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TMX-2010
Transport Multiplexer
ATSC Application N
March 200
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ATSC Application Note
TMX-2010 TRANSPORT MULTIPLEXER
TABLE OF CONTENTS
1 INTRODUCTION......................................................................................................3
2 TMX-2010 MULTIPLEXER ......................................................................................5
3 SE-2000 SINGLE CHANNEL ENCODER................................................................8
4 HIGH DEFINITION ENCODER ................................................................................9
5 ATSC ARCHITECTURES......................................................................................10
6 SUMMARY.............................................................................................................14
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ATSC Application Note
1 Introduction
With local network broadcast affiliates rushing to meet the FCC mandated on-air date
for transitioning to digital ATSC broadcasting, determining an entry-level but fully
compliant encoding and multiplexing solution that is extensible to future more
sophisticated ATSC broadcast applications has become a common goal in the industry.
For example, a new ATSC broadcaster may begin with a digitally compressed MPEG
version of their traditional programming along with the FCC compliant amount of
program and system information protocol (PSIP), but later grow to add more programs
(multicasting) including high definition and data services.
Motorola BCS has designed a modular system to best meet a phased approach to full
DTV operations. The basic building blocks include a transport multiplexer and
standalone encoders. The elements seamlessly fit together to facilitate cost-effective
compliance and rapid deployment of new services.
TMX-2010 TRANSPORT MULTIPLEXER
Digital Satellite Receiver
TMX-2010 Multiplexer
TMX-2010
TMX Element Manager
ASI
SSI
SSI
Broadcast Tower
ASI
Cable Plant
Monitor
High Definition Encoder
HD Encoder
Digital Video Encoder
PSIP Generator
Data Serve r
ASI
ASI
ASI
IP
Hub
An application-rich local network broadcast affiliate incorporates network feeds, local
created content, data services, server content and supports separate private networks
and cable distribution pipes.
The Motorola Broadband Communications Sector’s (Motorola BCS) TMX-2010
transport multiplexer is built upon a flexible, module-based chassis, providing basic
multiplexing, ATSC standard PSIP handling (A/65) and IP data encapsulation (A/90),
and bitrate transcoding. Additional functionality such as statistical multiplexing and
PC
DTV Set
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ATSC Application Note
digital program insertion are optional upgrades. Motorola BCS’ SE-2000 digital video
encoder is a one rack unit high device providing high quality standard definition
encoding and audio processing. The high definition encoder contains all of the
input/output connections necessary for converting incoming, full bandwidth HD video,
audio and data into the ATSC-compliant MPEG-2 bitstream.
TMX-2010 TRANSPORT MULTIPLEXER
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ATSC Application Note
2 TMX-2010 Multiplexer
The TMX-2010 Transport Multiplexer is Motorola BCS' new generation modular solution
for MPEG-2 cable, satellite and broadcast transport distribution architectures.
It supports many features to tailor MPEG-2 streams.
Service Multiplexing: Basic combining of multiple streams into one multiplex.
Grooming: The ability to select (add/drop) the streams that will appear in the
output transport.
TMX-2010 TRANSPORT MULTIPLEXER
The TMX Element Manager provides user friendly GUIs for simple and flexible selection
from the input MPEG-2 services into one or more customized transport stream outputs.
Video bit-rate transcoding
2 video elementary stream followed by a re-encode for the purpose of reducing the
video bitrate. The TMX-2010 supports transcoding of constant or variable bitrate
inputs into statistically multiplexed groups.
5
: Transcoding is a method of partially decoding a MPEG-
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ATSC Application Note
TMX-2010 TRANSPORT MULTIPLEXER
SE-1010 or SE-2000 Encoder
SE-1010 or SE-2000 Encoder
SE-1010 or SE-2000 Encoder
Hub 2
Closed High-Volume Network
1
TS
2
n
Router/Switch Hub
TMX-2010 Multiplexer
TMX-2010
TS
TMX Element Manager
Hub
Control Network
Statistical Multiplexing (Stat Mux) examines all of the incoming video feeds as a
group and automatically (and frequently) assigns compression bitrates based upon
the complexity and motion in each feed. The basic premise of Stat Mux (and the
reason for the word “statistical”) is that - at a given point in time- there will be some
feeds that have a lot of motion, some with very little, and some are “average”.
