WASHINGTON—The Joint Content Conformance Partners (JCCP), a jointly funded group supported by ATSC together with DASH-IF, the DVB Project, the Consumer Technology Association Web Application Video Ecosystem (WAVE) Project and the HbbTV Association, has released an improved, widely available tool that validates conformance of DASH content to relevant media specifications, the Advanced Television Systems Committee said today.

The specification, developed collaboratively by the five industry bodies, ensures DASH content conformance, which is important for interoperability. 

The DASH-IF Conformance Tool, available as either an online service or open-source software, was launched more than a decade ago and has been continuously updated and extended to test against relevant specifications from other bodies, ATSC said.

A joint project undertaken over the past two years has improved the tool, making it more reliable and accessible. Along with DASH content conformance, the new tool has options to check for CMAF and WAVE requirements, and for HLS (HTTP Live Streaming) requirements as well, according to the ATSC.

The five partners supporting development of the enhanced specifications are encouraging the industry to use the tool and are seeking feedback that can lead to further improvements, it said.

“ATSC was proud to be working in conjunction with these other organizations, as we see this as an important resource and look forward to continuing our collaboration for the betterment of the industry,” said ATSC president Madeleine Noland, 

The DASH-IF Conformance Tool will be presented and discussed during the online OSMART Workshop #2 on Dec. 6-7, 2023.

Over the past several years, the video streaming industry has been working on solutions to achieve low-latency OTT delivery in order to compete with traditional broadcast of live content. This was initially achieved with the MPEG DASH format, using CMAF, standardized in January 2018 by MPEG, followed in October 2019 by DVB delivering the low latency update of its DVB DASH specification. In June 2019, Apple announced during its Worldwide Developers Conference that the HLS protocol is being updated to support low latency, (the “Apple way,” of course).

The challenge: Two separate ecosystems exist today for the delivery of live content in DASH and HLS, the most popular delivery formats. In order for OTT to scale, we have to rationalize the two approaches and find a common groundwork for low latency.

CMAF: A FOUNDATION FOR CONVERGENCE

As a solution to possible convergence, Common Media Application format (CMAF), an ISO media format standardized in January 2018, provides a promising framework. When Microsoft, Apple and other industry players came together to propose the CMAF standard, many believed convergence was a done deal.

But this was not and is still not the case, and there are still some missing pieces to the puzzle. Service providers that wish to distribute their content in both formats (i.e., HLS and DASH) still need to have separate workflows at some points and duplication of media file caching in the network, which increases their overall costs; it also increases complexity and puts more stress on the OTT business model and therefore slows down OTT deployments.

WHY ISN'T THERE A SINGLE WORKFLOW FOR LIVE CONTENT DELIVERY?

Low-latency delivery is an essential feature for highly valuable content such as premium sports, which also drags the largest audience for live. Therefore, now more than ever, it is important for the industry to figure out a way to produce and cache a single set of media files in the network to optimize processing, caching and storage costs. This was the promise of CMAF from its onset, but hurdles with regards to low latency delivery methods need to be removed to make it a reality.

Indeed Low Latency DASH, also called “DASH LLC” (Low latency Chunk), and Low latency HLS, as proposed by Apple in June 2019 (LL-HLS), rely on different sets of tools and protocols for delivery, despite both using CMAF (including CMAF chunks) for the media file format. The former uses HTTP chunk transfer encoding while the latter (which is still an Apple draft specification) uses HTTP/2 and the more problematic HTTP/2 push method (not widely deployed or even supported), creating a lot of pushback from the CDN industry.

As a result, for the delivery of low latency services, the OTT industry is still grappling with two sets of media files, duplicate caching and high costs while fighting to find a profitable business model.

THE LATEST UPDATE ON LOW LATENCY

The end of 2019 brought about positive changes to the OTT industry. Apple and other industry players, including technology solution providers for encoding, packaging, origin, CDN and OTT players, expressed the willingness to find a compatible mode between DASH and HLS for low-latency content delivery.

It would be beneficial for the industry to see some evolutions on the current draft LL-HLS proposal to finally achieve the initial promise of having a real common format for media files and a common delivery workflow.

