Transcript Presentation

Digital TV &
MPEG-2 Technology
MPEG 101 and PSIP for Cable
SCTE-New Jersey Chapter
October 5, 2010
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Basic MPEG and PSIP in Cable
Triveni Digital
presents
Digital Television: MPEG 101
and
PSIP In Cable
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Page 2
Let’s talk about:
Digital Television
DTV is more about Data Transmission.
“Just so happens that some of the data being transmitted
ends up as Video”.
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Digital Television
There is much more data
beside video
being transmitted !
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Let’s first talk about:
DTV = Data Casting
Data is organized into ‘tables’
Examples:
Program Association ‘Table’
Progam Map ‘Table’
Conditional Access ‘Table’
Virtual Channel ‘Table’
Master Guide ‘Table’
Event Information ‘Tables’
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MPEG 101
Let’s talk about some
basic MPEG transport
technology
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MPEG 101+
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Training Overview
 MPEG Transport Stream Basics

Packet header


PAT
 PSI Tables metadata
PMT
 Elementary streams

Encoding/Group Of Pictures
(GOP)



Synchronization
Buffering
IP monitoring & synchronization
 Monitoring and Troubleshooting
In The 2nd half of this presentation:
PSIP Tables metadata
Static tables
Dynamic tables
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streams


StreamScope architecture
Typical use case
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DTV Broadcast Stream


Special case of MPEG-2 transport stream
May contain multiple virtual channels



Video channels



A video stream
One or more audio streams
Possibly one or more data streams
Audio channels


One or more audio streams
Possibly one or more data streams
Data-only channels

One or more data streams
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MPEG-2 Transport Stream

Made up of 188-byte transport packets, each with 4
byte header & 184 byte payload

Each packet contains any ONE kind of information–
audio, video, data, PSI, …
One
Transport
(MPEG)
Packet
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MPEG-2 Transport Stream (Contd.)

We say transport packets have multiple interleaved
elementary streams -- audio, video, data, PSI, ...

Packets belonging to the same elementary stream are
identified by packet id (PID) in packet header (same
color in our illustrations).
MPEG-2 Transport Stream
These three packets are the same color.
They have the same PID and belong to
the same Elementary stream.
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MPEG-2 Transport Stream – Header Fields
Noteworthy fields:
1) Sync Byte – Find packet boundary
2) PID – Used while demultiplexing stream
3) Continuity Counter – Identify packet loss
4) PCR stamp in adaptation field – Clock sync
MPEG-2 Transport Stream
Header (4 Bytes)
Sync
Byte
PID
188 Bytes
Continuity
Counter
Adaptation
Adaptation
Field
Field
(Optional)
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PES 1
x
Or other Payload (Pat, PMT, PSIP,
etc)……………………………...
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MPEG Header Fields: Sync Byte

When a decoder first tunes, all it sees are a stream of
0’s and 1’s

The decoder must first identify the beginning of
packets before it can interpret the stream

The decoder uses the Sync Byte field to do this
01010001111010010101101010001100011110010111000
MPEG Data Prior to
Packet Sync
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MPEG Header Fields: Sync Byte (Contd.)

The Sync Byte of a packet is always 0x47
(Hexadecimal) or 01000111 binary

The decoder looks for strings of zeros and ones which
match the pattern of the sync byte (see red below)
01010001111010010101101010001100011110010111000
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MPEG Header Fields: Sync Byte (Contd.)

Once the decoder finds a 0x47 in the stream, it looks 187 bytes
down the stream, and looks for another 0x47

If it finds three Sync Bytes in a row, then the Decoder has Found
Sync and assumes packet boundaries from then on

Each packet is tested for 0x47 as soon as it arrives. If a packet
arrives with an incorrect sync byte, the decoder starts over. This
is called SYNC LOSS
Found Sync
0x47
187 bytes
0x47
187 bytes
0x47
187 bytes
Packet 188 bytes
Sync Lost
Packet 188 bytes
Packet 188 bytes
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0x32
11010101010111011010101010001
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MPEG Header Fields: Sync Byte (Contd.)

If you don’t have Packet Sync, the decoder cannot find
packet boundaries. You will not be able to decode at
all

Packet Sync problems typically occur in hardware at
packet boundaries during format converters, edge
devices, demodulators etc:



ASI to Gig-E
ASI to Microwave or QAM
Satellite to ASI
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PIDs Defined - ATSC Bitstream
PSIP Tables
PSIP Generator
Video
PAT
Audio
PMT
Data channel
Data Server
Data
Null
PSIP
Dataenhanced
Audio/Video
channel
Audio/Video
channel
Data Server
Audio Encoder
Multiplexer
Video Encoder
Audio Encoder
Video Encoder
MPEG-2 Transport Stream
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PIDs Defined - Digital Cable Bitstream
Video/Audio
channel
Video/Audio
channel
Video/Audio
channel
Video/Audio
channel
Audio Encoder
PAT
Video Encoder
PMT
Audio Encoder
CAT
Video Encoder
Audio Encoder
Null
Video
Audio
Video
Audio
Video
Audio
Video
Audio
Multiplexer
Video Encoder
Audio Encoder
Video Encoder
MPEG-2 Transport Stream
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Transport Stream Demultiplexing

When a set top box first receives a Transport Stream, it
demultiplexes that stream based on PID.
Decoder: Receiver or
set top box
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MPEG 101 Knowledge Check #1
Q: How many of what must the decoder
see before it can begin decoding a digital
video stream ?
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PSI Meta Data In the
Stream
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‘Metadata’ ?
 Data about included data, is metadata
 Metadata tells the decoder which kinds of information
are contained in each PID, and which PID’s go
together.
 For DTV, we’re interested in two kinds of metadata:

Program Specific Information (PSI) - Tables in the
stream defined in the MPEG standards

Program and System Information Protocol (PSIP) Tables defined in ATSC A/65
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PSI Tables (MPEG-2 Tables)


PAT
- Program Association Table


Appears in PID 0x0000

The PAT is on PID 0x00. This is the first PID or ‘Base PID’ a
MPEG decoder looks for
Identifies MPEG-2 programs in transport stream and gives
PIDs for their PMTs
PMT - Program Map Table
Identifies elementary streams in program (virtual
channel), and gives their PIDs.
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MPEG-2 PSI Tables (Contd.)
PMT 1
Video PID 0x31
Audio PID 0x34
Audio PID 0x35
PCR_PID 0x31
PAT (always on PID 0x0)
Station TSID
PMT 2
PID 0x40
PMT 1 -> On PID 0x30
PMT 2 -> On PID 0x40
PMT 3 -> On PID 0x50
Video PID 0x41
Audio PID 0x44
Audio PID 0x45
PCR_PID 0x41
PMT 3
Video PID 0x51
Audio PID 0x54
Audio PID 0x55
PCR_PID 0x51
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MPEG-2 PSI Tables (Contd.)
Decoder: Receiver or
Set top Box
“WXXX Channel Video”
PID 0x31
“WXXX Channel Audio”
PID 0x34
PSI
PID assignments
These PIDS go together
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Continuity Counter
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MPEG Header: Continuity Counter

The continuity counter is a 4 bit field in the header
which increments by 1 each time a packet comes out
on a specific PID:
All Packets PID 0x52
0
1
2
3
4
5
6
7
…
8
14 15
0
1
 When a PID ‘skips’ one value of the continuity Counter,
we call it a ‘Continuity Error.’ This means one or more
packets were lost.
Continuity
Error Here
All Packets PID 0x54
0
1
2
3
7
8
9
10
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11
…
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MPEG Header: Continuity Counter (Contd.)
Identifies WHEN we lose
Packets, but not HOW MANY!

