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Internet Engineering Task Force (IETF) K. Kobayashi
Request for Comments: 6469 AICS, RIKEN
Obsoletes: 3189 K. Mishima
Category: Standards Track Keio University
ISSN: 2070-1721 S. Casner
Packet Design
C. Bormann
Universitaet Bremen TZI
December 2011
RTP Payload Format for DV (IEC 61834) Video
Abstract
This document specifies the packetization scheme for encapsulating
the compressed digital video data streams commonly known as "DV" into
a payload format for the Real-Time Transport Protocol (RTP). This
document obsoletes RFC 3189.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6469.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Kobayashi, et al. Standards Track [Page 1]
RFC 6469 RTP Payload Format for DV Video December 2011
This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
Table of Contents
1. Introduction ....................................................3
1.1. Terminology ................................................4
2. RTP Payload Format ..............................................4
2.1. The DV Format Encoding .....................................4
2.2. RTP Header Usage ...........................................5
2.3. Payload Structures .........................................6
3. Payload Format Parameters .......................................7
3.1. Media Type Registration ....................................7
3.1.1. Media Type Registration for DV Video ................8
3.1.2. Media Type Registration for DV Audio ................9
3.2. SDP Parameters ............................................11
3.2.1. Mapping of Payload Type Parameters to SDP ..........11
3.2.2. Usage with the SDP Offer/Answer Model ..............12
3.3. Examples ..................................................12
3.3.1. Example for Unbundled Streams ......................13
3.3.2. Example for Bundled Streams ........................13
4. Security Considerations ........................................14
5. Congestion Control .............................................14
6. IANA Considerations ............................................14
7. Major Changes from RFC 3189 ....................................15
8. Interoperability with Previous Implementations .................15
9. Acknowledgment .................................................16
10. References ....................................................16
10.1. Normative References .....................................16
10.2. Informative References ...................................17
Kobayashi, et al. Standards Track [Page 2]
RFC 6469 RTP Payload Format for DV Video December 2011
1. Introduction
This document specifies payload formats for encapsulating both
consumer- and professional-use Digital Video (DV) format data streams
into the Real-Time Transport Protocol (RTP) [RFC3550]. DV
compression audio and video formats were designed for a recording
format on helical-scan magnetic tape media. The DV standards for
consumer-market devices, the IEC 61883 and 61834 series, cover many
aspects of consumer-use digital video, including mechanical
specifications of a cassette, magnetic recording format, error
correction on the magnetic tape, Discrete Cosine Transform (DCT)
video encoding format, and audio encoding format [IEC61834]. The
digital interface part of IEC 61883 defines an interface on the IEEE
1394 system [IEC61883][IEEE1394]. This specification set supports
several video formats: SD-VCR (Standard Definition), HD-VCR (High
Definition), SDL-VCR (Standard Definition - Long), PALPlus, DVB
(Digital Video Broadcast), and ATV (Advanced Television). North
American formats are indicated with a number of lines and "/60",
while European formats use "/50". DV standards extended for
professional use were published by the Society of Motion Picture and
Television Engineers (SMPTE) as 314M and 370M, for different sampling
systems, higher color resolution, and higher bit rates
[SMPTE314M][SMPTE370M].
In summary, there are two kinds of DV, one for consumer use and the
other for professional. The original "DV" specification designed for
consumer-use digital VCRs is approved as the IEC 61834 standard set.
The specifications for professional DV are published as SMPTE 314M
and 370M. Both encoding formats are based on consumer DV and used in
SMPTE D-7, D-9, and D-12 video systems. The RTP payload format
specified in this document supports IEC 61834 consumer DV and
professional SMPTE 314M and 370M (DV-based) formats.
IEC 61834 also includes magnetic tape recording for digital TV
broadcasting systems (such as DVB and ATV) that use MPEG2 encoding.
The payload format for encapsulating MPEG2 into RTP has already been
defined in RFC 2250 [RFC2250] and elsewhere.
Consequently, the payload specified in this document will support six
video formats of the IEC standard: SD-VCR (525/60, 625/50), HD-VCR
(1125/60, 1250/50), and SDL-VCR (525/60, 625/50). It also supports
eight of the SMPTE standards: 314M 25 Mbit/s (525/60, 625/50), 314M
50 Mbit/s (525/60, 625/50), and 370M 100 Mbit/s (1080/60i, 1080/50i,
720/60p, and 720/50p). In the future, it can be extended into other
video formats managed by the 80-byte DV Digital Interface Format
(DIF) block.
