Internet DRAFT - draft-lugan-payload-rtp-jpegxs
draft-lugan-payload-rtp-jpegxs
Payload Working Group S. Lugan
Internet-Draft G. Rouvroy
Intended status: Standards Track A. Descampe
Expires: May 12, 2019 intoPIX
T. Richter
IIS
A. Willeme
UCL/ICTEAM
November 8, 2018
RTP Payload Format for ISO/IEC 21122 (JPEG XS)
draft-lugan-payload-rtp-jpegxs-01
Abstract
This document specifies a Real-Time Transport Protocol (RTP) payload
format to be used for transporting JPEG XS (ISO/IEC 21122) encoded
video. JPEG XS is a low-latency, lightweight image coding system
allowing for an increased resolution and frame rate, while offering
visually lossless quality with reduced amount of resources such as
power and bandwidth.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 12, 2019.
Copyright Notice
Copyright (c) 2018 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
(https://trustee.ietf.org/license-info) in effect on the date of
Lugan, et al. Expires May 12, 2019 [Page 1]
Internet-Draft RTP Payload Format for JPEG XS November 2018
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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions, Definitions, and Abbreviations . . . . . . . . . 3
3. Media Format Description . . . . . . . . . . . . . . . . . . 4
3.1. Image Data Structures . . . . . . . . . . . . . . . . . . 4
3.2. Codestream . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. Video Support Box . . . . . . . . . . . . . . . . . . . . 6
4. Payload Format . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Payload Header . . . . . . . . . . . . . . . . . . . . . 7
4.2. Payload Data . . . . . . . . . . . . . . . . . . . . . . 9
4.3. Traffic Shaping and Delivery Timing . . . . . . . . . . . 10
5. Congestion Control Considerations . . . . . . . . . . . . . . 10
6. Payload Format Parameters . . . . . . . . . . . . . . . . . . 11
6.1. Media Type Definition . . . . . . . . . . . . . . . . . . 11
6.2. Mapping to SDP . . . . . . . . . . . . . . . . . . . . . 14
6.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 14
6.2.2. Media type and subtype . . . . . . . . . . . . . . . 14
6.2.3. Traffic shaping . . . . . . . . . . . . . . . . . . . 15
6.2.4. Offer/Answer Considerations . . . . . . . . . . . . . 15
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
8. Security Considerations . . . . . . . . . . . . . . . . . . . 15
9. RFC Editor Considerations . . . . . . . . . . . . . . . . . . 16
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
10.1. Normative References . . . . . . . . . . . . . . . . . . 16
10.2. Informative References . . . . . . . . . . . . . . . . . 18
10.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction
This document specifies a payload format for packetization of JPEG XS
encoded video signals into the Real-time Transport Protocol (RTP)
[RFC3550].
JPEG XS is a low-latency, lightweight image coding system allowing
for an increased resolution and frame rate, while offering visually
lossless quality with reduced amount of resources such as power and
bandwidth.
Lugan, et al. Expires May 12, 2019 [Page 2]
Internet-Draft RTP Payload Format for JPEG XS November 2018
2. Conventions, Definitions, and Abbreviations
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].
Application Data Unit:
The unit of source data provided as payload to the transport
layer, and corresponding, in this RTP payload definition, to a
JPEG XS frame.
EOC Marker
A marker that consists of the two bytex 0xff 0x10 indicating the
start of a JPEG XS codestream.
JPEG XS codestream:
A sequence of bytes representing a compressed image formatted
according to JPEG XS Part 1 [ISO21122-1].
JPEG XS frame:
The concatenation of a Video Support Box, as defined in JPEG XS
Part 3 [ISO21122-3], and a JPEG XS codestream.
JPEG XS stream:
A JPEG XS stream is a sequence of frames, where each frame is
coded independently of each other. For the purpose of RTP
transport, each frame forms an Application Data Unit (ADU).
Marker:
A two-byte functional sequence that is part of a JPEG XS
codestream starting with a 0xff byte and a subsequent byte
defining its function.
Marker Segment:
A marker along with a 16-bit marker size and payload data
following the size.
JPEG XS Header:
A sequence of bytes at the beginning of each JPEG XS codestream
encoded in multiple markers and marker segments that does not
carry entropy coded data, but metadata such as the frame dimension
and component precision.
