draft-ietf-avt-smpte292-video-08.txt   rfc3497.txt 
INTERNET-DRAFT Ladan Gharai
<draft-ietf-avt-smpte292-video-08.txt> USC/ISI Network Working Group L. Gharai
Colin Perkins Request for Comments: 3497 C. Perkins
USC/ISI Category: Standards Track USC/ISI
Gary Goncher G. Goncher
Tektronix Tektronix
Allison Mankin A. Mankin
USC/ISI Bell Labs, Lucent Corporation
December 2, 2002 March 2003
RTP Payload Format for SMPTE 292M Video RTP Payload Format for
<draft-ietf-avt-smpte292-video-08.txt> Society of Motion Picture and Television Engineers (SMPTE) 292M Video
Status of this Memo Status of this Memo
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Abstract Abstract
This memo specifies a RTP payload format for encapsulating uncompressed This memo specifies an RTP payload format for encapsulating
High Definition Television (HDTV) as defined by the Society of Motion uncompressed High Definition Television (HDTV) as defined by the
Picture and Television Engineers standard, SMPTE 292M. SMPTE is the main Society of Motion Picture and Television Engineers (SMPTE) standard,
standardizing body in the motion imaging industry and the SMPTE 292M SMPTE 292M. SMPTE is the main standardizing body in the motion
standard defines a bit-serial digital interface for local area HDTV imaging industry and the SMPTE 292M standard defines a bit-serial
transport. digital interface for local area HDTV transport.
1. Introduction 1. Introduction
[Note to RFC Editor: All "RFC XXXX" in the IANA considerations section The serial digital interface, SMPTE 292M [1], defines a universal
should be filled in with the RFC number of this memo, when published.] medium of interchange for uncompressed High Definition Television
(HDTV) between various types of video equipment (cameras, encoders,
The serial digital interface, SMPTE 292M[1], defines a universal medium VTRs, etc.). SMPTE 292M stipulates that the source data be in 10 bit
of interchange for uncompressed High Definition Television (HDTV) words and the total data rate be either 1.485 Gbps or 1.485/1.001
between various types of video equipment (cameras, encoders, VTRs, Gbps.
etc.). SMPTE 292M stipulates that the source data be in 10 bit words and
the total data rate be either 1.485 Gbps or 1.485/1.001 Gbps.
The use of a dedicated serial interconnect is appropriate in a studio The use of a dedicated serial interconnect is appropriate in a studio
environment, but it is desirable to leverage the widespread availability environment, but it is desirable to leverage the widespread
of high bandwidth IP connectivity to allow efficient wide area delivery availability of high bandwidth IP connectivity to allow efficient
of SMPTE 292M format content. Accordingly, this memo defines an RTP wide area delivery of SMPTE 292M content. Accordingly, this memo
payload format for SMPTE 292M format video. defines an RTP payload format for SMPTE 292M format video.
It is to be noted that SMPTE 292M streams have a constant high bit rate It is to be noted that SMPTE 292M streams have a constant high bit
and are not congestion controlled. Accordingly, use of this payload rate and are not congestion controlled. Accordingly, use of this
format should be tightly controlled and limited to private networks or payload format should be tightly controlled and limited to private
those networks that provide resource reservation and enhanced quality of networks or those networks that provide resource reservation and
service. This is discussed further in section 9 "Security enhanced quality of service. This is discussed further in section 9.
Considerations".
This memo only addresses the transfer of uncompressed HDTV. Compressed This memo only addresses the transfer of uncompressed HDTV.
HDTV is a subset of MPEG-2 [9], which is fully described in document Compressed HDTV is a subset of MPEG-2 [9], which is fully described
A/53 [10] of the Advanced Television Standards Committee. The ATSC has in document A/53 [10] of the Advanced Television Standards Committee.
also adopted the MPEG-2 transport system (ISO/IEC 13818-1)[11]. The ATSC has also adopted the MPEG-2 transport system (ISO/IEC
Therefore RFC 2250 [12] sufficiently describes transport for compressed 13818-1) [11]. Therefore RFC 2250 [12] sufficiently describes
HDTV over RTP. transport for compressed HDTV over RTP.