Kobayashi, et al. Standards Track [Page 3]
RFC 6469 RTP Payload Format for DV Video December 2011
Throughout this specification, we make extensive use of the
terminology of IEC and SMPTE standards. The reader should consult
the original references for definitions of these terms.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. RTP Payload Format
2.1. The DV Format Encoding
The DV format only uses the DCT compression technique within each
frame, contrasted with the interframe compression of the MPEG video
standards [ISO/IEC11172][ISO/IEC13818]. All video data, including
audio and other system data, is managed within the picture frame unit
of video.
The DV video encoding is composed of a three-level hierarchical
structure, i.e., DCT super block, DCT macro block, and DCT block. A
picture frame is divided into rectangle- or clipped-rectangle-shaped
DCT super blocks. DCT super blocks are divided into 27 rectangle- or
square-shaped DCT macro blocks, and each DCT macro block consists of
a number of DCT blocks. Each DCT block consists of 8x8 pixels and
represents a rectangle region for each color, Y, Cb, and Cr.
Audio data is encoded in Pulse Code Modulation (PCM) format. The
sampling frequency is 32 kHz, 44.1 kHz, or 48 kHz and the
quantization is 12-bit non-linear, 16-bit linear, or 20-bit linear.
The number of channels may be up to 8. Only certain combinations of
these parameters are allowed, depending upon the video format; the
restrictions are specified in each document [IEC61834][SMPTE314M]
[SMPTE370M].
A frame of data in the DV format stream is divided into several "DIF
sequences". A DIF sequence is composed of an integral number of
80-byte DIF blocks. A DIF block is the primitive unit for all
treatment of DV streams. Each DIF block contains a 3-byte ID header
that specifies the type of the DIF block and its position in the DIF
sequence. Five types of DIF blocks are defined: DIF sequence header,
Subcode, Video Auxiliary (VAUX) information, Audio, and Video. Audio
DIF blocks are composed of 5 bytes of Audio Auxiliary (AAUX) data and
72 bytes of audio data.
Kobayashi, et al. Standards Track [Page 4]
RFC 6469 RTP Payload Format for DV Video December 2011
Each RTP packet starts with the RTP header as defined in RFC 3550
[RFC3550]. No additional payload-format-specific header is required
for this payload format.
2.2. RTP Header Usage
The RTP header fields that have a meaning specific to the DV format
are described as follows:
Payload type (PT): The payload type is dynamically assigned by means
outside the scope of this document. If multiple DV encoding formats
are to be used within one RTP session, then multiple dynamic payload
types MUST be assigned, one for each DV encoding format. The sender
MUST change to the corresponding payload type whenever the encoding
format is changed.
Timestamp: 32-bit 90 kHz timestamp representing the time at which the
first data in the frame was sampled. All RTP packets within the same
video frame MUST have the same timestamp. The timestamp SHOULD
increment by a multiple of the nominal interval for one DV frame
time, as given in the following table:
+----------+----------------+---------------------------------------+
| Mode | Frame rate | Increase of 90 kHz timestamp per DV |
| | (Hz) | frame |
+----------+----------------+---------------------------------------+
| 525-60 | 29.97 | 3003 |
| 625-50 | 25 | 3600 |
| 1125-60 | 30 | 3000 |
| 1250-50 | 25 | 3600 |
| 1080-60i | 29.97 | 3003 |
| 1080-50i | 25 | 3600 |
| 720-60p | 59.94 | 3003(*) |
| 720-50p | 50 | 3600(*) |
+----------+----------------+---------------------------------------+
(*) Note that even in the 720-line DV system, the data in two video
frames shall be processed within one DV frame duration of the 1080-
line system. Audio data and subcode data in the 720-line system are
processed in the same way as the 1080-line system. Therefore, in the
720-line system, the timestamp increase given in the third column
corresponds to two video frames time.
