Lesson 4

Understanding formats: codecs, bitrates, files and streams

Terrestrial television systems are encoding or formatting standards for the transmission and reception of terrestrial television signals. There were three main analogue television systems in use around the world until the late 2010s (expected): NTSC, PAL, and SECAM. Now in digital terrestrial television (DTT), there are four main systems in use around the world: ATSC, DVB, ISDB and DTMB. 

Most digital television systems are based on the MPEG transport stream standard, and use the H.262/MPEG-2 Part 2 video codec. They differ significantly in the details of how the transport stream is converted into a broadcast signal, in the video format prior to encoding (or alternatively, after decoding), and in the audio format. This has not prevented the creation of an international standard that includes both major systems, even though they are incompatible in almost every respect.


The two principal digital broadcasting systems are ATSC standards, developed by the Advanced Television Systems Committee and adopted as a standard in most of North America, and DVB-T, the Digital Video Broadcast – Terrestrial system used in most of the rest of the world. DVB-T was designed for format compatibility with existing direct broadcast satellite services in Europe (which use the DVB-S standard, and also sees some use in direct-to-home satellite dish providers in North America), and there is also a DVB-C version for cable television. While the ATSC standard also includes support for satellite and cable television systems, operators of those systems have chosen other technologies (principally DVB-S or proprietary systems for satellite and 256QAM replacing VSB for cable). Japan uses a third system, closely related to DVB-T, called ISDB-T, which is compatible with Brazil's SBTVD. The People's Republic of China has developed a fourth system, named DMB-T/H.


ATSC

The terrestrial ATSC system (unofficially ATSC-T) uses a proprietary Zenith-developed modulation called 8-VSB; as the name implies, it is a vestigial sideband technique. Essentially, analog VSB is to regular amplitude modulation as 8VSB is to eight-way quadrature amplitude modulation. This system was chosen specifically to provide for maximum spectral compatibility between existing analog TV and new digital stations in the United States' already-crowded television allocations system, although it is inferior to the other digital systems in dealing with multipath interference; however, it is better at dealing with impulse noise which is especially present on the VHF bands that other countries have discontinued from TV use, but are still used in the U.S. There is also no hierarchical modulation. After demodulation and error-correction, the 8-VSB modulation supports a digital data stream of about 19.39 Mbit/s, enough for one high-definition video stream or several standard-definition services. 


On November 17, 2017, the FCC voted 3-2 in favor of authorizing voluntary deployments of ATSC 3.0, which was designed as the successor to the original ATSC "1.0", and issued a Report and Order to that effect. Full-power stations will be required to maintain a simulcast of their channels on an ATSC 1.0-compatible signal if they decide to deploy an ATSC 3.0 service.


On cable, ATSC usually uses 256QAM, although some use 16VSB. Both of these double the throughput to 38.78 Mbit/s within the same 6 MHz bandwidth. ATSC is also used over satellite. While these are logically called ATSC-C and ATSC-S, these terms were never officially defined.


DTMB

DTMB is the digital television broadcasting standard of the People's Republic of China, Hong Kong and Macau. This is a fusion system, which is a compromise of different competing proposing standards from different Chinese Universities, which incorporates elements from DMB-T, ADTB-T and TiMi 3.


DVB

DVB-T uses coded orthogonal frequency division multiplexing (COFDM), which uses as many as 8000 independent carriers, each transmitting data at a comparatively low rate. This system was designed to provide superior immunity from multipath interference, and has a choice of system variants which allow data rates from 4 MBit/s up to 24 MBit/s. One US broadcaster, Sinclair Broadcasting, petitioned the Federal Communications Commission to permit the use of COFDM instead of 8-VSB, on the theory that this would improve prospects for digital TV reception by households without outside antennas (a majority in the US), but this request was denied. (However, one US digital station, WNYE-DT in New York, was temporarily converted to COFDM modulation on an emergency basis for datacasting information to emergency services personnel in lower Manhattan in the aftermath of the September 11 terrorist attacks).


