A Field Guide to IP Video A practical reference for STANDARDS found in the wild today
The Authoritative Reference – 1960’s
The Informative Reference – 2017
Wes Simpson • Accomplished protocol-spotter • President, Telecom Product Consulting www.telecompro.tv • Author “Video Over IP” and “IPTV and Internet Video” – Focal Press • Develops and delivers classes on IP Video and related technologies for IEEE, SMPTE, Media180 and custom courses for private clients • Columnist for TV Technology, frequent speaker at VidTrans, NAB • Contact: wes.simpson@gmail.com +1-203-376-3372 office/mobile
The IP Video Ecosystem
Common Name: PTP – Precision Time Protocol ver. 2 Standard: IEEE 1588-2008 Released: 2008 Habitat: IP Studio Network Infrastructure Behavior/Functions: Distributes accurate (within 1 microsecond) clock to video, audio and other devices to permit synchronization between sources, processors and receivers.
Applications: Distributes accurate (within 1 microsecond) clock to video, audio and other devices to permit synchronization between sources, processors and receivers. Using this clock, devices can accurately determine media synchronization (video frame sync, digital audio reference, etc.) without requiring a separate “house clock” or “black burst” feed to each device.
Common Name: RTP – Real Time Protocol Standard: IETF RFC 3550/3551 Released: 2003, some modifications since Habitat: Very popular in studio media networks; found in IPTV systems and a few specialized Internet applications Behavior/Functions: Low overhead protocol for timesensitive applications. Supports multicasting. No builtin error correction system – each application can choose a mechanism to handle (or conceal) errors. Applications: Used extensively in media transport applications, particularly for high-bitrate streams. Packet sequence numbers identify missing and out-of-sequence packets. Timestamps can be used to synchronize multiple content streams that use a common reference clock.
Common Name: IP – Internet Protocol Standard: IETF RFC 791 (also STD 5) Released: 1981, some modifications since Habitat: Found literally everywhere that packet transport is used; inhabits ISO Layer 3 - Network Behavior/Functions: Supports end-to-end delivery of packets across network fabric, with globally-scoped IP addresses. Layer 3 routers process IP addresses on a hop-by-hop basis using routing tables. Applications: IP is the core protocol of the modern Internet. Data communications as we know it would not be possible without the IP protocol. Used by huge range of fixed, mobile, private, public networks. IP packets can be transmitted over a variety of Layer 2 networks, including Ethernet, Wi-Fi, MPLS and mobile phone networks.
Common Name: Compressed Video Over IP Standard: SMPTE 2022-1, 2022-2 Released: 2007 (Descendant of Pro-MPEG CoP3) Habitat: Primarily found in long-haul networks, but has been observed in some studio environments Behavior/Functions: Moves MPEG-TS packets using RTP/UDP for consistent flow rates and multicasting. Adds optional Row/Column Forward Error Correction to re-create lost packets at receiver.
IP
TS
TS
RTP
TS
TS
UDP
RTP
TS
TS
UDP
RTP
TS
TS
Applications: The dominant standard today for compressed video/audio streams over IP networks, built into a variety of hardware and software devices. Supports constant-bit-rate streams up to around 200 Mbps. On multicast-enabled networks, a single source can feed thousands of destination points. Commonly used for IPTV systems to consumers and to enterprise desktop applications.
Common Name: Audio over IP Standard: AES67 Released: 2013 Habitat: Increasingly found in professional audio networks, particularly multi-vendor installations Behavior/Functions: Contains raw, uncompressed digital audio samples of up to 24 bits and multiple channels in a stream. Allows transparent transport of audio signals across IP networks.
Dante
Livewire+
Q-LAN
Ravenna
MNA Interop of AES67 during ISE, Feb. 2017
Applications: Provides a common, interoperable format for audio transport that has been implemented by a large number of device and system manufacturers. Allows fine-grained synchronization between multiple audio channels to preserve sound-field integrity and maintain stereo audio phase relationships.
Common Name: Professional Media over IP Networks (System and Timing) Standard: SMPTE 2110-10 Released: Expected in 2017 (Based on VSF TR-03) Habitat: Should be common at interops and inside the studio soon after the standard is released Behavior/Functions: Defines overall concepts and common system timing details including RTP timestamps for IP flows containing a single type of essence per stream (video, multiple audios, metadata, etc.) Applications: This standard forms the foundation of the 2110 series of standards, and should therefore become prevalent across the professional media production landscape. A variety of other standards in the 2110 series are being drafted to provide detailed specifications on individual media types, such as uncompressed video, uncompressed multi-channel audio, VANC data, etc.
Common Name: Professional Media over IP – Uncompressed Active Video Standard: SMPTE 2110-20 C’B Y0’ C’R Y1’ 1 Released: Expected in 2017 Habitat: Primarily for use inside the production facility
Behavior/Functions: Uncompressed, raw pixel data is inserted directly into RTP packets. Carries only the active pixels in a video image (no transport of audio or ancillary data).
