draft-ietf-avt-smpte292-video-04.txt   draft-ietf-avt-smpte292-video-05.txt 
INTERNET-DRAFT Ladan Gharai INTERNET-DRAFT Ladan Gharai
<draft-ietf-avt-smpte292-video-04.txt> USC/ISI <draft-ietf-avt-smpte292-video-05.txt> USC/ISI
Gary Goncher
Tektronix
Colin Perkins Colin Perkins
USC/ISI USC/ISI
David Richardson Gary Goncher
University of Washington Tektronix
Allison Mankin Allison Mankin
USC/ISI USC/ISI
March 1, 2002 May 30, 2002
RTP Payload Format for SMPTE 292M Video RTP Payload Format for SMPTE 292M Video
<draft-ietf-avt-smpte292-video-04.txt> <draft-ietf-avt-smpte292-video-05.txt>
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
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 41 skipping to change at page 1, line 39
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.
Abstract Abstract
This document specifies a RTP payload format for encapsulating This memo specifies a RTP payload format for encapsulating uncompressed
uncompressed HDTV as delivered by a SMPTE 292M transport stream. High Definition Television (HDTV) as defined by the Society of Motion
Picture and Television Engineers standard, SMPTE 292M. SMPTE is the main
standardizing body in the motion imaging industry and the SMPTE 292M
standard defines a bit-serial digital interface for local area HDTV
transport.
1. Introduction 1. Introduction
The serial digital interface, SMPTE 292M[1], defines a universal medium The serial digital interface, SMPTE 292M[1], defines a universal medium
of interchange for uncompressed High Definition Television (HDTV) of interchange for uncompressed High Definition Television (HDTV)
between various types of video equipment (cameras, encoders, VTRs, between various types of video equipment (cameras, encoders, VTRs,
etc.). SMPTE 292M stipulates that the source data be in 10bit words and etc.). SMPTE 292M stipulates that the source data be in 10bit words and
the total data rate be 1.485 Gbps or 1.485/1.001 Gbps. the total data rate be 1.485 Gbps or 1.485/1.001 Gbps.
A SMPTE 292M television line is divided into four parts: (1) start of A SMPTE 292M television line is divided into four parts, (figure 1): (1)
active video timing reference (SAV); (2) digital active line; (3) end start of active video timing reference (SAV); (2) digital active line;
of active video timing reference (EAV); and (4) digital line blanking. (3) end of active video timing reference (EAV); and (4) digital line
blanking. A SMPTE 292M line may also carry horizontal ancillary data
(H-ANC) or vertical ancillary data (V-ANC) instead of the blanking
level, and likewise, ancillary data may transported instead of a digital
active line.
The EAV and SAV are made up of three 10 bit words, with constant values The EAV and SAV are made up of three 10 bit words, with constant values
of 0x000 0x000 0x3FF and an additional word carrying a number of flags. of 0x000 0x000 0x3FF and an additional word (designated as XYZ in figure
This includes an F flag which designate which field (1 or 2) the line is 2), carrying a number of flags. This includes an F flag which designate
transporting and also a V flag which indicates field blanking. EAV is which field (1 or 2) the line is transporting and also a V flag which
followed by a line number field. Line number is a 11bit value set in two indicates field blanking. Table 1, further displays the code values in
10bit words. SAV and EAV. After EAV, are two words LN1 and LN2 (Table 2), which
carry the 11bit line number for the SMPTE 292M line, immediately
following. The Cyclic Redundancy Check, CRC, is a two word value, shown
as CR0 and CR1 in figure 2.
+------------+-------------------------+-----+-----------------------+
| | Digital Line Blanking | | Digital Active Line |
| EAV+LN+CRC | (Blanking level or | SAV | (Active Picture or |
| | Ancillary Data) | | Ancillary Data) |
+------------+-------------------------+-----+-----------------------+
Figure 1. The SMPTE 292M line format.