SOC Marker
A marker that consists of the two bytex 0xff 0x11 indicating the
end of a JPEG XS codestream.
Video Support Box:
Lugan, et al. Expires May 12, 2019 [Page 3]
Internet-Draft RTP Payload Format for JPEG XS November 2018
A ISO video support box in the sense of ISO/IEC 15444-1
[ISO15444-1] defined in ISO/IEC 21122-3 [ISO21122-3] that includes
metadata required to play back a JPEG XS video stream, such as its
color space, its maximum bitrate, its subsampling structure, its
buffer model and its frame rate.
JPEG XS Header Segment:
The concatenation of a Video Support Box and JPEG XS header.
Slice:
The smallest independently decodable unit of a JPEG XS codestream,
bearing in mind that it decodes to wavelet coefficients which
still require inverse wavelet filtering to give an image.
Slice group:
A contiguous sequence of slices.
Fragment:
A fragment consists of one slice group, possibly preceded by a
JPEG XS header segment (if the slice group is the first one of a
JPEG XS frame), and possibly followed by the EOC marker (if the
slice group is the last one of a JPEG XS frame).
3. Media Format Description
3.1. Image Data Structures
JPEG XS is a low-latency lightweight image coding system for coding
continuous-tone grayscale or continuous-tone color digital images.
This coding system provides an efficient representation of image
signals through the mathematical tool of wavelet analysis. The
wavelet filter process separates each component into multiple bands,
where each band consists of multiple coefficients describing the
image signal of a given component within a frequency domain specific
to the wavelet filter type, i.e. the particular filter corresponding
to the band.
Wavelet coefficients are grouped into precincts, where each precinct
includes all coefficients over all bands that contribute to a spatial
region of the image.
One or multiple precincts are furthermore combined into slices
consisting of an integral number of precincts. Precincts do not
cross slice boundaries, and wavelet coefficients in precincts that
are part of different slices can be decoded independently from each
other. Note, however, that the wavelet transformation runs across
Lugan, et al. Expires May 12, 2019 [Page 4]
Internet-Draft RTP Payload Format for JPEG XS November 2018
slice boundaries. A slice always extends over the full width of the
image, but may only cover parts of its height.
Multiple contiguous slices are combined into slice groups. Slice
groups along with preceding and/or following metadata form fragments.
A fragment, and by that the corresponding slice group, is sized such
that it is spread over at least two distinct RTP packets, except for
the last fragment of an Application Data Unit.
Slice groups within a frame are enumerated from top to bottom by the
slice group counter. That is, the first slice group of a frame is
slice group #0, and the slice group counter increments by 1 from top
to bottom for each slice group, and by that for each fragment.
Figure 1 shows an example of packets, slices, slice groups and
fragments. In this Figure, MDT indicates metadata preceding or
following slice groups, SlcGrp the slice groups and Slc the slices.
As seen there, a fragment may contain more than one slice if the
slices are too short to fill up an entire packet, and fragment and
packet boundaries need only to align at the start and the end of the
ADU. Fragments may extend over more than two packets, depending on
their size, but a packet never contains two entire fragments or more.
Slice group and fragment boundaries coincide, except for the first
and the last fragment, which include additional metadata. Unlike
regularly sized packets, the fragment and the slice group size may
vary.
<------------------- Application Data Unit (ADU) ------------------->
+-----------+-----------+-----------+-----------+-/ /-+-------------+
| Packet #0 | Packet #1 | Packet #2 | Packet #3 | | Packet #n-1 |
+-----------+---+-------+-----------+---+-------+-/ /-+-------------+
| Fragment #0 | Fragment #1 | Fragment #m-1 |
+---+-----------+-----------------------+---------/ /-----------+---+
|MDT| SlcGrp #0 | SlcGrp #1 | SlcGrp #m-1 | M |
+---+-----------+-----------------------+---------/ /-----------+---+
|MDT|Slc#0 Slc#1| Slc #2 | Slc #k-1 | M |
+---+-----------+-----------------------+---------/ /-----------+---+
Figure 1: Slice Groups and Fragments
3.2. Codestream
The overall codestream format, including the definition of all
markers, is further defined in ISO/IEC 21122-1 [ISO21122-1]. It
represents sample values of a single frame, bare any interpretation
relative to a colorspace.