Marker bit (M): The marker bit of the RTP fixed header is set to one
on the last packet of a video frame; on other packets, it MUST be
zero. The M bit allows the receiver to know that it has received the
last packet of a frame so it can display the image without waiting
for the first packet of the next frame to arrive to detect the frame
Kobayashi, et al. Standards Track [Page 5]
RFC 6469 RTP Payload Format for DV Video December 2011
change. However, detection of a frame change MUST NOT rely on the
marker bit since the last packet of the frame might be lost.
Detection of a frame change MUST be based on a difference in the RTP
timestamp.
2.3. Payload Structures
Integral DIF blocks are placed into the RTP payload beginning
immediately after the RTP header. Any number of DIF blocks may be
packed into one RTP packet, but all DIF blocks in one RTP packet MUST
be from the same video frame. DIF blocks from the next video frame
MUST NOT be packed into the same RTP packet even if more payload
space remains. This requirement stems from the fact that the
transition from one video frame to the next is indicated by a change
in the RTP timestamp. It also reduces the processing complexity on
the receiver. Since the RTP payload contains an integral number of
DIF blocks, the length of the RTP payload will be a multiple of 80
bytes.
Audio and video data may be transmitted as one bundled RTP stream or
in separate RTP streams (unbundled). The choice MUST be indicated as
part of the assignment of the dynamic payload type and MUST remain
unchanged for the duration of the RTP session to avoid complicated
procedures of sequence number synchronization. The RTP sender could
omit the DIF sequence header and subcode DIF blocks from a stream
when the information either is known from out-of-band sources or is
not required for the application. Note that time code in DIF blocks
is mandatory for professional video applications. When unbundled
audio and video streams are sent, any DIF sequence header and subcode
DIF blocks MUST be included and sent in the video stream.
DV streams include "source" and "source control" packs that carry
information indispensable for proper decoding, such as video signal
type, frame rate, aspect ratio, picture position, quantization of
audio sampling, number of audio samples in a frame, number of audio
channels, audio channel assignment, and language of the audio.
However, describing all of these attributes with a signaling protocol
would require large descriptions to enumerate all the combinations.
Therefore, no Session Description Protocol (SDP) [RFC4566] parameters
for these attributes are defined in this document. Instead, the RTP
sender MUST transmit at least those VAUX (Video Auxiliary) DIF blocks
and/or audio DIF blocks with AAUX (Audio Auxiliary) information bytes
that include "source" and "source control" packs containing the
indispensable information for decoding.
In the case of one bundled stream, DIF blocks for both audio and
video are packed into RTP packets in the same order as they were
encoded.
Kobayashi, et al. Standards Track [Page 6]
RFC 6469 RTP Payload Format for DV Video December 2011
In the case of an unbundled stream, only the header, subcode, video,
and VAUX DIF blocks are sent within the video stream. Audio is sent
in a different stream if desired, using a different RTP payload type.
It is also possible to send audio duplicated in a separate stream, in
addition to bundling it in with the video stream.
When using unbundled mode, it is RECOMMENDED that the audio stream
data be extracted from the DIF blocks and repackaged into the
corresponding RTP payload format for the audio encoding (DAT12, L16,
L20) [RFC3551][RFC3190] in order to maximize interoperability with
non-DV-capable receivers while maintaining the original source
quality.
In the case of unbundled transmission that is compelled to use both
audio and video in the DV format, the same timestamp SHOULD be used
for both audio and video data within the same frame to simplify the
lip synchronization effort on the receiver. Lip synchronization may
also be achieved using reference timestamps passed in RTP Control
Protocol (RTCP) as described in [RFC3550]. In this case, the audio
stream uses the 90 kHz clock rate, and the timestamp uses the same
clock rate as the video.
The sender MAY reduce the video frame rate by discarding the video
data and VAUX DIF blocks for some of the video frames. The RTP
timestamp MUST still be incremented to account for the discarded
frames. The sender MAY alternatively reduce bandwidth by discarding
video data DIF blocks for portions of the image that are unchanged
from the previous image. To enable this bandwidth reduction,
receivers SHOULD implement an error-concealment strategy to
accommodate lost or missing DIF blocks, e.g., repeating the
corresponding DIF block from the previous image.
3. Payload Format Parameters
This section specifies the parameters that MAY be used to select
optional features of the payload format and certain features of the
bitstream. The parameters are specified here as part of the media
type registration for the DV encoding. A mapping of the parameters
into the Session Description Protocol (SDP) [RFC4566] is also
provided for applications that use SDP. Equivalent parameters could
be defined elsewhere for use with control protocols that do not use
SDP.
