draft-ietf-fecframe-dvb-al-fec-03.txt   draft-ietf-fecframe-dvb-al-fec-04.txt 
FEC Framework A. Begen FEC Framework A. Begen
Internet-Draft Cisco Systems Internet-Draft Cisco
Intended status: Informational T. Stockhammer Intended status: Informational T. Stockhammer
Expires: March 20, 2010 Nomor Research Expires: June 18, 2010 Nomor Research
September 16, 2009 December 15, 2009
DVB-IPTV Application-Layer Hybrid FEC Protection Guidelines for Implementing DVB-IPTV Application-Layer Hybrid FEC
draft-ietf-fecframe-dvb-al-fec-03 Protection
draft-ietf-fecframe-dvb-al-fec-04
Abstract
The Annex E of the Digital Video Broadcasting (DVB)-IPTV technical
specification defines an optional Application-layer Forward Error
Correction (AL-FEC) protocol to protect the streaming media carried
over RTP transport. The DVB-IPTV AL-FEC protocol uses two layers for
FEC protection. The first (base) layer is based on the 1-D
interleaved parity code. The second (enhancement) layer is based on
the Raptor code. By offering a layered approach, the DVB-IPTV AL-FEC
protocol offers a good protection against both bursty and random
packet losses at a cost of decent complexity. This document
describes how one can implement the DVB-IPTV AL-FEC protocol by using
the 1-D interleaved parity code and Raptor code that have already
been specified in separate documents.
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
skipping to change at page 1, line 33 skipping to change at page 1, line 49
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on March 20, 2010. This Internet-Draft will expire on June 18, 2010.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of Provisions Relating to IETF Documents
publication of this document (http://trustee.ietf.org/license-info). (http://trustee.ietf.org/license-info) in effect on the date of
Please review these documents carefully, as they describe your rights publication of this document. Please review these documents
and restrictions with respect to this document. carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
Abstract include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
The Annex E of the DVB-IPTV technical specification defines an described in the BSD License.
optional Application-layer Forward Error Correction (AL-FEC) protocol
to protect the streaming media carried over RTP transport. The DVB-
IPTV AL-FEC protocol uses two layers for FEC protection. The first
(base) layer is based on the 1-D interleaved parity code. The second
(enhancement) layer is based on the Raptor code. By offering a
layered approach, the DVB-IPTV AL-FEC protocol offers a good
protection against both bursty and random packet losses at a cost of
decent complexity. This document describes how one can implement the
DVB-IPTV AL-FEC protocol by using the 1-D interleaved parity code and
Raptor code that have already been specified in separate documents.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. DVB-IPTV AL-FEC Specification . . . . . . . . . . . . . . . . 5 2. DVB-IPTV AL-FEC Specification . . . . . . . . . . . . . . . . 5
2.1. Base-Layer FEC . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Base-Layer FEC . . . . . . . . . . . . . . . . . . . . . . 5
2.2. Enhancement-Layer FEC . . . . . . . . . . . . . . . . . . 7 2.2. Enhancement-Layer FEC . . . . . . . . . . . . . . . . . . 7
2.3. Hybrid Decoding Procedures . . . . . . . . . . . . . . . . 8 2.3. Hybrid Decoding Procedures . . . . . . . . . . . . . . . . 8
3. Session Description Protocol (SDP) Signaling . . . . . . . . . 8 3. Session Description Protocol (SDP) Signaling . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 9 4. Security Considerations . . . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Normative References . . . . . . . . . . . . . . . . . . . 10 7.1. Normative References . . . . . . . . . . . . . . . . . . . 10
7.2. Informative References . . . . . . . . . . . . . . . . . . 11 7.2. Informative References . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
In 2007, the IP Infrastructure (IPI) Technical Module (TM) of the In 2007, the IP Infrastructure (IPI) Technical Module (TM) of the
Digital Video Broadcasting (DVB) consortium published a technical Digital Video Broadcasting (DVB) consortium published a technical
specification [ETSI-TS-102-034v1.3.1] through European specification [ETSI-TS-102-034v1.3.1] through European
Telecommunications Standards Institute (ETSI). This specification Telecommunications Standards Institute (ETSI).
covers several areas related to the transmission of MPEG2 transport [ETSI-TS-102-034v1.3.1] covers several areas related to the
stream-based services over IP networks. transmission of MPEG2 transport stream-based services over IP
networks.
