PERSONAL VIDEO RECORDERS (PVRs) & CONDITIONAL ACCESS (CA) CREATE NEW BUSINESS OPPORTUNITIES FOR PAY-MEDIA OPERATORS
by Norman Lievaart

PVRs, also known as Personal Digital Recorders (PDRs) or Digital Video Recorders (DVRs), are destined to fundamentally change the media delivery industry.

A PVR is a computer hard disk, operated either manually or coupled to an interactive programme guide for intelligent recording. It offers the capacity to digitally record and play back television programming. It is capable of recording whilst simultaneously rewinding and playing back, allowing live television to be “paused” and, in some implementations, skipping advertisements during recording or playback.

One of the factors behind the rapid success of the PVR has been the fact that hard disk prices have been falling quite rapidly (faster than RAM prices) over the past few years. During the same period, hard disk recording capacity has increased significantly.

The pioneering companies behind the PVR concept during the late 1990’s, TiVo and ReplayTV, have been joined by Set Top Box (STB) manufacturers, consumer electronics manufacturers, suppliers of interactive television software, as well as broadcasters and pay-media operators in their search for new revenue streams. This activity to integrate hard disk recording into other parts of the home entertainment value chain has created a large number of new product permutations. The PVR is thus undergoing an evolution from its initial use as a product to becoming a device within a service offering.

PVR SYSTEMS

Applications

A key distinction of PVRs is that they are inherently random-access devices. They can therefore offer very rapid access to stored material, compared to a VCR. The PVR also has the ability to record and play at the same time, allowing it to offer a range of facilities that cannot be matched by a VCR.

PVRs offer the traditional VCR modes of pause, slow motion, fast-forward and rewind to enable a new way for viewers to consume programming in a non-linear way. PVRs also have the intelligence to base automatic recording decisions on previously observed user behaviour. 

A variety of PVR service models can be envisioned for viable commercial services:

• PVR-STBs can be connected to a broadband network e.g. Asynchronous Digital Subscriber Line (ADSL) and be used to offer traditional Video On Demand (VOD) services. Several events could be stored on the hard disk and made available on-demand.  Movies would be stored in scrambled form and unscrambled only upon payment of the appropriate service fee.
  
  
• At the other extreme, PVR-STBs could be operated in trickle-fed mode with no return path but with perhaps a call centre to service individual PVR-VOD service requests.
  
  
• Broadcasting services could be used as a down-stream delivery mechanism, with a modem built into the PVR-integrated STB requesting unscrambling of the stored item.

Systems

PVR systems appear to be converging on the PVR-integrated STB development area, rather than stand-alone devices. Hard disk technology lends itself well to its incorporation into a new generation of STB’s. The PVR function thus becomes a feature of digital interactive television, with the hard disk equipped STB acting as a local storage device.

The important technological aspects of the PVR-integrated STB are:

• Hardware (Total STB solutions and key components)
  
  
• Software and Middleware solutions
  
  
• Services

The essential functionality of a typical PVR system is shown in the diagram below:

This system provides for recording 2 sources simultaneously, whilst playing out either stored or “real-time” content.  Other variations are possible e.g. a PVR is available with 3 tuners, where two tuners are dedicated to serving two TV sets in separate viewing environments, while the third tuner is dedicated to the hard disk.

Standards

Although several proprietary PVR systems are already available in some markets, many believe that PVRs will only come of age when they embrace “open” market standards. TV-Anytime (TVA), a pre-standardisation body, has developed specifications for the next generation of PVRs. In co-operative endeavour, it has specified a set of tools that allow better relationships to be developed between content producers, service providers and consumers.

In Phase 1, the TVA Forum has developed a set of open specifications that enable the inter-operable searching, selection, acquisition and management of content for PVRs. These functions are independent of the means of delivery of the service to the consumer.

TVA’s standards are being adapted to regional requirements in Europe by the Digital Video Broadcasting group (DVB), in the USA by the Advanced Television Systems Committee (ATSC) and in Japan by the Association of Radio Industries and Businesses (ARIB) standardisation groups. Liaisons have also been developed with other important industry standards groups to ensure on-going harmonisation of efforts in this field.