DVB-S is the original Digital Video Broadcasting forward error coding and modulation standard for satellite television and dates back to 1995. It is used via satellites serving every continent of the world, including North America. DVB-S is used in both MCPC and SCPC modes for broadcast network feeds, as well as for direct broadcast satellite services like Sky and Freesat in the British Isles, Sky Deutschland and HD+ in Germany and Austria, TNT SAT/FRANSAT and CanalSat in France, Dish Network in the US, and Bell TV in Canada. The MPEG transport stream delivered by DVB-S is mandated as MPEG-2.


DVB-C stands for Digital Video Broadcasting - Cable and it is the DVB European consortium standard for the broadcast transmission of digital television over cable. This system transmits an MPEG-2 family digital audio/video stream, using a QAM modulation with channel coding.


ISDB

ISDB is very similar to DVB, however it is broken into 13 subchannels. Twelve are used for TV, while the last serves either as a guard band, or for the 1seg (ISDB-H) service. Like the other DTV systems, the ISDB types differ mainly in the modulations used, due to the requirements of different frequency bands. The 12 GHz band ISDB-S uses PSK modulation, 2.6 GHz band digital sound broadcasting uses CDM and ISDB-T (in VHF and/or UHF band) uses COFDM with PSK/QAM. It was developed in Japan with MPEG-2, and is now used in Brazil with MPEG-4. Unlike other digital broadcast systems, ISDB includes digital rights management to restrict recording of programming.


DAM stands for Digital Asset Management.

And what is a Digital Asset? In our context of broadcast recording and re-purposing (re-distribution), a Digital Asset is any audio/video file, that was recorded in some digital format, and which is intended for redistribution to some viewers with rights to watch it.


Digital content media files are the currency of modern media broadcast systems, but managing large repositories of media files can be a major challenge for any broadcaster. Searching, storing, retrieving, and distributing video and audio files for broadcast can be time-consuming, managing multiple metadata even for the simplest of operations, as modern broadcasters do not live in a simple world.


Media Asset Management (MAM) demands have to accommodate complex realities, including:

  • Large volumes of metadata associated with digital asset
  • Workflow of multiple users collaborating to generate and broadcast content
  • The demands of networked, but geographically-dispersed broadcasters who need to work from a common platform
  • Accessible web services and control for system users running aspects of the station away from studio
  • Distribution over a variety of platforms including radio, terrestrial TV, CATV and digital signage


Benefits of DAM

  • Fast Searching across (literally) millions of stored items collected and managed in a single place. “One-stop-shopping” makes it easy to find content, powerful search tools in a DAM make it fast.
  • Easily share and distribute found content to others both internally, externally or to social networks using the tools that should be available in a robust DAM system.
  • Reduce costs by never having to recreate content that has been lost, misplaced, or the rights are not clear.
  • Collaborate across departments and users
  • Ensure brand integrity but making the most up-to-date versions of your content available to users across your organization
  • Keep track of how and where content has been used
  • Lower costs by centralizing that function


Digital asset management (DAM) has gone from an exclusive tool for large-scale enterprises to a component in every marketing department around the world. When DAM started, it was primarily focused on media library and the cataloging, storing, and sharing of assets that comes with it. By using and leveraging modern DAM tactics and tools, every business or organization can improve the impact of their digital content.


here are some considerations to make when choosing a DAM platform. Due to a major shift in digital data, companies are being forced to determine a cost-effective way to store, organize, retrieve, find, and distribute digital assets while making sure they have the highest level of security. DAM systems help organizations maximize the value of their current digital assets, giving relevant resources pertaining to other tasks or digital media. Here are the top five projected trends we can expect to see with digital asset management.


Artificial Intelligence


At this point, it should be no secret that artificial intelligence (AI) is beginning to take over every aspect of business. The trends in DAM show that AI will replace manual workloads for employees. Because DAM can automate the manual need to tag visual assets, it uses AI technology to scan content and automatically create corresponding metadata tags. This allows companies to find what they need faster while saving hours of organizing.


Experts predict that AI is only going to get more accurate and effective in upcoming years. This “machine learning” will allow DAM systems to better understand their own assets and users. Visual recognition will be able to predict a user’s needs based on their past behaviors. DAM systems will continue to incorporate AI for video to provide recommendations for using content based on their previous searches and overall user profiles.