Lugan, et al. Expires May 12, 2019 [Page 5]
Internet-Draft RTP Payload Format for JPEG XS November 2018
3.3. Video Support Box
While the information defined in the codestream is sufficient to
reconstruct the sample values of one video frame, the interpretation
of the samples remains undefined by the codestream itself. This
interpretation, including the color space, frame rate and other
information significant to play a JPEG XS stream are contained in the
Video Support Box, which precedes each JPEG XS codestream. The
syntax of the Video Support Box follows ISO/IEC 15444-1 [ISO15444-1];
it consists of multiple subboxes, each with a particular meaning.
Its contents, in particular its subboxes are defined in ISO/IEC
21122-3 [ISO21122-3].
4. Payload Format
This section specifies the payload format for JPEG XS video streams
over the Real-time Transport Protocol (RTP) [RFC3550].
In order to be transported over RTP, each JPEG XS stream is
transported in a distinct RTP stream, identified by a distinct SSRC.
Each of those RTP streams is divided into Application Data Units
(ADUs).
Each ADU is split into packets, depending e.g. on the Maximum
Transmission unit (MTU) of the network. Every packet shall have the
same size, except the last packet of every ADU which could be
shorter. Packet boundaries shall coincide with ADU boundaries, i.e.
the first (resp. last) byte of an ADU shall be the first (resp. last)
byte of an RTP packet payload data.
The following figure illustrates the RTP payload header used in order
to transport a JPEG XS stream.
Lugan, et al. Expires May 12, 2019 [Page 6]
Internet-Draft RTP Payload Format for JPEG XS November 2018
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
+---+-+-+-------+-+-------------+-------------------------------+
| V |P|X| CC |M| PT | Sequence number |
+---+-+-+-------+-+-------------+-------------------------------+
| Timestamp |
+---------------------------------------------------------------+
| Synchronization source (SSRC) identifier |
+===============================================================+
| Contributing source (CSRC) identifiers |
| .... |
+-----+-+-+---------+---------------------+---------------------+
| Ver |f|c| SlcGrp | SlcGrpOffset | Frame counter |
+-----+-+-+---------+---------------------+---------------------+
| Data |
+---------------------------------------------------------------+
Figure 2: RTP and payload headers
4.1. Payload Header
The version (V), padding (P), extension (X), CSRC count (CC),
sequence number, synchronization source (SSRC) and contributing
source (CSRC) fields follow their respective definitions in RFC 3550
[RFC3550].
The timestamp should be based on a globally synchronized 90 kHz clock
reference, and should correspond to the number of cycles since the
SMPTE Epoch (as per defined in SMPTE ST 2059-1:2015 [SMPTE-ST2059])
modulo 2^32:
timestamp = floor(time_since_epoch*90000) % 2^32
where time_since_epoch is the time elapsed since the SMPTE Epoch,
expressed in seconds as a real number, and floor indicates rounding
to the next lower integer.
As per specified in RFC 3550 [RFC3550] and RFC 4175 [RFC4175], the
RTP timestamp designates the sampling instant of the first octet of
the frame to which the RTP packet belongs. Packets shall not include
data from multiple frames, and all packets belonging to the same
frame shall have the same timestamp. Several successive RTP packets
will consequently have equal timestamps if they belong to the same
frame (that is until the marker bit is set to 1, marking the last
packet of the frame), and the timestamp is only increased when a new
frame begins.
Lugan, et al. Expires May 12, 2019 [Page 7]
Internet-Draft RTP Payload Format for JPEG XS November 2018
If the sampling instant does not correspond to an integer value of
the clock, the value shall be truncated to the next lowest integer,
with no ambiguity.
The remaining fields are defined as follows:
Marker (M) [1 bit]:
The marker bit is used to indicate the last packet of a frame.
This enables a decoder to finish decoding the frame, where it
otherwise may need to wait for the next packet to explicitly know
that the frame is finished.
Payload Type (PT) [7 bits]:
A dynamically allocated payload type field that designates the
payload as JPEG XS video.
Ver [3 bits]:
This field indicates the version number of the payload header.
The value of this field shall be 0 for the purpose of this edition
of the RFC.
f [1 bit]:
The f field shall be set if a new fragment is started within this
packet, i.e. if this packet contains the first byte of a fragment.