0 20 40 60 80 0 20 40
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|3FF| 0 | 0 |XYZ|LN1|LN2|CR0|CR1| |3FF| 0 | 0 |XYZ|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
<---- EAV -----> <- LN-> <- CRC-> <----- SAV ----->
Figure 2. Timing reference format.
Table 1: Timing reference codes.
+---------------------------------------------------------+
| (MSB) (LSB) |
| Word 9 8 7 6 5 4 3 2 1 0 |
+---------------------------------------------------------+
| 3FF 1 1 1 1 1 1 1 1 1 1 |
| 000 0 0 0 0 0 0 0 0 0 0 |
| 000 0 0 0 0 0 0 0 0 0 0 |
| XYZ 1 F V H P P P P P P |
+---------------------------------------------------------+
| NOTES: |
| F=0 during field 1; F=1 during field 2. |
| V=0 elsewhere; V=1 during field blanking. |
| H=0 in SAV; H=1 in EAV. |
| MSB=most significant bit; LSB=least significant bit.|
| P= protected bits defined in Table 2 of SMPTE 292M |
+---------------------------------------------------------+
Table 2: Line number data.
+---------------------------------------------------------+
| (MSB) (LSB) |
| Word 9 8 7 6 5 4 3 2 1 0 |
+---------------------------------------------------------+
| LN0 R L6 L5 L4 L3 L2 L1 L0 R R |
| LN1 R R R R L10 L9 L8 L7 R R |
+---------------------------------------------------------+
| NOTES: |
| LN0 - L10 - line number in binary code. |
| R = reserved, set to "0". |
+---------------------------------------------------------+
The number of words and format for active lines and line blanking is The number of words and format for active lines and line blanking is
defined by source format documents. Currently, source video formats defined by source format documents. Currently, source video formats
transfered by SMPTE 292M includes SMPTE 260M, 295M, 274M and 296M[2-5]. transfered by SMPTE 292M includes SMPTE 260M, 295M, 274M and 296M[2-5].
In this memo we specify how to transfer SMPTE 292M over RTP, In this memo we specify how to transfer SMPTE 292M over RTP,
irrespective of the source format. irrespective of the source format.
This memo only addresses the transfer of uncompressed HDTV. Compressed This memo only addresses the transfer of uncompressed HDTV. Compressed
HDTV is a subset of MPEG-2 [6], which is fully described in document HDTV is a subset of MPEG-2 [6], which is fully described in document
A/53 [7] of the Advanced Television Standards Committee. The ATSC has A/53 [7] of the Advanced Television Standards Committee. The ATSC has
also adopted the MPEG-2 transport system (ISO/IEC 13818-1)[8]. also adopted the MPEG-2 transport system (ISO/IEC 13818-1)[8].
Therefore RFC 2250 [9] sufficiently describes transport for compressed Therefore RFC 2250 [9] sufficiently describes transport for compressed
HDTV. HDTV over RTP.
2. Conventions Used in this Document 2. Conventions Used in this Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119[10]. document are to be interpreted as described in RFC 2119[10].
3. Payload Design 3. Payload Design
Each SMPTE 292M data line is packetized into a number of RTP packets. Each SMPTE 292M data line is packetized into one or more RTP packets.
All active, vertical blanking and timing information is packetized. This includes all timing signals, blanking levels, active lines and/or
ancillary data. Start of active video (SAV) and end of active video
(EAV) signals MUST NOT be fragmented across packets, as the SMPTE 292M
decoder uses the sync info in the scan lines to detect the start of scan
lines.
Start of active video (SAV) and end of active video (EAV) signals SHOULD The standard RTP header is followed by a 4 octet payload header. All
NOT be fragmented across packets, as the SMPTE 292M decoder uses the information in the payload header, pertains to the first data sample in
sync info in the scan lines to detect the start of scan lines. All the packet. The end of a video frame is marked by the M bit in the RTP
payload header information, i.e., line number, pertains to the first header.
data sample in the packet. The end of a frame is marked by the M bit in
the RTP header.