Stat Mux works by having all of the Single Channel Encoders(SE) that are included
in a Stat Mux group report their compression demands (need parameter) to one
decision maker - the TMX-2010. The TMX considers all of the demands (including
each SE’s minimum bitrate setting, maximum bitrate, and priority), decides on the
bitrate to assign to each SE, and then communicates that decision back to each
SE via the SE/TMX Ethernet connection. This “negotiation” for bitrate takes place
at least once per video frame to ensure that even the slightest change in scene
complexity becomes part of the decision making process.
Splicing: MPEG-2 video splicing is defined as the seamless replacement of one
MPEG-2 video packetized elementary stream with another. Performing a
replacement in the compressed MPEG-2 domain has cost benefits for digital
networks, especially when the video services are not encoded locally. MPEG-2
video slicing involves I-frame insertion, bitrate adjustments and, in some cases,
resolution changes.
Motorola BCS’ standards-based approach to digital program insertion (DPI)
supports the transmission of DVS 253 DPI messages across a digital network. The
TMX-2010 is used to interpret such messages and subsequently perform an
MPEG-2 video splice with a local digital server. Utilizing DVS-380, the standardsbased application program interface (API ) between the server and TMX-2010, the
digital splice is synchronized to sub-frame accuracy. The TMX-2010 translates
MPEG PTS timing to common time-base (i.e. NTP) to ensure accurate insertion.
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ATSC Application Note
TMX-2010 TRANSPORT MULTIPLEXER
Time
i.e. NTP
ASI
DVS-253
TMX-2010
TMX-2010 Multiplexer
Cue Request: SIT with
common time base
TCP/IP socket
Splice Request
ASI
Server
EASHANGE
C
INTERNA TIONAL
Encoder management: The TMX Element Manager provides easy-to-use
configuration of the SE-1010/2000 encoders via SNMP.
IP data encapsulation
: For datacasting applications, the TMX-2010 can accept and
encapsulate externally supplied UDP/IP Multicast data into MPEG-2 packetized
transport streams via standard transport input interfaces – and include those data
streams as part of the output ATSC-compliant DTV multiplex.
PSIP handling
: The TMX-2010 supports the pass-through of PSIP tables supplied
by an external PSIP Generation system, or can internally create the minimum A65
Program Specific Information Protocol (PSIP) data for a compliant ATSC
broadcast.
Multiple output formats: Provides standard transport interfaces DVB-ASI, DS-3,
DHEI, and SMPTE-310 for interoperability across a variety of applications. The
TMX-2010 also generates a simultaneous DVB-ASI output for monitoring purposes
when another output port is chosen.
The TMX-2010 transport multiplexer's option module architecture allows for flexible
feature customization and future expandability.
Figure 2 –TMX-2010 Transport Multiplexer
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ATSC Application Note
3 SE-2000 Single Channel Encoder
The Motorola BCS SE-2000 digital video encoder is ideally suited for the cable
headend, broadcast, and high bandwidth contribution applications.
The SE-2000’s key features include:
High quality video processing: Motorola BCS's fifth generation video compression
technology. Accepts either analog composite or digital CCIR-601 video. The
compact SE-2000 employs advanced processing techniques including; dual-pass
encoding, scene change detection, adaptive quantization level processing,
adaptive temporal noise filtering and frame synchronization to ensure high quailty
results while conserving bandwidth.
Flexible audio processing: Two stereo audio channels are compressed with either
Dolby® brand AC-3® encoding or AC5.1 pass through support. Supports inputs
from embedded audio from D1 video, external digital audio and analog audio.
Flexible input and output options: The Motorola BCS SE-2000 provides three types
of outputs, DVB-ASI, digital headend expansion interface (DHEI), and DS-3, for
easy interoperability with cable headends and broadcast equipment.
ATSC closed-caption support: NTSC and 525D1 modes. Line 21 (field 1) and line
22 (field 2) per the EIA-708 standard format.
The Motorola BCS SE-2000 digital video encoder offers front panel controls, factory
presets and user modifiable configurations.
TMX-2010 TRANSPORT MULTIPLEXER
Figure 3 – SE-2000 Single Channel Encoder
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ATSC Application Note
4 High Definition Encoder
The DigiCipher® II high definition encoder is part of Motorola BCS’ MPEG-2 encoding
system and incorporates sophisticated video processing algorithms that are the results
of more than eight years experience with three generations of high definition systems.