NOTE: The JPEG XS header segment and the first slice group form a
fragment. For that reason, the f-bit remains unset in the packet
that contains the first byte of slice group 0 but does not also
contains the first byte of the Video Support box. All other slice
groups form fragments of their own. The f bit allows a quick
identification of packets that start a fragment. The SlcGrpOffset
field (see below) can be used to identify the start of a slice
group.
c [1 bit]:
The c field is a one-bit field that is set if the fragment to
which the first byte of the packet belongs extends througout a
subsequent packet.
SlcGrp [5 bits]:
The SlcGrp (Slice Group) field contains the slice group index
modulo 32 that is contained in the fragment that is started in
this packet. If no fragment starts in this packet, it contains
the slice group index modulo 64 of the slice group that is
contained in the fragment to which the first byte of the payload
data of this packet belongs.
SlcGrpOffset [11 bits]:
Lugan, et al. Expires May 12, 2019 [Page 8]
Internet-Draft RTP Payload Format for JPEG XS November 2018
This field indicates the byte offset of the slice header marker
(SLH, hex 0xff20, see ISO/IEC 21122-1 [ISO21122-1]) of the slice
group that starts in this packet, relative to the Ver field. If
no slice group starts in this packet, this field shall be 0.
NOTE: Since the payload data has a non-zero offset within a
packet, this field can also be used to identify whether a slice
group starts in a packet. If 0, no slice group starts in this
packet. Consequently, for all slice groups in a frame except the
first one, this field will be non-zero if and only if the f-field
is set.
Frame counter [11 bits]:
Counter indicating the current frame number modulo 2^11. The
frame number is incremented by one at the beginning of each frame,
and stays constant throughout all packets that contribute to to
the same frame.
4.2. Payload Data
The payload data of a JPEG XS transport stream consists of a
concatenation of multiple JPEG XS Frames.
Each JPEG XS frame is the concatenation of multiple fragments where
each fragment contains one and only one slice group. The first
fragment of a frame also contains the Video Support box and the JPEG
XS header, the last fragment also contains the EOC marker. Figure 3
depicts this layout.
^ +-------------------------------------------+ ^
| | Video Support Box | |
| | +-------------------------------------+ | |
| | | Sub boxes of the Video Support Box | | |
Frag- | +-------------------------------------+ | JPEG
ment | : additional sub-boxes of the VE-Box : | XS
#0 | +-------------------------------------+ | Header
| | | Seg-
| +-------------------------------------------+ ment
| | JPEG XS Header | |
| | +-------------------------------------+ | |
| | | SOC Marker | | |
| | +-------------------------------------+ | |
| | : Additional Marker Segments : | |
| | +-------------------------------------+ | |
| | | |
| +-------------------------------------------+ v
| | Slice Group #0 |
| | +-------------------------------------+ |
Lugan, et al. Expires May 12, 2019 [Page 9]
Internet-Draft RTP Payload Format for JPEG XS November 2018
| | | Slice #0 of Slice Group #0 | |
| | | +-------------------------------+ | |
| | | | SLH Marker | | |
| | | +-------------------------------+ | |
| | | : Entropy Coded Data : | |
| | | +-------------------------------+ | |
| | +-------------------------------------+ |
| | | Slice #1 of Slice Group #0 | |
| | : : |
| | +-------------------------------------+ |
| | | Slice #n-1 of Slice Group #0 | |
| | : : |
v | +-------------------------------------+ |
^ +-------------------------------------------+
| | Slice Group #1 |
Frag- : :
ment : :
#1 : :
| : :
v +-------------------------------------------+
: :
^ +-------------------------------------------+
| | Slice Group #n-1 |
Frag- : :
ment : :
#n-1 +-------------------------------------------+
| | EOC Marker |
v +-------------------------------------------+
Figure 3: JPEG XS Payload Data
4.3. Traffic Shaping and Delivery Timing
The traffic shaping and delivery timing shall be in accordance with
the Network Compatibility Model compliance definitions specified in
SMPTE ST 2110-21 [SMPTE-ST2110-21] for either Narrow Linear Senders
(Type NL) or Wide Senders (Type W).
NOTE: The Virtual Receiver Buffer Model compliance definitions of ST
2110-21 do not apply.
5. Congestion Control Considerations
Congestion control for RTP SHALL be used in accordance with RFC 3550
[RFC3550], and with any applicable RTP profile: e.g., RFC 3551
[RFC3551]. An additional requirement if best-effort service is being
used is users of this payload format MUST monitor packet loss to
ensure that the packet loss rate is within acceptable parameters.
