Glass to Glass Internet Ecosysten Introduction
draft-deen-daigle-ggie-00
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draft-deen-daigle-ggie-00
Network Working Group G. Deen
Internet-Draft NBCUniversal
Intended status: Informational L. Daigle
Expires: September 22, 2016 Thinking Cat Enterprises LLC
March 21, 2016
Glass to Glass Internet Ecosysten Introduction
draft-deen-daigle-ggie-00
Abstract
This document introduces the Glass to Glass Internet Ecosystem
(GGIE). The GGIE goal is to improve how the Internet is used for all
video, both amateur and professional, reflecting that the line
between amature and professional video technology is increasinly
blurred. As the Glass to Glass (camera lens to viewing screen) name
implies GGIE's scope is from the original recording by a lens,
through the steps of editing, packaging, distributed and searching,
and finally viewing. GGIE is not a complete end to end architecture
or solution, it is use cases and technical specifications that can
serve as foundational building blocks for new Internet video
innovation.
This is a companion effort to the GGIE W3C Taskforce in the W3C Web
and TV Interest Group.
This document is being discussed on the ggie@ietg.org mailing list.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 22, 2016.
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Copyright Notice
Copyright (c) 2016 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
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Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Video is filling up the pipes . . . . . . . . . . . . . . . . 4
4. Video is different . . . . . . . . . . . . . . . . . . . . . 4
5. Historical Approaches to supporting Video on the Internet . . 5
5.1. Video as an application . . . . . . . . . . . . . . . . . 5
5.2. Video as a network problem . . . . . . . . . . . . . . . 6
6. GGIE: Building blocks to support video through network and
application . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1. Affected IETF work areas . . . . . . . . . . . . . . . . 7
6.2. Related work: W3C GGIE Taskforce . . . . . . . . . . . . 7
7. Setting the stage for GGIE . . . . . . . . . . . . . . . . . 7
7.1. Media Lifecycle . . . . . . . . . . . . . . . . . . . . . 8
7.2. Video is not like other Internet data . . . . . . . . . . 10
7.3. Video Transport . . . . . . . . . . . . . . . . . . . . . 12
8. Conclusion and Next Steps . . . . . . . . . . . . . . . . . . 12
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
11. Security Considerations . . . . . . . . . . . . . . . . . . . 13
12. Normative References . . . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
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 [RFC2119].
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2. Introduction
The proliferation of users with Internet connected devices capable of
capturing, and devices for watching streamed video has created what
is in terms of shear bandwidth the Internet's larget use without any
close second competitor. As of 2015 there are reports that youtube
users upload over 500 hours of video every minute, and that during
evening hours NetFlix accounts for a staggering 1/3 of Internet
traffic. The number of users using the Internet for both ends of the
video create-view lifecycle grows daily worldwide, and this is
creating an enormous strain put on the underlying Internet
infrastructure at nearly every point from the core to the edge.
While video is one of the most conceptually simple uses of the
Internet, it is perhaps one of the most complex technically built
from standards created by a large number of organizations and groups
some dating from before the modern Internet even existed. Many
critical parts of this complex ecosystem were not created with either
video's particular charateristics or vaste scale of populurity in
mind which has lead to both the degradation of the viewer experience,
and many Internet policy issues around access to bandwidth for video
and the needed infrastructure to support the continued explosion in
video transport on the Internet.
Bandwidth increases at all levels of the Internet are expected to
continue this is not currently, and is not expected to be the sole
solution to the video scalability problem facing the Internet. To
meet future expectations work is also needed to find ways of more
efficiently use the network for creation, publication, and delivery
of video advances in existing technology and standards.
Conceptually, people watch video when their play back device receives
the encoded video data from a source, decodes it, and displays it for
the viewer. However, the technical details behind making this simple
concept happen are often far from simple due video viewers demand for
smooth display of video frame by frame in at a constant rate without
delay or skipped frames. Contiguous frames shown at a constant rate
and the large size of video data combine to make distribution over
Internet difficult and requiring sophisticated engineering to be done
consistently well.