3.1. Media Type Registration
This registration is done using the template defined in RFC 4288
[RFC4288] and following RFC 4855 [RFC4855].
Kobayashi, et al. Standards Track [Page 7]
RFC 6469 RTP Payload Format for DV Video December 2011
3.1.1. Media Type Registration for DV Video
Type name: video
Subtype name: DV
Required parameters:
encode: type of DV format. Permissible values for encode are:
SD-VCR/525-60
SD-VCR/625-50
HD-VCR/1125-60
HD-VCR/1250-50
SDL-VCR/525-60
SDL-VCR/625-50
314M-25/525-60
314M-25/625-50
314M-50/525-60
314M-50/625-50
370M/1080-60i
370M/1080-50i
370M/720-60p
370M/720-50p
306M/525-60 (for backward compatibility)
306M/625-50 (for backward compatibility)
Optional parameters:
audio: whether the DV stream includes audio data or not.
Permissible values for audio are bundled and none. Defaults to
none.
Encoding considerations:
DV video can be transmitted with RTP as specified in RFC 6469
(this document). Other transport methods are not specified.
Security considerations:
See Section 4 of RFC 6469 (this document).
Interoperability considerations: Interoperability with previous
implementations is discussed in Section 8.
Kobayashi, et al. Standards Track [Page 8]
RFC 6469 RTP Payload Format for DV Video December 2011
Public specifications:
IEC 61834 Standard
SMPTE 314M
SMPTE 370M
RFC 6469 (this document)
SMPTE 306M (for backward compatibility)
Applications that use this media type: Audio and video streaming and
conferencing tools.
Additional information: NONE
Person & email address to contact for further information:
Katsushi Kobayashi
ikob@riken.jp
Intended usage: COMMON
Restrictions on usage: This media type depends on RTP framing and
hence is only defined for transfer via RTP [RFC3550]. Transfer
within other framing protocols is not defined at this time.
Author:
Katsushi Kobayashi
Change controller:
IETF Audio/Video Transport working group delegated from the
IESG
3.1.2. Media Type Registration for DV Audio
Type name: audio
Subtype name: DV
Required parameters:
encode: type of DV format. Permissible values for encode are:
SD-VCR/525-60
SD-VCR/625-50
HD-VCR/1125-60
HD-VCR/1250-50
SDL-VCR/525-60
SDL-VCR/625-50
Kobayashi, et al. Standards Track [Page 9]
RFC 6469 RTP Payload Format for DV Video December 2011
314M-25/525-60
314M-25/625-50
314M-50/525-60
314M-50/625-50
370M/1080-60i
370M/1080-50i
370M/720-60p
370M/720-50p
306M/525-60 (for backward compatibility)
306M/625-50 (for backward compatibility)
Optional parameters:
audio: whether the DV stream includes audio data or not.
Permissible values for audio are bundled and none. Defaults to
none.
Encoding considerations:
DV audio can be transmitted with RTP as specified in RFC 6469
(this document). Other transport methods are not specified.
Security considerations:
See Section 4 of RFC 6469 (this document).
Interoperability considerations: Interoperability with previous
implementations is discussed in Section 8.
Published specifications:
IEC 61834 Standard
SMPTE 314M
SMPTE 370M
RFC 6469 (this document)
SMPTE 306M (for backward compatibility).
Applications that use this media type: Audio and video streaming and
conferencing tools.
Additional information: NONE
Person & email address to contact for further information:
Katsushi Kobayashi
ikob@riken.jp
Intended usage: COMMON
Kobayashi, et al. Standards Track [Page 10]
RFC 6469 RTP Payload Format for DV Video December 2011
Restrictions on usage: This media type depends on RTP framing and
hence is only defined for transfer via RTP [RFC3550]. Transfer
within other framing protocols is not defined at this time.
