Monitoring Broadcast Content to the Home

Monday, July 09, 2012

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Generally, workflows and processes related to handling baseband level signals have been greatly reduced when comparing current broadcast facilities to similar systems commonly in use 10 years ago.
Test and Measurement systems based on analysis of both Quality of Service (QoS) and Quality of Experience (QoE) for compressed video systems verify the picture and audio quality as delivered from the content provider to the consumer at home.

Dave Guerrero from Harris outlines the need for monitoring key nodes through a broadcast network.  Signals passing through a broadcast chain from satellite reception, through master control and emitted to either an IP or RF network can be monitored simultaneously. The products armed with the ability of remote monitoring allows for the analysis of information collected locally to be viewed at remote viewing or control points through standard network topology, including the Internet. 

In today’s fast-paced world of multichannel television, it is imperative to monitor all the details of content as it passes through a broadcast operation workflow.  Digital compression provides an enormous number of parameters that must be verified prior to passing the content to our customers. 

For a broadcast satellite operator, the customers may be broadcasters, cable TV distributors, or the consumers themselves, receiving the content directly at home.  For broadcasters, the customer may be network affiliates, cable TV distributors, IPTV networks or consumers – at home and on the move. Broadcast networks may also originate content and feed it to satellite operators.  

Fiber-optic-based land lines typically tie to common broadcast-related operations for distribution, back-haul and point-to-point.  There is also the Internet, the most powerful distribution network in the world.  The Internet is somewhat limited in bandwidth for broadcast transactions, but certainly is used to transfer content to a multitude of customers with varying monitoring requirements.

Every ‘customer’ may have a specific set of monitoring requirements, but the broadcast operator needs to understand every requirement for every entity handling his content.  This is to ensure that all technical parameters are correct and will satisfy every customer prior to streaming content to subsequent operators.

Every content distributor, originator, broadcast facility and otherwise will have an internal distribution network.  The details of these networks are very different, but can generally be summarized as having high-speed connections to control rooms, satellite closets, equipment racks, operations terminals, QA terminals, editing facilities, master control centers, routing and distribution systems, and final point(s) of demarcation to customers.  

Many challenges that occur in these facilities include storing, archiving, mixing, logging, QA, editing, transcoding and processing content of varying technical formats and complexities. The most common method of internal distribution when designing a low-cost infrastructure is video over IP.  This enables the operator to carry video over the Ethernet infrastructure that is used for day-to-day business.  

Broadcasters save capital in both new construction and updates to existing facilities by using an Ethernet network, reducing the need for additional switching and routing, distribution amplifiers and processing equipment, among other components 

Content arrives in various formats depending on where it is moving through the broadcast chain.  Most origination points produce content as baseband audio and/or video signals. This format carries the highest bit rate and quality, resulting in a scenario where baseband signals cannot be practically distributed beyond internal monitoring points within a broadcast facility.  Generally, workflows and processes related to handling baseband level signals have been greatly reduced when comparing current broadcast facilities to similar systems commonly in use 10 years ago.  

Most baseband signals are processed and converted directly to a file very soon after production.  The converted baseband signal then will live on a SAN as an MXF, LXF, QuickTime, RAW or other wrapped file, awaiting distribution.  At the time of distribution, the file is played out from the server network, either as a compressed signal (such as JPEG-2000, MPEG-2, H.264, etc.) or again as baseband, only to be converted into a compressed format for distribution as determined by the medium.

As these signals are moved and changed from one place to another, the content is checked in its native format to verify that the signal was received properly.  Furthermore, the signal must be checked with every change to verify that the changes did not negatively affect the content.  

Metadata is contained within the distributed content for technical and compliance reasons.  For example, data such as sub-titles and captions must be carried with the signal.  It would otherwise be very costly to reconstruct this data at the point of final transmission.  Region-specific metadata is sometimes added (including sub-titles and language translations).  This data is generated locally but needs to be carried through all the local distribution networks.
It is very easy to imagine that a broadcast engineer or technician could have some difficulty in monitoring signal quality due to the changes that may occur to the signal through normal handling.  It becomes very apparent that a monitoring device needs to offer the sophistication of monitoring multiple instances of the same content sampled at different nodes along the workflow.  An engineer can then determine that all required content parameters are compliant for his broadcast operation.  

