Broadcasters have many options for storing their media assets and typically employ several types of storage media throughout their facilities. By taking advantage of techniques such as rule based file migration or automatic format conversion and combining them with a unified search and retrieval interface, a MAM system can guarantee ease-of-use for production teams while optimizing storage infrastructure costs.

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Implementing an intelligent storage policy
with media asset management
by Nicolas Hans Product Strategy Director, Dalet,
nhans@dalet.com.
Abstract
Broadcasters have many options for storing their media assets and typically employ several types of
storage media throughout their facilities. Examples include, but are not limited to, hard disk drive
based systems, optical jukeboxes and tape libraries. Each of these storage solutions has its own cost,
accessibility, capacity, and portability characteristics. Therefore managing them in a cost effective
manner without negatively impacting productivity can be a challenge. Additionally, searching for
and retrieving media assets in a mixed media environment may be another significant issue. These
challenges can be addressed by implementing an intelligent storage policy through the use of a
Media Asset Management (MAM) system. By taking advantage of techniques such as rule based
file migration or automatic format conversion and combining them with a unified search and
retrieval interface, a MAM system can guarantee ease-of-use for production teams while optimizing
storage infrastructure costs.
Introduction
Eliminating video tapes and moving to a file based digital media production system potentially
provides broadcasters with improved synergy, shorter time-to-air, better productivity and lower
operational costs. The ability to share files across the network eliminates the need for tape
duplication. It allows for different departments to access simultaneously the same recordings. The
possibility of transferring video faster than real time improves the turn-around of material and
enables editors and journalists to meet tighter deadlines. The option to preview clips from any
production desktop drastically increases productivity and simplifies the re-use of production
archives.
Today, computer storage technologies are reaching price points that make it financially feasible to
abandon tapes in the production realm. An increasing number of Non Linear Editing (NLE) systems
are networked. Video servers are becoming the norm for play-out operations; Electronic News
Gathering (ENG) teams are already experimenting with hard-disk based recorders. As a result,
broadcasters store an increasing amount of video material on Hard Disk Drives (HDD) and on-line
tape libraries attached to computer servers. Yet manipulating video files across a broadcaster’s
digital infrastructure presents a number of issues which are not met by Hierarchical Storage
Management (HSM) systems and other storage virtualization architectures developed by players of
the Information Technology (IT) world.
In addition to networked attached systems and storage area networks used in corporate
environments, broadcasters heavily rely on video servers. Although modern video servers are built
with standard IT components, they typically run real-time operating systems with built-in quality of
service (QOS) functionality to guarantee disk and network bandwidths. Transferring video files to
and from such ingest and play-out devices requires the use of proprietary protocols or Application
Programming Interfaces (API). As a result, integrating such devices with the rest of a broadcaster’s
IT infrastructure constitutes a challenge that can be solved by implementing an intelligent storage
management policy. Such a policy takes production workflow constraints into account to optimize
storage allocation and minimize associated costs. It leverages a Media Asset Management (MAM)

