Monitoring whole mpeg transport stream


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Monitoring whole mpeg transport stream

  1. 1. Monitoring the Whole MPEG Transport StreamGary Learner, CTO Volicon THE BEGINNING OF BROADCAST MONITORINGSince the days of pure analog broadcast infrastructure, the broadcasters saw the needfor logging and monitoring system for both regulatory compliance and internal qualitymonitoring and assurance. The broadcasters used multiple VTR machines to recordtheir own broadcasts and those of their competitors, a process that required theconstant changing of tapes and acceptance of a relatively poor-quality recording.Beyond these issues were other problems including the limited shelf life of tape and thegradual degradation of video each time the tape is used.The duplication of tape-based media for monitoring also is a cumbersome process. It’sa slow process, and the end result is never as good as the original. Furthermore, thecontent being copied is unavailable to other users until the duplication process iscomplete and the tape restored to the library.The greatest limitation of the tape-based model, however, is in broadcasters’ ability toaccess and distribute recorded content. To find a specific piece of content on tapemeans going into the tape library, looking up a tape in the library catalog, tracking downthat tape, and using a tape playback machine to scan for that content or move to thedesired point in the broadcast. In some cases, this is like looking through the pages of abook, trying to find a passage without knowing where it is.When recording to tape, the broadcaster doesn’t have access to that content until thetape is finished. If the broadcast is being recorded to an eight-hour tape, then it can takenearly that long to be able to provide internal quality control or external clients withverification of the content aired.The shift of the broadcast industry toward digital operations has allowed for theintroduction of new technologies, which in turn offer much greater functionality thanearlier analog systems. TRANSITION TO DIGITALThe digital broadcast logging and monitoring solutions deliver the power and capabilitiesof professional AV control rooms to ordinary desktop computers. Multiple channels ofcontent are available on-demand, live or archived, from any desktop, where users can 1
  2. 2. search, retrieve, view, analyze, annotate, share, and export video. A Web-based GUIturns mission-critical video broadcasts and analysis into work material to increaseefficiency and streamline workflows.Technology like this has been made possible through advances in digital videocompression and in the development of Internet-based tools. At one time the argumentfor tape-based monitoring was the low cost of tapes and ease of integrating VTRs intoexisting analog environments. Now, however, the cost of digital storage andinfrastructure has dropped. It’s easier than ever to store video, and continuousimprovements in storage technology have brought down storage costs, making itfeasible to store digital data inexpensively over long periods of time.Web-based work tools used over high-speed Internet connections now enable easysharing and distribution of digital media to just about anywhere. Here, too, costs havedropped, and many companies already have access to the necessary networkinfrastructure needed to make digital media available to remote users.Among the many benefits of monitoring broadcasts using digital media is that everythingis instantaneous. Any queries or complaints about a particular broadcast or ad can beaddressed instantly because data becomes available immediately, as soon as it’srecorded, not four or eight hours later. Users across a facility, or working remotely overa high-speed network, can access content simultaneously. Thus, media is available toany authorized user, anywhere, at any time following the broadcast.Duplication of recorded media takes place much more rapidly in the digital environment,without the loss associated with VHS tape. Nonlinear or random access to content, asopposed to sequential access on tape, offers tremendous time savings in finding andaccessing the desired portion of a media asset.While digital loggers present many benefits over tape-based loggers and greatlyimprove the usability of such system, these loggers still fall short on several keyfeatures. Access to original broadcast content is not available, just the compressed,proxy version of the broadcast is stored and viewed over local or wide-area networks.Logging and monitoring of the many types of metadata present in today’s broadcast isoften impossible, as some of this metadata only exists in the transport stream version ofthe broadcast.With completion of the DTV rollout, the landscape for the broadcast logging andmonitoring systems changes yet again, enabling implementation of new key features,increasing the value of such systems and extending its use across more disciplineswithin the broadcast infrastructure. 2