Automation


It is safe to say that automation will take over asset organization in marketing companies and departments. Machine learning algorithms will allow the DAM software to recommend specific assets for a specific task within a campaign or activity. The marketer can then choose the asset that works best for them either based on their own personal preference or from the analytical insight. Over time, as the DAM software learns from the data and patterns of usage, it will be able to pull more appropriate assets from the system. Automation is needed to support the digital marketers of today and the future. Without quick access to relevant digital assets, customer service and job productivity will suffer.


Cloud-Based DAM


The acceptance and adoption of “the cloud” in recent years has grown substantially. This allows an organization to purchase an enterprise license without having to be responsible for hosting it. It provides a safe and efficient way for an organization to store and protect their business income and assets. A cloud-based DAM is better than traditional cloud file storage, hard drives, and shared drives because it offers file sharing regardless of file size.


In the upcoming years DAM systems will continue to embrace the cloud. This type of DAM storage includes features like version control, rights management, file rendering, and workflow templates. There is little to no IT involvement needed when using a cloud DAM system, and the security of these systems is generally better than organizations that structure their own access to content through platforms like Dropbox  and the like.


Metadata Management


One of the best reasons to use a DAM tool is to optimize the overall time an organization has. A lot of companies are working to make sure that their digital assets are embedded with metadata., but it takes a while to manually complete this task. Tools and software can now predict associations between digital assets, which allows the DAM system to suggest options for metadata automatically. This means that organizations will have more precision over the level of metadata detail they can maintain in their files, allowing endless opportunities for searching and cataloging digit asset libraries.


Blockchain


Blockchain is a secure and localized online ledger system that sets up, manages and invests in DAM strategies. Blockchain protects the ownership of digital assets and protects the information from being misused. It does this by identifying the integrity and security of the people using the assets before giving them access.


Blockchain is important for organizations that deal with high-security data. This type of technology is said to have created the backbone to a new type of internet by allowing digital assets to be distributed but not copied. Many experts foresee blockchain as playing a key part in the digital asset exchange that occurs between marketers and their clients. This type of integration will allow users to track and record asset usage without the time-consuming task of doing it manually.


By committing to a digital asset management platform, businesses provide a seamless experience for consumers across all technology channels. It offers a platform to deliver a unique experience and brand awareness to customers while keeping assets and valuable information in the hands of the right people.   There are a few things that are needed to best  utilize a digital asset management program  for your organization, but by focusing on what is coming up in the DAM world, businesses can make sure they are prepared to incorporate the latest technology into their business plan.


In the broadcast industry, we refer to the term MAM, or Media Asset Management, which is a subcategory of DAM.


The birth of MAM

MAM as we know it today first exploded onto the scene around 15 years ago with vendors like Dalet, Ardendo (since acquired by Vizrt), and Blueorder (since acquired by Avid). At that time, broadcasters were making the first forays into digitalisation and with that came more complexity and a number of efficiency challenges when it came to managing a rise in digital content.


The first MAMs were highly bespoke and usually involved a significant upfront investment. The first MAMs also meant on-premise installations. However, the value of being able to properly manage huge amounts of media files, something simply not possible previously, and the subsequent leap in efficiency for broadcasters meant it was well worth the investment in time, money, and valuable space. And so what we saw was more content for less effort and some very happy broadcasters – and happy MAM providers.


A MAM system would have to handle not only the physical storage of the assets, but also their capture (ingestion, input), categorization (annotation, tagging, ordering, Metadata), retrieval (search, preview, extraction), and finally distribution (format transcoding, user rights, physical delivery). A MAM system would necessarily include capabilities to encode, decode and transcode Video and Audio formats.


MAM is a system to archive and manage time-based media and workflows in a distributed and collaborative environment. MAM is a multi-format, multi-vendor, multi-workflow federated content repository which encourages innovation, traction, and operational efficiency over the complete life-cycle of an asset. Media asset management vendors are having to evolve as workflows move to the cloud. One way they are doing so is to segment part of their product offer into orchestration but – just as with MAM - it’s not entirely clear that everyone means the same thing when they use the term. Orchestration is an important and integral part of a MAM system, but it is not a MAM system. This requires integration with other platforms (development, newsroom systems, playout automation, CMS, VOD platforms, storage management, video processing). This integration is best delivered through some form of Enterprise Service Bus. This has been the ‘holy grail’ of media and broadcast, but with so many disparate systems and methods of integration, it has been, and will remain, a huge challenge.

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