IEC 62514:2010

IEC 62514 ®
Edition 1.0 2010-05
INTERNATIONAL
STANDARD
colour
inside
Multimedia gateway in home networks – Guidelines

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IEC 62514 ®
Edition 1.0 2010-05
INTERNATIONAL
STANDARD
colour
inside
Multimedia gateway in home networks – Guidelines

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XA
ICS 33.160.60; 35.110; 35.200 ISBN 978-2-88910-946-3
– 2 – 62514 © IEC:2010(E)
CONTENTS
FOREWORD.5
INTRODUCTION.7
1 Scope.8
2 Normative references .8
3 Terms，definitions and abbreviations .9
3.1 Terms and definitions .9
3.2 Abbreviations .10
4 HMG architecture .12
4.1 Architecture of a home multimedia network .12
4.2 HMG architecture .13
4.2.1 General .13
4.2.2 AV processing .13
4.2.3 Home automation .13
4.2.4 QoS.13
4.2.5 Security.14
4.2.6 Interconnection.14
4.2.7 Interfaces and access.14
5 Interconnection requirements .14
5.1 General connection requirements .14
5.2 Address assignment and resolution .15
5.2.1 Address assignment .15
5.2.2 Address resolution.15
5.3 Data transfer .15
5.4 Protocol translation .16
6 AV processing requirements.16
6.1 General .16
6.2 Multimedia transformation service .16
6.2.1 Requirements summary .16
6.2.2 Applications mode .16
6.3 Multimedia stream control service .22
6.3.1 Requirements summary .22
6.3.2 Application mode.22
6.3.3 Content directory service.30
6.4 Media format requirements.32
7 Home automation requirements .33
7.1 Requirements summary.33
7.2 Devices in directory.33
7.2.1 Printer .33
7.2.2 Surveillance cameras .33
7.2.3 Intelligent household appliance.34
7.3 Multimedia message application .34
7.3.1 Requirements summary for HMG .34
7.3.2 Multimedia message.34
7.3.3 Requirements for multimedia message .34
7.3.4 Multimedia message format .35
7.3.5 Send a message.36

62514 © IEC:2010(E) – 3 –
7.3.6 Delete a message.36
7.3.7 Requirements for HMG .36
7.4 Devices management by HMG .36
7.4.1 Device status.36
7.4.2 Connection status.36
7.4.3 Energy saving and power management .37
7.5 Meters reading .37
7.6 Household appliance control .38
8 QoS.38
8.1 General .38
8.2 QoS requirements for HMG .39
9 Security requirements.40
9.1 Requirements summary.40
9.2 DRM.40
9.3 Key management .41
9.4 Authentication .41
9.5 Credibility of HMG .42
10 Performance requirements .42
11 Requirements for interfaces and protocols of HMG.42
11.1 General .42
11.2 WAN side interfaces .43
11.3 LAN side interfaces .44
Annex A (informative) Application Scenario .45
Bibliography.57

Figure 1 – Architecture for a home multimedia network .12
Figure 2 – HMG architecture .13
Figure 3 – Conversion of media streams.17
Figure 4 – HMRec requests media conversion from HMG .18
Figure 5 – HMRec requests WMS to support redirection .19
Figure 6 – HMSou actively sends media to HMRec .21
Figure 7 – Video clip.22
Figure 8 – AV media stream division.23
Figure 9 – Stream division process .23
Figure 10 – Combination of media streams .24
Figure 11 – Stream combination process .24
Figure 12 – Duplication of media streams .25
Figure 13 – HMRec1 duplicates media stream to HMRec2 .26
Figure 14 – HMRec2 requests to join the multicast group of the program being played on
HMRec1.26
Figure 15 – HMRec1 requests media stream from HMG and duplicates media stream to
HMRec2.27
Figure 16 – HMRec1 duplicates media stream to HMRec2 after requesting MS to redirect
media stream to HMG .28
Figure 17 – Media stream redirection.29
Figure 18 – HMRec1 requests to redirect media stream to HMRec2.30

– 4 – 62514 © IEC:2010(E)
Figure 19 – HMRec selects media contents through the directory service of HMG .31
Figure 20 – QoS architecture overview .39

Table 1 – Mandatory and Optional Media Formats .32
Table 2 – Multimedia Message Format Recommended .35
Table 3 – WAN Side Interfaces .43
Table 4 – LAN Side Interfaces .44