Packet loss causes many other kinds of analysis to ‘reset’ or give
bogus results.

Any analysis based on an average over many packets will
automatically reset when it encounters continuity problems.

Since a continuity error mean ‘some packets’ have been lost,
frequent continuity errors should be one of the FIRST things you
look for when debugging.
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Three Things to Remember

Three main monitoring and troubleshooting lessons:



Fix Continuity Problems first


Continuity errors create bogus alarms in other areas.
Until you resolve the continuity problems, it will be very hard to
determine if you have other problems in your stream
To Be Discussed
To Be Discussed
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MPEG 101 Knowledge Check #3
Q: If the continuity counter on a
given PID changes from 3 to 7, how
many packets have been lost?
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Elementary streams:
Encoding Video & Audio
Data
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MPEG-2 Video/Audio Encoding
MPEG Video






It all starts at the encoder
The encoder compresses baseband video & audio
Video is a sequence of frames
A frame is a single image from a video sequence
In USA, one frame occurs every 33 milliseconds
Each frame is encoded in one of three ways:
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MPEG-2 Video/Audio Encoding
I Frames

I-picture: intra-picture encoding, similar to jpeg encoding
(exploiting spatial redundancy).





Compressed solely on information found in the frame
Highest amount of data of all other frame types
‘Group Of Pictures’ always start with an I frame
B & P frames are calculated from the I frame
“I” stands for “Intra” coded
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MPEG-2 Video/Audio Encoding
B Frames

B-picture: bi-directional encoding, using motion adjusted
deltas from a previous and a future frame (exploiting temporal
redundancy).



Uses Data from preceding and following I & P frames
Depends on data before and/or after in video sequence
Cannot calculate from another B frame
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MPEG-2 Video/Audio Encoding
P Frames

P-picture: predictive encoding, using motion adjusted deltas
from a previous reference frame (exploiting temporal
redundancy).


Compressed using data from closest preceding I or P frame
GOP with back-to-back P frames usually indicate fast motion
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MPEG-2 Video/Audio Encoding



Encoder emits sequence of encoded frames

PES packets are packed into MPEG-2 transport packets
(All packets for single video stream have same PID
value)


Overall compression ratio is 50:1 or more
Sizes of encoded frames vary
Encoded frames are packed into packetized
elementary stream (PES) packets.
Closed captioning associated with video frame is
encoded here
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MPEG-2 Video/Audio Encoding
Group of Pictures = GOP


Series of frames consisting of a single ‘I’ frame with P & B frames

All frames within the GOP depend directly or indirectly on data from
the I frame



Relationships between GOPs: Either OPEN or CLOSED
A GOP begins with an ‘I’ frame and ends with last frame before the
next ‘I’ frame
Closed GOP is self-contained. No dependance on data outside GOP
Open GOP can use data from I frame of following GOP
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MPEG-2 Video/Audio Encoding (Contd.)
Example 1. Panning Camera
I-picture
B-picture
I-picture
B-picture
I-picture
Example 2. Moving Object
I-picture
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MPEG-2 Video/Audio Encoding
Typical GOP Structures
I Frame
216.6 Kb
B Frame
49.9 Kb
I
B B
P B
B P B B P B
B
I
B
P Frame
83.45 Kb
B P B B P B
B P
B B
Typical low motion GOP sequence
I Frame
183.2 Kb
P Frame
59.9 Kb
P
P P
P P
P P
P P P
P P
I
P
P Frame
44.5 Kb
P P P P
P P
P P
P P
Typical high motion GOP sequence
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ATSC/SCTE Audio Formats

ATSC uses AC-3 audio encoding, with up to 6 audio
channels: left, right, center, left surround, right
surround, low frequency enhancement.



The full set is often called 5.1 audio.
The sampling rate is always 48 kHz.
The encoded bit rate may be up to 384 kbps.
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AC-3 Audio Encoding

Audio frames, each 32 milliseconds in length, are
encoded.


Encoded frame size depends only on bitrate.

PES packets are packed into MPEG-2 transport packets.
(All packets for single audio stream have same PID
value.)
Encoded frames are packed into packetized
elementary stream (PES) packets.
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MPEG 101 Knowledge Check #4
Q: In MPEG-2 video encoding, what
are the three video frame types
called?
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Video and Audio
Syncronization using
PCR
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Audio-Video Synchronization

Audio, video are encoded independently, must be
synchronized during play

MPEG has to allow for great distances AND network
processing between the Encoder and Decoder and still
allow for Correct Decode of the transport stream
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How to Assure Audio/Video Sync?

In order for the audio and video Elementary Streams to
remain in Sync, the Encoder Clock and the Decoder
Clock must remain in sync

The next few slides will demonstrate how this happens
and what components to check when it fails…
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Page 45
Encoder Inserts PCR timestamps

When the encoder creates streams of packets, it
embeds the current value of it’s 27 MHz clock into
some of the packets in the stream

This time reference is called the PCR: Program Clock
Reference

MPEG demands that one PCR packet appear in the
stream every 100ms
Encoder
27Mhz Clock
MPEG Packets
MPEG
Packet with
PCR Stamp
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The Encoder and Decoder Clock

The MPEG encoder and MPEG decoder use a 27Mhz
‘clock’ to encode/decode incoming audio and video

The clock is actually a ‘counter’ which advances every
1/27000000 seconds
Encoder
Decoder
27Mhz Clock
27Mhz Clock
1,2,3,4…..
1,2,3,4…..
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The Encoder and Decoder Clock

The MPEG encoder and MPEG decoder use a 27Mhz
‘clock’ to encode/decode incoming audio and video

The clock is actually a ‘counter’ which advances every
1/27000000 seconds
Encoder
Decoder
27Mhz Clock
27Mhz Clock
1,2,3,4…..
1,2,3,4…..
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The Encoder and Decoder Clock

The MPEG encoder and MPEG decoder use a 27Mhz
‘clock’ to encode/decode incoming audio and video

The clock is actually a ‘counter’ which advances every
1/27000000 seconds
Decoder
Encoder
27Mhz Clock
Massive
Network
Processing
1,2,3,4…..
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27Mhz Clock
1,2,3,4…..
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PCR Timestamp Issue


What could conceptually cause PCR timestamp issues?