Lugan, et al. Expires May 12, 2019 [Page 10]
Internet-Draft RTP Payload Format for JPEG XS November 2018
Circuit Breakers [RFC8083] is an update to RTP [RFC3550] that defines
criteria for when one is required to stop sending RTP Packet Streams
and applications implementing this standard MUST comply with it. RFC
8085 [RFC8083] provides additional information on the best practices
for applying congestion control to UDP streams.
6. Payload Format Parameters
6.1. Media Type Definition
Type name: video
Subtype name: jpeg-xs
Required parameters:
rate: The RTP timestamp clock rate. Applications using this
payload format SHOULD use a value of 90000.
Optional parameters:
profile: The JPEG XS profile in use, as defined in JPEG XS Part 2
[ISO21122-2].
level: The JPEG XS level in use, as defined in JPEG XS Part 2
[ISO21122-2].
sublevel: The JPEG XS sublevel in use, as defined in JPEG XS Part 2
[ISO21122-2].
sampling: Signals the color difference signal sub-sampling
structure.
Signals utilizing the non-constant luminance Y'C'B C'R signal
format of Recommendation ITU-R BT.601-7, Recommendation ITU-R
BT.709-6, Recommendation ITU-R BT.2020-2, or Recommendation ITU-R
BT.2100 shall use the appropriate one of the following values for
the Media Type Parameter "sampling":
YCbCr-4:4:4 (4:4:4 sampling)
YCbCr-4:2:2 (4:2:2 sampling)
YCbCr-4:2:0 (4:2:0 sampling)
Signals utilizing the Constant Luminance Y'C C'BC C'RC signal
format of Recommendation ITU-R BT.2020-2 shall use the appropriate
one of the following values for the Media Type Parameter
"sampling":
Lugan, et al. Expires May 12, 2019 [Page 11]
Internet-Draft RTP Payload Format for JPEG XS November 2018
CLYCbCr-4:4:4 (4:4:4 sampling)
CLYCbCr-4:2:2 (4:2:2 sampling)
CLYCbCr-4:2:0 (4:2:0 sampling)
Signals utilizing the constant intensity I CT CP signal format of
Recommendation ITU-R BT.2100 shall use the appropriate one of the
following values for the Media Type Parameter "sampling":
ICtCp-4:4:4 (4:4:4 sampling)
ICtCp-4:2:2 (4:2:2 sampling)
ICtCp-4:2:0 (4:2:0 sampling)
Signals utilizing the 4:4:4 R' G' B' or RGB signal format (such as
that of Recommendation ITU-R BT.601, Recommendation ITU-R BT.709,
Recommendation ITU-R BT.2020, Recommendation ITU-R BT.2100, SMPTE
ST 2065-1 or ST 2065-3) shall use the following value for the Media
Type Parameter sampling.
RGB RGB or R' G' B' samples
Signals utilizing the 4:4:4 X' Y' Z' signal format (such as defined
in SMPTE ST 428-1) shall use the following value for the Media Type
Parameter sampling.
XYZ X' Y' Z' samples
Key signals as defined in SMPTE RP 157 shall use the value key for
the Media Type Parameter sampling. The Key signal is represented
as a single component.
KEY samples of the key signal
depth: Determines the number of bits per sample. This is an
integer with typical values including 8, 10, 12, and 16.
width: Determines the number of pixels per line. This is an
integer between 1 and 32767.
height: Determines the number of lines per frame. This is an
integer between 1 and 32767.
exactframerate: Signals the frame rate in frames per second.
Integer frame rates shall be signaled as a single decimal number
(e.g. "25") whilst non-integer frame rates shall be signaled as a
ratio of two integer decimal numbers separated by a "forward-slash"
character (e.g. "30000/1001"), utilizing the numerically smallest
numerator value possible.