The Annex E of [ETSI-TS-102-034v1.3.1] defines an optional protocol The Annex E of [ETSI-TS-102-034v1.3.1] defines an optional protocol
for Application-layer Forward Error Correction (AL-FEC) to protect for Application-layer Forward Error Correction (AL-FEC) to protect
the streaming media for DVB-IP services carried over RTP [RFC3550] the streaming media for DVB-IP services carried over RTP [RFC3550]
transport. In 2009, DVB updated the specification in a new revision transport. In 2009, DVB updated the specification in a new revision
that has been published as a DVB Bluebook [DVB-A086r8] and serves as that is available as [ETSI-TS-102-034v1.4.1]. Among others, some
draft ETSI TS-102-034v1.4.1 until the final ETSI publication updates and modifications to the AL-FEC protocol have been made.
(expected late 2009). Among others, some updates and modifications This document describes how one can implement the DVB-IPTV AL-FEC
to the AL-FEC protocol have been made. protocol by using the 1-D interleaved parity code
[I-D.ietf-fecframe-interleaved-fec-scheme] and Raptor code
specifications [I-D.ietf-fecframe-raptor],
[I-D.watson-fecframe-rtp-raptor].
The DVB-IPTV AL-FEC protocol uses two layers for protection: a base The DVB-IPTV AL-FEC protocol uses two layers for protection: a base
layer that is produced by the 1-D interleaved parity code (also layer that is produced by the 1-D interleaved parity code (also
simply referred to as parity code in the remainder of this document), simply referred to as parity code in the remainder of this document),
and an enhancement layer that is produced by the Raptor code. and an enhancement layer that is produced by the Raptor code.
Whenever a receiver supports the DVB-IPTV AL-FEC protocol, the Whenever a receiver supports the DVB-IPTV AL-FEC protocol, the
decoding support for the base-layer FEC is mandatory while the decoding support for the base-layer FEC is mandatory while the
decoding support for the enhancement-layer FEC is optional. Both the decoding support for the enhancement-layer FEC is optional. Both the
interleaved parity code and the Raptor code are systematic FEC codes, interleaved parity code and the Raptor code are systematic FEC codes,
meaning that source packets are not modified in any way during the meaning that source packets are not modified in any way during the
FEC encoding process. FEC encoding process.
The normative DVB-IPTV AL-FEC protocol considers protection of The DVB-IPTV AL-FEC protocol considers protection of single-sequence
single-sequence source RTP flows only. In the AL-FEC protocol, the source RTP flows only. In the AL-FEC protocol, the source stream can
source stream can only be an MPEG-2 transport stream. The FEC data only be an MPEG-2 transport stream. The FEC data at each layer are
at each layer are generated based on some configuration information, generated based on some configuration information, which also
which also determines the exact associations and relationships determines the exact associations and relationships between the
between the source and repair packets. This document shows how this source and repair packets. This document shows how this
configuration may be communicated out-of-band in the Session configuration may be communicated out-of-band in the Session
Description Protocol (SDP) [RFC4566]. Description Protocol (SDP) [RFC4566].
In DVB-IPTV AL-FEC, the source packets are carried in the source RTP In DVB-IPTV AL-FEC, the source packets are carried in the source RTP
stream and the generated FEC repair packets at each layer are carried stream and the generated FEC repair packets at each layer are carried
in separate streams. At the receiver side, if all of the source in separate streams. At the receiver side, if all of the source
packets are successfully received, there is no need for FEC recovery packets are successfully received, there is no need for FEC recovery
and the repair packets may be discarded. However, if there are and the repair packets may be discarded. However, if there are
missing source packets, the repair packets can be used to recover the missing source packets, the repair packets can be used to recover the
missing information. missing information.
skipping to change at page 6, line 19 skipping to change at page 6, line 32
based on [SMPTE2022-1]. based on [SMPTE2022-1].