62514 © IEC:2010(E) – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MULTIMEDIA GATEWAY IN HOME NETWORKS –
GUIDELINES
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62514 has been prepared by technical area 9: Audio, video and
multimedia applications for end-user network, of IEC technical committee 100: Audio, video and
multimedia systems and equipment.
The text of this standard is based on the following documents:
FDIS Report on voting
100/1672/FDIS 100/1705/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 6 – 62514 © IEC:2010(E)
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62514 © IEC:2010(E) – 7 –
INTRODUCTION
In a digital home, in order to meet the various requirements of digital living, all kinds of
communication devices (computers, consumer-electrical products etc) are integrated into a
home network. Such a network (comprising home information, entertainment, control services,
etc.) thus forms a system of information exchange with outside networks.
A home network system is a Local Area Network (LAN) connecting such terminal devices as
information devices, communication devices, entertainment devices, household appliances,
meters of gas, water and electricity, health-care equipment, lighting and security systems, etc.
to implement the network management and services and share the resources and services in the
network.
The multimedia services and the management for devices mentioned above can be performed
through a home multimedia gateway.

– 8 – 62514 © IEC:2010(E)
MULTIMEDIA GATEWAY IN HOME NETWORKS –
GUIDELINES
1 Scope
This International Standard describes the general guidelines for typical applications of the home
multimedia gateway in home networks supporting IP networking.
This standard specifies recommended functions and services to be supported by the home
multimedia gateway and, where appropriate, refers to existing standards supported in the
market. For general requirements, it is expected that widely adopted standards and
technologies will be considered by implementers.
This standard gives supplementary application to IEC 62481, which specifies a central
management model in home network supporting various interfaces in LAN side and WAN side
(optional).
This standard is applicable to home multimedia gateways in the home network or networks of
similar environment.
2 Normative references
The following referenced documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of the
referenced document (including any amendments) applies.
IEC 62481 (all parts), Digital living network alliance (DLNA) home networked device
interoperability guidelines
IEC 62481-1:2007, Digital living network alliance (DLNA) home networked device
interoperability guidelines – Part 1: Architecture and protocols
IEC 62481-2, Digital living network alliance (DLNA) home networked device interoperability
guidelines – Part 2: Media formats
ISO/IEC 14762, Information technology – Functional safety requirements for home and building
electronic systems (HBES)
ISO/IEC 29341 (all parts), Information technology – UPnP Device Architecture
ISO/IEC 29341-1, Information technology – UpnP Device Architecture – Part 1: UpnP Device
Architecture Version 1.0
ISO/IEC 29341-3 (all Parts 3), Information technology – UpnP Device Architecture – Part 3:
Audio Visual Device Control Protocol
ISO/IEC 15045-1, Information technology – Home electronic system (HES) gateway – Part 1:
A residential gateway model for HES
ITU-T G.9960 /9961/G.hn Next generation home networking transceivers
UPnP Forum: Quality of Service:3 (all parts), http://www.upnp.org/specs/qos/qos3.asp

62514 © IEC:2010(E) – 9 –
RFC 2663, IP Network Address Translator (NAT) Terminology and Considerations
RFC 3022, Traditional IP Network Address Translator (Traditional NAT)
IEEE 802.16, IEEE Standard for Local and metropolitan area networks Media Access Control
(MAC) Bridges
3 Terms, definitions and abbreviations
For the purposes of this document, the following terms, definitions and abbreviations apply.
3.1 Terms and definitions
3.1.1
home multimedia network
high speed network system to transport multimedia information within the home network
3.1.2
home multimedia gateway
HMG
logical device in the home network, which provides such functions as multimedia processing and
home automations, interconnection, QoS and security, etc; it can also connect LAN with outside
networks (for example internet), implementing protocol translation and offer various network
services
3.1.3
home control network
network that transports control information in the home network
3.1.4
home control gateway
provides protocol translation, device management, network management and control services in
a home control network which can be combined with HMG in the form of a physical device
3.1.5
control point
retrieves device and service descriptions, sends actions to services, polls for service state
variables and receives events from Services
NOTE ’Service’ is a term that is also defined in the ISO/IEC 29341 series.
3.1.6
terminal device
devices in the home network that can be controlled and managed by HMG and control point
3.1.7
media receiver
MR
device that receives media contents
NOTE It normally refers to the media content player.
3.1.8
home media receiver
HMRec
device that receives media contents in the home network