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system to seamlessly handle files across a local or wide area network and automate the format
conversions that bandwidth constraints impose. Finally, it offers editors and program makers a
unified search and retrieval interface to achieve their day-to-day production tasks.
Analyze workflow needs to optimize storage infrastructure
IT storage systems are not born equal. A wide range of solutions are available to broadcasters.
Storage capacity, bandwidth performance, redundancy and reliability define the technical
characteristics of a given storage system and determine its price. Broadcasters need to take
advantage of the variety of solutions available to minimize the cost of their infrastructure while
guaranteeing that the performance meets their operational requirements.
When considering the workflow of a broadcaster, distinct types of storage areas may be segmented.
As illustrated by FIGURE 1, a multi-channel facility will typically require 100 hours worth of video
to ensure continuous broadcast, 300 hours worth of storage capacity for production and 5000 hours
for production archives. Deep archives require very high storage capacities – typically beyond a
Petabyte (1000 Terabytes!) – to store tens of thousands of hours of material in broadcast quality.
Logarithmic scale
100 000 hours
Deep Archives
5000 hours
Production
Archives
300 hours
Production
Area
100 hours
Broadcast
Buffer
FIGURE 1 – The storage requirements of a broadcast operation can be segmented.
Each of these different storage areas has distinct technical requirements. While a broadcast buffer
requires high availability and extreme reliability, deep archives need to be highly scalable to ensure
for future growth. The storage system used for the production area must sustain high bandwidth
performance to support simultaneous access by multiple users; the one used for archives should
primarily offer large storage capacity with reasonable access times.
By distinguishing the technical requirements of each of these distinct areas, broadcasters can
optimize their storage costs and deploy various classes of storage systems (TABLE 1). These may
range from high performance video servers, to Storage Area Networks (SAN) based on fibre
channel arrays, to Network Attached Storage (NAS) appliances built on Small Computer System
Interface (SCSI) drives, to jukeboxes filled with recordable digital versatile disks (DVD-R) or
robotic libraries that use Linear Tape Open (LTO) cartridges.

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Storage type Average
seek time
Average
bandwidth
Cost for
100 Hours*
Cost for
10 000 hours*
HDD with Fibre
Channel controller
4 ms 70 MBps 55 000 USD 4 000 000 USD
HDD with SCSI
controller
6 to 8 ms 60 MBps 20 000 USD 1 400 000 USD
HDD with IDE
controllers
10 ms 30 MBps 12 000 USD 700 000 USD
LTO Tape Library 3 to 8 minutes 15 MBps 18 000 USD 225 000 USD
(*) On the basis of MPEG-2 4.2.2 i-Frame 30 Mbps encoding i.e., 100 Hours requires 1,5 TB.
TABLE 1 – Distinct storage types for distinct cost and performance levels (Q1/2004).
Merge heterogeneous storage environments
Successfully implementing such a local area data network does not boil down to interconnecting a
collection of different storage devices. A MAM system is required to ensure that file operations are
optimized and made as seamless as possible for production staff. Such intelligent storage
management is all the more a challenge that different storage units often require the use of distinct
access protocols (FIGURE 2). These access protocols use IT standards such as File Transfer
Protocol (FTP), Network File System (NFS), Common Internet File System (CIFS) or NT File
System (NTFS). They also involve proprietary APIs or broadcast specific protocols such as Video
Disk Control Protocol (VDCP) initially developed by Louth or Network Device Control Protocol
(NDCP) introduced by Harris.
FIGURE 2 – Merging multiple storage units requires that different protocols be supported.
Protocols are not the only issue. Hierarchical storage management systems allow for the seamless
combination of HDD based on-line storage with tertiary media near-line systems such as tape
libraries or optical disk jukeboxes. This type of storage systems is well adapted to both production
and deep archives because of its cost. Handling broadcast material requires specific features that are
rarely provided by standard IT solutions.