In a recent liaison from IETF AVT WG to DVB TM-IPI, it has been In a recent liaison from IETF AVT WG to DVB TM-IPI, it has been
recommended that DVB TM-IPI defines a new RTP profile for the AL-FEC recommended that DVB TM-IPI defines a new RTP profile for the AL-FEC
protocol since in the new profile, several of the issues could easily protocol since in the new profile, several of the issues could easily
be addressed without jeopardizing the compliance to RTP [RFC3550]. be addressed without jeopardizing the compliance to RTP [RFC3550].
At the writing of this document, it was not clear whether or not a At the writing of this document, it was not clear whether or not a
new RTP profile would be defined for the AL-FEC protocol. DVB TM-IPI new RTP profile would be defined for the AL-FEC protocol. DVB TM-IPI
attempted to address some of the issues in the updated specification attempted to address some of the issues in the updated specification
[DVB-A086r8], however, there are still outstanding issues. Note that [ETSI-TS-102-034v1.4.1], however, there are still outstanding issues.
[DVB-A086r8] does not obsolete [ETSI-TS-102-034v1.3.1] but DVB TM-IPI
will exclusively use [DVB-A086r8] for any future revisions of the DVB
IPTV Handbook.
The following is a list of the exceptions that need to be considered The following is a list of the exceptions that need to be considered
by an implementation adopting by an implementation adopting
[I-D.ietf-fecframe-interleaved-fec-scheme] to be in compliant with [I-D.ietf-fecframe-interleaved-fec-scheme] to be in compliant with
the DVB-IPTV AL-FEC protocol as specified in [DVB-A086r8]. the DVB-IPTV AL-FEC protocol as specified in [ETSI-TS-102-034v1.4.1].
o SSRC o SSRC
The DVB-IPTV AL-FEC protocol requires the SSRC fields of the FEC The DVB-IPTV AL-FEC protocol requires the SSRC fields of the FEC
packets to be set to zero. packets to be set to zero.
This requirement conflicts with RTP [RFC3550]. Unless signaled This requirement conflicts with RTP [RFC3550]. Unless signaled
otherwise, RTP uses random SSRC values with collision detection. otherwise, RTP uses random SSRC values with collision detection.
An explicit SSRC signaling mechanism is currently defined in An explicit SSRC signaling mechanism is currently defined in
[RFC5576] and can be used for this purpose. [RFC5576] and can be used for this purpose.
skipping to change at page 7, line 26 skipping to change at page 7, line 34
may assign 96 as the payload type for the base-layer FEC packets. may assign 96 as the payload type for the base-layer FEC packets.
In implementations that are based on In implementations that are based on
[I-D.ietf-fecframe-interleaved-fec-scheme] and are willing to be in [I-D.ietf-fecframe-interleaved-fec-scheme] and are willing to be in
compliant with the DVB-IPTV AL-FEC protocol as specified in compliant with the DVB-IPTV AL-FEC protocol as specified in
[ETSI-TS-102-034v1.3.1], all these exceptions must be considered as [ETSI-TS-102-034v1.3.1], all these exceptions must be considered as
well, however, in this case, the sender does not have to select a well, however, in this case, the sender does not have to select a
random initial sequence number for the FEC stream as suggested by random initial sequence number for the FEC stream as suggested by
[RFC3550]. [RFC3550].