Author:
Katsushi Kobayashi
Change controller:
IETF Audio/Video Transport working group delegated from the
IESG
3.2. SDP Parameters
3.2.1. Mapping of Payload Type Parameters to SDP
The information carried in the media type specification has a
specific mapping to fields in the Session Description Protocol (SDP),
which is commonly used to describe RTP sessions. When SDP is used to
specify sessions employing the DV encoding, the mapping is as
follows:
o The media type ("video") goes in SDP "m=" as the media name.
o The media subtype ("DV") goes in SDP "a=rtpmap" as the encoding
name. The RTP clock rate in "a=rtpmap" MUST be 90000, which for
the payload format defined in this document is a 90 kHz clock.
o Any remaining parameters go in the SDP "a=fmtp" attribute by
copying them directly from the media type string as a semicolon-
separated list of parameter=value pairs.
In the DV video payload format, the "a=fmtp" line will be used to
show the encoding type within the DV video and will be used as below:
a=fmtp:<payload type> encode=<DV-video encoding>
The required parameter "encode" specifies which type of DV format is
used. The DV format name will be one of the following values:
SD-VCR/525-60
SD-VCR/625-50
HD-VCR/1125-60
HD-VCR/1250-50
SDL-VCR/525-60
SDL-VCR/625-50
314M-25/525-60
Kobayashi, et al. Standards Track [Page 11]
RFC 6469 RTP Payload Format for DV Video December 2011
314M-25/625-50
314M-50/525-60
314M-50/625-50
370M/1080-60i
370M/1080-50i
370M/720-60p
370M/720-50p
306M/525-60 (for backward compatibility)
306M/625-50 (for backward compatibility)
In order to show whether or not the audio data is bundled into the DV
stream, a format-specific parameter is defined:
a=fmtp:<payload type> encode=<DV-video encoding> audio=<audio
bundled>
The optional parameter "audio" will be one of the following values:
bundled
none (default)
If the fmtp "audio" parameter is not present, then audio data MUST
NOT be bundled into the DV video stream.
3.2.2. Usage with the SDP Offer/Answer Model
The following considerations apply when using SDP offer/answer
procedures [RFC3264] to negotiate the use of the DV payload in RTP:
o The "encode" parameter can be used for sendrecv, sendonly, and
recvonly streams. Each encode type MUST use a separate payload
type number.
o Any unknown parameter in an offer MUST be ignored by the receiver
and MUST NOT be included in the answer.
In an offer for unbundled streams, the group attribute as defined in
the Session Description Protocol (SDP) Grouping Framework [RFC5888]
can be used in order to associate the related audio and video. The
example usage of SDP grouping is detailed in [RFC5888].
3.3. Examples
Some example SDP session descriptions utilizing DV encoding formats
follow.
Kobayashi, et al. Standards Track [Page 12]
RFC 6469 RTP Payload Format for DV Video December 2011
3.3.1. Example for Unbundled Streams
When using unbundled mode, the RTP streams for video and audio will
be sent separately to different ports or different multicast groups.
When unbundled audio and video streams are sent, SDP carries several
"m=" lines, one for each media type of the session (see [RFC4566]).
An example SDP description using these attributes is:
v=0
o=ikob 2890844526 2890842807 IN IP4 192.0.2.1
s=POI Seminar
i=A Seminar on how to make Presentations on the Internet
u=http://www.example.net/~ikob/POI/index.html
e=ikob@example.net (Katsushi Kobayashi)
c=IN IP4 233.252.0.1/127
t=2873397496 2873404696
m=audio 49170 RTP/AVP 112
a=rtpmap:112 L16/32000/2
m=video 50000 RTP/AVP 113
a=rtpmap:113 DV/90000
a=fmtp:113 encode=SD-VCR/525-60 audio=none
This describes a session where audio and video streams are sent
separately. The session is sent to a multicast group 233.252.0.1.
The audio is sent using L16 format, and the video is sent using
SD-VCR 525/60 format, which corresponds to NTSC format in consumer
DV.
3.3.2. Example for Bundled Streams
When sending a bundled stream, all the DIF blocks including system
data will be sent through a single RTP stream.