– 10 – 62514 © IEC:2010(E)
NOTE HMRec should fully support the function of DMR and DMP which are DLNA device classes defined by
IEC 62481-1.
3.1.9
media source
MS
device that owns media resources and sends media contents
3.1.10
home media source
HMSou
device that provides media contents in the home network; it can be a media server
NOTE HMSou should fully support the function of DMS and +PU+, which are defined by IEC 62481-1 and
IEC 62481-2.
3.1.11
WAN media source
device that provides media contents in the Wide Area Network (WAN)
3.2 Abbreviations
+DN+ Download Controller
+PR+ Printing Controller
+PU+ Push Uploader
+UP+ Upload Controller
AAC Advanced Audio Coding
ADSL Asymmetric Digital Subscriber Line
ANSI American National Standards Institute
ARP Address Resolution Protocol
ATA Analog Telephone Adapter
ATRAC Adaptive Transform Acoustic Coding
AV Audio and Video
AVC Advanced Video Codec
CDS Content Distribution Service
CPU Central Processing Unit
DHCP Dynamic Host Configuration Protocol
DLNA Digital Living Network Alliance
DMC Digital Media Controller
DMR Digital Media Renderer
DMP Digital Media Player
DMPr Digital Media Printer
DNS Domain Name System
DRM Digital Rights Management
DSCP Differentiated Service Code Point
DSL Digital Subscriber Line
DTV Digital Television
EPG Electronic Program Guide
ETH Ethernet
FTP File Transfer Protocol
62514 © IEC:2010(E) – 11 –
GENA General Event Notification Architecture
HMRec Home Media Receiver
HMG Home Multimedia Gateway
HMSou Home Media Source
HTTP Hyper Text Transfer Protocol
ICMP Internet Control Message Protocol
ID Identification
IGD Internet Gateway Device
IGMP Internet Group Management Protocol
IP Internet Protocol
IPTV Internet Protocol Television
ITU International Telecommunication Union
JEPG Joint Photographic Experts Group
LAN Local Area Network
LPCM Linear Pulse Code Modulation
MAC Media Access Control
MIU Media Interoperability Unit
MPEG Moving Picture Experts Group
MR Media Receiver
MRCP MediaRenderer:1 Control Point
MS Media Source
MSCP MediaServer:1 Control Point
NAT Network Address Translation
NAPT Port-Level NAT
NID Network Infrastructure Device
PAN Personal Area Network
PC Personal Computer
QoS Quality of Service
RID Request Identity
RIP Routing Information Protocol
SOAP Simple Object Access Protocol
STB Set Top Box
TCP Transmission Control Protocol
UDP User Datagram Protocol
UpnP Univeral Plug and Play
URI Uniform Resource Identifier
URL Uniform Resource Locator
VDSL Very-high-bit-rate Digital Subscriber Line
VOD Video on Demand
VOIP Voice over Internet Protocol
WAN Wide Area Network
WMS WAN Media Source
WMM Wireless Multimedia
··· ··· ···
HMG
Access area to outside
networks
– 12 – 62514 © IEC:2010(E)
4 HMG architecture
4.1 Architecture of a home multimedia network
A home multimedia network adopts a multiple levels network topology consisting of two network
segments, i.e. a home multimedia network and a home control sub-network. The home control
sub-network is optional, where appropriate.
The home multimedia network supports the central management mode which can be
functioned by HMG, as well as supporting peer-to-peer mechanism as specified in the
IEC 62481 series. The home multimedia network can access the outside network through an
HMG while the home control sub-network can be connected to the home multimedia network
through a home control sub-network gateway. The devices in a home control sub-network can
intercommunicate and further access outside networks by sub-gateways and HMG.
The typical architecture of a home multimedia system is shown in Figure 1 as follows.
Control Control sub-network 1
Outside Home
sub-gateway
network Multimedia
Terminal Terminal Control Control
Network
·· ··
Device 11 Device 1n Point 11 Point 1m
Control Control Sub-network n
sub-gateway n
Terminal Terminal Control Control
·· ··
Device n1 Device nn Point n1 Point nm
Terminal device
Terminal device
Control point 1
Control point x
IEC  1077/10
Figure 1 – Architecture for a home multimedia network

Various application devices
AV processing
Home
automation
Other applications
Internet or other outside networks
62514 © IEC:2010(E) – 13 –
4.2 HMG architecture
4.2.1 General
From the aspect of functional structure, the HMG provides such functions as multimedia
processing and applications, interconnection, QoS and security, etc. The architecture of the
HMG is shown in Figure 2 below.