This document outlines the scope of the video problem for the
Internet, proposes that a path forward must include foundational
building blocks for video at both the application and network layers,
and provides an outline of the video production lifecycle as a
baseline for developing a problem statement and requirements for IETF
work on the Glass to Glass Internet Ecosystem (GGIE).
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3. Video is filling up the pipes
Video is without rival the top use of Internet bandwidth, and its
ever growing demand for more bandwidth easily out paces the new
capacity being added both globally and regionally with no let up in
sight.
Continuous innovation introducing new higher resolutions, higher
video quality, new distribution services, new viewing and creation
devices all contribute to this every growing demand upon the
Internet. The Cisco Visual Networking Index projects that by 2019
there will be nearly a million minutes of video per second
transported by the Internet, a making up 80-90 of all IP traffic.
The growth in video bandwidth need is exceeding the growth in the
bandwidth provisioning.
Video has been the top use of Internet bandwidth for several years
and is larger than the bandwidth used by all other applications
combined. This trend is not likely to ease or reverse itself as
users of the Internet continue to make Internet transported video as
one of their uses of the Internet, either for uploading and sharing
video they creator, or as a primary sources for viewing video to a
wide variety of viewing devices: computers, tablets, phones,
connected televisions, game consoles, and AV receivers.
4. Video is different
Video is different than other data carried due to its extreme size of
megabits per second, and gigebytes per hour of video, and when
streamed for viewing its exteme sensitivity to latency and dropped
packets. This makes video unique amongst all other applications
using the Internet for while some have latency and packet loss
sensitivities they do not have exteme data sizes, and while others
may have exteme data size they do not care about latency, time to
restransmit lost packets, or in some cases loss of some individual
packets at all. A email user can tolerate an extra moment to
retransmit dropped packets, and a web page user can tolerate a slow
DNS lookup, but a video viewer sees both problems as jittery playback
and as a failure of the network to meet their need. (Audio has
similar challenges in terms of intolerance of delay and jitter, but
the data sizes are significantly smaller).
Video data sizes continue to grow large as cameras and playback
devices are able to capture and display higher quality images. Early
digital video was often captured at either 320x240 pixel resolution
or 640x480 standard defintion resolution. High definition or HD
video at 1920x1080 became possible on some parts of the Internet
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after 2011, although even in 2016 it remains unavailble or unreliable
through many connections such as DSL and many mobile networks.
Camera and player technology is currently expanding again to permit
4K or 3840x2160 pixel resolution reflecting a 4x data increase over
HD.
Streaming is very demanding requiring consistent frame to frame
playback in consistent constant time. Advanced features such as
pause, fast forward, rewind, slow motion, and fine scrubbing are
considered by users as standard features players that the network
must support and serve to further the challenge facing the Internet.
New video abilities such as live streaming by users both one to one
and one to many bring what has traditionally done professional
broadcasters with dedicated broadcast infrastructure into the realm
of every day users with connected smartphones using the Internet as a
realtime global broadcast infrastructure.
5. Historical Approaches to supporting Video on the Internet
5.1. Video as an application
Internet video engineering began by adapting preexisting standards
used for over the air broadcast (OTA) and physical media. Video
encodings, such as AVI and MPEG2, originally designed for playback
from local storage connected to the player where added to the data
types carried by existing protocols like HTTP, and new protocols such
as RTSP and HLS. Early use of the Internet for video was a copy-and-
play model replacing the use of OTA broadcast and physical media to
copy video between systems.
As Internet bandwidth grew sufficient to allow delivery of video data
at the same rate it was being decoded, it became possible to stream
video originally at very low resolutions such as 160x120 pixels (19.2
kilopixels), eventually permitting standard defintion (SD) 640x480
pixels (0.3 megapixels), and later high defintion of 1920x1080 pixels
(2 gigapixels). This trend continues with some providers beginning
to offer 4K or 3840x2160 pixels (8.3 gigapixels) requiring very
reliable and generous Internet bandwidth end to end connection
between the viewer and source.