The Harris MSA (Multi-Source Analyzer) Series is designed specifically for these complex workflows.  Natively (via multiple Ethernet ports), the MSA Series can monitor TS over UDP, RTP/UDP, TCP, and Namepipe.  Other supported protocols include SAP, Signaling RTSP, Transport RTP, MP4V-ES, RTMP, Transport RTMP/TCP, Apple HTTP Live and TS/TCP.   

Compression formats covered include MPEG-1, MPEG-2, MPEG-4 Part 2, H.264/AVC, and SMPTE VC-1 in stream and file formats.  DVB-T, DVB-S2, ATSC, DVB-ASI formats of RF and compressed streams are also supported.  Physical interconnections include BNC for optional DVB-ASI, and F-type connectors for RF.  It is extremely important to consider the total and types of physical interfaces required to monitor when designing a test plan for your facility.

The MSA Series’ flexibility in physical interfaces, and its ability to monitor protocol/signal types simultaneously, makes it a very powerful weapon in an engineer’s toolkit for facilities of any size.  Simple configurations allow the engineer/operator to monitor (on-screen) as few as four programs or many more based on optional configurations and available network bandwidth.  

In a basic configuration (Figure 1), an engineer desires to monitor an incoming program via a satellite receiver, the output of his master control and the back-haul to confirm signal path integrity.  The MSA series is adept at producing Quality of Service and Quality of Experience measurements, as well as threshold alarms, affording logging, trend/pie charts of data and confirmation of metadata presence and compliance. 
The engineer/operator can monitor images, audio levels and metadata on screen and offer instant feedback of any impending system problems.  This enables proactive correction of issues long before viewers at home have the opportunity to notice.  

Larger systems are designed to monitor locally and from remote locations.  A complex system may include 20 or more programs depicting the program sampled from specified ‘nodes’ within the system.  

For example, the engineer/operator may have a need to monitor his incoming program content on an IP network via TS-over-UDP.  This transport stream may carry a number of programs from which he may select to pass through., The operator may also be receiving feeds via a satellite distribution network utilizing a DVB-ASI interface, which will be mixed at his master control point with the feed from the IP network.  

Programs may be distributed to the Internet (company web portal), various affiliate stations and locally over the air as a terrestrial radio frequency (RF) stream.  The master control point is co-located with the terrestrial transmitter; the operator is positioned in a technical monitoring position within the company’s office complex in a ‘downtown’ location.

Let’s review the monitoring requirements for this system.  To begin, the operator needs to verify the content being received on the UDP IP stream (let’s say four programs).  These programs will be tested and monitored 24 hours a day, seven days a week.  The operator would also like to be proactive and know if and when there is a problem with the reception of the satellite receiver for troubleshooting prior to reaching air, assuming the mux on the DVB-ASI steam carries four more programs requiring distribution.  

The operator’s master control system is capable of distributing four programs, one of which will go to the website, another that is emitted locally over the terrestrial network, and the remaining two of which are distributed to affiliated stations.  The master control system adds branding and locally inserted commercial content in the process.   

The third requirement of this monitoring system is verification of delivery to customers (web portal, RF network and two affiliates connected through fiber-optic distribution and received as UDP-over-IP).  The final piece of the monitoring system produces all data remotely to the operator’s position “downtown.”
The MSA product can be deployed for this configuration, and will provide an ‘onscreen’ view of all programs: eight inbound, four outbound and four from back-haul services.  A total of 16 programs onscreen, with all testing and logging required to verify program content and metadata, is correct throughout the workflow.  Using the MSA system’s remote view client, the operator can monitor all aspects required from any remote location on a standard PC running the MSA software.  

In summary, Harris’ Multi Source Analyzers offers customers exactly what is needed to verify technical compliance and quality of content as it is distributed, either incoming or outbound from the facility.  The MSA is user-configured and requires very little (if any) training, as its interfaces and GUI are industry-standard and intuitive based on common PC operations.  The MSA is at home in any monitoring environment, no matter the size or complexity.  


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