An example SDP description for a bundled DV stream is:
v=0
o=ikob 2890844526 2890842807 IN IP4 192.0.2.1
s=POI Seminar
i=A Seminar on how to make Presentations on the Internet
u=http://www.example.net/~ikob/POI/index.html
e=ikob@example.net (Katsushi Kobayashi)
c=IN IP4 233.252.0.1/127
t=2873397496 2873404696
m=video 49170 RTP/AVP 112 113
a=rtpmap:112 DV/90000
a=fmtp:112 encode=SD-VCR/525-60 audio=bundled
a=fmtp:113 encode=314M-50/525-60 audio=bundled
Kobayashi, et al. Standards Track [Page 13]
RFC 6469 RTP Payload Format for DV Video December 2011
This SDP record describes a session where audio and video streams are
sent bundled. The session is sent to a multicast group 233.252.0.1.
The video is sent using both 525/60 consumer DV and SMPTE standard
314M 50 Mbit/s formats, when the payload type is 112 and 113,
respectively.
4. Security Considerations
RTP packets using the payload format defined in this specification
are subject to the security considerations discussed in the RTP
specification [RFC3550] and any appropriate RTP profile. This
implies that confidentiality of the media streams is achieved by
encryption. Because the data compression used with this payload
format is applied end-to-end, encryption may be performed after
compression so there is no conflict between the two operations.
A potential denial-of-service threat exists for data encodings using
compression techniques that have non-uniform receiver-end
computational load. The attacker can inject pathological datagrams
into the stream that are complex to decode and cause the receiver to
be overloaded. However, this encoding does not exhibit any
significant non-uniformity.
As with any IP-based protocol, in some circumstances, a receiver may
be overloaded simply by the receipt of too many packets, either
desired or undesired. Network-layer authentication may be used to
discard packets from undesired sources, but the processing cost of
the authentication itself may be too high. In a multicast
environment, mechanisms for joining and pruning of specific sources
are specified in IGMPv3, Multicast Listener Discovery Version 2
(MLDv2) [RFC3376][RFC3810] or Lightweight-IGMPv3 (LW-IGMPv3),
LW-MLDv2 [RFC5790] and in multicast routing protocols to allow a
receiver to select which sources are allowed to reach it [RFC4607].
5. Congestion Control
The general congestion control considerations for transporting RTP
data apply; see RTP [RFC3550] and any applicable RTP profile like
Audio-Visual Profile (AVP) [RFC3551].
6. IANA Considerations
This document obsoletes [RFC3189], and some registration forms have
been updated by this document. The registration forms (based on the
RFC 4855 [RFC4855] definition) for the media types for both video and
audio are shown in Section 3.1.
Kobayashi, et al. Standards Track [Page 14]
RFC 6469 RTP Payload Format for DV Video December 2011
7. Major Changes from RFC 3189
The changes from [RFC3189] are:
1. Specified that support for SMPTE 306M is only for backward
interoperability, since it is covered by SMPTE 314M format.
2. Added SMPTE 370M 100 Mbit/s High Definition Television (HDTV)
(1080/60i, 1080/50i, 720/60p, and 720/50p) format.
3. Incorporated the Source-Specific Multicast (SSM) specification
for avoiding overloaded traffic source in multicast usage. Added
a reference to the Source-Specific Multicast (SSM) specification
as a way to reduce unwanted traffic in a multicast application.
4. Clarified the case where a sender omits subcode DIF block data
from the stream.
5. Added considerations for the offer/answer model.
6. Revised media types registration form based on new registration
rule [RFC4855].
8. Interoperability with Previous Implementations
In this section, we discuss interoperability with implementations
based on [RFC3189], which is obsoleted by this document.
[RFC3189] regards SMPTE 306M [SMPTE306M] and SMPTE 314M [SMPTE314M]
as different encoding formats, although the format of SMPTE 306M is
already covered by SMPTE 314M. Therefore, this document recommends
that the definition depending on SMPTE 306M SHOULD NOT be used, and
SMPTE 314M SHOULD be used instead. An RTP application could handle a
stream identified in SMPTE 306M encoding as SMPTE 314M encoding
instead.
An offer MAY include SMPTE 306M encoding coming from a legacy system,
and receivers SHOULD support this value.
If an initial offer that did not include SMPTE 306M was rejected, the
offerer MAY try a new offer with SMPTE 306M. For this case, an RTP
application MAY handle a stream identified in SMPTE 306M encoding as
SMPTE 314M encoding instead.
In addition, the SDP examples in [RFC3189] provide incorrect SDP
"a=fmtp" attribute usage.