Unlike the Web, email, and network file sharing which have been
engineered and standardized in Internet focused organizations such as
the W3C and IETF, video is dependent on standards developed by a very
large number of groups, companies, and organizations which include
the IETF, W3C but also MPEG, SMPTE, CEA, IEEE, ANSI, ISO, networking
and technology companies, many others. In contrast to the extensive
end to end expert knowledge and engineering done to create the Web
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and email, Internet video has largely been an evolved cobbling and
adaption exercise done by engineers with their focus on a few, or
one, particular aspect or problem at a time, and little interaction
between other parts of the Internet video ecosystem. While it is
very much possible to deliver video over the Internet, this
uncoordinated cobbling has resulted in many areas of inefficiency
where engineering done from an end to end perspective provide the
opportunity to vastly improve how video uses the Internet, which
offers the hope of improving the quality of video and increasing the
amount of video which can be delivered instead of relying solely on
bandwidth growth to enable growth.
5.2. Video as a network problem
Network, video, and application engineers have constructed elaborate
solutions for dealing with bandwidth and processing limitations,
network congestion, lossy transport protocols, and the ever growing
size of video data. These solutions commonly fall into one of
several solution types:
1. Reducing data sizes through resolution changes, compression, and
more efficient encodings
2. Downloading before playing instead of realtime streaming
3. Positioning the data close to the viewer via caches, typically on
the network edge
4. Fetching of video data at a rate faster than playback
5. Transport protocols that attempt to deliver video data such that
the data arrives as if it were done on a congestion free/lossless
network
6. Dynamic reselection of sources and transport routes on either a
realtime or frequent intervals, 10-15 seconds, using player
feedback mechanisms or network telemetry
6. GGIE: Building blocks to support video through network and
application
GGIE, the Glass to Glass Internet Ecosystem, is an effort to improve
video's use of the Internet by examining the end to end video
ecosystem from the glass lens of the camera through to the glass the
screen, and to identify areas of simplifications, standardization,
and reengineering to make better use of bandwidth enabling smarter
network use by video creators, distributors, and viewers. GGIE is
focused on how video uses the Internet, and not on how it is encoded
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or compressed. Like wise GGIE does not deal with content protection.
GGIE scope however does include creator and viewer privacy, content
identifiction and recognition as a means to enable smarter network
usage, edge caching, and discoverability.
Beyond improving the simplistic task of a viewer using the Internet
to watch linear video, it is hoped, that through having a set of
improved Internet video standards, the innovators can build using
such standards as a foundation to create the next generation of
Internet video such as multisource personalized composite
experiences, interactive stories, and live personal broadcasting to
name a few.
Due to the very diverse and large deployment of existing video
playback devices and infrastructure, it is viewed as essential that
any evolved ecosystem continues to work with the majority of the
legacy deployment.
6.1. Affected IETF work areas
It is expected that significant improvement is possible in the video
transport ecosystem by modest evolution and adaption of existing
standards for addressing, transporting, and routing of video data
flows between sources and display.
6.2. Related work: W3C GGIE Taskforce
A companion effort was begun in 2015 in the W3C Web and TV Interest
Group's GGIE Taskforce. The W3C GGIE group developed a series of
use-cases on discovery, search, delivery, identity, and metadata
which can be found at https://www.w3.org/2011/webtv/wiki/GGIE_TF
7. Setting the stage for GGIE
This section outlines the details of the video lifecycle -- from
creation to consumption -- including the key handholds for building
applications and services around this complex data. The section also
provides more detail about the scope and requirements of video (scale
of data, realtime requirements).
Note: this document only deals with streaming video as used by
movies, TV shows, news broadcasts, sports events, music concert
broadcasts, product videos, personal videos, etc. It does not deal
with video conferencing or WebRTC style video transport.
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7.1. Media Lifecycle
The complex workflow of creating media and consuming it is
decomposable into a series of distinct common phases.