CONTENT PROTECTION: DRM AND AD INSERTION

For service providers, content needs to be monetized, so DRM and ad insertion tools are therefore critical to ensuring that service providers can take advantage of the abundant revenue opportunities in the OTT environment. As part of the global workflows for content delivery, there should also be a way to build common methods for these features.

There is now unified support for the CBCS encryption scheme by all of the major DRM systems such as Apple FairPlay for HLS, and Google Widevine and Microsoft PlayReady for DASH. With this approach a single media file can be encrypted in the CBCS format and distributed to any player, no matter what DRM system is in use. This fulfills the initial promise of CMAF. Detailed discussions still need to take place around DRM, but the industry is headed in the right direction.

Ad insertion—in particular dynamic and targeted ad insertion—is increasingly being used by OTT service providers to make ads more relevant. Through dynamic ad insertion solutions, service providers can dramatically boost their OTT revenues by creating more value for advertisers and improving the end-user experience.

For targeted ads to be successful, service providers need to ensure a seamless video experience, with smooth dynamic ad insertion. Both DASH and HLS Low Latency specifications are currently scrutinized to make sure the industry practices used in legacy workflows can be used or slightly adapted to take into account the additional constraints brought about by the shorter delivery path. Guidelines for both HLS and DASH will have to be updated to properly use the timing information for inserting ads in the low latency streams. It is still a work in progress but there is hope this can be achieved to enable a common workflow.

CONCLUSION

At Harmonic, we believe that the industry has to develop a unified CMAF based, Live OTT streaming system that supports: common encryption (already done with CBCS), ad insertion and low latency for both delivery formats (HLS and DASH).

Under this approach, media files are only stored once, which saves processing, storage and delivery costs. And, of course, there are two different HLS and DASH manifests that can always be cached separately.

This will create an optimized delivery scheme that will enable all of the key features OTT operators are looking for. Failing to accomplish this will fragment the market, make OTT less profitable and slow down its development.

Patrick Gendron is director of innovation at Harmonic.

PORTLAND, ORE.—Amazon Web Services has launched SPEKE (Secure Packager and Encoder Key Exchange), an open, extensible API specification developed to streamline integration of Digital Rights Management (DRM) with encoders, transcoders, and origin servers (encryptors).

Most integrations usually require a custom API for each DRM solutions provider and each encryptor, which can be costly and time consuming, and even delay the launch of new services. SPEKE provides a standardized method for key exchange between encryptors and DRM systems. It also enables customers to use SPEKE-enabled key servers or encryptors in on-premises, cloud, or hybrid infrastructures. SPEKE is designed for both live and on-demand media workflows.

Built on the DASH Industry Forum’s Content Protection Information Exchange Format (CPIX) standard for key exchange, AWS says SPEKE provides a universal, secure way for SPEKE-enabled key servers and encryptors to encrypt content. An API specification supports HLS, MSS and DASH packaging as well as standard DRM platforms, including Apple FairPlay Streaming, Microsoft PlayReady, Google Widevine, AES-128, and proprietary DRMs.

Multiple APN partners already have implemented SPEKE, including AWS, Axinom, castLabs, EZDRM, INKA Entworks, Insys Video Technologies, Intertrust Technologies, Irdeto, Kaltura, NAGRA, NEXTSCAPE, Verimatrix, Viaccess-Orca, VUALTO, and WebStream.

"SPEKE is an exciting development for our industry. Building on the CPIX API, it further improves operational efficiencies and reduces both the time and costs involved in launching OTT services,” said Will Law, founding board member and Vice-Chairman, DASH Industry Forum.

”Prior to SPEKE, integration required a custom API tailored to each DRM solutions provider and each individual encoder, transcoder, and packager,” said Michael Callahan, Head of Media Solutions Marketing at AWS Elemental. ”This often resulted in delayed new service launches for customers. SPEKE simplifies DRM integration to a single secure API. Any SPEKE-enabled DRM key server works with any SPEKE-enabled encryptor out of the box without the need for proprietary integration.”