Kobayashi, et al. Standards Track [Page 15]
RFC 6469 RTP Payload Format for DV Video December 2011
9. Acknowledgment
Thanks to Akimichi Ogawa, a former author of this document.
10. References
10.1. Normative References
[IEC61834] IEC, "IEC 61834, Helical-scan digital video cassette
recording system using 6,35 mm magnetic tape for
consumer use (525-60, 625-50, 1125-60 and 1250-50
systems)".
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3190] Kobayashi, K., Ogawa, A., Casner, S., and C. Bormann,
"RTP Payload Format for 12-bit DAT Audio and 20- and
24-bit Linear Sampled Audio", RFC 3190, January 2002.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer
Model with Session Description Protocol (SDP)",
RFC 3264, June 2002.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, July 2003.
[RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio
and Video Conferences with Minimal Control", STD 65,
RFC 3551, July 2003.
[RFC4288] Freed, N. and J. Klensin, "Media Type Specifications
and Registration Procedures", BCP 13, RFC 4288,
December 2005.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP:
Session Description Protocol", RFC 4566, July 2006.
[RFC4855] Casner, S., "Media Type Registration of RTP Payload
Formats", RFC 4855, February 2007.
[RFC5888] Camarillo, G. and H. Schulzrinne, "The Session
Description Protocol (SDP) Grouping Framework",
RFC 5888, June 2010.
[SMPTE306M] SMPTE, "SMPTE 306M, 6.35-mm Type D-7 Component Format
- Video Compression at 25Mb/s - 525/60 and 625/50".
Kobayashi, et al. Standards Track [Page 16]
RFC 6469 RTP Payload Format for DV Video December 2011
[SMPTE314M] SMPTE, "SMPTE 314M, Data Structure for DV-Based Audio
and Compressed Video - 25 and 50Mb/s".
[SMPTE370M] SMPTE, "SMPTE 370M, Data Structure for DV-Based
Audio, Data and Compressed Video at 100 Mb/s 1080/
60i, 1080/50i, 720/60p, and 720/50p".
10.2. Informative References
[IEC61883] IEC, "IEC 61883, Consumer audio/video equipment -
Digital interface".
[IEEE1394] IEEE, "IEEE Std 1394-1995, Standard for a High
Performance Serial Bus".
[ISO/IEC11172] ISO/IEC, "ISO/IEC 11172, Coding of moving pictures
and associated audio for digital storage media up to
about 1,5 Mbit/s".
[ISO/IEC13818] ISO/IEC, "ISO/IEC 13818, Generic coding of moving
pictures and associated audio information".
[RFC2250] Hoffman, D., Fernando, G., Goyal, V., and M.
Civanlar, "RTP Payload Format for MPEG1/MPEG2 Video",
RFC 2250, January 1998.
[RFC3189] Kobayashi, K., Ogawa, A., Casner, S., and C. Bormann,
"RTP Payload Format for DV (IEC 61834) Video",
RFC 3189, January 2002.
[RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and
A. Thyagarajan, "Internet Group Management Protocol,
Version 3", RFC 3376, October 2002.
[RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery
Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.
[RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast
for IP", RFC 4607, August 2006.
[RFC5790] Liu, H., Cao, W., and H. Asaeda, "Lightweight
Internet Group Management Protocol Version 3 (IGMPv3)
and Multicast Listener Discovery Version 2 (MLDv2)
Protocols", RFC 5790, February 2010.
Kobayashi, et al. Standards Track [Page 17]
RFC 6469 RTP Payload Format for DV Video December 2011
Authors' Addresses
Katsushi Kobayashi
Advanced Institute for Computational Science, RIKEN
7-1-26 Minatojima-minami
Chuo-ku, Kobe, Hyogo 760-0045
Japan
EMail: ikob@riken.jp
Kazuhiro Mishima
Keio University
5322 Endo
Fujisawa, Kanagawa 252-8520
Japan
EMail: three@sfc.wide.ad.jp
Stephen L. Casner
Packet Design
2455 Augustine Drive
Santa Clara, CA 95054
United States
EMail: casner@acm.org
Carsten Bormann
Universitaet Bremen TZI
Postfach 330440
D-28334, Bremen
Germany
Phone: +49 421 218 63921
Fax: +49 421 218 7000
EMail: cabo@tzi.org
Kobayashi, et al. Standards Track [Page 18]