Interface Interface
and and
Access access
(LAN
(WAN
QoS Security
Side)
Side)
Interconnection
IEC  1078/10
Figure 2 – HMG architecture
4.2.2 AV processing
The HMG shall provide various application services of video and audio in the home multimedia
network. It shall fully support all the functions of MIU (includes MSCP, MRCP), DMPr and
+UP+/+DN+/+PR+, which are defined in IEC 62481-1 and IEC 62481-2.
4.2.3 Home automation
The HMG can offer local management and remote management as well as various control
services to the devices in the home network.
4.2.4 QoS
HMG should support QoS features in order to transport multimedia contents effectively in the
home network where the HMG is involved.
If HMG supports QoS features, then HMG shall use priority tag of QoS in order to transfer the
multimedia contents that have IEEE 802.1Q User Priority, WMM Access Category or DSCP.
The detailed requirements of QoS shall be compliant with Networking and Connectivity: QoS
requirements in IEC 62481-1.
– 14 – 62514 © IEC:2010(E)
4.2.5 Security
The HMG shall support DRM, key management, authentication and security to log on outside
networks.
4.2.6 Interconnection
HMG shall support the network management, protocol translation, address assignment,
configuration and management on the home networked devices, in different multimedia
networks.
4.2.7 Interfaces and access
These provide the connection between the home network and outside networks (for example the
Internet) when necessary, which is optional.
The detailed interface and communication protocol requirements on both LAN side and WAN
side are specified in Clause 11. The specific protocol that is to be applied depends on the
application case.
5 Interconnection requirements
5.1 General connection requirements
Where the home multimedia network is an IP network, the requirements for the HMG should be
as follows:
a) HMG shall implement a Dynamic Host Configuration Protocol (DHCP) server in order to
assign IP address to DHCP client in the home network where the HMG is involved.
b) HMG should support Domain Name System (DNS) in order to use device name for better
user experience.
c) Those messages are formatted by using the SOAP HTTP binding, which shall be compliant
with ISO/IEC 29341-1.
d) HMG should collect information with respect to all the devices connected to the home
network by using device description and service description of each device in order to
manage the devices.
e) HMG also should control other devices such as HMRec and HMSou by using appropriate
actions to realize use cases described in this standard.
HMG shall also conform to the following requirements defined and specified in IEC 62481-1.
f) HMG shall support a TCP/IP stack that includes IPv4, TCP, UDP, ARP, and ICMP.
g) HMG may also support general capability recommendations and device recommendations.
h) The detailed methods of interconnection shall be compliant with 7.3 of IEC 62481-1:2007
(Device discovery and control).
i) HMG shall support Simple Object Access Protocol (SOAP) header and body elements, and
the messages are delivered via HTTP. The HMG as well as HMSou and HMRec support the
messaging scheme by using GENA protocol to exchange the event information inside the
high-speed system. A control point invokes the action to the device's service in order to
control it and when the action has completed or failed, the service returns any results or
errors of the action.
j) HMG shall support the detailed methods of device management.