Advanced techniques that carefully subdivide the full bandwidth HD signal for efficient
processing, process the individual “panels”, then re-combine for a seamless, high
quality ATSC-compliant signal are the basis of the HD system. The HD encoder’s
sophisticated video processing include:
Panel Overlap Processing: Allows the passing of motion vectors between adjacent
horizontal panels. Eliminates artifacts caused by motion across panel boundaries.
Inter-panel statistical multiplexing: Different bitrates are automatically assigned to
individual panels based on picture complexity. Overall consistent picture quality
instead of artifacts occurring in demanding portions of the picture.
TMX-2010 TRANSPORT MULTIPLEXER
Scene-Change Detection: System can differentiate between adjacent video frames
that are parts of different scenes, vs. adjacent frames with high motion. The MPEG
group of pictures (GOP) is gracefully closed and a new one is started – resulting in
higher video quality, since bandwidth is used for frame content vs. motion.
Fade-Detection: System differentiates between “fade-to-black” sequence vs.
motion sequence. Bitrate is used to represent picture content (different luminance
values) instead of motion – resulting in higher quality video.
The HD encoder chassis contains all of the input/output connections necessary for
converting incoming, full bandwidth HD video, audio and data into the ATSC-compliant
MPEG-2 bitstream.
Internal AC-3 stereo processing: The HD encoding system can multiplex up to
three stereo pairs into the output transport stream. These three audio “programs”
can be a mix of externally pre-compressed audio and internally compressed AC-3
audio, selected from the six (6) audio input ports. Additionally, audio can be
accepted as embedded in the serial digital stream in compliance with SMPTE
299M. Supports surround and stereo audio compression bit rates of 96kbps to
640kbps, default to 384kbps for surround-sound coding and 192kbps for stereo
coding. Supports audio sampling rate of 44.1ksps and 48ksps for stereo audio
coding and 48ksps for surround-sound coding.
Complies with MPEG-2 Main Profile/High Level (MP @ HL) video syntax.
Performs film mode (inverse telecine) processing. Provides switch-to-black
capability upon video loss. Supports I-frame refresh with selectable refresh rates.
Supports fully encrypted video at bit rates of up to 40Mbps. Supports MPEG-2
processing: I-frame, P-frame, and B-frame
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ATSC Application Note
5 ATSC Architectures
From the most simple to the most complicated ATSC architectures, Motorola BCS’
multiplexers and encoders will provide a building block approach allowing the
broadcaster to grow a system seamlessly as the business model evolves over time.
Single Network Feed Pass Through
For basic ATSC broadcast compliance a broadcaster can opt to re-purpose their
network feed. With only minor alterations, a satellite feed can be re-purposed for local
broadcast. In this model (figure 4), there is no investment in equipment to create new
DTV content. The TMX-2010 transport multiplexer accepts the ASI output from a
digital satellite receiver and provides bitrate transcoding and PSIP handling
functionality.
Digital Satellite Receiver
ASI
TMX-2010 TRANSPORT MULTIPLEXER
TMX-2010 Multiplexer
TMX-2010
SSI
Broadcast Tower
ASI
Local Monitori ng
TMX Element Manager
FIGURE 4: Network Pass through with local PSIP branding
The TMX-2010 can be used to pass through or create the minimum ATSC compliant
A65 PSIP information. It provides the ability to change master guide tables (MGTs),
system time tables (STTs), terrestrial virtual channel tables (TVCTs), rating region
tables (RRT), and 12-hour blocks of event information tables (EIT) which can assist
broadcast affiliates in re-branding network content for their local market.
The TMX Element Manager “program editor” GUIs .
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ATSC Application Note
Local Encoding (Figure 5)
Another approach to rapidly deploy a DTV channel would be to digitalize an existing
analog broadcast channel. A locally produced analog channel can be fed to a SE-2000
digital video encoder to create a high quality compressed MPEG-2 stream. The TMX2010 multiplexer is used to create PSIP information.
Analog
Content
Digital Video Encoder
ASI
TMX-2010 TRANSPORT MULTIPLEXER
TMX-2010 Multiplexer
TMX-2010
SSI
Broadcas t Tower
ASI
Local Monitoring
TMX Element Manager
FIGURE 5: Local SD Encoding with local PSIP branding
Multi-Channel Broadcasts
As shown in figure 6, by combining a network feed and a local encoded channel, a
broadcaster can rapidly move into a multi-channel environment. The TMX-2010
multiplexer is used to combine the two streams into a single output transport, provide
any necessary bitrate transcoding and coordinate basic PSIP information. In addition to
the SMPTE310 output, an ASI output is automatically generated by the TMX-2010
which can be used for local monitoring.