2. Overview of SMPTE 292M 2. Overview of SMPTE 292M
A SMPTE 292M television line comprises two interleaved streams, one A SMPTE 292M television line comprises two interleaved streams, one
containing the luminance (Y) samples, the other chrominance (CrCb) containing the luminance (Y) samples, the other chrominance (CrCb)
values. Since chrominance is horizontally sub-sampled (4:2:2 coding) the values. Since chrominance is horizontally sub-sampled (4:2:2 coding)
lengths of the two streams match (see Figure 3 of SMPTE 292M[1]). In the lengths of the two streams match (see Figure 3 of SMPTE 292M
addition to being the same length the streams also have identical [1]). In addition to being the same length the streams also have
structures: each stream is divided into four parts, (figure 1): (1) identical structures: each stream is divided into four parts, (figure
start of active video timing reference (SAV); (2) digital active line; 1): (1) start of active video timing reference (SAV); (2) digital
(3) end of active video timing reference (EAV); and (4) digital line active line; (3) end of active video timing reference (EAV); and (4)
blanking. A SMPTE 292M line may also carry horizontal ancillary data digital line blanking. A SMPTE 292M line may also carry horizontal
(H-ANC) or vertical ancillary data (V-ANC) instead of the blanking ancillary data (H-ANC) or vertical ancillary data (V-ANC) instead of
level, and likewise, ancillary data may be transported instead of a the blanking level; Likewise, ancillary data may be transported
digital active line. 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
of 0x3FF 0x000 0x000 and an additional word (designated as XYZ in values of 0x3FF 0x000 0x000 and an additional word (designated as XYZ
figure 2), carrying a number of flags. This includes an F flag which in figure 2), carrying a number of flags. This includes an F flag
designate which field (1 or 2) the line is transporting and also a V which designates which field (1 or 2) the line is transporting and
flag which indicates field blanking. Table 1, further displays the code also a V flag which indicates field blanking. Table 1, further
values in SAV and EAV. After EAV, are two words LN0 and LN1 (Table 2), displays the code values in SAV and EAV. After EAV, are two words,
which carry the 11 bit line number for the SMPTE 292M line. The Cyclic LN0 and LN1 (Table 2), that carry the 11 bit line number for the
Redundancy Check, CRC, is also a two word value, shown as CR0 and CR1 in SMPTE 292M line. The Cyclic Redundancy Check, CRC, is also a two
figure 2. word value, shown as CR0 and CR1 in figure 2.
+------------+-----------------------+-----+---------------------+ +------------+-----------------------+-----+---------------------+
| | Digital Line Blanking | | Digital Active Line | | | Digital Line Blanking | | Digital Active Line |
| EAV+LN+CRC | (Blanking level or | SAV | (Active Picture or | | EAV+LN+CRC | (Blanking level or | SAV | (Active Picture or |
| | Ancillary Data) | | Ancillary Data) | | | Ancillary Data) | | Ancillary Data) |
+------------+-----------------------+-----+---------------------+ +------------+-----------------------+-----+---------------------+
Figure 1. The SMPTE 292M line format. Figure 1. The SMPTE 292M line format.
0 20 40 60 80 0 20 40 0 20 40 60 80 0 20 40
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|3FF| 0 | 0 |XYZ|LN1|LN2|CR0|CR1| |3FF| 0 | 0 |XYZ| |3FF| 0 | 0 |XYZ|LN1|LN2|CR0|CR1| |3FF| 0 | 0 |XYZ|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
<---- EAV -----> <- LN-> <- CRC-> <----- SAV -----> <---- EAV -----> <- LN-> <- CRC-> <----- SAV ----->
Figure 2. Timing reference format. Figure 2. Timing reference format.