62514 © IEC:2010(E) – 15 –
5.2 Address assignment and resolution
5.2.1 Address assignment
The HMG shall support the functions of address assignment as follows:
a) HMG shall assign the identifiers to each control sub-network in order to identify different
sub-networks.
b) The control sub-network gateway shall apply for the addresses, which comply for the
higher-level network protocol and are composed of sub-network identifier and network
address, from the HMG.
c) The HMG shall have the following address assignment functions.
1) The HMG shall support DHCP server to assign the addresses for the devices managed in
the home network. Through a management and configuration interface on the HMG, the
DHCP can be enabled or disabled, and the data such as address pool assignment on the
DHCP can be configured as well.
2) The terminal devices shall also support AutoIP in case there is no DHCP server in the
sub-network.
5.2.2 Address resolution
The HMG shall support the functions and requirements of address resolution as follows:
a) If the source devices and destination devices are located in the same control sub-network or
multimedia network, then the HMG shall forward the data packet directly without any
processing.
b) If the source devices and the destination devices are not located in the same control
sub-network or multimedia network, then
1) The source devices shall know the identifier and network address of the control
sub-network or multimedia network in which the destination devices are located.
2) The HMG shall resolve the data packet sent from the source devices and identify the
identifiers and network addresses of the control sub-network or multimedia network in
which the source devices and destination devices are located respectively.
3) The HMG shall confirm the network and address of the destination devices located
according to the identifier and network address of that control sub-network or multimedia
network.
4) The HMG shall confirm the communication protocol of the destination devices from the
device registry.
5) The HMG shall then re-pack the data and send to the destination device in accordance
with the communication protocol confirmed.
c) The HMG shall support the ARP protocol as well.
5.3 Data transfer
The HMG
a) shall support router working mode, bridge working mode or the hybrid working mode of both
router and bridge,
b) shall support the static router in the router working mode,
c) should support the dynamic router and support RIP V1/V2 in the router working mode.
d) shall support NAT and NAPT in accordance with RFC 2663 and RFC 3022 in the bridge
working mode.
e) shall support the transparent bridge protocol in accordance with IEEE 802.1d in the bridge
working mode.
– 16 – 62514 © IEC:2010(E)
f) shall support the relevant functions of both router working mode and bridge working mode
when working the hybrid mode of router and bridge.
5.4 Protocol translation
The HMG shall support the application protocol translations when communicating and
interacting among different networks or sub-networks.
6 AV processing requirements
6.1 General
The HMG may offer services for applications in home network systems. In summary, service
requirements include multimedia transformation and multimedia stream control and may be
fulfilled by using the services and actions which are defined by UPnP AV specifications
(ISO/IEC 29341-3) and DLNA guidelines (IEC 62481). All these AV processing services need
some requirements for hardware and software of the HMG.
6.2 Multimedia transformation service
6.2.1 Requirements summary
The following requirements apply.
a) The HMG shall provide the media conversion service, including code conversion
(transcoding), resolution conversion (transcaling), and shall provide the media conversion
service of frame rate conversion (transrating).
b) The HMG should support voice code conversion.
c) The media conversion service request message shall include the URI of the media resources,
which specifies media code format, resolution, frame rate and transport protocols needed by
the requester. In the case of getting contents from WMS, it can also include the code format,
resolution and frame rate of the requested contents, as well as the media transport protocols
supported by the media content owner.
d) The HMG should be able to convert audio streams into voice streams.
e) The HMG should be able to convert voice streams into audio streams.
f) The HMG should be able to provide the video clip function, which shall be done in
accordance with the capability of receiving terminals.
6.2.2 Applications mode
6.2.2.1 Media conversion
6.2.2.1.1 General
Media stream conversion is to convert a media stream from one mode to another. It includes
code conversion, resolution conversion, rate conversion and transport protocol translation. As
shown in Figure 3, the green media stream indicates a dynamic conversion process; the HMG
converts a MPEG2 media stream transmitted from the HMSou into an H.264 media stream
transmitted through the hyper text transfer protocol (HTTP); then the HMG sends the stream to
the HMRec. In case the media server can know the devices at the user's home and the media
formats supported, it can use the remaining capabilities of the HMG to convert the media
contents on the media server into the format needed by the players. In this way, when such
contents are played, they need not be dynamically converted, as the conversion might affect the
QoS in real-time playback.
62514 © IEC:2010(E) – 17 –
DTV
Home network
Home
media
server
H.264
stream
MPEG2 stream
HMG
IEC  1079/10
Figure 3 – Conversion of media streams
As shown in the Figure 3, media conversion can be performed in two modes. In the first mode,
the media sender sends the media to the HMG; then the HMG converts the media and sends it
to the media receiver. The one that requests media conversion might be the media sender or the
media receiver. In the second mode, the device sends the media to the HMG. After being
converted, and the media is returned to the device and is irrelevant with other application
devices. In this mode, the HMG can be regarded as an extension of the device. In this case,
there is no transport protocol translation.
The following text will describe the possible work modes of the HMG.
6.2.2.1.2 HMRec requests media conversion service
Figure 4 shows the process of how the HMRec requests the media conversion service from the
HMG when HMRec gets media resource from HMSou Here it is supposed that:
a) The HMG has obtained the uniform resource identifier (URI) for media resources on HMSou.
The HMG can browse/search the directory of devices providing media contents and obtain
the URI. The HMG also has obtained the code format, resolution and frame rate of the media
resources.
b) The HMG shall support to convert the media format and expose all of them in the CDS which
is defined in the ISO/IEC 29341 series
c) The HMRec has obtained the uniform resource identifier (URI) for media resources on HMG.
The HMRec can browse/search the directory of devices providing media contents and obtain
the URI. The HMRec also has obtained the code format, resolution and frame rate of the
media resources.
The request process is as follows:
1. The HMRec sends a request content message to the converted media URI of HMG.
2. The HMG sends a request content message to the original media URI of HMSou.
3. The HMSou accepts the request of the HMG and sends the original media stream to the
HMG.
4. The HMG converts the media stream and sends the converted media stream to the HMRec.