Encoder possibly time stamped incorrectly

Decoder possibly failed to consume time stamps

PCR packet was accidentally lost in transmission
When PCR time stamps go awry, we have “PCR jitter”
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PCR Jitter Defined
PCR Jitter is:
 Difference between
the Actual Value of the PCR time stamped by
encoder
and
the Expected Value of the PCR as calculated by
decoder based on the clock rate and the time
at which the PCR value is received.
 PCR Jitter spec:
500ns
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PCR Rate (Frequency) Offset
PCR Frequency Offset is:
 Difference between
the clock frequency calculated at decoder
based on actual PCR values received
and
an “ideal” 27 MHz clock, which is the clock rate
dictated by the MPEG-2 standard
 PCR Frequency Offset Spec:
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+/- 810 Hz
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PCR Intervals, Jitter and Rate
PCR spec summary:



Transmit interval: 100 ms

Most streams seen in the field are compliant, but every
now and then extreme jitter shows up.
Jitter: no more than 500 ns
Rate: 27 MHz +/- 810 Hz
 Here’s Why
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PCR Packet Spacing Before Muxing

Note the Number of Packets between each PCR packet
in each Input Stream
Video 0x31
PID
Video 0x41
Video 0x51
Packet
Spacing
0x31
2 Packets
0x41
1 Packet
0x51
0 Packets
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Transport
Stream
MUX
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PCR Packet Spacing After Muxing

Note that the PCR packet spacing has changed!
Video 0x31
Video 0x41
Video 0x51
Transport
Stream
MUX
PID
Old Spacing
New Spacing
0x31
2 Packets
8 Packets
0x41
1 Packet
5 Packets
0x51
0 Packets
2 Packets
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Muxing Causes PCR Jitter

When we MUX multiple streams together, the
spacing between the PCR packets in each
stream CHANGES

The physical shift results in a TEMPORAL shift
as well, throwing the time stamps off

The TEMPORAL shift in PCR values is referred
to as “PCR jitter”
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Muxing Causes PCR Jitter (Contd.)

The MUX has to RESTAMP all the PCR values
to correct for the change in the packet
spacing – THIS IS VERY HARD TO DO

The more services on the output, the harder it is to
restamp

The fewer ‘null’ packets at the output, the harder it
is to restamp
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PCR Timestamp Issue (Contd.)

What in your network facility could cause PCR
timestamp issues?

Three of the most common are:

It can happen any time you MUX streams



It can happen on any IP link – due to network lag
It can happen at the source encoding
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PCR Jitter From Incorrect Encoding

If the MPEG encoder’s parameters are set up
incorrectly, you can introduce jitter at the source

This is relatively rare, however

If a national programmer sent it’s stream up to the bird with
jitter in it, the result would effect all receive sites !


Re-encoded streams at the headend may also create PCR jitter
Local broadcast streams could create PCR jitter at the encoder
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Page 59
PCR Timestamp Issue (Contd.)

What in your network facility could cause PCR
timestamp issues?

Three of the most common are:

It can happen any time you MUX streams

It can happen at the source encoding


lag
It can happen on any IP link – due to network
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PCR Jitter Due to IP Carriage

Network lag can conceal MPEG jitter problems on an IP
link. The network jitter is usually so much larger than
the PCR jitter that the PCR jitter is ‘lost in the noise.’

Hopefully, the IP-ASI or IP-QAM edge device will
provide buffering and use ‘high level math’ to smooth
out the network lag.

MT-40 provides a way to separate the Network Lag
from PCR Jitter.
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MPEG 101 Knowledge Check #5
Q: What is the key element for
synchronizing audio and video?
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Video and Audio Buffers
& Presentation Time
Stamp (PTS)
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Presentation Time Stamp - PTS

Each Frame is marked with a PTS – “Presentation Time
Stamp” – a positive number

The value of the PTS is set to the value of the Encoder
Clock when the frame is encoded
Encoder
27Mhz Clock
MPEG Packets
1,2,3,4…..
F1
PTS
500
F2
PTS
950
Packetizer
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Packets Assigned to Decode Buffer

As packets flow into the Decoder, a space in memory is
set aside for them, one buffer for each PID.
Decoder
27Mhz Clock
MPEG Packets
1,2,3,4…..
Buffer 1 Pid 0x31 Video
Buffer 2 Pid 0x34 Audio
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Reconstruction of Frames From Buffer

Packets form Video and Audio Frames in the buffer
Decoder
27Mhz Clock
MPEG Packets
1,2,3,4…..
Buffer 1 Pid 0x31 Video
F1
PTS
500
F2
PTS
675
F3
PTS
950
Buffer 2 Pid 0x34 Audio
F1
PTS
200
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F2
PTS
990
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The Magic of Decode

When the value of the Decode clock MATCHES the PTS
on the frame, that frame is sent to the decode
hardware
Decoder
Decode
Hardware
27Mhz Clock
MPEG Packets
F1
PTS
200
= 200
Buffer 1 Pid 0x31 Video
F1
PTS
500
F2
PTS
675
F3
PTS
950
Buffer 2 Pid 0x34 Audio
F2
PTS
990
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Another Frame Goes to Decode Hardware

Next Frame
Decoder
Decode
Hardware
27Mhz Clock
MPEG Packets
F1
PTS
500
= 500
Buffer 1 Pid 0x31 Video
F2
PTS
675
F3
PTS
950
Buffer 2 Pid 0x34 Audio
F2
PTS
990
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One More Frame Heads to Decode

And the next frame…
Decoder
Decode
Hardware
27Mhz Clock
MPEG Packets
F2
PTS
675
= 675
Buffer 1 Pid 0x31 Video
F3
PTS
950
Buffer 2 Pid 0x34 Audio
F2
PTS
990
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Page 69
Audio and Video Buffers

Receiver must buffer audio and video frame data until
presentation time.

If data appears too late in the transport stream, buffer
underflow results.

If data appears too early in the transport stream,
buffer overflow results.

Either condition results in garbled play or incorrect
synchronization.