+---------------------------------------------------------+ +---------------------------------------------------------+
| (MSB) (LSB) | | (MSB) (LSB) |
| Word 9 8 7 6 5 4 3 2 1 0 | | Word 9 8 7 6 5 4 3 2 1 0 |
+---------------------------------------------------------+ +---------------------------------------------------------+
| 3FF 1 1 1 1 1 1 1 1 1 1 | | 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 |
| 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 | | XYZ 1 F V H P P P P P P |
+---------------------------------------------------------+ +---------------------------------------------------------+
| NOTES: | | NOTES: |
| F=0 during field 1; F=1 during field 2. | | F=0 during field 1; F=1 during field 2. |
| V=0 elsewhere; V=1 during field blanking. | | V=0 elsewhere; V=1 during field blanking. |
| H=0 in SAV; H=1 in EAV. | | H=0 in SAV; H=1 in EAV. |
| MSB=most significant bit; LSB=least significant bit.| | MSB=most significant bit; LSB=least significant bit.|
| P= protected bits defined in Table 2 of SMPTE 292M | | P= protected bits defined in Table 2 of SMPTE 292M |
+---------------------------------------------------------+ +---------------------------------------------------------+
Table 1: Timing reference codes.
+---------------------------------------------------------+ Table 1: Timing reference codes.
| (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". |
+---------------------------------------------------------+
Table 2: Line number data.
The number of words and format for active lines and line blanking is +---------------------------------------------------------+
defined by source format documents. Currently, source video formats | (MSB) (LSB) |
transfered by SMPTE 292M include SMPTE 260M, 295M, 274M and 296M[5-8]. | Word 9 8 7 6 5 4 3 2 1 0 |
In this memo we specify how to transfer SMPTE 292M over RTP, +---------------------------------------------------------+
irrespective of the source format. | 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". |
+---------------------------------------------------------+
Table 2: Line number data.
The number of words and the format for active lines and line blanking
is defined by source format documents. Currently, source video
formats transfered by SMPTE 292M include SMPTE 260M, 295M, 274M and
296M [5-8]. In this memo, we specify how to transfer SMPTE 292M over
RTP, irrespective of the source format.
3. Conventions Used in this Document 3. 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[2]. document are to be interpreted as described in BCP 14, RFC 2119 [2].
4. Payload Design 4. Payload Design
Each SMPTE 292M data line is packetized into one or more RTP packets. Each SMPTE 292M data line is packetized into one or more RTP packets.
This includes all timing signals, blanking levels, active lines and/or This includes all timing signals, blanking levels, active lines
ancillary data. Start of active video (SAV) and end of active video and/or ancillary data. Start of active video (SAV) and end of active
(EAV+LN+CRC) signals MUST NOT be fragmented across packets, as the SMPTE video (EAV+LN+CRC) signals MUST NOT be fragmented across packets, as
292M decoder uses them to detect the start of scan lines. the SMPTE 292M decoder uses them to detect the start of scan lines.
The standard RTP header is followed by a 4 octet payload header. All The standard RTP header is followed by a 4 octet payload header. All
information in the payload header pertains to the first data sample in information in the payload header pertains to the first data sample
the packet. The end of a video frame (the packet containing the last in the packet. The end of a video frame (the packet containing the
sample before the EAV) is marked by the M bit in the RTP header. last sample before the EAV) is marked by the M bit in the RTP header.
The payload header contains a 16 bit extension to the standard 16 bit The payload header contains a 16 bit extension to the standard 16 bit
RTP sequence number, thereby extending the sequence number to 32 bits RTP sequence number, thereby extending the sequence number to 32 bits
and enabling RTP to accommodate HDTV's high data rates. At 1.485 Gbps, and enabling RTP to accommodate HDTV's high data rates. At 1.485
with packet sizes of at least one thousand octets, 32 bits allows for an Gbps, with packet sizes of at least one thousand octets, 32 bits
approximate 6 hour period before the sequence number wraps around. Given allows for an approximate 6 hour period before the sequence number
the same assumptions, the standard 16 bit RTP sequence number wraps wraps around. Given the same assumptions, the standard 16 bit RTP
around in less than a second (336 milliseconds) which is clearly not sequence number wraps around in less than a second (336
sufficient for the purpose of detecting loss and out of order packets. milliseconds), which is clearly not sufficient for the purpose of
detecting loss and out of order packets.