  3. 3. TRANSPORT STREAM MONITORINGWith continuously increasing amount of programming, Networks, Stations, Cable andIPTV operators are continually challenged to do more with less. Staff members need toassure an ever increasing array of high quality digital programming, handle broadeningarray of regulatory requests, while delivering an increasingly complex metadata (DVBsubtitles, EIT/PSIP, interactivity) to leverage the new digital TV ecosystem. To do this,networks, stations and operators must be able to proactively monitor and quicklytroubleshoot items from the details of MPEG metadata all the way down to the quality ofthe rendered content.MPEG Transport Stream (TS) logging enables networks, broadcasters, Cable and IPTVoperators to do more than ever before. With continuous logging of MPEG transportstreams, monitoring program QoE (quality of experience), and the ability to seamlesslyexport and stream MPEG TS or low resolution proxies, the MPEG Transport Streamallows for efficient operation with WAN and enterprise wide clients.By capturing the native Transport Stream at the handoff point, using ASI, 8VSB/OFDM,QAM or IP ensures isolation and ability to troubleshoot of all the issues at the finalproduct level.Network Bandwidth utilization and need for proxyLogging the native MPEG Transport Stream greatly simplifies troubleshooting, chronicissues resolution, and regulatory proof of conformance. However, streaming the loggedtransport stream over wide-area networks (WAN) presents a challenge, The typical HDservice is encoded at 8-12Mbps and some of the network to station hand-offs can reach40Mbps. Streaming at these bit-rates over WAN would be impractical and would likelyimpose operational strain on the LAN bandwidth consumption as well. The need tocreate low bit-rate proxy of the TS becomes a mandatory feature for MPEG TransportStream Loggers. Transcoded low bit-rate proxy for a typical program consumes 0.5-1Mbps for SD and 1-2Mbps for HD, sufficient for streaming within the WAN enterprise,delivering full frame-rate video streaming to remote locations.Being connected over low bandwidth network doesn’t restrict the user to proxy viewingonly; once the content of interest has been identified by streaming the proxy, the originalTS version of the same content can be exported and saved locally for an unrestricted,full-resolution, full bit-rate viewing and analysis.TS and proxy storage considerationAnother point to consider in regards to low bit-rate proxy is storage. While we continueto benefit from continuously decreasing cost of hard-disk drives, archiving MPEGTransport Stream for extended periods of time would still drive up the transport streamlogger cost significantly. A single ATSC stream (19.38 Mbps) occupies 6.3TB over aperiod of 30 days. For a single 256QAM stream this storage would double. To balance 3
  4. 4. the need for extended content retention with the cost of storage is to log the nativetransport stream for shorter period of time, while extending the storage of the low bit-rate proxy. For example, storing the transport stream for 7 days and proxy (1HD and1SD) for 90 days would only require 3.4TB of storage; a 47% saving in storage, yetachieving retention of content for 90 days.Segmenting contentRecording all of the content is by its nature chronologically structured, but withoutinformation such as an as-run log or electronic program guide (EPG), there is no way toknow where programs begin and end. This knowledge is quite valuable in allowing theoperator to segment content and/or sort it according to various criteria including not onlytype of program or program name, but also length of the program. Segments of similarduration often fall into similar categories. For example, segments of just 15 or 30seconds most likely are commercials. The ability to identify and sort segments in thismanner offers users a quick way of finding or isolating specific content.Quality of Service (QoS) MonitoringSophisticated monitoring systems not only allow broadcasters to assure that materialwent to air as intended, but also to provide a valuable tool for evaluating the integrityand quality of the broadcast audio, video and metadata. Staff members can review airedmaterial for on-air discrepancies, signal problems, and other issues that may interferewith the quality of the programming. Immediate access to any content that aired and theability to access that content quickly significantly enhance the quality of broadcastproductions.Current monitoring technology can detect variety of false signals, reporting on errorsand alerting the broadcaster via email or SNMP traps that something is wrong with thebroadcast. Immediate detection of loss of audio, a blank or frozen screen (no motiondetected), and loss of closed captioning helps minimize down time, thus preserving theintegrity of the on-air product, meeting the expectations of viewers and advertisers, andprotecting station or network revenues. METADATA MONITORINGThe MPEG Transport Stream, as a container, is well suited to multiplex multipleprograms into a single stream (MPTS), as well as multiple content and metadata tracks,associated with a single program, into the same transport. This container does nolonger restrict embedding of the metadata into VANC (sometimes HANC) and audiotracks. MPEG transport stream makes it trivial to encapsulate variety of metadata typesinto separate PIDs, while keeping them synchronized with the rest of the content.Encapsulation of the metadata in its own PID (instead of VANC), simplifies decoding ofsuch data, as it’s no longer required to decode the video first in order to extract anddecode the VANC. This approach also allows the audio/video content to remain 4