Digital Satellite Receiver
Digital Video Encoder
TMX-2010 Multiplexer
TMX-2010
TMX Element Manager
SSI
Broadcast Tower
ASI
Local Monitoring
FIGURE 6: Single Network Feed With One Local Encoded Channel
Grooming Of Multiple Content Sources and Distribution to Multiple Networks (Figure 7)
As a broadcaster chooses to increase the number of standard definition channels
included in an ATSC broadcast, bandwidth usage is pushed to the maximum. The
Motorola BCS SE-2000 encoders and the TMX-2010 multiplexer can work in concert to
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ATSC Application Note
efficiently manage bandwidth consumption. The TMX-2010 multiplexer supports both
standard definition statistical multiplexing and add/drop service grooming. Motorola
BCS’ SE-2000 local encoders excel at advanced compression techniques to ensure
high quality video at lower bit rates. The end result is mix of network and local encoded
content, groomed to fit the 19.393 Mbps distribution pipe provided to ATSC broadcasts.
The TMX-2010 supports the creation of multiple output streams to manage different
business scenarios, such as, different daytime and primetime programming, HD vs. SD
broadcasts and direct feeds to cable plants and private networks.
Digital Satellite Receiver
Digital Satellite Receiver
TMX-2010 TRANSPORT MULTIPLEXER
TMX-2010 Multiplexer
TMX-2010
HD
4x SD
Broadcast Tower
High Definition Encoder
HD Encoder
Digital Video Encoder
TMX Element Manager
Digital Video Encoder
HD
Cable Plant
Local Monitoring
FIGURE 7: Multi-Channel SD/HD Distribution To Multiple Networks
The TMX-2010 multiplexer can deliver up to 6 different output streams in a variety of
ASI, DHEI, SMPTE-310 and DS-3 combinations. For example, a broadcaster may
choose to send the HD multiplex direct to a cable headend through a separate ASI or
DS3 output multiplex. Alternately, another multiplex of multiple SD channels may be
created to support a private education or government network.
Advanced Applications (Figure 8)
Motorola BCS’ modular broadcast solution is designed to provide quick integration of
data services and advanced applications.
Datacasting: The TMX-2010 provides standards-based A/90 UDP/IP multicast data
encapsulation into the output ATSC bitstream. Applications such as file transfer,
interactive television, or streaming video are just a few ways broadcasters are
considering such a data pipe.
External PSIP Generation: At any time, external PSIP generators may be added to
increase the ability to provide days worth of program guide information to the TMX-2010
output multiplex.
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ATSC Application Note
Digital Satellite Receiver
High Definition Encoder
HD Encoder
Digital Video Encoder
TMX-2010 TRANSPORT MULTIPLEXER
TMX-2010 Multiplexer
TMX-2010
TMX Element Manager
ASI
SSI
SSI
Broadcast Tower
ASI
Cable Plant
PC
DTV Set
PSIP Generator
Hub
Data Serve r
Monitor
FIGURE 8: Datacasting and External PSIP Generation
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ATSC Application Note
6 Summary
Motorola BCS has designed a modular ATSC system to best meet evolving business
models and demographics. The basic building blocks include a transport multiplexer
and standalone encoders. The elements seamlessly fit together to facilitate costeffective compliance and rapid deployment of new services.
Encoder features
SE-2000 compact 1 rack unit SD encoder design
o Analog or digital inputs
o Dolby brand AC-3 and AC5.1 pass-through support
TMX-2010 TRANSPORT MULTIPLEXER
o Dual-pass video encoding
Full featured HD encoder
o Advanced video panel processing
o Internal audio support
TMX-2010 Multiplexer features
Modular 3 RU design
MPEG-2 service multiplexing
IP Encapsulation (A/90)
10 (up to 30) ASI input for extensibility to multicasting
2 (up to 6) ASI and SMPTE-310 output
Simple to use TMX-Element Manager
ATSC PSIP service table generation (A/65)
MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All other product or service names are
the property of their respective owners. Dolby and AC-3 are trademarks of Dolby Laboratories.
© Motorola 2003.
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