A 148.5 MHz (or 148.5/1.001 MHz) time-stamp is used as the RTP A 148.5 MHz (or 148.5/1.001 MHz) time-stamp is used as the RTP
timestamp. This allows the receiver to reconstruct the timing of the timestamp. This allows the receiver to reconstruct the timing of the
SMPTE 292M stream, without knowledge of the exact type of source format SMPTE 292M stream, without knowledge of the exact type of source
(e.g. SMPTE 274M or SMPTE 296M). With this timestamp, the location of format (e.g., SMPTE 274M or SMPTE 296M). With this timestamp, the
the first byte of each packet can be uniquely identified in the SMPTE location of the first sample of each packet can be uniquely
292M stream. At 148.5 MHz the 32 bit timestamp wraps around in 21 identified in the SMPTE 292M stream. At 148.5 MHz, the 32 bit
seconds. timestamp wraps around in 21 seconds.
The payload header also carries the 11 bit line number from the SMPTE The payload header also carries the 11 bit line number from the SMPTE
292M timing signals. This provides more information at the application 292M timing signals. This provides more information at the
level and adds a level of resiliency, in case the packet containing the application level and adds a level of resiliency, in case the packet
EAV is lost. containing the EAV is lost.
The bit length of both timing signals, SAV and EAV+LN+CRC, are multiples The bit length of both timing signals, SAV and EAV+LN+CRC, are
of 8 bits, 40 bits and 80 bits, respectively, and therefore are multiples of 8 bits, 40 bits and 80 bits, respectively, and therefore
naturally octet aligned. are naturally octet aligned.
For the video content it is desirable for the video to both octet align For the video content, it is desirable for the video to both octet
when packetized and also adhere to the principles of application level align when packetized and also adhere to the principles of
framing, also known as ALF [13]. For YCrCb video, the ALF principle application level framing, also known as ALF [13]. For YCrCb video,
translates into not fragmenting related luminance and chrominance values the ALF principle translates into not fragmenting related luminance
across packets. For example with the 4:2:0 color subsampling a 4 pixel and chrominance values across packets. For example, with the 4:2:0
group is represented by 6 values, Y1 Y2 Y3 Y4 Cr Cb, and video content color subsampling, a 4 pixel group is represented by 6 values, Y1 Y2
should be packetized such that these values are not fragmented across 2 Y3 Y4 Cr Cb, and video content should be packetized such that these
packets. However, with 10 bit words this is a 60 bit value which is not values are not fragmented across 2 packets. However, with 10 bit
octet aligned. To be both octet aligned, and adhere to ALF, an ALF unit words, this is a 60 bit value which is not octet aligned. To be both
must represent 2 groups of 4 Pixels, thereby becoming octet aligned on a octet aligned, and adhere to ALF, an ALF unit must represent 2 groups
15 octet boundary. This length is referred to as the pixel group or of 4 Pixels, thereby becoming octet aligned on a 15 octet boundary.
pgroup, and it is conveyed in the SDP parameters. Table 3 displays the This length is referred to as the pixel group or pgroup, and it is
pgroup value for various color samplings. Typical source formats use conveyed in the SDP parameters. Table 3 displays the pgroup value
4:2:2 sampling, and require a pgroup of 5 octets, other values are for various color samplings. Typical source formats use 4:2:2
included for completeness. sampling, and require a pgroup of 5 octets, other values are included
for completeness.
The contents of the Digital Active Line SHOULD NOT be fragmented within The contents of the Digital Active Line SHOULD NOT be fragmented
a pgroup. A pgroup of 1 indicates that data may be split at any octet within a pgroup. A pgroup of 1 indicates that data may be split at
boundary (this is applicable to instances where the source format is not any octet boundary (this is applicable to instances where the source
known). The SAV and EAV+LN+CRC fields MUST NOT be fragmented. format is not known). The SAV and EAV+LN+CRC fields MUST NOT be
fragmented.