Different set top boxes may respond differently to the
same underlying buffer violations
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Page 70
Summary: Audio/Video Sync

PCR values help the Encoder Clock and the Decoder
Clock to remain in sync

PCR jitter can cause synchronization problems for
elementary streams

Ensure




PCR jitter and frequency offsets are within standard limits
Elementary stream buffers limits are NOT violated
Large PCR jitter values can cause “Lip sync” error
Buffer over- or underflow problems may cause “tiling”,
“pixelization”/”macroblocking” errors
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Page 71
MPEG 101 Knowledge Check #6
Q: What is one potential result of
“video buffer underflow” ?
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Page 72
Overall Jitter versus MPEG Jitter

Use ‘Overall’ or ‘MPEG’ jitter settings when measuring
from constant bit rate sources like ASI

Use ‘MPEG’ jitter setting when measuring jitter on ‘GigE’ links to exclude the network associated jitter from
the jitter calculation.

Use ‘Overall’ jitter setting when measuring jitter on
‘Gig-E’ links if you want to see the total jitter due to
network lag AND MPEG issues (requires Gig-E w/PCR
option)
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Page 73
Overall Jitter versus MPEG Jitter (Contd.)

Gigabyte Ethernet offers specific difficulties when
monitoring PCR related issues


The network delay on a typical UDP network is usually orders
of magnitude greater than the PCR Jitter detected on the
network
Be sure to use the appropriate setting for ‘MPEG’ or
‘Overall’ jitter when measuring PCR on Gigabyte
Ethernet networks (see previous slide)
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Page 74
Three Things to Remember

Three main monitoring and troubleshooting lessons:



Fix Continuity Problems first


Continuity errors create bogus alarms in other areas
Until you resolve the continuity problems, it will be very hard to
determine if you have other problems in your stream
Check for PCR jitter


PCR jitter can cause packet over- or underflow problems
Lip synch errors may also be result of PCR jitter
To Be Discussed
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Page 75
MPEG Troubleshooting
using an analyzer
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Why use a Transport Stream Analyzer?

With analog transmission, if audio/video did not have
any anomalies on a TV set up in the studio, it would
show up intact on the end user’s TV

For digital transmission, this assumption is NOT valid
as digital signals rely on the decoder’s



Firmware implementation
Buffer sizes
Software decoding capability
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Page 77
Why use a Transport Stream Analyzer? (Contd.)

The transition to digital has introduced some specific
challenges for broadcast engineers
• Not all Set top boxes will respond the same way to the same
underlying problem
• Standards violations in digital Transport Streams may show up on a
receiver only intermittently

The only streams which will consistently decode are
those which are compliant

The best way to assure compliance is with a Transport
stream Analyzer/Monitor
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Page 78
MT-40: Collaborative Mode Debugging

Two or more technicians use MT-40 to examine the
same input.

Customers leverage subject matter experts from many
different geographical locations
Head End
Tech Operations Center
LAN
WAN
LAN
MT-40
IRD
MUX
Encoder
Modulator
Equipment Room
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Page 79
MT-40: Multi- Channel Fleet Monitoring
Local DTV Station or Headend
Chief Engineer’s Office
Remote location with MT-40
MT-40 Visualization
Client viewing all
sources, all channels
simultaneously
Network
Equipment Room
Remote location with MT-40
MT-40
Monitoring
local channel
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Page 80
Troubleshooting Example – Audio Outage
• Customer calls into station or NOC – audio dropping out on their set
• In station video monitors & set top boxes do not have any problems
• How serious is this problem? Are other Customers seeing it?
Broadcast Scenario
Encoders
Encoders
Encoders
Encoders
QPSK
Satellite
Dish
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
Television
Transmitter
MUX
Network
Processing
QAM
Modulator
PSIP Gen
Data Gen
Digital to
Analog Mod
Cable TV Scenario
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Page 81
Troubleshooting Example (Contd.)
 Start at the end…..Off-air or combined RF output….
Encoders
Encoders
Encoders
Encoders
QPSK
Satellite
Dish
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
Broadcast Scenario
Gigabit-IP,
ASI or
SMPTE 310
ASI
ASI
MUX
ASI
Television
Transmitter
Network
Processing
Gigabit-IP
ASI
PSIP Gen
QAM
Modulator
Data Gen
Digital to
Analog Mod
Cable TV Scenario
Transport Stream
Analyzer
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RF Input (8VSB or QAM)
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Page 82
Troubleshooting Example (Contd.)

Check of the MPEG analyzer shows Standards violation has occurred
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Page 83
Troubleshooting Example (Contd.)

Move back in the network toward the beginning....
 Input to the QAM modulator OR…..
Encoders
Encoders
Encoders
Encoders
QPSK
Satellite
Dish
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
Broadcast Scenario
ASI
ASI
PSIP Gen
Data Gen
Gigabit-IP,
ASI or
SMPTE 310
ASI
ASI
MUX
Network
Processing
Gigabit
Ethernet
Input
Television
Transmitter
Gigabit-IP
QAM
Modulator
Digital to
Analog Mod
Cable TV Scenario
Transport Stream
Analyzer
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Page 84
Troubleshooting Example (Contd.)
 Input to the transmitter….
Encoders
Encoders
Encoders
Encoders
QPSK
Satellite
Dish
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
Broadcast Scenario
Gigabit-IP,
ASI or
SMPTE 310
ASI
ASI
MUX
ASI
Network
Processing
Gigabit-IP
ASI
PSIP Gen
Television
Transmitter
QAM
Modulator
Data Gen
ASI or
SMPTE 310
Input
Digital to
Analog Mod
Cable TV Scenario
Transport Stream
Analyzer
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Page 85
Troubleshooting Example (Contd.)

Standards violation is still present
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Page 86
Troubleshooting Example (Contd.)
 Move further back…..
Encoders
Encoders
Encoders
Encoders
QPSK
Satellite
Dish
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
Broadcast Scenario
Gigabit-IP,
ASI or
SMPTE 310
ASI
ASI
MUX
ASI
Television
Transmitter
Network
Processing
Gigabit-IP
ASI
PSIP Gen
ASI
Input
Data Gen
QAM
Modulator
Digital to
Analog Mod
Cable TV Scenario
Transport Stream
Analyzer
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Page 87
Troubleshooting Example (Contd.)