As OTT (Over-The-Top) technology has gotten more mature and established robust standards over the years, the concept of OTT monitoring is gaining popularity. With customer expectations soaring, it’s vital for OTT providers to deliver superior-quality content. To deliver Quality of Experience (QoE) on par with linear TV broadcast, the entire system, starting from ingest to multi-bitrate encoding to delivery to CDN must be monitored continuously.

Streaming service providers and broadcasters understand the complexities involved in OTT delivery and the media distribution chain—from content acquisition to actual transmission. OTT monitoring primarily involves monitoring the status of all key elements in the pipeline starting with the media source, encoders, decoders, output of Content Distribution Network (CDN), etc. The amount of media consumed over OTT is growing at a staggering pace, and people’s viewing habits are rapidly moving towards a unified multiscreen experience. These rapid changes demand a strong comprehensive monitoring solution that takes care of all the aspects in the OTT chain and makes it easy for people at various levels in broadcast operations to monitor and control the entire system.

The primary goals of monitoring OTT are to guarantee Quality of Service (QoS), Quality of Experience (QoE) and compliance monitoring. These quality metrics include media quality for confidence monitoring and delivery of captions, both for primary and secondary languages, to increase user engagement. In addition to QoS and QoE monitoring, broadcasters have another challenge to track viewership using ID3 Tag technology.

A comprehensive monitoring system includes the following:

• Encoder status, start/stop streaming, alarms, etc. It is essential to ensure proper encoding of content that comes in from multiple sources. As opposed to traditional broadcasts, live cloud OTT workflows are much more complex as it involves delivery to individual devices with multiple profiles. It is critical to monitor for all possible issues like frame misalignment, syntax errors, over-compression, absence of markers & metadata, dropped packets, and compliance slips as these issues can negatively impact a positive viewer experience. A monitoring system should be able to monitor end-to-end workflow, raise alarms, report streaming status, and notify issues that occur anywhere in the end-to-end system. This helps to quickly resolve issues before the end customers get affected.

• CDN status (concurrent connections, origin, visitors’ statistics, etc.) The CDN plays a crucial part in delivering content to end customers. It is critical to monitor the origin of the content, viewers’ statistics, and CDN edge.

• RTMP Surveillance and analysis of local encoders' output

• External report on streaming services availability at CDN outputs, ping, etc.

• Monitoring of website accessibility, CDN status, network status, etc.

• Video-on-Demand accessibility and Quality Control Analysis. In addition to live streaming, VOD clips must be monitored for quality.

• End-user experience status report

• End-user experience report for developers

• Server-Side Ad Insertion

• Captions

OTT Monitoring Advances

OTT monitoring is evolving at a rapid pace. Early on, OTT monitoring had largely been limited to IT infrastructure monitoring, and to some extent, monitoring streams at edge locations as a proof of delivery.

With the market growing, more and more OTT broadcasters are starting to see the value of monitoring. Efforts are on to converge OTT platforms and optimize streaming protocols.

OTT providers use various streaming protocols for media delivery, including Real Time Streaming Protocol (RTSP), Real-time Transport Protocol, Smoothing Streaming, etc. Often, the receiving devices support only one or two protocols requiring service providers to stream their content in multiple protocols. Nowadays, the media streaming process is largely being performed in the cloud, making use of the CDN. The data that goes in and is delivered out from the CDN needs to be monitored to guarantee QoE.

Also, transmission errors can occur while transporting media data using the IP network; errors could pertain to packet latency, jitter, packet loss, etc. This makes it important for service providers to introduce complete quality monitoring solutions, including video monitoring at the CDN data centers and at the edge locations.

Cloud-based monitoring is extremely efficient as it works like a virtual machine (VM) that can be moved to any place within a particular network. This makes it easier to store, manage and process data, thereby saving a lot of time, effort, and money. Cloud-based monitoring allows monitoring in geo-restricted streams and regions as well as scaling up monitoring, particularly with server-side ad insertions.