+-------------------------------------------------------+ +-------------------------------------------------------+
| Color 10 bit | | Color 10 bit |
|Subsampling Pixels words aligned on octet# pgroup| |Subsampling Pixels words aligned on octet# pgroup|
+-----------+-------+--------+-------------------+------+ +-----------+-------+--------+-------------------+------+
| 4:2:0 | 4 | 6*10 | 2*60/8 = 15 | 15 | | 4:2:0 | 4 | 6*10 | 2*60/8 = 15 | 15 |
+-----------+-------+--------+-------------------+------+ +-----------+-------+--------+-------------------+------+
| 4:2:2 | 2 | 4*10 | 40/8 = 5 | 5 | | 4:2:2 | 2 | 4*10 | 40/8 = 5 | 5 |
+-----------+-------+--------+-------------------+------+ +-----------+-------+--------+-------------------+------+
| 4:4:4 | 1 | 3*10 | 4*30/8 = 15 | 15 | | 4:4:4 | 1 | 3*10 | 4*30/8 = 15 | 15 |
+-----------+-------+--------+-------------------+------+ +-----------+-------+--------+-------------------+------+
Table 3. Color subsampling and pgroups.
Table 3. Color subsampling and pgroups.
5. RTP Packetization 5. RTP Packetization
The standard RTP header is followed by a 4 octet payload header, and the The standard RTP header is followed by a 4 octet payload header, and
payload data, as shown in Figure 4. the payload data, as shown in Figure 3.
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) |F|V| Z | line no | | sequence# (high bits) |F|V| Z | line no |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
: SMPTE 292M data : : SMPTE 292M data :
: : : :
| | | |
+---------------------------------------------------------------+ +---------------------------------------------------------------+
Figure 4: RTP Packet showing SMPTE 292M headers and payload
Figure 3: RTP Packet showing SMPTE 292M headers and payload
5.1. The RTP Header 5.1. 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 (the other fields in the RTP header are used in their encapsulation (the other fields in the RTP header are used in their
usual manner): usual manner):
Payload Type (PT): 7 bits Payload Type (PT): 7 bits
A dynamically allocated payload type field which designates the A dynamically allocated payload type field that 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 148.5 MHz (or 148.5/1.001 Gbps), the timestamp field contains a 148.5 MHz (or 148.5/1.001
MHz) timestamp, respectively. This allows for a unique timestamp MHz) timestamp, respectively. This allows for a unique timestamp
for each 10 bit word. for each 10 bit word.
Marker bit (M): 1 bit Marker bit (M): 1 bit
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.
5.2. Payload Header 5.2. Payload Header
Sequence Number (high bits): 16 bits Sequence Number (high bits): 16 bits
The high order bits for the 32 bit RTP sequence counter, in network The high order bits for the 32 bit RTP sequence counter, in
byte order. network byte order.
F: 1 bit F: 1 bit
The F bit as defined in the SMPTE 292M timing signals (see The F bit as defined in the SMPTE 292M timing signals (see Table
Table 1). F=1 identifies field 2 and F=0 identifies field 1. 1). F=1 identifies field 2 and F=0 identifies field 1.
V: 1 bit V: 1 bit
The V bit as defined in the SMPTE 292M timing signals (see The V bit as defined in the SMPTE 292M timing signals (see Table
Table 1). V=1 during field blanking, and V=0 else where. 1). V=1 during field blanking, and V=0 else where.
Z: 2 bits Z: 2 bits
SHOULD be set to zero by the sender and MUST be ignored by SHOULD be set to zero by the sender and MUST be ignored by
receivers. receivers.
Line No: 11 bits Line No: 11 bits
The line number of the source data format, extracted from the The line number of the source data format, extracted from the
SMPTE 292M stream (see Table 2). The line number MUST correspond SMPTE 292M stream (see Table 2). The line number MUST correspond
to the line number of the first 10 bit word in the packet. to the line number of the first 10 bit word in the packet.
6. RTCP Considerations 6. RTCP Considerations
RFC1889 recommends transmission of RTCP packets every 5 seconds or at a RFC 1889 should be used as specified in RFC 1889 [3], which specifies
reduced minimum in seconds of 360 divided by the session bandwidth in two limits on the RTCP packet rate: RTCP bandwidth should be limited
kilobits/second. At 1.485 Gbps the reduced minimum interval computes to to 5% of the data rate, and the minimum for the average of the
0.2ms or 4028 packets per second. randomized intervals between RTCP packets should be 5 seconds.
Considering the high data rate of this payload format, the minimum
interval is the governing factor in this case.
