing it as files on the playout storage and running a QC on the result.
For outputs, customers may specify digital video (SDI / HDSDI). Then the onward processes for broadcasting include MPEG2 or MPEG4 (H.264) compression and multiplexing with other channels and data streams, such as subtitles, for digital transmission as a DVB / ATSC ASI stream. Alternatively, PlayBox can supply the output directly as DVB ASI. For delivery over the internet the video needs to be in a suitable file format. All such output processes may be included as part of the playout package or provided by the broadcaster who may already have some or all of the necessary equipment in place,
These days people know that ‘digital’ can produce variable quality. Accepting various types of file format and outputting as SDI or MPEG may well involve transcoding or decode/recode cycles. The quality of this process is often not specified and, as there can be a big difference between ‘good’ and ‘not so good’, it should be thoroughly checked.
Playout may involve much more than replaying video and audio and this is an area where a well designed integrated IT-based approach can have the advantage of adding functionality without adding boxes. For example, the channel ID bug in a top corner might be added directly. Stations will also require graphics, text and subtitles. All these can also be in the one ‘box’ if required, or connected via a network.
The graphics requirement depends on the station’s style and content but often involves interactive animated graphics and text. Today there are other sources of text such as SMS messages, on-line voting and live databases showing, for example, financial data or instant analysis of sports. Linking the graphics engine to such resources automates a whole raft of live text and data for on-air presentations. For some info channels, this may comprise their entire output.
Broadcasters have become accustomed to using ‘automation’ as something that cues and runs the many events needed to keep channels on air. By using appropriate IT-based systems, there’s no need for any separate ‘automation’ box as the various modules of playout can communicate unaided. With PlayBox Technology, the AirBox playout server performs the traditional ‘automation’ tasks. It accepts playlists from ListBox, or other schedulers, cues graphics replays from TitleBox as well as controlling a router if needed. It also cues and runs itself but can also cue a CaptureBox ingest server to include live footage into the programme output, or to recording the footage, or both.
SafeBox orchestrates the flow of media through the whole PlayBox playout solution, making sure the right media is in the right place at the right time. If anything’s amiss then it sends messages and alarms to the operator. It is also responsible for deleting old media from AirBox storage.
UNATTENDED AUTOMATED REMOTE PLAYOUT
So far the systems described offer solutions for traditional, and some newer style, playout applications. However, if the equipment is highly competent, it encourages thinking outside the ‘box’ and taking things further. Given a playout solution that is reliable and can be controlled and supplied via a network, then it should perform well providing a full playout service in a remote location, with low operating costs.
It is relatively easy to produce a headend ‘remote’ station that’s a copy of a generic or global channel. However, people prefer to watch something that includes local branding with ads, IDs and promos, a local look station. Traditionally this is created using staff to package the local material into the playlists and sending the material over video links to the remote transmitter. The costs add up and may tip the balance making the station not commercially viable. Now there is another approach that should generate a different looking balance sheet. It has been built by PlayBox Technology in conjunction with FOX International Channels Italy, and nicknamed ‘FoxBox’. This allows content owners to play channels into any remote markets from an established broadcast centre, complete with locally branded content, in a cost-effective way. In the case of FOX, the requirement includes multilingual audio and subtitles as well as local advertising.
The solution allows launching locally branded channels throughout the world via a tapeless operational environment. A flexible approach in both product and system design is essential to tap into an existing broadcast centre. This may involve integrating the new remote playout into the current, or preferred, infrastructure such as traffic management, storage, MAM, ingest, transcoding and file transfer systems – as required by the customer.
The link from the content owner’s broadcast centre to the remote site carries file-based content media. This fits with the use of public internet as the only transport system to and from the remote site. It carries everything including the video, audio and all other data including the playlists, subtitles, control commands, monitoring and even compliance data. The operating costs are low and the remote can be placed anywhere that has internet access.
The choice of media format used at the remote location depends on factors including the amount of new media per day, the bit rate chosen for playout and the available internet capacity. For SD, MPEG2 IBP at 10 Mb/s is popular, however H.264 at 4 or 8 Mb/s, or less, is a very good alternative. Ultimately it is the broadcaster’s decision.