Note that neither [ETSI-TS-102-034v1.3.1] nor [DVB-A086r8] implements Note that neither [ETSI-TS-102-034v1.3.1] nor [ETSI-TS-102-034v1.4.1]
the 1-D interleaved parity code as specified in implements the 1-D interleaved parity code as specified in
[I-D.ietf-fecframe-interleaved-fec-scheme]. Thus, the payload format [I-D.ietf-fecframe-interleaved-fec-scheme]. Thus, the payload format
registered in [I-D.ietf-fecframe-interleaved-fec-scheme] must not be registered in [I-D.ietf-fecframe-interleaved-fec-scheme] must not be
used by the implementations that are compliant with the used by the implementations that are compliant with the
[ETSI-TS-102-034v1.3.1] or [DVB-A086r8] specification. [ETSI-TS-102-034v1.3.1] or [ETSI-TS-102-034v1.4.1] specification.
2.2. Enhancement-Layer FEC 2.2. Enhancement-Layer FEC
The Raptor code is a fountain code where as many encoding symbols as The Raptor code is a fountain code where as many encoding symbols as
needed can be generated by the encoder on-the-fly from source data. needed can be generated by the encoder on-the-fly from source data.
Due to the fountain property of the Raptor code, multiple enhancement Due to the fountain property of the Raptor code, multiple enhancement
layers may also be specified, if needed. layers may also be specified, if needed.
The details of the Raptor code are provided in The details of the Raptor code are provided in
[I-D.ietf-fecframe-raptor]. The RTP payload format for Raptor FEC is [I-D.ietf-fecframe-raptor]. The RTP payload format for Raptor FEC is
specified in [I-D.watson-fecframe-rtp-raptor]. specified in [I-D.watson-fecframe-rtp-raptor].
It is important to note that the DVB-IPTV AL-FEC protocol in the It is important to note that the DVB-IPTV AL-FEC protocol in the
latest specification [DVB-A086r8] allows only RTP-over-UDP latest specification [ETSI-TS-102-034v1.4.1] allows both UDP-only and
encapsulation for the enhancement-layer FEC stream. The initial RTP-over-UDP encapsulations for the enhancement-layer FEC stream.
specification [ETSI-TS-102-034v1.3.1] exclusively permits UDP-only The initial specification [ETSI-TS-102-034v1.3.1] exclusively permits
encapsulation for the enhancement-layer FEC stream. UDP-only encapsulation for the enhancement-layer FEC stream.
When SDP is used for signaling, the transport protocol identifier When SDP is used for signaling, the transport protocol identifier
permits to distinguish whether an RTP-over-UDP or UDP-only permits to distinguish whether an RTP-over-UDP or UDP-only
encapsulation is used. In case of any other signaling framework, the encapsulation is used. In case of any other signaling framework, the
differentiation of the protocol for the enhancement-layer stream is differentiation of the protocol for the enhancement-layer stream is
achieved either explicitly through a protocol identifier or achieved either explicitly through a protocol identifier or
implicitly by the version number of the DVB IPTV Handbook. If none implicitly by the version number of the DVB IPTV Handbook. If none
of the above signaling is provided, the receiver shall concur from of the above signaling is provided, the receiver shall concur from
the packet size of the repair packets if RTP-over-UDP or UDP-only the packet size of the repair packets if RTP-over-UDP or UDP-only
encapsulation is used. encapsulation is used.
skipping to change at page 8, line 37 skipping to change at page 8, line 47
3. Hybrid Decoding: If there are still missing source packets after 3. Hybrid Decoding: If there are still missing source packets after
the second step, the unprocessed base-layer (parity) repair the second step, the unprocessed base-layer (parity) repair
packets are converted to a form in which they can be added to the packets are converted to a form in which they can be added to the
Raptor decoding process. With this additional information, Raptor decoding process. With this additional information,
Raptor decoding may potentially recover any remaining missing Raptor decoding may potentially recover any remaining missing
source packet. source packet.
The procedure that should be followed to benefit from the base-layer The procedure that should be followed to benefit from the base-layer
repair packets in the Raptor decoding process is explained in detail repair packets in the Raptor decoding process is explained in detail
in Section E.5.2 of [ETSI-TS-102-034v1.3.1] and [DVB-A086r8]. in Section E.5.2 of [ETSI-TS-102-034v1.4.1].