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 the octet count and number of packets lost since
beginning of transmission, as defined in RFC1889. Therefore for network the beginning of transmission, as defined in RFC 1889. Therefore,
monitoring purposes or any other application which requires the sender's for network monitoring purposes or any other application that
octet count and the cumulative number of packets lost since the requires the sender's octet count and the cumulative number of
beginning of transmission, the application itself must keep track of the packets lost since the beginning of transmission, the application
number of rollovers of these fields via a counter. itself must keep track of the number of rollovers of these fields via
a counter.
7. IANA Considerations 7. 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
SMPTE292M. The MIME registration form for SMPTE 292M video is enclosed type, SMPTE292M. The MIME registration form for SMPTE 292M video is
below: enclosed below:
MIME media type name: video
MIME subtype name: SMPTE292M MIME media type name: video
Required parameters: rate MIME subtype name: SMPTE292M
The RTP timestamp clock rate. The clock runs at either 148500000 Hz
or 148500000/1.001 Hz. If the latter rate is used a timestamp of
148351648 MUST be used, and receivers MUST interpret this as
148500000/1.001 Hz.
Optional parameters: pgroup Required parameters: rate
The RECOMMENDED grouping for aligning 10 bit words and octets. The RTP timestamp clock rate. The clock runs at either 148500000
Defaults to 1 octet, if not present. Hz or 148500000/1.001 Hz. If the latter rate is used a timestamp
of 148351648 MUST be used, and receivers MUST interpret this as
148500000/1.001 Hz.
Encoding considerations: SMPTE292M video can be transmitted with Optional parameters: pgroup
RTP as specified in RFC XXXX. The RECOMMENDED grouping for aligning 10 bit words and octets.
Defaults to 1 octet, if not present.
Security considerations: see RFC XXXX section 9. Encoding considerations: SMPTE292M video can be transmitted with RTP
as specified in RFC 3497.
Interoperability considerations: NONE Security considerations: see RFC 3497 section 9.
Published specification: SMPTE292M Interoperability considerations: NONE
RFC XXXX
Applications which use this media type: Published specification: SMPTE292M
Video communication. RFC 3497
Additional information: None Applications which use this media type:
Magic number(s): None Video communication.
File extension(s): None Additional information: None
Macintosh File Type Code(s): None Magic number(s): None
Person & email address to contact for further information: File extension(s): None
Ladan Gharai <ladan@isi.edu>
IETF AVT working group.
Intended usage: COMMON Macintosh File Type Code(s): None
Author/Change controller: Person & email address to contact for further information:
Ladan Gharai <ladan@isi.edu> Ladan Gharai <ladan@isi.edu>
IETF AVT working group.
Intended usage: COMMON
Author/Change controller:
Ladan Gharai <ladan@isi.edu>
8. Mapping to SDP Parameters 8. Mapping to SDP Parameters
Parameters are mapped to SDP [14] as follows: Parameters are mapped to SDP [14] as follows:
m=video 30000 RTP/AVP 111 m=video 30000 RTP/AVP 111
a=rtpmap:111 SMPTE292M/148500000 a=rtpmap:111 SMPTE292M/148500000
a=fmtp:111 pgroup=5 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.
RTP timestamp is 148500000 Hz and the SDP parameter pgroup, indicates The RTP timestamp is 148500000 Hz and the SDP parameter pgroup
that for video data after the SAV signal, must be packetized in indicates that for video data after the SAV signal, it must be
multiples of 5 octets. packetized in multiples of 5 octets.
9. Security Considerations 9. Security Considerations
RTP sessions using the payload format defined in this specification are RTP sessions using the payload format defined in this specification
subject to the security considerations discussed in the RTP are subject to the security considerations discussed in the RTP
specification [3] and any appropriate RTP profile (e.g. [4]). specification [3] and any appropriate RTP profile (e.g., [4]).
This payload format does not exhibit any significant non-uniformity in This payload format does not exhibit any significant non-uniformity
the receiver side computational complexity for packet processing to in the receiver side computational complexity for packet processing
cause a potential denial-of-service threat for intended receivers. to cause a potential denial-of-service threat for intended receivers.