Lugan, et al. Expires May 12, 2019 [Page 12]
Internet-Draft RTP Payload Format for JPEG XS November 2018
colorimetry: Specifies the system colorimetry used by the image
samples. Valid values and their specification are:
BT601-5 ITU Recommendation BT.601-5
BT709-2 ITU Recommendation BT.709-2
SMPTE240M SMPTE standard 240M
BT601 as specified in Recommendation ITU-R BT.601-7
BT709 as specified in Recommendation ITU-R BT.709-6
BT2020 as specified in Recommendation ITU-R BT.2020-2
BT2100 as specified in Recommendation ITU-R BT.2100
Table 2 titled "System colorimetry"
ST2065-1 as specified in SMPTE ST 2065-1 Academy Color
Encoding Specification (ACES)
ST2065-3 as specified for Academy Density Exchange
Encoding (ADX) in SMPTE ST 2065-3
XYZ as specified in ISO 11664-1 section titled
"1931 Observer"
Signals utilizing the Recommendation ITU-R BT.2100 colorimetry
should also signal the representational range using the optional
parameter RANGE defined below.
interlace: If this OPTIONAL parameter name is present, it indicates
that the video is interlaced. If this parameter name is not
present, the progressive video format shall be assumed.
TCS: Transfer Characteristic System. This parameter specifies the
transfer characteristic system of the image samples. Valid values
and their specification are:
SDR (Standard Dynamic Range) Video streams of standard
dynamic range, that utilize the OETF of Recommendation
ITU-R BT.709 or Recommendation ITU-R BT.2020. Such
streams shall be assumed to target the EOTF specified
in ITU-R BT.1886.
PQ Video streams of high dynamic range video that utilize
the Perceptual Quantization system of Recommendation
ITU-R BT.2100
HLG Video streams of high dynamic range video that utilize
the Hybrid Log-Gamma system of Recommendation ITU-R
BT.2100
RANGE: This parameter should be used to signal the encoding range
of the sample values within the stream. When paired with ITU Rec
BT.2100 colorimetry, this parameter has two allowed values NARROW
and FULL, corresponding to the ranges specified in table 9 of ITU
Rec BT.2100. In any other context, this parameter has three
allowed values: NARROW, FULLPROTECT, and FULL, which correspond to
Lugan, et al. Expires May 12, 2019 [Page 13]
Internet-Draft RTP Payload Format for JPEG XS November 2018
the ranges specified in SMPTE RP 2077. In the absence of this
parameter, NARROW shall be the assumed value in either case.
Encoding considerations:
This media type is framed and binary; see Section 4.8 in RFC 6838
[RFC6838].
Security considerations:
Please see the Security Considerations section in RFC XXXX
6.2. Mapping to SDP
6.2.1. General
A Session Description Protocol (SDP) object shall be created for each
RTP stream and it shall be in accordance with the provisions of SMPTE
ST 2110-10 [SMPTE-ST2110-10].
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.
6.2.2. Media type and subtype
The media type ("video") goes in SDP "m=" as the media name.
The media subtype ("jpeg-xs") 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. The
remaining parameters go in the SDP "a=fmtp" attribute by copying them
directly from the MIME media type string as a semicolon-separated
list of parameter=value pairs.
A sample SDP mapping for JPEG XS video is as follows:
m=video 30000 RTP/AVP 112
a=rtpmap:112 jpeg-xs/90000
a=fmtp:112 sampling=YCbCr-4:2:2; width=1920; height=1080;
depth=10; colorimetry=BT709; TCS=SDR; RANGE=FULL
In this example, a dynamic payload type 112 is used for JPEG XS
video. The RTP sampling clock is 90 kHz. Note that the "a=fmtp:"
line has been wrapped to fit this page, and will be a single long
line in the SDP file.
Lugan, et al. Expires May 12, 2019 [Page 14]
Internet-Draft RTP Payload Format for JPEG XS November 2018
6.2.3. Traffic shaping
The SDP object shall include the TP parameter and may include the
CMAX parameter as specified in SMPTE ST 2110-21 [SMPTE-ST2110-21].
6.2.4. Offer/Answer Considerations
The following considerations apply when using SDP offer/answer
procedures [RFC3264] to negotiate the use of the JPEG XS 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.
7. IANA Considerations
This memo requests that IANA registers video/jpeg-xs as specified in
Section 6.1. The media type is also requested to be added to the
IANA registry for "RTP Payload Format MIME types" [1].
8. 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 in any applicable RTP profile such as
RTP/AVP [RFC3551], RTP/AVPF [RFC4585], RTP/SAVP [RFC3711], or RTP/
SAVPF [RFC5124]. This implies that confidentiality of the media
streams is achieved by encryption.