The standard 16 bit RTP sequence counter is extended to 32 bits to The payload header contains a 16bit extension to the standard 16 bit RTP
accommodate HDTV's high data rates. At 1.485 Gbps, with packet sizes of sequence number, thereby extending the sequence number to 32 bits and
at least 1kByte, 32bits allows for an approximate 6 hour period before enabling RTP to accommodate HDTV's high data rates. At 1.485 Gbps, with
the sequence counter wraps around. packet sizes of at least one thousand octets, 32bits allows for an
approximate 6 hour period before the sequence number wraps around.
A 148500 Hz (or 148500/1.001 Hz) timestamp is used as the RTP timestamp. The payload header also carries the 11bit line number from the SMPTE
This allows the receiver to reconstruct the timing of the SMPTE 292M 292M timing signals. This provides more information at the application
stream, without knowledge of the exact type of source format (e.g. SMPTE level and adds a level of resiliency, in case the packet containing the
274M or SMPTE 296M). EAV is lost.
A source formats video line MUST NOT be fragmented across related Y and A 148.5 MHz (or 148.5/1.001 MHz) time-stamp is used as the RTP
Cb and Cr values. For 4:2:0 this translates to 4 pixels, represented as timestamp. This allows the receiver to reconstruct the timing of the
Y1, Y2, Y3, Y4, Cr, Cb, in 6 10bit words. For 4:2:2 video this SMPTE 292M stream, without knowledge of the exact type of source format
translates to 2 pixels (Y1, Y2, Cr, Cb) and 4 10bit words. for 4:4:4 (e.g. SMPTE 274M or SMPTE 296M).
video this translates to 1 pixel (Y, Cr, Cb) and 3 10bit words.
The bit length of both timing signals, SAV and EAV+LN+CRC, are multiples
of 8bits, 40bits and 80bits, respectively, and therefore are naturally
octet aligned.
For the video content it is desirable for the video to both octet align
when packetized and also adhere to the principles of application level
framing, also known as ALF [11]. For YCrCb video, the ALF principle
translates into not fragmenting related luminance and chrominance values
across packets. For example with the 4:2:0 color subsampling a 4 pixel
group is represented by 6 values, Y1 Y2 Y3 Y4 Cr Cb, and video content
should be packetized such that these values are not fragmented across 2
packets. However, with 10bit words this is a 60bit value which is not
octet aligned. To be both octet aligned, and adhere to ALF, an ALF unit
must represent 2 groups of 4 Pixels, thereby becoming octet aligned on a
15 octet boundary. This length is referred to as the pixel group or
pgroup, and it is conveyed in the SDP parameters. The table below,
displays the pgroup value for 4:2:2 and 4:4:4 color samplings.
When packetizing digital active line content, video data MUST NOT be
fragmented within a pgroup. This restraint only applies to active video
data between the SAV and EAV timing signals. A pgroup of 1 indicates
that data may be split at any octet boundary. This is applicable to
instances where the source format is not known.
Color 10bit
Subsampling Pixels words aligned on octet# pgroup
+-----------+------+-------+------------------+-----+
| 4:2:0 | 4 | 6*10 | 2*60/8 = 15 | 15 |
+-----------+------+-------+------------------+-----+
| 4:2:2 | 2 | 4*10 | 40/8 = 5 | 5 |
+-----------+------+-------+------------------+-----+
| 4:4:4 | 1 | 3*10 | 4*30/8 = 15 | 15 |
+-----------+------+-------+------------------+-----+
4. RTP Packetization 4. RTP Packetization
The standard RTP header is followed by a 4 byte payload header, and the The standard RTP header is followed by a 4 octet payload header, and the
payload data. payload data.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| V |P|X| CC |M| PT | sequence# (low bits) | | V |P|X| CC |M| PT | sequence# (low bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| time stamp | | time stamp |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ssrc | | ssrc |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sequence# (high bits) | line no |F|V| Z | | sequence# (high bits) |F|V| Z | line no |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. SMPTE 292M data .