PAY-MEDIA & THE PVR

Business Opportunities

The compelling features of an integrated PVR STB offer a strong incentive for pay-media operators to upgrade their current STBs to PVR-integrated STBs. These devices improve subscribers’ impressions of the services they purchase. This leads to:

• A reduction in “churn”
  
  
• Differentiation from the competition
  
  
• Increase in subscriber satisfaction
  
  
• Attractive offerings to attract new subscribers
  
  
• Improved Average Revenue Per Subscriber (ARPU), arising from the ability to launch new services

Compared to a broadband network, PVR services offer the pay-media operator an alternative in-home entertainment platform. The PVR-integrated STB offers several advantages:

• Pre-caching: A typical hard disk can store the contents of at least the 15 currently most popular movies. These could be downloaded and made available as part of a subscription or VOD service, while reserving perhaps 10 hours of PVR space for subscriber-initiated recording.
  
  
• Network bandwidth that is freed up by the pre-caching system can be released for other services or for less popular or niche content.

Pay-media Requirements

The following elements are required to securely enable the above service opportunities:

• A CA system to manage the subscriber’s rights to the stored material
  
  
• Integration of the PVR functionality and the operator’s Electronic Programme Guide (EPG)
  
  
• Design verification and testing of the PVR functionality, the CA system and the operator’s chosen STB

The benefits of secure storage of content on the local hard disk are:

• Content protection is assured for the content rights owners
  
  
• Content usage can be validated (based on purchase conditions)
  
  
• Accurate usage information is available for invoicing
  
  
• Stored content cannot be misused

PVRs & IRDETO ACCESS CA

Irdeto Access envisages two models for CA systems that support PVR services: 

PVR Option 1: STB Provides All PVR Functionality

In this PVR variant, the STB or Integrated Receiver Decoder (IRD) descrambles the selected channel.  The “clear” digital content is then applied to a Triple Data Encryption Standard (DES) scrambler within the STB, before it is stored on the Hard Disk Drive (HDD). Stored content that is to be viewed has to be descrambled by a key before it is presented to the STB’s decompression system.

The PVR is thus “on” or “off”, depending on a reserved product on the Irdeto Access smart card, which would be downloaded from the operator’s Subscriber Management System (SMS). This variant would allow the operator to charge additional monthly subscription fees to subscribers who purchase PVR-equipped STB’s and who wish to invoke the PVR functionality.

PVR Option 2: Session & Event-based PVR Management

In this PVR variant, the selected session or event is streamed to the HDD, where it is stored in scrambled format. The STB allocates the session or event an ID number to facilitate later playback of the content. The STB’s smart card stores the relevant keys for the subsequent descrambling process.

Two sub-variants are possible:

• Session-based CA Encryption: This variant permits basic rules to be applied for the replaying of stored content. Sessions, as opposed to events, are recorded i.e. the granularity of operator-control is coarse.
  
  
• Event-based CA Encryption: This variant implements a suite of Digital Rights Management (DRM) rules in the play-out of recorded events.

Irdeto Access is currently developing CA support for a variant that combines both session and event-based PVR management

CONCLUSION

PVRs based on hard disks will offer low-cost mass storage for home entertainment applications in the future. Users will be exposed to new types of programme services and will experience traditional broadcasting in new ways, as PVR’s permit viewers to “watch what they want, when they want”.

Note that technological feasibility should not be confused with commercial viability. Success will be based on determining those features or services that interest the consumer to the point that they purchase the offered service.

Conditional Access is an efficient solution for ensuring payment for and the proper use of advanced services capable of being delivered to users by PVR-integrated STBs. These services include VOD, interactive applications and similar revenue-generating sources for pay-media operators. The addition of a PVR capability to operator-STBs is thus likely to raise ARPU figures and reduce the time taken to amortise the cost of STB subsidies.