The bandwidth of this payload format is high enough (1.485 Gbps without The bandwidth of this payload format is high enough (1.485 Gbps
the RTP overhead) to cause potential for denial-of-service if without the RTP overhead) to cause potential for denial-of-service if
transmitted onto most currently available Internet paths. Since transmitted onto most currently available Internet paths. Since
congestion control is not possible for SMPTE-292M over RTP flows, use of congestion control is not possible for SMPTE 292M over RTP flows, use
the payload SHOULD be narrowly limited to suitably connected network of the payload SHOULD be narrowly limited to suitably connected
endpoints, or to networks where QoS guarantees are available. network endpoints, or to networks where QoS guarantees are available.
If QoS enhanced service is used, RTP receivers SHOULD monitor packet If QoS enhanced service is used, RTP receivers SHOULD monitor packet
loss to ensure that the service that was requested is actually being loss to ensure that the service that was requested is actually being
delivered. If it is not, then they SHOULD assume that they are delivered. If it is not, then they SHOULD assume that they are
receiving best-effort service and behave accordingly. receiving best-effort service and behave accordingly.
If best-effort service is being used, RTP receivers MUST monitor packet If best-effort service is being used, RTP receivers MUST monitor
loss to ensure that the packet loss rate is within acceptable parameters packet loss to ensure that the packet loss rate is within acceptable
and MUST leave the session is the loss rate is too high. The loss rate parameters and MUST leave the session if the loss rate is too high.
is considered acceptable if a TCP flow across the same network path, The loss rate is considered acceptable if a TCP flow across the same
experiencing the same network conditions, would achieve an average network path, experiencing the same network conditions, would achieve
throughput, measured on a reasonable timescale, that is not less than an average throughput, measured on a reasonable timescale, that is
the RTP flow is achieving. Since congestion control is not possible for not less than the RTP flow is achieving. Since congestion control is
SMPTE-292M flows, this condition can only be satisfied if receivers not possible for SMPTE 292M flows, this condition can only be
leave the session if the loss rate is unacceptably high. satisfied if receivers leave the session if the loss rate is
unacceptably high.
10. Full Copyright Statement 10. Acknowledgments
Copyright (C) The Internet Society (2002). All Rights Reserved. We would like to thank David Richardson for his insightful comments
and contributions to the document. We would also like to thank Chuck
Harrison for his input and for explaining the intricacies of SMPTE
292M.
This document and translations of it may be copied and furnished to 11. Normative References
others, and derivative works that comment on or otherwise explain it or
assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are included
on all such copies and derivative works.
However, this document itself may not be modified in any way, such as by [1] Society of Motion Picture and Television Engineers, Bit-Serial
removing the copyright notice or references to the Internet Society or Digital Interface for High-Definition Television Systems, SMPTE
other Internet organizations, except as needed for the purpose of 292M-1998.
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be followed,
or as required to translate it into languages other than English.
The limited permissions granted above are perpetual and will not be [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement
revoked by the Internet Society or its successors or assigns. Levels", BCP 14, RFC 2119, March 1997.
This document and the information contained herein is provided on an "AS [3] Schulzrinne, H., Casner, S., Frederick, R. and V. Jacobson,
IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK "RTP: A Transport Protocol for Real-Time Applications", RFC
FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT 1889, January 1996.
LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT
INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE."
11. Authors' Addresses [4] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and Video
Conferences with Minimal Control", RFC 1890, January 1996.
Ladan Gharai 12. Informative References
ladan@isi.edu
Colin Perkins
csp@isi.edu
Allison Mankin [5] Society of Motion Picture and Television Engineers, Digital
mankin@isi.edu Representation and Bit-Parallel Interface - 1125/60 High-
USC Information Sciences Institute Definition Production System, SMPTE 260M-1999.
3811 N. Fairfax Drive
Arlington, VA 22203-1695
Gary Goncher [6] Society of Motion Picture and Television Engineers, 1920x1080
ggoncher@tek.com 50Hz, Scanning and Interface, SMPTE 295M-1997.
Tektronix, Inc.