. .
| |
+---------------------------------------------------------------+
4.1. The RTP Header 4.1. The RTP Header
The following fields of the RTP fixed header are used for SMPTE 292M The following fields of the RTP fixed header are used for SMPTE 292M
encapsulation: encapsulation:
Payload Type (PT): 7bits Payload Type (PT): 7bits
A dynamically allocated payload type field which designates the A dynamically allocated payload type field which designates the
payload as SMPTE 292M. payload as SMPTE 292M.
Timestamp: 32 bits Timestamp: 32 bits
For a SMPTE 292M transport stream at 1.485 Gbps (or 1.485/1.001 For a SMPTE 292M transport stream at 1.485 Gbps (or 1.485/1.001
Gbps), the timestamp field contains a 148500 Hz (or 148500/1.001 Gbps), the timestamp field contains a 148.5 MHz (or 148.5/1.001
Hz) MHz) timestamp, respectively. This allows for a unique timestamp
timestamp, respectively. This allows for a unique timestamp for for each 10bit word.
each 10bit word.
Marker bit (M): 1bit Marker bit (M): 1bit
The Marker bit denotes the end of a video frame, and is set to 1 The Marker bit denotes the end of a video frame, and is set to 1
for the last packet of the video frame and is otherwise set to 0 for the last packet of the video frame and is otherwise set to 0
for all other packets. for all other packets.
Sequence Number (low bits): 16 bits Sequence Number (low bits): 16 bits
The low order bits for RTP sequence counter. The standard 16 bit The low order bits for RTP sequence counter. The standard 16 bit
RTP sequence number is augmented with another 16 bits in the RTP sequence number is augmented with another 16 bits in the
payload header in order to accommodate the 1.485 Gbps data rate of payload header in order to accommodate the 1.485 Gbps data rate of
SMPTE 292M. SMPTE 292M.
4.2. Payload Header 4.2. Payload Header
Sequence Number (high bits): 16bits Sequence Number (high bits): 16bits
The high order bits for the 32bit RTP sequence counter. The high order bits for the 32bit RTP sequence counter.
Line No: 11bits
The line number of the source data format, extracted from the
SMPTE 292M stream. The line number MUST correspond to the line
number of the first 10bit word in the packet.
F: 1bit F: 1bit
Identifies field 1 and 2. F=1 identifies field 2 and F=0 identifies The F bit as defined in the SMPTE 292M timing signals (see
field 1. Table 1). F=1 identifies field 2 and F=0 identifies field 1.
V: 1bit V: 1bit
If the first date sample in the packet is a blanking level, V=1, The V bit as defined in the SMPTE 292M timing signals (see
otherwise V=0. Table 1). V=1 during field blanking, and V=0 else where.
Z: 2bits Z: 2bits
Set to zero at sender. Ignored at receiver. SHOULD be set to zero by the sender and MUST be ignored by
receivers.
Line No: 11bits
The line number of the source data format, extracted from the
SMPTE 292M stream (see Table 2). The line number MUST correspond
to the line number of the first 10bit word in the packet.
5. RTCP Considerations 5. RTCP Considerations
RFC1889 recommends transmission of RTCP packets every 5 seconds or at a RFC1889 recommends transmission of RTCP packets every 5 seconds or at a
reduced minimum in seconds of 360 divided by the session bandwidth in reduced minimum in seconds of 360 divided by the session bandwidth in
kilobits/seconds. At 1.485 Gbps the reduced minimum interval computes to kilobits/seconds. At 1.485 Gbps the reduced minimum interval computes to
0.2ms or 4028 packets per second. 0.2ms or 4028 packets per second.
It should be noted that the sender's octet count in SR packets wraps It should be noted that the sender's octet count in SR packets wraps
around in 23 seconds, and that the cumulative number of packets lost around in 23 seconds, and that the cumulative number of packets lost
wraps around in 93 seconds. This means these two fields cannot wraps around in 93 seconds. This means these two fields cannot
accurately represent octet count and number of packets lost since the accurately represent octet count and number of packets lost since the
beginning of transmission, as defined in RFC1889. Therefore for network beginning of transmission, as defined in RFC1889. Therefore for network
monitoring purposes other means of keeping track of these variables monitoring purposes other means of keeping track of these variables
should be used. should be used.