Standards violation is still present
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Page 88
Troubleshooting Example (Contd.)
 And further back…..
Encoders
Encoders
Encoders
Encoders
QPSK
Satellite
Dish
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
Broadcast Scenario
Gigabit-IP,
ASI or
SMPTE 310
ASI
ASI
MUX
ASI
Television
Transmitter
Network
Processing
Gigabit-IP
ASI
PSIP Gen
ASI
Input
Data Gen
QAM
Modulator
Digital to
Analog Mod
Cable TV Scenario
Transport Stream
Analyzer
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Page 89
Troubleshooting Example (Contd.)
 Go all the way back to signal entry point…..
Encoders
Encoders
Encoders
Encoders
QPSK
Satellite
Dish
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
Broadcast Scenario
Gigabit-IP,
ASI or
SMPTE 310
ASI
ASI
MUX
ASI
Television
Transmitter
Network
Processing
Gigabit-IP
ASI
PSIP Gen
QAM
Modulator
Data Gen
Digital to
Analog Mod
QPSK
Input
Cable TV Scenario
Transport Stream
Analyzer
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Page 90
Troubleshooting Example (Contd.)
 Using record capability to collect data…..
Encoders
Encoders
Encoders
Encoders
QPSK
Satellite
Dish
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
Broadcast Scenario
Gigabit-IP,
ASI or
SMPTE 310
ASI
ASI
MUX
ASI
Network
Processing
Gigabit-IP
ASI
PSIP Gen
Television
Transmitter
QAM
Modulator
Data Gen
Record at
this point
Record at
this point
Digital to
Analog Mod
Cable TV Scenario
Transport Stream
Analyzer
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Page 91
Summary: MPEG Monitoring Over the Long Term
 Complete and continous monitoring…..
Encoders
Encoders
Encoders
Encoders
QPSK
Satellite
Dish
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
Analyze, Monitor or
Record Streams at any Broadcast Scenario
of these points
Gigabit-IP,
ASI or
SMPTE 310
ASI
ASI
MUX
ASI
Network
Processing
Gigabit-IP
ASI
PSIP Gen
Television
Transmitter
QAM
Modulator
Data Gen
Digital to
Analog Mod
Cable TV Scenario
Error Alerts:
SNMP,
SMS,
E-Mail,
Triggered Recording or
Contact Closure
Error
Notification
Transport Stream
Analyzer or
Remote Monitor
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RF Input (8VSB or QAM)
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Page 92
Three Things to Remember

Three main monitoring and troubleshooting lessons:



Fix Continuity Problems first


Continuity errors create bogus alarms in other areas
Until you resolve the continuity problems, it will be very hard to
determine if you have other problems in your stream
Check for PCR jitter


PCR jitter can cause packet over- or underflow problems
Lip synch errors may also be result of PCR jitter
Move Backward through your network as you debug

Isolate the offending device first, then go for detailed problem
solving steps (recording a file, etc.)
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Page 93
Summary: MPEG’s 7 Basic Parameters
Per ATSC standards:



PAT Interval:
100ms
PMT Interval:
400ms
PCR Interval:
100ms
Max Jitter:
500ns
Max Freq. Offset: +/- 810 Hz
Also check:
Video Buffer
Audio Buffer
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Page 94
References

Information Technology -- Generic Coding of Moving Pictures and
Associated Audio Information: Systems (MPEG-2 Systems
standard), ISO/IEC 13818-1.


ATSC Digital Television Standard, ATSC Doc. A/53.



ATSC Data Broadcast Standard, ATSC Doc. A/90.
Program and System Information Protocol for Terrestrial
Broadcast and Cable, ATSC Doc. A/65 (with amendments).
ATSC A/78 Recommended Practice on Bitstream Verification.
Video Over IP by Wes Simpson
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Page 95
Let’s Talk PSIP
in Cable
How do you spell PSIP?
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PSIP In Cable
So What Is PSIP ?
Technical answer:
PSIP is a type of ‘metadata’ that enhances digital
television transport streams.
•Defines virtual channels
•Enables tuning
•Provides an Electronic Program Guide
•Channel branding
•V-Chip
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PSIP In Cable
So What Is PSIP ?
Practical answer:
PSIP enhances the viewers experience:
•Increased Ease of Use
•Channel and Brand Recognition
•Navigating the Multitude of Services Offered
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PSIP in cable
“PSIP is Metadata“
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PSIP In Cable
Meta Data
Mentioned earlier, what is it?
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What is ‘metadata’?
PSI and PSIP are types of ‘metadata’
A form of
‘metadata’.
The label
tells you
what is in the
can.
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Page 101
What is ‘Metadata’ ?
 Data about included data, is metadata
 Metadata tells the decoder which kinds of information
are contained in each PID, and which PID’s go
together.
 For DTV, we’re interested in two kinds of metadata:

Program Specific Information (PSI) - Tables in the
stream defined in the MPEG standards

Program and System Information Protocol (PSIP) Tables defined in ATSC A/65
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PSIP In Cable
PSIP MetaData In the Stream
(Program and System Information
Protocol)
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PSIP Background



Program and System Information Protocol
Metadata inserted into broadcast stream
Enables:








Tuning to virtual channels
Displaying channel name (on channel changes)
Interactive electronic program guides (EPGs)
Automatic language selection for audio track
Caption decoding
“V-Chip” function (parental content blocking)
Accurate receiver time-of-day clock setting
Redistribution Control
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Page 104
Basic functions of PSIP Tables
 Branding – Station call letters and channel number
 Signaling – V-Chip data, information about audio and
Video PID’s, Virtual Channel Table
 Announcement – Electronic Program Guide (EPG)
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Page 105
Signaling vs. Announcement

Signaling




Information about what is "on now"
Used to assemble program elements into whole


Provides linkages
Ex: PMT and/or VCT used to link different components of television
program (i.e. video and audio)
Used to define characteristics of current program (descriptors)

Captioning, ratings, redistribution…
Announcement



Information about what will be available in the future

Typically does not provide linkages between program elements
Program Guide information (name, description schedule)
Characteristics of future programs (captioning, ratings,
redistribution…)
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PSIP Generation Architecture
Traffic/Program
System
Encoder(s)
Time
PSIP
Generator
Remote
GUI(s)
Automation
System
Listing
Service
Staging
Server
M
U
X
F
I
R
E
W
A
L
L
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Page 107
PSIP metadata found in the ‘Payload’
Noteworthy fields:
Payload contains PSIP, PAT, PMT metadata
PSIP
metadata
found in the
packet
‘Payload’
MPEG-2 Transport Stream
Header (4 Bytes)
Sync
Byte
PID
188 Bytes
Continuity
Counter
Adaptation
Adaptation
Field
Field
(Optional)
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PES 1
x
Or other Payload (Pat, PMT, PSIP,
etc)……………………………...
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Page 108
PSIP In Cable
ATSC (A/65) PSIP Metadata
North American Standard
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Page 109
DTV PSIP Tables

VCT - Virtual Channel Table Transmit Interval: 400ms
- Identifies and describes virtual channels.
*** Two Different Types of VCT: CVCT and TVCT ***

MGT - Master Guide Table
Interval: 150ms
- Appears in PID 0x1FFB.
- Gives PIDs, sizes, and version numbers of other PSIP
tables (except STT). A directory of all PSIP tables.