P.O. Box 500, M/S 50-480
Beaverton, OR 97077
12. Acknowledgment [7] Society of Motion Picture and Television Engineers, 1920x1080
Scanning and Analog and Parallel Digital Interfaces for Multiple
Picture Rates, SMPTE 274M-1998.
We would like to thank David Richardson for his insightful comments and [8] Society of Motion Picture and Television Engineers, 1280x720
contributions to the draft. We would also like to thank Chuck Harrison Scanning, Analog and Digital Representation and Analog
for his input and for explaining the intricacies of SMPTE 292M. Interfaces, SMPTE 296M-1998.
13. Normative References [9] ISO/IEC International Standard 13818-2; "Generic coding of
moving pictures and associated audio information: Video", 1996.
[1] Society of Motion Picture and Television Engineers, [10] ATSC Digital Television Standard Document A/53, September 1995,
Bit-Serial Digital Interface for High-Definition Television http://www.atsc.org
Systems, SMPTE 292M-1998.
[2] S. Bradner, "Key words for use in RFCs to Indicate [11] ISO/IEC International Standard 13818-1; "Generic coding of
Requirement Levels", RFC 2119. moving pictures and associated audio information: Systems",1996.
[3] H. Schulzrinne, S. Casner, R. Frederick and V. Jacobson, "RTP: A [12] Hoffman, D., Fernando, G., Goyal, V. and M. Civanlar, "RTP
Transport Protocol for Real-Time Applications", IETF, Work in Payload Format for MPEG1/MPEG2 Video", RFC 2250, January 1998.
Progress (draft-ietf-avt-rtp-new-11.txt)
[4] H. Schulzrinee and S. Casner, "RTP Profile for Audio and Video [13] Clark, D. D., and Tennenhouse, D. L., "Architectural
Conferences with Minimal Control", IETF, Work in progress, Considerations for a New Generation of Protocols", In
(draft-ietf-avt-profile-new-12.txt). Proceedings of SIGCOMM '90 (Philadelphia, PA, Sept. 1990), ACM.
14. Informative References [14] Handley, H. and V. Jacobson, "SDP: Session Description
Protocol", RFC 2327, April 1998.
[5] Society of Motion Picture and Television Engineers, 13. Authors' Addresses
Digital Representation and Bit-Parallel Interface - 1125/60
High-Definition Production System, SMPTE 260M-1999.
[6] Society of Motion Picture and Television Engineers, Ladan Gharai
1920x1080 50Hz, Scanning and Interface, SMPTE 295M-1997. USC/ISI
3811 Fairfax Dr.
Arlington VA 22203
[7] Society of Motion Picture and Television Engineers, EMail: ladan@isi.edu
1920x1080 Scanning and Analog and Parallel Digital Interfaces
for Multiple Picture Rates, SMPTE 274M-1998.
[8] Society of Motion Picture and Television Engineers, Colin Perkins
1280x720 Scanning, Analog and Digital Representation and Analog USC/ISI
Interfaces, SMPTE 296M-1998. 3811 Fairfax Dr.
Arlington VA 22203
[9] ISO/IEC International Standard 13818-2; "Generic coding of EMail: csp@csperkins.org
moving pictures and associated audio information: Video", 1996.
[10] ATSC Digital Television Standard Document A/53, September 1995, Allison Mankin
http://www.atsc.org Bell Labs, Lucent Corporation
[11] ISO/IEC International Standard 13818-1; "Generic coding of EMail: mankin@psg.com
moving pictures and associated audio information: Systems",1996.
[12] Hoffman, Fernando, Goyal, Civanlar, "RTP Payload Format for Gary Goncher
MPEG1/MPEG2 Video", RFC 2250, IETF, January 1998. Tektronix, Inc.
P.O. Box 500, M/S 50-480
Beaverton, OR 97077
[13] Clark, D. D., and Tennenhouse, D. L., "Architectural Considerations EMail: Gary.Goncher@tek.com
for a New Generation of Protocols", In Proceedings of SIGCOMM '90
(Philadelphia, PA, Sept. 1990), ACM.
[14] M. Handley and V. Jacobson, "SDP: Session Description Protocol", 14. Full Copyright Statement
RFC 2327, April 1998.
Copyright (C) The Internet Society (2003). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
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