  5. 5. encrypted, while still fully capable to process the metadata content. Such examplesinclude SCTE-35 (digital cue tones) and SCTE-18 (EAS messages).Other forms of metadata include interactive components (ads) and local content(weather, news), which greatly enhance the utilization of the broadcast medium and in-turn further engage the viewer. LOUDNESS MONITORINGWith recent approval to adapt the CALM Act by the FCC (FCC 11-182), the focus onLoudness Monitoring gained front page attention. The enforcement of the CALM Actgoes into effect on Dec 13, 2012 and regulates both Broadcasters (call-letter stations)and MVPDs (multichannel video programming distributors). Cable Networks areregulated through MVPDs under this regulation. While the broadcasters have beenfocusing on deploying the equipment and implementing procedures to assure that allthe assets have their loudness ‘normalized’ prior to being aired, the burden of ‘proof ofcompliance’ is still lies with MPEG Transport Stream loggers. By implementing theATSC-A/85 and EBU-R128, both are based on BS.1770-2 loudness measurementspecification, the loggers both measure and alert on loudness violations. Forbroadcasters, networks and video service providers, loudness monitoring is atroubleshooting tool to ensure and prove compliance with loudness regulations. Bycombining loudness measurements with transport stream logging, thus retaining theoriginal AC-3 audio track, the operator is able to quickly troubleshoot, easily generateconvincing affidavits, as well as proactively monitor for compliance. While frameaccuracy is not mandatory for loudness measurement results, synchronization withaudio/video content must be offered by the MPEG transport stream logger. An ability toexport the content with burnt-in loudness measurement results is a very useful featureto facilitate timely loudness issue resolution, by having all the relevant data on the samescreen fully synchronized with the content. By combining momentary (M), short-term(S), short-term integrated (SI), long-term integrated (LI) as well as loudness range(LRA) with the logged content into an intelligent dashboard eliminates the need toswitch among multiple screens during the loudness troubleshooting. An ability to exportthe content with burnt-in loudness measurement is very useful in facilitating timely issueresolution, by having all the relevant data inseparable, part of the same exported clip.Ability to export the original AC-3 audio tracks to measure loudness by an independent,agency approved loudness meter provides the ultimate proof of compliance in front ofregulatory agency. TRANSPORT STREAM ANALYSISAmong a few features enabled by capturing the native transport stream is the ability toperform TSA (transport stream analysis) on the acquired content. The importance of thetransport analysis has been recognized in the industry to establish measurementguidelines for DVB systems standard (ETSI TR 101 290). While there is plethora oftransport stream analyzers in the marketplace to implement this standard, these 5
  6. 6. systems are mostly used for real-time, spot-check transport stream analysis, as theylack the ability to continuously store the full transport stream for post-broadcast analysisand troubleshooting.Combining the MPEG Transport Stream logger’s ability to capture the full stream andexport it either as a full MPTS, a single program or even a single PID with the post-broadcast TSA ability greatly improves broadcaster’s ability to respond to complaintsand troubleshoot problems in a timely manner. CONTENT REPURPOSINGDistribution of media assets to viewers over new platforms such as the Web and mobiledevices offers broadcasters the opportunity to increase revenues leveraging assets theyalready own. MPEG Transport Stream logging and monitoring systems feature toolsthrough which recorded original Transport Stream content can be de-multiplexed (PIDfiltered), clipped and easily published to a Web site or pushed to mobile customers viatablets, smart phones and other portable devices. The broadcasters have alreadyinvested in high-end broadcast encoder to assure the highest quality of contentdelivered, so reusing the original transport stream for distribution through othermediums results in higher quality of that content as well. LOOKING AHEADBecause digital video technologies are continuously evolving, Broadcast Logging andMonitoring systems grow even more powerful and robust in providing tools for improvingthe on-air product and, ultimately, adding to the bottom line. Use of transport streamcontent opens the door to many enhancements in broadcast verification, analysis andrepurposing.The shift toward monitoring systems based on transport stream offers more thanconvenience; it provides a new way of looking at and evaluating aired content. Fewer ofthe broadcasters will rely on baseband-based monitoring. More and more broadcastersare aware, however, that once they get a transport stream monitoring system in place,they can take advantage of it in so many different ways just not possible with previousgeneration monitoring model.As the industry continues to adopt advanced monitoring solutions, the trend resemblesthe earlier adoption of email or the cell phone. The first few adopters understood thepotential of the new technology, and subsequent adopters in greater numbers found thatthey couldn’t survive without it. The competitive edge delivered by the logging andmonitoring systems allows broadcasters to make significant improvements to theirbroadcasts, ratings, and ad revenues. Once one broadcaster in a market implementsthis powerful tool, competitors likely will find it to be a critical addition to their operations,as well. 6
  7. 7. Digital monitoring systems continue to evolve in functionality and, as they are developedfurther, in the value-added features they provide. With these developments,broadcasters with advanced digital monitoring systems in place will gain the opportunityto extend the use of the system for even more streamlined, cost-efficient, andcompetitive broadcast operations.Contact Us:Volicon111 South Bedford StreetBurlington, MA 01803 USA+1 781 221 7