However, as "Securing the RTP Framework: Why RTP Does Not Mandate a
Single Media Security Solution" [RFC7202] discusses, it is not an RTP
payload format's responsibility to discuss or mandate what solutions
are used to meet the basic security goals like confidentiality,
integrity, and source authenticity for RTP in general. This
responsibility lies on anyone using RTP in an application. They can
find guidance on available security mechanisms and important
considerations in "Options for Securing RTP Sessions" [RFC7201].
Applications SHOULD use one or more appropriate strong security
mechanisms.
This payload format and the JPEG XS encoding do not exhibit any
substantial non-uniformity, either in output or in complexity to
perform the decoding operation and thus are unlikely to pose a
Lugan, et al. Expires May 12, 2019 [Page 15]
Internet-Draft RTP Payload Format for JPEG XS November 2018
denial-of-service threat due to the receipt of pathological
datagrams.
It is important to note that HD or UHDTV JPEG XS-encoded video can
have significant bandwidth requirements (typically more than 1 Gbps
for ultra high-definition video, especially if using high framerate).
This is sufficient to cause potential for denial-of-service if
transmitted onto most currently available Internet paths.
Accordingly, if best-effort service is being used, users of this
payload format MUST monitor packet loss to ensure that the packet
loss rate is within acceptable parameters. Packet loss is considered
acceptable if a TCP flow across the same network path, and
experiencing the same network conditions, would achieve an average
throughput, measured on a reasonable timescale, that is not less than
the RTP flow is achieving. This condition can be satisfied by
implementing congestion control mechanisms to adapt the transmission
rate (or the number of layers subscribed for a layered multicast
session), or by arranging for a receiver to leave the session if the
loss rate is unacceptably high.
This payload format may also be used in networks that provide
quality-of-service guarantees. If enhanced service is being used,
receivers SHOULD monitor packet loss to ensure that the service that
was requested is actually being delivered. If it is not, then they
SHOULD assume that they are receiving best-effort service and behave
accordingly.
9. RFC Editor Considerations
Note to RFC Editor: This section may be removed after carrying out
all the instructions of this section.
RFC XXXX is to be replaced by the RFC number this specification
receives when published.
10. References
10.1. Normative References
[ISO15444-1]
International Organization for Standardization (ISO) -
International Electrotechnical Commission (IEC),
"Information technology - JPEG 2000 image coding system:
Core coding system", ISO/IEC IS 15444-1, 2016,
<https://www.iso.org/standard/70018.html>.
Lugan, et al. Expires May 12, 2019 [Page 16]
Internet-Draft RTP Payload Format for JPEG XS November 2018
[ISO21122-1]
International Organization for Standardization (ISO) -
International Electrotechnical Commission (IEC),
"Information technology - Low-latency lightweight image
coding system - Part 1: Core coding system", ISO/IEC DIS
21122-1, under development,
<https://www.iso.org/standard/74535.html>.
[ISO21122-2]
International Organization for Standardization (ISO) -
International Electrotechnical Commission (IEC),
"Information technology - Low-latency lightweight image
coding system - Part 2: Profiles and buffer models", ISO/
IEC DIS 21122-2, under development,
<https://www.iso.org/standard/74535.html>.
[ISO21122-3]
International Organization for Standardization (ISO) -
International Electrotechnical Commission (IEC),
"Information technology - Low-latency lightweight image
coding system - Part 3: Transport and container formats",
ISO/IEC NP 21122-3, under development,
<https://www.iso.org/standard/74537.html>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264,
DOI 10.17487/RFC3264, June 2002,
<https://www.rfc-editor.org/info/rfc3264>.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550,
July 2003, <https://www.rfc-editor.org/info/rfc3550>.
[RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and
Video Conferences with Minimal Control", STD 65, RFC 3551,
DOI 10.17487/RFC3551, July 2003,
<https://www.rfc-editor.org/info/rfc3551>.
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
Norrman, "The Secure Real-time Transport Protocol (SRTP)",
RFC 3711, DOI 10.17487/RFC3711, March 2004,
<https://www.rfc-editor.org/info/rfc3711>.
Lugan, et al. Expires May 12, 2019 [Page 17]
Internet-Draft RTP Payload Format for JPEG XS November 2018
[RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type
Specifications and Registration Procedures", BCP 13,
RFC 6838, DOI 10.17487/RFC6838, January 2013,
<https://www.rfc-editor.org/info/rfc6838>.