6. IANA Considerations 6. IANA Considerations
This document defines a new RTP payload format and associated MIME type, This document defines a new RTP payload format and associated MIME type,
SMPTE292M. The MIME registration forms for SMPTE 292M video is enclosed SMPTE292M. The MIME registration form for SMPTE 292M video is enclosed
below: below:
MIME media type name: video MIME media type name: video
MIME subtype name: SMPTE292M MIME subtype name: SMPTE292M
Required parameters: rate Required parameters: rate
The RTP timestamp clock rate. The clock runs at either 148500 Hz or The RTP timestamp clock rate. The clock runs at either 148500000 Hz or
148500/1.001 Hz. If the latter rate is used a timestamp of 148351 148500000/1.001 Hz. If the latter rate is used a timestamp of
MUST be used, and receivers MUST interpret this as 148500/1.001 Hz. 148351000
MUST be used, and receivers MUST interpret this as 148500000/1.001 Hz.
Optional parameters: length Optional parameters: pgroup
The RECOMMENDED packet size in octets. The RECOMMENDED grouping for aligning 10bit words and octets.
Encoding considerations: SMPTE292M video can be transmitted with Encoding considerations: SMPTE292M video can be transmitted with
RTP as specified in "draft-ietf-avt-smpte292-video-04". RTP as specified in "draft-ietf-avt-smpte292-video-05".
Security considerations: see draft "draft-ietf-avt-smpte292-video-04" Security considerations: see draft "draft-ietf-avt-smpte292-video-05"
section 8. section 8.
Interoperability considerations: NONE Interoperability considerations: NONE
Published specification: SMPTE292M Published specification: SMPTE292M
draft-ietf-avt-smpte292-video-04 draft-ietf-avt-smpte292-video-05
Applications which use this media type: Applications which use this media type:
Video communication. Video communication.
Additional information: None Additional information: None
Magic number(s): None Magic number(s): None
File extension(s): File extension(s): None
Macintosh File Type Code(s): None Macintosh File Type Code(s): None
Person & email address to contact for further information: Person & email address to contact for further information:
Ladan Gharai <ladan@isi.edu> Ladan Gharai <ladan@isi.edu>
IETF AVT working group. IETF AVT working group.
Intended usage: COMMON Intended usage: COMMON
Author/Change controller: Author/Change controller:
Ladan Gharai <ladan@isi.edu> Ladan Gharai <ladan@isi.edu>
7. Mapping to SDP Parameters 7. Mapping to SDP Parameters
Parameters are mapped to SDP [12] as follows: Parameters are mapped to SDP [12] as follows:
m=video 30000 RTP/AVP 111 m=video 30000 RTP/AVP 111
a=rtpmap:111 SMPTE292M/148500 a=rtpmap:111 SMPTE292M/148500000
a=fmtp:111 length=560 a=fmtp:111 pgroup=5
In this example, a dynamic payload type 111 is used for SMPTE292M. The In this example, a dynamic payload type 111 is used for SMPTE292M. The
length field indicates the number of video samples in each packet, 560, RTP timestamp is 148500000 Hz and the SDP parameter pgroup, indicates
which means the payload length is 1400bytes. that for video data after the SAV signal, must be packetized in
multiples of 5 octets.
8. Security Considerations 8. Security Considerations
RTP packets using the payload format defined in this specification are RTP packets using the payload format defined in this specification are
subject to the security considerations discussed in the RTP subject to the security considerations discussed in the RTP
specification, and any appropriate RTP profile. This implies that specification, and any appropriate RTP profile. This implies that
confidentiality of the media streams is achieved by encryption. confidentiality of the media streams is achieved by encryption.