3. Session Description Protocol (SDP) Signaling 3. Session Description Protocol (SDP) Signaling
This section provides an SDP [RFC4566] example for [DVB-A086r8]. The This section provides an SDP [RFC4566] example for
example uses the FEC grouping semantics [I-D.ietf-mmusic-rfc4756bis].
[ETSI-TS-102-034v1.4.1]. The example uses the FEC grouping semantics
[I-D.ietf-mmusic-rfc4756bis].
In the example, we have one source video stream (mid:S1), one FEC In the example, we have one source video stream (mid:S1), one FEC
repair stream (mid:R1) that is produced by the 1-D interleaved parity repair stream (mid:R1) that is produced by the 1-D interleaved parity
FEC code as well as another FEC repair stream (mid:R2) that is FEC code as well as another FEC repair stream (mid:R2) that is
produced by the Raptor FEC code. We form one FEC group with the produced by the Raptor FEC code. We form one FEC group with the
"a=group:FEC-XR S1 R1 R2" line. The source and repair streams are "a=group:FEC-XR S1 R1 R2" line. The source and repair streams are
sent to the same port on different multicast groups. The source, sent to the same port on different multicast groups. The source,
base-layer FEC and enhancement-layer FEC streams are all encapsulated base-layer FEC and enhancement-layer FEC streams are all encapsulated
in RTP. in RTP.
Due to the exceptions described in Section 2.1, a [DVB-A086r8]- Due to the exceptions described in Section 2.1, a
compliant implementation must not use the RTP payload format defined [ETSI-TS-102-034v1.4.1]-compliant implementation must not use the RTP
in [I-D.ietf-fecframe-interleaved-fec-scheme]. Instead, it may use payload format defined in [I-D.ietf-fecframe-interleaved-fec-scheme].
the payload format that has been registered by DVB TM-IPI for Instead, it may use the payload format that has been registered by
[ETSI-TS-102-034v1.3.1]. DVB TM-IPI for [ETSI-TS-102-034v1.3.1].
v=0 v=0
o=ali 1122334455 1122334466 IN IP4 fec.example.com o=ali 1122334455 1122334466 IN IP4 fec.example.com
s=DVB-IPTV AL-FEC Example s=DVB-IPTV AL-FEC Example
t=0 0 t=0 0
a=group:FEC-XR S1 R1 R2 a=group:FEC-XR S1 R1 R2
m=video 30000 RTP/AVP 100 m=video 30000 RTP/AVP 100
c=IN IP4 233.252.0.1/127 c=IN IP4 233.252.0.1/127
a=rtpmap:100 MP2T/90000 a=rtpmap:100 MP2T/90000
a=mid:S1 a=mid:S1
skipping to change at page 9, line 38 skipping to change at page 9, line 49
a=mid:R2 a=mid:R2
Note that in the example above, the payload type has been chosen as Note that in the example above, the payload type has been chosen as
96 for the base-layer FEC stream and there is no "a=fmtp:" line to 96 for the base-layer FEC stream and there is no "a=fmtp:" line to
specify the format parameters. Due to the lack of the format specify the format parameters. Due to the lack of the format
parameters for "vnd.dvb.iptv.alfec-base", it is not possible to learn parameters for "vnd.dvb.iptv.alfec-base", it is not possible to learn
the FEC parameters from the SDP description. the FEC parameters from the SDP description.
4. Security Considerations 4. Security Considerations
There are no security considerations in this document. This specification adds no new security considerations to the DVB-
IPTV AL-FEC protocol.
5. IANA Considerations 5. IANA Considerations
There are no IANA considerations in this document. There are no IANA considerations in this document.
6. Acknowledgments 6. Acknowledgments
This document is based on [ETSI-TS-102-034v1.3.1] and [DVB-A086r8]. This document is based on [ETSI-TS-102-034v1.3.1] and
Thus, the authors would like to thank the editors of [ETSI-TS-102-034v1.4.1]. Thus, the authors would like to thank the
[ETSI-TS-102-034v1.3.1] and [DVB-A086r8]. The authors also would editors of [ETSI-TS-102-034v1.3.1] and [ETSI-TS-102-034v1.4.1]. The
like to thank those who reviewed earlier versions of this document. authors also would like to thank those who reviewed earlier versions
of this document.