[RFC8083] Perkins, C. and V. Singh, "Multimedia Congestion Control:
Circuit Breakers for Unicast RTP Sessions", RFC 8083,
DOI 10.17487/RFC8083, March 2017,
<https://www.rfc-editor.org/info/rfc8083>.
[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
March 2017, <https://www.rfc-editor.org/info/rfc8085>.
[SMPTE-ST2110-10]
Society of Motion Picture and Television Engineers, "SMPTE
Standard - Professional Media Over Managed IP Networks:
System Timing and Definitions", SMPTE ST 2110-10:2017,
2017, <https://doi.org/10.5594/SMPTE.ST2110-10.2017>.
[SMPTE-ST2110-21]
Society of Motion Picture and Television Engineers, "SMPTE
Standard - Professional Media Over Managed IP Networks:
Traffic Shaping and Delivery Timing for Video", SMPTE ST
2110-21:2017, 2017,
<https://doi.org/10.5594/SMPTE.ST2110-21.2017>.
10.2. Informative References
[RFC4175] Gharai, L. and C. Perkins, "RTP Payload Format for
Uncompressed Video", RFC 4175, DOI 10.17487/RFC4175,
September 2005, <https://www.rfc-editor.org/info/rfc4175>.
[RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey,
"Extended RTP Profile for Real-time Transport Control
Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585,
DOI 10.17487/RFC4585, July 2006,
<https://www.rfc-editor.org/info/rfc4585>.
[RFC5124] Ott, J. and E. Carrara, "Extended Secure RTP Profile for
Real-time Transport Control Protocol (RTCP)-Based Feedback
(RTP/SAVPF)", RFC 5124, DOI 10.17487/RFC5124, February
2008, <https://www.rfc-editor.org/info/rfc5124>.
[RFC7201] Westerlund, M. and C. Perkins, "Options for Securing RTP
Sessions", RFC 7201, DOI 10.17487/RFC7201, April 2014,
<https://www.rfc-editor.org/info/rfc7201>.
Lugan, et al. Expires May 12, 2019 [Page 18]
Internet-Draft RTP Payload Format for JPEG XS November 2018
[RFC7202] Perkins, C. and M. Westerlund, "Securing the RTP
Framework: Why RTP Does Not Mandate a Single Media
Security Solution", RFC 7202, DOI 10.17487/RFC7202, April
2014, <https://www.rfc-editor.org/info/rfc7202>.
[SMPTE-ST2059]
Society of Motion Picture and Television Engineers, "SMPTE
Standard - Generation and Alignment of Interface Signals
to the SMPTE Epoch", SMPTE ST 2059-1:2015, 2015,
<https://doi.org/10.5594/SMPTE.ST2059-1.2015>.
10.3. URIs
[1] http://www.iana.org/assignments/rtp-parameters
Authors' Addresses
Sebastien Lugan
intoPIX S.A.
Rue Emile Francqui, 9
1435 Mont-Saint-Guibert
Belgium
Phone: +32 10 23 84 70
Email: s.lugan@sine.sd2.net
URI: http://www.intopix.com
Gael Rouvroy
intoPIX S.A.
Rue Emile Francqui, 9
1435 Mont-Saint-Guibert
Belgium
Phone: +32 10 23 84 70
Email: g.rouvroy@intopix.com
URI: http://www.intopix.com
Antonin Descampe
intoPIX S.A.
Rue Emile Francqui, 9
1435 Mont-Saint-Guibert
Belgium
Phone: +32 10 23 84 70
Email: a.descampe@intopix.com
URI: http://www.intopix.com
Lugan, et al. Expires May 12, 2019 [Page 19]
Internet-Draft RTP Payload Format for JPEG XS November 2018
Thomas Richter
Fraunhofer IIS
Am Wolfsmantel 33
91048 Erlangen
Germany
Phone: +49 9131 776 5126
Email: thomas.richter@iis.fraunhofer.de
URI: https://www.iis.fraunhofer.de/
Alexandre Willeme
Universite catholique de Louvain
Place du Levant, 2 - bte L5.04.04
1348 Louvain-la-Neuve
Belgium
Phone: +32 10 47 80 82
Email: alexandre.willeme@uclouvain.be
URI: https://uclouvain.be/en/icteam
Lugan, et al. Expires May 12, 2019 [Page 20]