7.1.1. Capture
The capture phase involves the original recording of the elements
which will be edited together to make the final work. Captured media
elements can be static images, images with audio, audio only, video
only, or video with audio. In sophisticated capture scenarios more
than one device maybe simulatneously recording.
7.1.1.1. Capture Metadata
The creation of metadata for the element, and for the final video
begins at capture. Typical basic capture metadata includes Camera
ID, exposure, encoder, capture time, and capture format. Some
systems record GPS location data, assigned asset ids, assigned camera
name, camera spatial location and orientation.
7.1.2. Store
The storage phase involves the transport and storage of captured
elements data. During the capture phase, an element is typically
captured into memory in the capture device and is then stored onto
persistent storage such as disc, SD or memory card. Storage can
involve network transport from the recording device to an external
storage system using either storage over IP protocols such as iSCSI,
a data transport such as FTP, or encapsulated data transport over a
protocol such as HTTP.
Storage systems can range from basic disk block storage, to
sophisticated media asset libraries
7.1.2.1. Storage Metadata
Storage systems add to the metadata associated with media elements.
For basic block storage, a file name, file size is typical, as is a
hierarchical grouping, and creation date, last-access date. For
library system a identifier unique to the library is typical, a
grouping by one or more attributes, a time stamp recording the
addition to the library, and a last access time.
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7.1.3. Edit
Editing is the phase where one or more elements are combined and
modified to create the final video work. In the case of live
streaming, the edit phase maybe bypassed.
7.1.4. Package
Packaging is the phase in which the work is encoded in one or more
video and audio codecs. These maybe produce multiple data files, or
they may be combined into a single file container. Typically it is
in the packaging phase is the creation or registration of a unique
work identifier for example an Entertainment Identifier from EIDR.
7.1.4.1. Package Metadata
7.1.5. Distribute
The distribute phase is publishing or sharing the packaged work to
viewers. Often it is uploading it to a site such as YouTube, or
Facebook for social media, or sending the packaged media to streaming
sites such as Hulu.
It is common for the distribution site to repackage the video often
transcoding it to codecs and bitrates chosen by the distributor as
more efficient for their needs. Distribution of content expected to
be widely viewed often includes prepositioning of the content on a
CDN (Content Distribution Network).
Distribution involves delivery of the video data to the viewer.
7.1.5.1. Distribution Metadata
Distribution often adds or changes considerable amounts of metadata.
The distributor typically assigns a Content Identifier to the work,
that is unique to the distributor and their content management system
(CMS). Additional actions by the distributor such as repacking and
transcoding to new codecs or bitrates can require significant changes
to the media metadata.
A secondary use of distribution metadata is enabling easy discovery
of the content either through a library catalog, EPG (electronic
program guide), or search engine. This phase often includes
significant new metadata generation involving tagging the work by
genre (sci-fi, drama, comedy), sub-genre (space opera, horror,
fantasy), actors, director, release date, similar works, rating level
(PG, PG-13), language level, etc.
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7.1.6. Discover
The discover phase is the precursor to viewing of the work. It is
where the viewer locates the work either through a library catalog, a
playlist, an EPG, or a search. The discover phase connects
interested viewers with distribution sources.
7.1.6.1. Discovery Metadata
It is typical for discovery systems to parse media metadata to use
the information as part of the discovery process. Discovery systems
may parse the content to extract imagery and audio as additional new
metadata for the work to ease the viewers navigation of the discovery
process perhaps as UI elements. The system may import externally
generated new metadata about the work and associate it in its search
system, such as viewer reviews, metadata cross reference indices.
7.1.7. View
The view phase encompasses the consumption of the work from the
distributor. For Internet delivered video it is typical for delivery
to involve a CDN to perform the actual delivery.