This payload type does not exhibit any significant non-uniformity in the This payload type does not exhibit any significant non-uniformity in the
receiver side computational complexity for packet processing to cause a receiver side computational complexity for packet processing to cause a
skipping to change at page 6, line 48 skipping to change at page 9, line 4
RTP packets using the payload format defined in this specification are RTP packets using the payload format defined in this specification are
subject to the security considerations discussed in the RTP subject to the security considerations discussed in the RTP
specification, and any appropriate RTP profile. This implies that specification, and any appropriate RTP profile. This implies that
confidentiality of the media streams is achieved by encryption. confidentiality of the media streams is achieved by encryption.
This payload type does not exhibit any significant non-uniformity in the This payload type does not exhibit any significant non-uniformity in the
receiver side computational complexity for packet processing to cause a receiver side computational complexity for packet processing to cause a
potential denial-of-service threat. potential denial-of-service threat.
It is perhaps to be noted that the bandwidth of this payload is high It is perhaps to be noted that the bandwidth of this payload is high
enough (1.485 Gbps without the RTP overhead) to cause potential for enough (1.485 Gbps without the RTP overhead) to cause potential for
denial-of-service if transmitted onto most currently available Internet denial-of-service if transmitted onto most currently available Internet
paths. In the absence from the standards track of a suitable congestion paths. In the absence from the standards track of a suitable congestion
control mechanism for flows of this sort, use of the payload should be control mechanism for flows of this sort, use of the payload should be
narrowly limited to suitably connected network endpoints and great care narrowly limited to suitably connected network endpoints, or to networks
taken with the scope of multicast transmissions. This potential threat where QoS guarantees are available, and great care taken with the scope
is common to all high bit rate applications without congestion control. of multicast transmissions. This potential threat is common to all high
bit rate applications without congestion control.
9. Full Copyright Statement 9. Full Copyright Statement
Copyright (C) The Internet Society (2002). All Rights Reserved. Copyright (C) The Internet Society (2002). All Rights Reserved.
This document and translations of it may be copied and furnished to This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it or others, and derivative works that comment on or otherwise explain it or
assist in its implementation may be prepared, copied, published and assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind, distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are included provided that the above copyright notice and this paragraph are included
on all such copies and derivative works. on all such copies and derivative works.
However, this document itself may not be modified in any way, such as by However, this document itself may not be modified in any way, such as by
removing the copyright notice or references to the Internet Soci- ety or removing the copyright notice or references to the Internet Society or
other Internet organizations, except as needed for the purpose of other Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be fol- lowed, copyrights defined in the Internet Standards process must be followed,
or as required to translate it into languages other than English. or as required to translate it into languages other than English.
The limited permissions granted above are perpetual and will not be The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns. revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an "AS This document and the information contained herein is provided on an "AS
IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK
FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT
LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT
INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MER- CHANTABILITY OR INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE." FITNESS FOR A PARTICULAR PURPOSE."
10. Authors' Addresses 10. Authors' Addresses
Ladan Gharai Ladan Gharai
ladan@isi.edu ladan@isi.edu
USC/ISI USC/ISI
3811 Fairfax Dr 3811 Fairfax Dr
Arlington, VA 22203-1695 Arlington, VA 22203-1695
Gary Goncher Gary Goncher
ggoncher@tek.com ggoncher@tek.com
Colin Perkins Colin Perkins
csp@isi.edu csp@isi.edu
USC/ISI USC/ISI
3811 Fairfax Dr 3811 Fairfax Dr
Arlington, VA 22203-1695 Arlington, VA 22203-1695
Allison Mankin Allison Mankin
mankin@isi.edu mankin@isi.edu
USC/ISI USC/ISI
3811 Fairfax Dr 3811 Fairfax Dr
skipping to change at page 8, line 16 skipping to change at page 10, line 19
USC/ISI USC/ISI
3811 Fairfax Dr 3811 Fairfax Dr
Arlington, VA 22203-1695 Arlington, VA 22203-1695
Allison Mankin Allison Mankin
mankin@isi.edu mankin@isi.edu
USC/ISI USC/ISI
3811 Fairfax Dr 3811 Fairfax Dr
Arlington, VA 22203-1695 Arlington, VA 22203-1695
11. Bibliography 11. Acknowledgment
We would like to thank David Richardson for his insightful comments and
contributions to the draft.