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Sports and news production units often need partial file retrieval. Consider the recording of a soccer
game from which a producer wants to extract a one minute segment – the “killer goal” for example.
Suppose that the match was saved as two 45 minutes files which are stored on a near-line tape
system. As illustrated by TABLE 2, retrieving on-line the recording of the second period will
typically take 13 to 14 minutes. Although this is a fraction of the time that would be required for
retrieving a tape from a traditional shelf-based archive, it can be dramatically improved. Using a
partial file retrieval system, these thirteen minutes and thirty seconds are cut down to five minutes.
Transfer speed of a tape drive
Theoretical drive speed 30 MBps
Nominal drive speed 15 MBps
Seek time of tape library
Time for moving tape to drive 1 to 2 minutes
Time for positioning head on tape 2 to 5 minutes
Time required for retrieving a 45 minute recording in MPEG-2 4.2.2 at 30 Mbps
Transfer time (depends of nominal speed drive) 6 to 11 minutes
Total time for retrieving 45 minutes 9 to 18 minutes – average: 13’30”
Time required for retrieving 1 minute recording in MPEG-2 4.2.2 at 30 Mbps
Transfer time (depends of nominal speed drive) 8 to 15 seconds
Total time for retrieving 1 minute 3 to 7 minutes – average: 5’
TABLE 2 – Partial file retrieval is a worthwhile extension to HSM systems.
Simplifying the management of a distributed storage architecture is all the more necessary as an
increasing number of broadcasters run multi-site operations. They need to merge content
distribution networks into their standard production infrastructure. An example of such a distributed
model is the use of the Internet as a contribution network by ENG teams. Another is the deployment
of leased data lines to aggregate and consolidate in a central-cast facility news packages and stories
produced by remote local offices. Such models require that video files be managed beyond the
Local Area Network (LAN), across Metropolitan (MAN) or even Wide Area Networks (WAN).
Move from video feeds to data files and streams
In a distributed environment, a MAM system needs to minimize or compensate for the delays
inherent to manipulating video files across a network. Despite the use of compression techniques,
broadcast quality video remains bandwidth hungry. Consider a recording in MPEG-2 4.2.2 i-Frame
at 30 Mbps. Add 1.5 Mbps for a single stereo audio channel. Transfer the resulting 31.5 Mbps data
stream over an Ethernet network: bandwidth consumption nearly reaches 35 Mbps because of
Internet Protocol (IP) communication overheads. A Gigabit Ethernet network provides 600 Mbps of
useful bandwidth. As a result, transferring an MPEG-2 recording such as the one described above
will occur at a maximum speed of 17 times real time. In other words, copying or moving a one
minute clip will take three and half seconds and a one hour package three and a half minutes!
Such figures are dramatically better than the real-time transfer speed achieved through a Serial
Digital Interface (SDI) or the four times faster than real-time Serial Data Transport Interface (SDTI)
networks provide. Video data transfers remain nonetheless time consuming and as such may impact
the production workflow. So as to limit that impact, implementing an intelligent storage
management policy requires video to be managed not only as files but also as data streams. Features
such as edit while record, convert while record or broadcast while record need to be supported
across storage units. In addition, the implementation of a multi-resolution architecture whereby
broadcast quality video material is always available in a lower bit rate format for browsing and
editing is often required.

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Although switched Ethernet and recent storage systems can support high resolution browse and edit
operations over the network, many workflow scenarios require the need for low resolution clones
(often referred to as ‘proxies’). Producers and editors need to browse material archived near-line in
the tape libraries or even off-line on shelved video tapes. Broadcasters that operate multi-site
networks require their editors to browse material available in other stations or on remote video
servers. In such scenarios, the generation of low resolution proxy files that correspond to broadcast
quality material is a necessity. This operation requires the choice of an adapted format as well as the
implementation of rule-based conversion mechanisms to ensure the proper synchronization of both
low and high resolution content.
The selection of a low resolution format is primarily conditioned by the need to provide editing
functionality. Whereas browse-only operations do not require frame accuracy, editing and voice-
over recordings do. Although MPEG-1 was a format of choice until recently, MPEG-4 and
Windows Media provide better image quality at relatively lower bit rates. Beyond the choice of a
proper format, successfully implementing a proxy architecture primarily relies on the ability to
ensure the consistent synchronization of low and high resolution versions. Such a process can only
be ensured by properly tracking all media assets across every step of the workflow – from ingest to
broadcast – and by triggering conversions according to predefined rules (FIGURE 3).
FIGURE 3 – A multi-resolution architecture is driven by stringent rules.
Such rules may also be used to ensure format or resolution conversions that are not related to proxy
generation. For example, production material typically needs to be converted to a different type of
encoding for remote contribution or broadcast purposes. A package in DV will be compressed to
MPEG-2 long GOP so as to be transferred over a WAN or broadcast by a video server. As the
Material eXchange Format (MXF) standard comes of age, automated wrapper conversions will also
be required.
Provide a unified search and retrieval interface
The key to successfully implementing an intelligent storage policy in a broadcast environment is to
provide editors and program staff with a unified view of available content. The underlying
complexity of the network infrastructure as well as the various file and conversion operations must