The State of Logging and Compliance

Logging and compliance of traditional broadcasts are being done by a lot of companies. However, these types of loggings neither cover OTT content nor do they cover content that has advertisements inserted at the MSO. Relying on logs to understand what happens to the content could turn out to be wrong.

OTT operations have changed the way that advertisements are delivered; they can specify ads for a specific market or a community. However, these broadcasts generally are poorly monitored, or at times not monitored at all compared to traditional broadcasts.

Thus far, there has been no major push from the industry to monitor OTT due to minimal FCC compliance requirements and a lack of an industry standard on OTT. Rapid innovations are being made in OTT and broadcast video delivery. Content owners are under constant pressure to respond to the surge in OTT content consumption.

OTT video service delivery technique is making use of dynamic adaptive video streaming over HTTP (DASH). Over the past year, MPEG-DASH has seen rapid growth and has also gained strong ground in OTT technologies.

The ATSC 3.0 specification is making use of DASH for Hybrid Broadcast-Broadband TV. ATSC 3.0 offers broadcasters the opportunity to deliver broadcast and broadband services to provide better a television experience.

Statistical multiplexing (Statmux) helps in providing high-quality ATSC 3.0 streams and facilitates efficient use of available bandwidth and supports to optimize bitrates and video quality of channels that share the same physical layer pipes. OTT content travels via a broadband connection in the receiver and DASH acts as the enabler in this scenario.

OTT Monitoring Best Practices

According to the image above, the entire OTT video delivery process is carried out in three different layers. The three OTT Layers: Operations Layer, Media Layer, and Distribution Layer are monitored by three groups of API Integration. These API integrations monitor content throughout the workflow right from content acquisition to content consumption to content delivery. Monitoring includes minute observations for all touch points of the workflow and provides all the technical error data, which works as an alarm, and helps provide users uninterrupted video.

The key to improving operational efficiency is to create a fault-tolerant OTT streaming infrastructure. In case of an eventual fault, reducing the resolution time to minimum is fundamental. As highlighted in the diagram above, a comprehensive and easy- to-use dashboard that captures and controls the health of the entire infrastructure real-time can add value to the overall operation.

Current Cloud-based Challenges

• Multiple protocols being used to support a wide range of devices OTT providers use multiple streaming protocols for media delivery, and the receiving devices support only one or two protocols, which prompts OTT service providers to stream their content in multiple protocols. The data that goes in and comes out from the CDN needs to be monitored to guarantee the quality of experience (QoE).

• Last mile monitoring cloud-based OTT monitoring must handle the problem of last mile monitoring. Cloud-based applications must be monitored at various levels including user experience. Physically, there is a considerable distance between where the application is running and where the users are. Conventional monitoring, being part of the application environment, makes it technically difficult to monitor how an application behaves at the user’s end—be it a mobile app or a web browser. Internet issues specific to each region are to be monitored. Bad internet connectivity could impact user experience. 

Multiple multi-bitrate results in an increased resource requirement. Another major challenge of OTT content streaming is that the devices and networks are far more diverse than those assembled in controlled environments like satellite, cable, etc. An adaptable architecture is necessary to address the varied needs of network conditions and device requirements.

Streaming videos are being delivered to a range of devices, including computers, smartphones, and tablets, making the monitoring process more complex. Bitrates and profiles with which each variant is encoded are different. So, from a monitoring and quality control perspective, operators need to put in more efforts as they have many versions for each piece of content.

Networks used by some of the devices need to tolerate dynamically fluctuating characteristics. Also, the underlying technology used in adaptive bitrate streaming is not standardized.

The aforementioned are not specific to all cloud-based applications, but to OTT monitoring in general.

Future OTT Monitoring Fixes:

• Simulating last mile bandwidth variations
• Convergence of protocols
• Limiting the number of manifests and reducing error rates while switching from one manifest to another

Future Advances in Cloud-based Monitoring of OTT Content

• Converging of streaming protocols, a widely adapted industry standard; MPEG-DASH for instance
• A protocol based on segmented delivery with near zero latency
• Advances in video compression, partly promised by H265 and efficient utilization of available bandwidth for best QoS

Hiren Hindocha is the CEO of Digital Nirvana.