STT - System Time Table
- Appears in PID 0x1FFB
- Gives current UTC time.
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Interval: 1,000ms (1 sec)
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DTV PSIP Tables (Contd.)
 RRT- Rating Region Table
Interval: 60,000ms (1 min)
- Describes content advisory system(s) being used to rate
events.
EIT has variable intervals:
 EIT - Event Information Table
EIT-0: 500ms
EIT-1: 3,000ms
EIT-2 & up: 60,000ms
- Gives titles, start times, durations, content advisory
ratings of events (TV programs).
 ETT - Extended Text Table
Interval: Follows it’s EIT
- Gives extended textual descriptions of virtual channels
and events.
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Page 111
Details of FCC R&O – PSIP related
 "…fully implement PSIP to the extent that ATSC A/65B
requires."

Required transmission of all mandatory tables and descriptors

MGT, TVCT, EIT-03, STT, RRT (except region 1)
 Required tables and descriptors must be populated
with proper and correct information
 At least 12 hours of populated EITs


(EIT-0 thru 3)
EITs must contain correct schedule information
Each EIT contains 3 hours worth of event information
 Major channel rules from PSIP (A/65B) adopted
 Correct Major Channel number must be used
 Correct TSIDs (Transport Stream ID) must be used
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Page 112
VCT -- Virtual Channel Concept (In General)
 Breaks the link between RF channel number and user’s
notion of channel number

Analog broadcast  “channel number” was the same as the
RF carrier designation

Digital broadcast  “channel number” is defined by Virtual
Channel Table (VCT)
 One digital TS can include multiple channels of
programming
 8-VSB carrier freq. may have (probably) shifted during
transition (June 2009)
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VCT: Two Part Channel Numbers
 1st part: “major channel” (Original analog channel)
 Example: 10.1, 10.2, 10.3
 2nd part: “minor channel” 10.1, 10.2, 10.3
 Broadcasters retain their brand identity
 Digital services groupable with analog
 KXTV has been associated with Channel 10 for years;
KXTV-DT can be found on Channel 10-1

They keep their brand in tact:
(even though their RF carrier is now on Ch. 61)
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Page 114
Virtual Channel Table (VCT)
 Has same info as PAT & PMTs, plus more.
 Allows tuning by virtual major-minor channel number,
rather than physical channel number and MPEG-2
“program” number.
 Allows language track selection.
 Allows channel name to be displayed on channel
changes and in EPG.
 ATSC receivers are designed to use VCT; may have
trouble with PAT and PMTs alone.
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Page 115
Comparing PAT vs. VCT
PAT (Program Association Table)
Table ID
Section Syntax Indicator
Section Length
Transport Stream ID (TSID)
Version Number
Current Next Indicator
Section Number
Last Section Number
Program Number
Program Map PID
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VCT (Virtual Channel Table)
Table ID
Section Syntax Indicator
Section Length
Transport Stream ID (TSID)
Version Number
Current Next Indicator
Section Number
Last Section Number
ATSC protocol version
Number of Channels in Section
Short Name
Major Channel Number
Minor Channel Number
Modulation Mode
Channel TSID
Program Number
Extended Text Message Location
Descriptor Length
Descriptor ( )
Source ID
Service Type
Access Controlled
Hidden / Hide Guide
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Page 116
PSIP and PSI Link
Table Information for a
Digital Television Stream
PAT
(On PID 0x0)
PMT 1
(On PID 0x30)
Station TSID
Video PID 0x31
Audio PID 0x34
PCR_PID 0x31
PMT 1 -> On PID 0x30
PAT and PMT Tables
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VCT
On Pid 0x1FFB
11-1
WXIA
Video PID 0x31
Audio PID 0x34
PSIP Tables
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Page 117
PIDs in the Stream
PID
Program Association
Table (PAT)
0
1
CAT
2
TSDT
TSID = 4100
PMT PID =1025
program_number = 2000
PAT
PAT
points
points
to to
PMT
PMT
Program Map Table
(PMT) (section)
program_number = 2000
MPEG-2
Transport
Stream
PSIP
metadata
tables: VCT,
MGT, STT,
EITs & ETTs
1025
program
number
2000
8187
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501
Video
601
Audio (English)
602
Audio (French)
SI Base PID
...
Video PID = 501
Audio PID (English) = 601
Audio PID (French) = 602
STT, MGT, VCT, RRT
EIT-n, ETT-n, other
tables referenced
by MGT
Page 118
PSIP In Cable
‘SI’ (Service Information)
or TR 101 290
aka: Digital Video Broadcast (DVB)
International Standard
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Page 119
DVB ‘SI’ Tables
DVB Standard uses different tables,
different repetition rates than A/65
 NIT – Network Information Table
 SI Repetition – Interval – how often System Info is sent
 SDT – Service Description Time Table
 RST – Running Status Table
 TDT – Time & Date Table
 No Virtual Channel Table: Uses PAT/PMT & CAT
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Page 120
PSIP In Cable
There is even more
data in the stream! :
Descriptors
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PSIP In Cable: Service Descriptors
What are ‘Descriptors’ ?
Descriptors inform the viewer/receiver that services
such as ‘Closed Captioning’ and ‘Alternate Audio’ are
available in the stream.
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PSIP In Cable
Examples of Service Descriptors
AC-3 audio descriptor
2 channel or Surround Sound ?
Which is Primary Audio, which is Secondary Audio?
Now includes ISO 639 langauge bit
Caption Service descriptor
Does stream contain closed captioning data?
If so, in what langauge?
Has captioning control information for the receiver
Content Advisory descriptor
Parental control (V-Chip) information
ISO 639 Langauge descriptor
Send this descriptor for older digital receivers
Redistribution Control descriptor
Similar to ‘copy right’ protection (could effect TiVO)
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PSIP In Cable
What is TSID?
Transport Stream ID
(Uniquely identifies the Multiplex)
In terrestrial broadcast, helps distinguish between
two stations on the same channel
oIndicates which PSIP is correct for a given station
Used differently in Broadband/Cable
More on TSID later
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Page 124
PSIP In Cable
So let’s put it all together and
see how PSIP creates an
Electronic Program Guide (EPG)
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Page 125
Main PSIP Tables
System
Time
Table (STT)
Required for Terrestrial Broadcast
(first four timeslots)
3-hour
time slot
3-hour
time slot
Event
Information
Table (EIT)
Event
Information
Table (EIT)
Master
Guide
Table (MGT)
...
Virtual
Channel
Table (VCT)
Extended
Text
Table (ETT)
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...
Extended
Text
Table (ETT)
Page 126
Version "Bubbling"