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be hidden from users. Such a unified user interface provides the search and retrieval features
required by production teams. It also needs to extend beyond media management to provide flexible
media and metadata management and simplified user rights management. Such a media warehouse
can empower the whole production workflow.
A unified search and retrieval interface should not reflect the structure of the network nor refer to
files on specific storage units. It must offer users with a layer of abstraction to provide them with a
relevant view of available assets i.e., recordings, clips, Edit Decision Lists (EDL) and associated
metadata. As such, it requires that technical, descriptive and legal metadata be customizable. In
addition, a flexible category structure can be used to drive assets across the workflow. For example,
by drag-and-dropping a specific clip from one category to another, a producer seamlessly triggers
the conversion and transfer of the corresponding file from one storage unit to another located on the
same LAN or WAN. Less than a passive catalog, such a unified user interface provides a front-
office view to the various back-office processes required to merge heterogeneous storage
environments.
A media warehouse also needs to simplify user rights management. To enable collaboration,
different roles and associated resources must be defined. Whereas all users may have access to the
low resolution version of available material, broadcast quality video should only be accessed by
authorized users. The same logic applies to metadata. Associated information regarding specific
assets is contextual. Whereas journalists focus on descriptive information (the “who, what, where,
when, why” mantra), editors are concerned by technical characteristics of a recording and archivists
by copyright information. As such, the view that users have of an asset needs to depend on their
profile. In addition, the ability to allocate quotas and resources to users is all the more required as
tapes are replaced by files and video information gains in fluidity. The needs for storage capacity
tend to inflate if no control process is implemented.
FIGURE 4 – Workflow drives media migrations across the storage network.
To constitute the backbone of the production process, a media warehouse also needs to optimize the
relationship between assets and production staff. It must embed workflow engine features such as
task assignment, status hierarchy and corresponding notification processes. For example, assigning
the creation of a package notifies the corresponding producer. Changing the status of an EDL from

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‘To be validated’ to ‘Approved’ triggers the rendering of the original material and the creation of a
new clip. Inserting the corresponding asset in a rundown moves the resulting clip from the
production area to the broadcast buffer (FIGURE 4).
Conclusion
By analyzing their workflow, broadcasters can segment their storage requirements and gain
flexibility. By moving away from the proprietary central video server model which was the rule in
the SDI world, they take advantage of the distinct classes of storage systems available today. This
minimizes the cost of their digital production and archive infrastructure. The use of a flexible media
asset management platform empowers them to implement an intelligent storage policy whereby
heterogeneous systems are merged into a unified storage network both locally and across multiple
sites. Such a network provides the infrastructure needed to manipulate the large files and bandwidth
intensive data streams that broadcast quality video requires. By providing a unified search and
retrieval interface to their production teams, they can hide the various media allocation, migration,
conversion and security rules that are required in a distributed broadcast environment. More
importantly, digital broadcasters build the framework they require to manage media and associated
metadata. As such, an intelligent storage policy seeks seeks to rip the productivity gains made
possible by the elimination of tapes and provides broadcasters with the digital backbone they need
to move to an asset production model that covers the whole workflow – from ingest to broadcast,
from archive to distribution.
Aknowledgements
The author wishes to thank his colleagues Benjamin Desbois, Janice Dolan, Stéphane Guez and
Thomas Zugmeyer for their help and support as well as Michael Elhadad for his careful reading of
this paper and his many suggestions.
Document history
This paper was initially presented at Broadcast Asia 2004. Since then, it’s been presented at the
ABE conference in Sydney.