7. References 7. References
7.1. Normative References 7.1. Normative References
[ETSI-TS-102-034v1.3.1] [ETSI-TS-102-034v1.3.1]
ETSI TS 102 034 V1.3.1, "Transport of MPEG 2 TS Based DVB ETSI TS 102 034 V1.3.1, "Transport of MPEG 2 TS Based DVB
Services over IP Based Networks", October 2007. Services over IP Based Networks", October 2007.
[DVB-A086r8] [ETSI-TS-102-034v1.4.1]
DVB Document A086 Rev. 8 (Draft ETSI TS 102 034 V1.4.1), ETSI TS 102 034 V1.4.1, "Transport of MPEG 2 TS Based DVB
"Transport of MPEG 2 TS Based DVB Services over IP Based Services over IP Based Networks", August 2009.
Networks", July 2009.
[I-D.ietf-fecframe-interleaved-fec-scheme] [I-D.ietf-fecframe-interleaved-fec-scheme]
Begen, A., "RTP Payload Format for 1-D Interleaved Parity Begen, A., "RTP Payload Format for 1-D Interleaved Parity
FEC", draft-ietf-fecframe-interleaved-fec-scheme-05 (work FEC", draft-ietf-fecframe-interleaved-fec-scheme-05 (work
in progress), May 2009. in progress), May 2009.
[I-D.ietf-fecframe-raptor] [I-D.ietf-fecframe-raptor]
Watson, M., "Raptor FEC Schemes for FECFRAME", Watson, M., "Raptor FEC Schemes for FECFRAME",
draft-ietf-fecframe-raptor-01 (work in progress), draft-ietf-fecframe-raptor-01 (work in progress),
July 2009. July 2009.
skipping to change at page 10, line 47 skipping to change at page 11, line 10
[RFC5576] Lennox, J., Ott, J., and T. Schierl, "Source-Specific [RFC5576] Lennox, J., Ott, J., and T. Schierl, "Source-Specific
Media Attributes in the Session Description Protocol Media Attributes in the Session Description Protocol
(SDP)", RFC 5576, June 2009. (SDP)", RFC 5576, June 2009.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006. Description Protocol", RFC 4566, July 2006.
[I-D.ietf-mmusic-rfc4756bis] [I-D.ietf-mmusic-rfc4756bis]
Begen, A., "Forward Error Correction Grouping Semantics in Begen, A., "Forward Error Correction Grouping Semantics in
Session Description Protocol", Session Description Protocol",
draft-ietf-mmusic-rfc4756bis-02 (work in progress), draft-ietf-mmusic-rfc4756bis-05 (work in progress),
April 2009. October 2009.
7.2. Informative References 7.2. Informative References
[DVB-A115] [DVB-A115]
Available at: http://www.dvb.org/technology/standards/ Available at: http://www.dvb.org/technology/standards/
a115.tm3783.AL-FEC_Evaluation.pdf, "DVB Application Layer a115.tm3783.AL-FEC_Evaluation.pdf, "DVB Application Layer
FEC Evaluations (DVB Document A115)", May 2007. FEC Evaluations (DVB Document A115)", May 2007.
[SMPTE2022-1] [SMPTE2022-1]
SMPTE 2022-1-2007, "Forward Error Correction for Real-Time SMPTE 2022-1-2007, "Forward Error Correction for Real-Time
Video/Audio Transport over IP Networks", 2007. Video/Audio Transport over IP Networks", 2007.
Authors' Addresses Authors' Addresses
Ali Begen Ali Begen
Cisco Systems Cisco
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
USA USA
Email: abegen@cisco.com Email: abegen@cisco.com
Thomas Stockhammer Thomas Stockhammer
Nomor Research Nomor Research
Brecherspitzstrasse 8 Brecherspitzstrasse 8
Munich, 81541 Munich, 81541
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