MPEG "rule": Any time the
contents of a table changes,
its version number must
increment
Application: Each level in a
table hierarchy carries the
version number of a
referenced, lower level table.
Thus: Any change in a table
will “bubble” upwards
Consequence: Any change in
a PSIP table will be reflected
by a version change in the
MGT!
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Hour 0-3
MGT
PID A
Table Ref 1
EIT-0
Table Ref 2
RRT
Event 1
Event 2
Table Ref 3
VCT
Event 3
Table Ref 4
Event 4
VC 1
Table Ref 5
VC 2
EIT-0
Table Ref 6
Event 1
Table Re 7
Event 2
DCCT
PID Z
DCCSCT
ETT
PID V
ETT
ETT
ETT
ETT
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Page 127
Master Guide Table (MGT)
 MGT is the top-level “roadmap”



Identifies what PSIP tables are in transport stream
Gives PIDs so receiver can find them
Indicates when any table has been updated
MGT (PID 0x1FFB)
Table Reference
• Table Type (VCT, EIT-0, etc.)
• PID where table can be found
• Referenced Table Version
• Referenced Table Size
• <descriptors>
Table Ref 1
Table Ref 2
Table Ref 3
Table Ref 4
(PID 0x1FFB)
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Page 128
Virtual Channel Table (VCT)
A view of what is in the VCT using an MPEG analyzer to look at
the table ‘SectionArray’
(PID 0x1FFB)
Virtual Channel
• Short Channel Name
• Major Channel Number
• Minor Channel Number
• Modulation Mode
• Frequency
• TS ID (of Virtual Channel)
• Program Number (in Stream)
• Extended Text Location
• Access Controlled ?
• Hidden ? Hide from Guide?
• Service Type (A/V/D)
• Source ID
• Service Location Descr
• other descriptors
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Video Stream
Eng Audio Stream
Fre Audio Stream
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Page 129
Event Information Tables (EITs)
A closer look at the EIT Section Array using an MPEG analyzer
 Describe “events” (TV programs).
 EIT-0 through EIT-127; each covers 3 hour period
 EIT-0 thru EIT-3 required.
Event
•
•
•
•
•
VCT
VC 1
VC 2
Event ID
Start Time (GPS)
Duration in Seconds
Title (multiple languages)
Extended Text Location
Descriptors
• Content Advisory
• Closed Captioning
• AC-3 Audio
• Broadcast Flag
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Electronic Program Guide (EPG)
The EPG gets filled in using data from EIT’s, VCT and STT
Channel
6:30pm
7:00pm
7:30pm
KXYZ-DT
(7-1)
Local News
Ben’s Lab
Thunder Car
KXYZ-D2
(7-2)
KXYZ-D3
(7-3)
Movie: “Frontier Brain Surgeon”
Movie: “Burnout”
(5:00)
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Gena
Horace Horse
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EIT Contents
Handling the cross-over between EIT-0 and EIT-1
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At 3-Hour Boundary
What was EIT-1, now becomes EIT-0
More data is plugged into the new EIT-3
(or whatever the last EIT is)
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Page 133
Extended Text Tables (ETTs)
Use the ETT to describe the story line, name the actors,
when the program was made and other details about an event




ETT-0 thru ETT-127, plus a “channel ETT”
Text descriptions for channels and events
May use Huffman coding to reduce bandwidth
May be in multiple languages
EIT-n 1
Event
Event 2
Event 3
Event 4
Event 5
VCT
VC 1
VC 2
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Page 134
Multilingual Text
 Everywhere text is used


Program titles & descriptions
Exception: “short” channel name
 Context-sensitive Huffman coding (English lang.)