12. Bibliography
[1] Society of Motion Picture and Television Engineers, [1] Society of Motion Picture and Television Engineers,
Bit-Serial Digital Interface for High-Definition Television Bit-Serial Digital Interface for High-Definition Television
Systems, SMPTE 292M, 1998. Systems, SMPTE 292M-1998.
[2] Society of Motion Picture and Television Engineers, [2] Society of Motion Picture and Television Engineers,
Digital Representation and Bit-Parallel Interface - 1125/60 Digital Representation and Bit-Parallel Interface - 1125/60
High-Definition Production System, SMPTE 260M, 1992. High-Definition Production System, SMPTE 260M-1999.
[3] Society of Motion Picture and Television Engineers, [3] Society of Motion Picture and Television Engineers,
1920x1080 50Hz, Scanning and Interface, SMPTE 295M, 1997. 1920x1080 50Hz, Scanning and Interface, SMPTE 295M-1997.
[4] Society of Motion Picture and Television Engineers, [4] Society of Motion Picture and Television Engineers,
1920x1080 Scanning and Analog and Parallel Digital Interfaces 1920x1080 Scanning and Analog and Parallel Digital Interfaces
for Multiple Picture Rates, SMPTE 272M. for Multiple Picture Rates, SMPTE 274M-1998.
[5] Society of Motion Picture and Television Engineers, [5] Society of Motion Picture and Television Engineers,
1280x720 Scanning, Analog and Digital Representation and Analog 1280x720 Scanning, Analog and Digital Representation and Analog
Interfaces, SMPTE 296M, 1998. Interfaces, SMPTE 296M-1998.
[6] ISO/IEC International Standard 13818-2; "Generic coding of [6] ISO/IEC International Standard 13818-2; "Generic coding of
moving pictures and associated audio information: Video", 1996. moving pictures and associated audio information: Video", 1996.
[7] ATSC Digital Television Standard Document A/53, September 1995, [7] ATSC Digital Television Standard Document A/53, September 1995,
http://www.atsc.org http://www.atsc.org
[8] ISO/IEC International Standard 13818-1; "Generic coding of [8] ISO/IEC International Standard 13818-1; "Generic coding of
moving pictures and associated audio information: Systems",1996. moving pictures and associated audio information: Systems",1996.
[9] Hoffman, Fernando, Goyal, Civanlar, "RTP Payload Format for [9] Hoffman, Fernando, Goyal, Civanlar, "RTP Payload Format for
MPEG1/MPEG2 Video", RFC 2250, IETF, January 1998. MPEG1/MPEG2 Video", RFC 2250, IETF, January 1998.
[10] IETF RFC 2119, "Key words for use in RFCs to Indicate [10] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels". Requirement Levels", RFC 2119.
[11] D. Tynan, "RTP Payload Format for BT.656 Video Encoding", [11] Clark, D. D., and Tennenhouse, D. L., "Architectural Considerations
RFC 2431, October 1998. for a New Generation of Protocols", In Proceedings of SIGCOMM '90
(Philadelphia, PA, Sept. 1990), ACM.
[12] M. Handley and V. Jacobson, "SDP: Session Description Protocol", [12] M. Handley and V. Jacobson, "SDP: Session Description Protocol",
RFC 2327, April 1998. RFC 2327, April 1998.
[13] Schulzrinne, Casner, Frederick, Jacobson, "RTP: A transport
protocol for real time Applications", RFC 1889, IETF,
January 1996.
[14] Schulzrinne, "RTP Profile for Audio and Video Conferences with
Minimal Control", RFC 1890, IETF, January 1996.
 End of changes. 

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