7.2. Video is not like other Internet data
Video is distinctly different from other Internet data. There are a
number of characteristics that contribute to video's unique Internet
needs. The most significant characteristics are:
1. large size of video data ( Mbps to Gbps)
2. low latency demands of streamed video
3. responsiveness to trick play requests by the user (stop, fast
forward, fast reverse, jump ahead, jump back)
4. multiplicity of formats and encodings/bit rates that are
acceptable substitutes for one another
7.2.1. Data Sizes
Simply put compared to all other common Internet data sizes, video is
huge. A still image often ranges from 100KB to 10MB. A video file
can commonly range from 100MB to 50GB. Encoding and compression
options permit streaming videos using bandwidth ranging from 700Kbps
for extremely compressed SD video, to 1.5-3.0 Mbps for SD video, to
2.5-6.0 Mbps for HD video, and 11-30Mbps for 4K video.
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Still images have 4 dimensional properties that affect their data
size:
1. number of horizontal X pixels
2. number of vertical Y pixels
3. bytes per pixel
4. compression factor for the image encoding.
Video adds to this:
1. frames per second playback rate
2. visual continuity between frames (meaning users notice when
frames are skipped or played out of order)
3. discontinguous jumps between frames such as skipping forward or
backwards to inserting frames from other sources between
contigous frames (advertisement placement)
Each video format roughly increases by x4 the data needs of the
previously resolution: (1) SD is 640x480 pixels; (2) HD is 1920x1080
pixels; (3) 4K is 3840x2160 pixels.
Video, like still images, assigns a number of pixels to store color
and luminance information. This currently evolving alongside
resolutions after being stagnant for many years. The introduction of
high dynamic range videos or HDR has changed the color gamut for
video and increased the number of bits needed to carry luminance from
8 to 10 and in some formats more.
Compression is often misunderstood by viewers. Compression does not
change the video resolution, SD is still 640x480 pixels, HD is still
1980x1080 pixels. What changes is the quality of the detail in each
frame, and between frames. Compression algorithms work with the
video images and movement to reduce data sizes through encoding of
repetitive and
Video is in its simplest form a series of still images shown
sequentially over time, adding an additional attribute to manage.
7.2.2. Low Latency Transport
Viewers demand that video plays back without any stutter, skips, or
pauses, which translates into low latency transport for the video
data.
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7.2.3. Multiplicity of Acceptable Formats
One of the unique aspects of video viewing is that there can exist
multiple different encodings/versions of the same video, many of
which are acceptable substitutes for one another. This is a unique
aspect of video viewing and differentiates video delivery from other
data transports.
An email is the email, this is what enables digital signatures to
operate on the email body. One composed and sent, there is only one
version of the email which is the original, untouched, acceptable
version of the email.
7.3. Video Transport
7.3.1. File vs Stream
There are two common ways of transporting video on the Internet: 1)
File based; 2) Streaming. File based transport can use any file
transport protocol with FTP and BitTorrent being two popular choices.
Streaming
File based playback involves copying a file and then playing it.
There are schemes which permit playing portions of the file while it
progressively is copied, but these schemes involve moving the file
from A->B then playing on B. FTP and BitTorrent are examples of file
copy protocols.
Streaming playback is most similar to a traditional Cable or OTA
viewing of a video. The video is delivered from the streaming
service to the playback device in real time enabling the the playback
device to receive, decode, and display the video data in real time.
Communication between the player and the source enable pausing, fast
forward, rewind by managing the data blocks which are sent to the
player device.
8. Conclusion and Next Steps
GGIE seeks to held address this problem by establish standards based
foundational building blocks that innovators can build upon creating
smarter delivery and transport architectures instead of relying on
raw bandwidth growth to satisfy video's growth.
Next steps will include introducing for discusion issues relevant to
the IETF based on use cases developed in the W3C GGIE Taskforce, as
methods for enabling networks to identify video and enable smart
routing and addressing choices by edge devices.
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9. Acknowledgements
10. IANA Considerations
None (yet).
11. Security Considerations
None (yet).
12. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
Authors' Addresses
Glenn Deen
NBCUniversal
Email: rgd.ietf@gmail.com
Leslie Daigle
Thinking Cat Enterprises LLC
Email: ldaigle@thinkingcat.com
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