2
3
4
5
Sampling Format
8 bits per sample
10 bits per sample
12 bits per sample
YCbCr 4:2:2 YCbCr 4:4:4
2 pixels/4 octets Livewire+ 1 pix/3 oct
2 pix/5 oct Q-LAN 4 pix/15 oct
2 pix/6 oct Ravenna 2 pix/ 9 oct
YCbCr 4:1:1
4 pix/6 oct
8 pix/15 oct
4 pix/9 oct
YCbCr 4:2:0
4 pix/6 oct
8 pix/15 oct
4 pix/9 oct
Applications: This format supports a huge variety of video formats, with different sample depths, different chroma configurations and different color subsampling, including High Dynamic Range/Wide Color Gamut and Ultra-High Definition 1 and 2. By transporting only the active picture area, this format requires significantly less bandwidth than systems that transport encapsulated SDI signals, while also allowing audio signals to be routed differently than video signals.
Common Name: Professional Media over IP Networks – PCM Digital Audio Standard: SMPTE 2110-30
RTP Timestamp of First Audio Sample
Released: Expected in 2017 (Derived from AES67) Habitat: Increasingly found in professional audio networks, particularly multi-vendor installations Behavior/Functions: Contains raw, uncompressed digital audio samples of up to 24 bits and multiple channels in a stream. Allows transparent transport of audio signals across IP networks.
IP
UDP
RTP
Applications: Provides a common, interoperable format for audio transport that has been implemented by a large number of device and system manufacturers. Allows fine-grained synchronization between multiple audio channels to preserve sound-field integrity and maintain stereo audio phase relationships.
Common Name: Professional Media over IP Networks – Ancillary Data Standard: SMPTE 2110-40 Released: Expected in 2017 Habitat: Commonly found in 2110 applications where SDI signals have been converted into IP streams Ancillary Flag DID SDID DC Behavior/Functions: Encapsulates data from the 000 3FF 3FF 41 07 xx VANC (primarily) portion of an SDI signal for transport in an all-IP environment. Based on an IETF draft document: draft-ietf-payload-rtp-ancillary RTP Hdr. Line No. Offset DID SDID DC SSRC, &
mm
nnn
41
07
xx
User Data SCTE 104
CS ANC Data zz Packet
User Data SCTE 104
CS RTP zz Datagram
Applications: Many different types of signals are transported using ancillary data packets within SDI signals, including time code, ad insertion messages, captions, active format descriptions, and other types of data. Note that the line numbers used in the 2110-40 packet headers are referenced to SDI signal line numbers, and hence are not aligned with the line numbers used in 2110-20.
Common Name: SDP – Session Description Protocol v=0 Standard: IETF RFC 4566 o=audio 1311738121 Released: 2006 Habitat: Within media production networks and particularly as the contents of NMOS messages Behavior/Functions: SDP text files are supplied by senders to give receivers the information they need to properly connect to and identify streams. Information includes IP addresses, UDP port numbers, RTP types, clock identifiers, media sampling/channels, etc.
1311738121 IN IP4
192.168.1.1 s=Stage left I/O c=IN IP4 192.168.1.1 t=0 0 m=audio 5004 RTP/AVP 96 i=Channels 1-8 a=rtpmap:96 L24/48000/8 a=sendonly a=ptime:0.250 a=ts-refclk:ptp=IEEE1588-2008:39-A794-FF-FE-07-CB-D0:domain-nmbr=0 a=mediaclk:direct=0
Applications: SDP files greatly simplify the configuration of media devices, because they contain a complete description of the contents of an RTP media stream. This eliminates the laborious process of adjusting settings in a receiver to properly decode an incoming signal. SDP files are made up of simple text strings, and thus may be delivered using a variety of mechanisms, such as web sockets, NMOS API’s, multicast packets, e-mail or any other mechanism available to delivery a small text file to a receiver.
Common Name: NMOS – Networked Media Open Specifications Standard: AMWA - NMOS Released: Ongoing (releases as needed) Habitat: Large and small media production networks Behavior/Functions: Defines a standard interfaces that all elements (nodes) of a network must provide to convey information about the media signals that are able to be generated and received by the node. Applications: Provides a way for devices to register themselves with a central registry or on an ad-hoc basis, discover other devices in the network, establish connections between devices, provide identity information about and within streams, and to manage timing relationships between streams.
Thank You! Please visit these websites for information about upcoming training classes: Customized training on IP, Video and Media Technology: www.telcompro.tv IP Video for Media Professionals: http://bts.ieee.org/educational-programs.html Essentials of IP Media Transport for Broadcasters: https://www.smpte.org/education/courses wes.simpson@gmail.com