Two tables, one optimized for titles, one for descriptions
Compression efficiency is approx. 2:1
 Uses ISO 639 Language coding
 May be included with the AC-3 descriptor
 May have it’s own descriptor
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Page 135
PSIP Tables: The Big Picture
Data is constantly being moved. EIT-0 thru EIT-3 are required.
More EITs can be used, but will take up more bandwidth
Hour 0-3
Hour 3-6
Hour 6-9
Hour 9-12
MGT
PID A
PID B
PID C
PID D
Table Ref 1
EIT-0
EIT-1
EIT-2
EIT-3
Event 1
Event 5
Event 7
Event 8
Event 2
Event 6
Event 8
Event 9
Event 3
Event 7
Table Ref 2
Table Ref 3
RRT
VCT
Table Ref 4
Event 10
Event 4
VC 1
Event 11
Table Ref 5
VC 2
Table Ref 6
EIT-0
EIT-1
EIT-2
EIT-3
Event 1
Event 3
Event 5
Event 9
Event 2
Event 4
Event 6
Event 10
Event 5
Event 7
Event 11
Table Re 7
DCCT
PID Z
DCCSCT
Event 8
ETT
ETT
PID V
PID W
PID X
PID Y
ETT
ETT
ETT
ETT
ETT
ETT
ETT
ETT
ETT
ETT
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Page 136
PSIP Servers Hide the Complexity
Getting all the PSIP and EPG data into
the right table is made easy with good software
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Page 137
EIT
VCT
ETT
STT
VCT
EIT
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Page 138
PSIP In Cable
How is PSIP in Cable different
from PSIP in Terrestrial Broadcast?
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Page 139
PSIP In Cable
Cable has several different scenerios to contend with
Factors that will influence how PSIP plays in a Cable or IPTV environment:
Multiple targeted service levels
Encrypted programs
Clear QAM
Digital Set-top Boxes
Tru2Way
Digital-To-Analog Set-top Boxes
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Page 140
PSIP In Cable
FCC PSIP Rule for Cable
The FCC requires that PSIP information must be present
in the Cable feed:
For channels containing PSIP on ingest
Channels carried in the clear (Clear QAM)
To enable a subscriber viewing experience, similar to Off-Air DTV
•For those subscribers without STB or Tru2Way
•Might include those with Digital TVs with QAM tuners
•Subscribers with older analog TVs needing a DTA
To conserve bandwidth, amount of PSIP data can be modified:
Only the first 4 EITs need to be carried
ETTs can be removed
Service Location descriptor (SLD) is not required in the CVCT
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PSIP In Cable
Cable PSIP vs. Broadcast PSIP
CVCT (Cable Virtual Channel Table)
•Virtual Channel Name
•Channel Number (1 or 2 parts)
•MPEG-2 Program Number
•Service Type
•Source_ID
•No SLD required
Cable
•Relies on PMT
•Descriptors are in the PMT
•SLD information is in the PMT
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TVCT (Terrestial Virtual Channel Table)
•Virtual Channel Name
•Channel Number—Major & Minor
•MPEG-2 Program Number
•Service Type
•Source_ID
•SLD required
Broadcast
•Descriptors are in the EIT
•TVCT has PID values for all streams
•Service Location Descriptor
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PSIP In Cable
Descriptors: Cable vs. Broadcast
Descriptor
Cable-PMT
CVCT
Broadcast-EIT
AC-3 audio
X
X
Caption Service
X
X
Content Advisory
X
X
ISO 639 Langauge
If used X
Ext Channel Name
Service Location
Broadcast-VCT
X
X
Option
X
X
X
Time Shifted Serv
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Page 143
PSIP In Cable
TSID: Cable vs. Broadcast
The Transport Stream ID (TSID) uniquely identifies the Multiplex
In Broadcast:
In cases where there are two stations on the same channel, TSID
identifies the correct PSIP information for the selected station
The FCC assigns a unique TSID to every broadcast station
In Cable:
TSID simply identifies a given multiplex
Can be a random or arbitrary number assigned by the MSO
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Page 144
PSIP In Cable
Bottomline:
PSIP in Cable
is different than PSIP
in Broadcast
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PSIP In Cable
PSIP in Cable Applications
Three scenerios:
1. Support for EPG with ClearQAM and DTAs
2. Support Lower Cost DTAs
3. Digital and HD delivery to Multiple Dwelling Units
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PSIP In Cable
Typical Digital Television Station Generating PSIP metadata
HD Encoder
PSIP
TVCT,
MGT,
EIT, ETT
SD Encoder
SD Encoder
SD Encoder
Listing
Service
M
U
X
PSIP
Generator
Limited
Signal
Processing
Digital
Television
Broadcast
Transmitter
Various
configurations such
as redundant and
replicated outputs
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Page 147
PSIP in Cable
Typical major Cable TV network
TVCT
Off-Airs
Off-Airs
Off-Airs
Off-Airs
Off-Airs
Encoders
Encoders
Encoders
Ingested PSIP is
groomed. Output is
A/65 Compliant.
PAT/PMT & CVCT
Digital Settop Box
OR
QAM
Modulator
CherryPicker,
BMR, BNP
Tru2Way
Digital TV
Cable/HFC
Network
Digital to
Analog Mod
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
Proprietary
Out-Of-Band
Data Channel
Satellite
Dish
Listing
Service
Full EPG info on
High End Digital
Set-top Boxes.
DACS type Set-top Control &
Encryption
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AND
Digital-ToAnalog Conv
Only Channel
Number &
Name,
no Guide Info.
OR
ClearQAM
cable ready TV
‘EIT & ETT’ like
information in
a
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proprietary format
Page 148
PSIP In Cable
CAUTION !!!
In a Cable TV network, don’t multiplex
off-air broadcast streams without Grooming !
The result would be:
Multiple different table versions for: VCT, MGT, STT, SLD
Duplicate PID values
Collisions of various pointers, such as source_id
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PSIP in Cable
Any Cable TV network
Add PSIP
metadata:
Full EPG info on
High End Digital
Set-top Boxes.
TVCT
Off-Airs
Off-Airs
Off-Airs
Off-Airs
Off-Airs
PSIP
Metadata
Generator
Encoders
Encoders
Encoders
OR
CherryPicker,
BMR, BNP
QAM
Modulator
Tru2Way
Digital TV
Cable/HFC
Network
Digital to
Analog Mod
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
Listing
Service
Digital Settop Box
AND
Digital-ToAnalog Conv
DACS type Set-top Control &
Encryption
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Now Full EPG
info on
ClearQAM and
DTAs
OR
ClearQAM
cable ready TV
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PSIP In Cable
Function of the PSIP generator:
The PSIP metadata generator will:
Handle all PSI and PSIP information
Leaves multiplexers responsible for video and audio streams only
Extracts PSI and PSIP data packets from incoming streams
Decodes extracted tables
Information then used to:
Create A/65 compliant streams on the output
Merges with each transport per operator configuration
Information included: Channel numbering, PIDs, EITs also
oMGT and CVCT
oMovement of descriptor information from EIT to PMT
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Page 151
PSIP in Cable Encryption, DACS & Set-tops: Cost Prohibitive
Add ‘Lower Cost DTAs’: Use ‘SI’ data for PSIP:
Now Add PSIP (A/65) metadata:
TVCT
Off-Airs
Off-Airs
Off-Airs
Off-Airs
Off-Airs
SI Metadata
Generator
Encoders
Encoders
Encoders
PACE or
Evolution
type lower
cost DTA
Digital-ToAnalog Conv
CherryPicker,
BMR, BNP
QAM
Modulator
Cable/HFC
Network
Digital to
Analog Mod
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
PSIP
Metadata
Generator
AND/OR
ClearQAM
cable ready TV
Now Full EPG info
on ClearQAM TVs
and DTAs
Listing
Service
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Page 152
PSIP In Cable
Why is ‘SI’ used for these DTAs ?
Lower cost due to being widely used internationally
These DTAs were originally developed for the DVB standard
Why is a ‘PSIP’ generator needed for ClearQAM?
Digital TVs used in the USA are built to the ATSC-A/65 standard
Cannot decode MPEG or SI metadata
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Page 153
PSIP in Cable
Digital Channels Delivered to an MDU:
TVCT
Off-Airs
Off-Airs
Off-Airs
Off-Airs
Off-Airs
PSIP
Metadata
Generator
Encoders
Encoders
Encoders
Dedicated
Fiber
ClearQAM
TV
CherryPicker,
BMR, BNP
Satellite
Receivers
Satellite
Receivers
Satellite
Receivers
QAM
Modulator
Fiber
Optic
Trans
mitter
ClearQAM
TV
Hotel, Resort or
College Dormitory
Full EPG info on
ClearQAM TVs
Listing
Service
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Page 154
PSIP In Cable
Dedicated service to MDUs
Allows for:
Creation of a custom channel line-up
Special purpose channels included
All digital video service
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Page 155
Further Information
 ATSC A/65B – PSIP standard

http://www.atsc.org/standards/a_65b.pdf
 ATSC A/69 – PSIP Implementation Guidelines

http://www.atsc.org/standards/a_69.pdf

http://www.psip.org/
 Additional PSIP information
 "Channel Branding and Navigation for DTV :
Understanding PSIP", NAB Science & Technology Dept
 "PSIP: Program & System Information Protocol", Mark
Eyer
 “Video Over IP”
by Wes Simpson; SCTE Bookstore
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PSIP In Cable
GuideBuilder ®
Industry leading A/65 standard PSIP generator for
fixed based and mobile digital television service.
GuideBuilder -SI®
Industry leading ETR 101 290 DVB standard PSIP
generator for fixed based digital television service.
StreamScope®
Analysis and stream monitoring tools for MPEG
digital video transport.
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Page 157
Thanks
Digital TV &
MPEG-2 Technology
MPEG 101 and PSIP for Cable
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