Various levels of protection can be applied. The diagram (above) shows a single-channel playout protected with full redundancy; there are also triple-redundant power supplies in each of the AirBox playout servers. The connection to each remote location is via a file transfer server and a firewall at each end, and can include a file transfer system agent to speed up transfer times as well as using multiple internet paths and so allowing checking the file validity. On the playout side a Crystal Vision Smart Switch monitors video and audio output from the main AirBox playout server and, in the case of failure, automatically switches to the backup.
Daily playlists are created in the broadcast centre’s traffic system that is integrated with the MAM. These lists are sent to the remote AirBox playout servers and converted, where necessary, to the PlayBox Technology PLY playlist format. Using error detection algorithms, transferred files are checked against the original and then sent to the remote AirBox servers. This way, if any file is corrupted during transfer it will not affect the output of both servers.
The PlayBox Remote Service Application (RSA) checks for the media required by the playlist and searches locally for it. If not found it generates a Missing Items List (MIL), sends it to the MAM requesting the media and any associated subtitle files. The RSA resends the MIL until the media arrives.
On receipt of the MIL, the MAM first checks if the media is available in the correct delivery format to send to the remote location. If not it then checks if the media is available in another format. If it is, the MAM sends the media for file transcoding and then to the remote location where it is distributed to both master and backup AirBox servers. If the media is not available, the MAM generates a capture list for the media’s ingest, transcoding and delivery to the remote location.
The remote package includes TitleBox graphics and CG, including interactive graphics such as SMS-to-screen, voting, gaming, crawls, etc., added to AirBox. TitleBox is scheduled in the traffic system and many different projects and templates can be created using TitleBox preparation and sent to the AirBox / TitleBox server for playout. AirBox creates the ‘As Run’ logs that are converted to the appropriated traffic format, if needed, and returned to the Traffic System for billing, etc.
SafeBox traffic management is installed on each AirBox to transfer media arriving on the local File Transfer Server to the AirBox servers’ hard drives. It also scans the daily playlists and local drives, deleting any media not requested over a set period. Media can also be removed from both the File Transfer Sever and AirBox servers by a purge list from the broadcast centre.
Monitoring and Control
Remote monitoring is vital, especially where channels cannot be viewed by a backhaul feed. Monitoring of the AirBox, TitleBox and Smart Switch uses SNMP to send fault alarms. All the remote servers are also connected to a VPN that is accessible from anywhere according to rules defined in the firewall.
For remote video and audio monitoring three SlingBox units are connected to the output of each server and to the main output of the Smart Switch, enabling the broadcast centre to see any problems. Monitoring of catastrophic failure involves a 2RU video/audio unit switched between the main and redundant playout servers and the main Smart Switch output.
Local commercials, content and QC
Local commercials and content can be ingested at the remote site and sent to the broadcast centre. Commercials and small volumes of local content can be sent in high res format for quality control and then stored on the MAM for the usual transcoding and transfer to the remote playout. Larger volumes can be transcoded into the channel’s playout format and sent to the broadcast centre for QC as before. Although this involves content travelling back and forth, it is the best solution for QC and for reliability.
Subtitle files can be prepared in the usual way. PlayBox SubtitlePlus, installed on the AirBox servers, can receive and automatically check files from most preparation systems and include them as open subtitles during transmission. Playout is automatic and programmes requiring subtitles are flagged if the subtitle file is missing. SubtitlePlus DVB supports DVB subtitles and multiple languages and channels.
AirBox can playout multiple audio tracks. Where the multilingual tracks need to be added, AirBox can work with video AVI files and separate audio WAV files. WAV files can be created and edited using simple audio tools and once completed multiple dual audio or stereo WAV files can be played out.
Compliance recording, mandatory in many countries, provides evidence for programme or advertising disputes and is an aid for fault finding in remote playout systems. CaptureBox Compliance can record 30, 60, 90 or more days, with time stamp, at a low bit rate. These files, recorded in one-hour blocks, are easily retrievable over internet for viewing.
The playout-in-a-box idea has matured with proven reliability and a complete range of functions for full playout support for start-up channels to international broadcasters. Although the products are IT-based, expertise in both that area and broadcast technology is essential for success, as systems must be fully integrated into broadcast infrastructure and must meet broadcast standards. Now the remote playout solution opens new opportunities for broadcasters to extend their reach with more affordable local look and feel stations.