– 18 – 62514 © IEC:2010(E)
HMRec HMG HMSou
1. Request content 2. Request content
(converted media URI) (original media URI)
4. Converted media 3. Original media
IEC  1080/10
Figure 4 – HMRec requests media conversion from HMG
When the MS is the WMS, if DRM and authority management are taken into account, the process
shall include the procedure of how the HMG can pass the WMS authentication. Because there
are a rich variety of DRM and authority management modes, the HMG can hardly support all
DRM systems and authority management modes.
Figure 5 shows an optimized process. Before the HMRec requests the media conversion service
from the HMG, it first requests media stream redirection from the WMS. Here it is supposed that:
a) The HMRec has obtained the URI of needed media resources.
b) The HMRec might have obtained the code format, resolution and frame rate of the needed
media resources.
c) The HMRec might have known the media transport protocol used by the media sender.
d) The HMRec needs the conversion service for sure.
e) The HMRec has finished necessary DRM authentication and device authentication with the
WMS.
The process is as follows:
1. The HMRec sends a Request Redirection message to the WMS, which includes:
• The URI of the media resources on the WMS requested by the HMRec.
2. The WMS satisfies the request of the HMRec and allocates a Request identity (RID) in the
response message.
NOTE When the media source receives a media service request from the media receiver, it allocates an identity
to authenticate the media conversion service device, that is, the HMG, provided by the media receiver (MR). This
identify is called the request identity. The media conversion service is originated by the media receiver; the
request identify allocated by the media source is transferred to the HMG. When obtaining original media contents
from the media source, the HMG needs to provide the request identity to the media source to prove its validity.
3. The HMRec sends a request conversion message to the HMG, which includes:
• The URI of the media resources on the WMS requested by the HMRec
• The media code format, resolution and frame rate needed by the HMRec
• Media transport protocols supported by the HMRec
• RID allocated by the WMS
• (Optional) media code format, resolution and frame rate of the media contents requested
by the HMRec
• (Optional) media transport protocols supported by the WMS
4. If the HMG can accept the conversion request, it can send a message to the HMRec,
indicating that the request is accepted; otherwise the HMG shall send a message to refuse
the request.
62514 © IEC:2010(E) – 19 –
5. The HMG requests the media resources needed by the HMRec from the WMS. The request
message shall include the RID and the URI of the media resources on the WMS requested by
the HMRec; or the RID shall be sent back upon the request of the WMS. In case the HMG
cannot request resources, or if the HMG cannot make conversion after the resources are
obtained, it shall send a message to the HMRec, indicating that the service cannot be fulfilled
6. The WMS accepts the request of the HMG after authenticating the RID. Then it sends the
original media stream to the HMG.
7. The HMG converts the media stream and sends the converted media stream to the HMRec
according to the media code format, resolution and frame rate needed by the HMRec.
In the above procedure, the WMS does not implement DRM authentication on the HMG but
transmits the media stream directly. DRM authentication is completed by the HMRec before step
1. The WMS authenticates the RID to verify the validity of the HMG. In this way, the HMG does
not need to support various DRM methods, but has new requirements on the WMS.
In practice, encrypted transmission is needed between the WMS and the HMG, and between the
HMG and the HMRec. As a result, keys need to be exchanged between the WMS and the HMG,
and between the HMG and the HMRec. It is easy to exchange keys between the HMRec and the
HMG, as both devices are at home and can adopt a standard method. Because different service
systems in the WAN adopt different DRM
...