ATSC Program and System Information Protocol (PSIP)

Transcription

1 ATSC Program and System Information Protocol (PSIP) Michael Isnardi Broadcast Technology Society April 8, 2000 Reproduction in any form requires written permission from the

2 Why PSIP exists Avoids rebranding expense by broadcasters Provides a basic channel selection method using an electronic program guide Simple enough to go in every receiver Extensible for higher end products Small change in tuning paradigm for consumer Compatible with printed media Supports V-Chip and Conditional Access

3 ATSC Standards Standards documents: A/52: AC-3 Audio Compression A/53: ATSC DTV Standard (contains video formats) A/54: Guide to use of the ATSC DTV Standard A/55: Program Guide (Optional) A/56: System Information (Optional) A/57: Program/Episode/Version Identification A/58: Harmonization with DVB SI (Rec. Practice) A/63: Standard for Coding 25/50 Hz Video A/64: Transmission Measurement & Compliance... A/65: Program and System Information Protocol A/66: PSIP Technical Corrigendum No. 1 A/67: PSIP Technical Amendment No. 1 A/70: Conditional Access System for Terrestrial Broadcast A/80: Modulation and Coding Reqt s for DTV Apps. Over Satellite For more info, see replaced by

4 PSIP = Your DTV Identity PSIP = Program and System Information Protocol Covered by ATSC Standard A/65, A/66, A/67 Combines and Compacts A/55 and A/56 Must be transmitted by ATSC terrestrial broadcasters in their DTV Transport Stream Is an ATSC (not FCC) requirement

5 Program and System Info Protocol PSIP features: allows navigation and access to each of the channels within the Transport Stream preserves channel branding program guide (from 12 hours to 16 days) gives the user information for browsing and selection key system info (e.g., carrier freqs and source ID s) rating and content advisory info ATSC Receiver can scan active channels for PSIP and can build an integrated guide

6 Electronic Program Guides Chan Name 6:00 pm 6:30 pm 7:00 pm 7:30 pm 8:00 pm 8:30 pm 6-0 CBZ City Life Travel Movie: Texas Wild II 6-1 CBZ City Life Travel 6-2 CBZ Movie: Secret Agent 6-3 LCL Local News Airport Info Movie: Texas Wild II (HDTV) Interactive and Useful - Event and Channel Information - Automatic Recording - With Future Extensions, can enable Thematic Browsing and Sorting

7 Scope of PSIP May describe associated analog channel s programming. PSIP Data Must describe its own DTV programming. May describe another DTV channel s programming. Ch. 2 Ch. 31 Ch. 46 WXYZ WXYZ-DT WPQR-DT Analog Digital Digital (6 MHz) (6 MHz) (6 MHz)

8 ATSC Transmission System Video (one of 18 formats) Audio (up to 5.1 channels) Data PAT: PMT: PSI: SP: MP: Program Association Table Program Map Table Program Specific Information Single Program Multi Program Single-Program Encoder MPEG-2 Encoder AC-3 Encoder MPEG-2 Bitstream AC-3 Bitstream PMT Transport Mux PSI and PSIP Generator Program and System Info System Time SP Transport Stream (3-18 Mb/s) MP SP Transport Stream PAT PSIP Transport Mux 6 MHz RF Channel MP Transport Stream (19.4 Mb/s) DTV Transmitter Channel Coder & 8-VSB Modulator

9 ATSC Decoder Single-Program Decoder DTV Tuner Physical Channel Select Transport Stream (19.4 Mb/s) 8-VSB Demodulator Transport Demux MPEG-2 Bitstream AC-3 Bitstream Time Stamps PCR s MPEG-2 Decoder AC-3 Decoder Clock Recovery and A/V Synchronization Display Processing Video Audio Program Select PSIP Data Program Select (from User) Program Guide Database On-Screen Display

10 Tuning Example - PSIP Multi- Program Transport Stream PID 0x1FFB PID # Type PID-V Video PID-P PCR PID-A Audio To A/V/D Decoders PID-D Data Create Program Guide Virtual Channel Table Look Up PID s Filter PID s for Elementary Streams Dump Other Packets Tune to Program

11 PSIP Tables Table STT MGT VCT RRT EIT ETT Description System Time Table - provides date and time Master Guide Table - provides version, size and PID s of all other tables (except STT) Virtual Channel Table - provides attributes for all virtual channels in this Transport Stream Rating Region Table - provides rating information for multiple geographic regions Event Information Table - provides information for events on the virtual channels Extended Text Table - provides detailed descriptions of virtual channels and events

12 PSIP and MPEG Acronyms bslbf CRC ETM PAT PMT PTC sb rpchof uimsbf UTC bit serial, leftmost bit first Cyclic Redundancy Check Extended Text Message Program Association Table Program Map Table Physical Transmission Channel smoothing buffer remainder polynomial coefficients, highest order first unsigned integer, most significant bit first Coordinated Universal Time

13 What s Required for Transmission? an ATSC, not FCC, requirement... Update Table STT MGT VCT RRT EIT ETT Required for Broadcast? (TVCT) (EIT-0, -1, -2, -3) (all others optional) optional Required for Cable? (CVCT) optional optional Note: CEA and NCTA have agreed on PSIP over cable. Out-of-band profiles are defined in SCTE DVS-234r

14 Table Hierarchy Base PID 0x1FFB STT RRT MGT VCT Chan A Chan B Chan Z PID-ETTV ETT-V STT, RRT, MGT and VCT are carried in Transport Packets with Base PID MGT contains PID values for EIT and ETT Transport Packets EIT s carry event information for 3-hour time slots PID-EIT0 EIT-0 Event(s) Event(s) Event(s) ETT-0 PID-ETT0 PID-EIT1 EIT-1 Event(s) Event(s) Event(s) ETT-1 PID-ETT1 PID-EIT2 EIT-2 Event(s) Event(s) Event(s) ETT-2 PID-ETT2 PID-EIT3 EIT-3 Event(s) Event(s) Event(s) ETT-3 PID-ETT3 Program Grid

15 Generic PSIP Table Format PSIP tables follow format of MPEG-2 Systems Private Sections 9-byte header; N bytes of table data; 4-byte CRC (check sum) trailer 10+N bytes following section_length field 13+N bytes total size Header Syntax of MPEG-2 Private Section Bytes Bits Format table_id 1 8 uimsbf section_syntax_indicator 1 1 private_indicator reserved 2 11 section_length 12 uimsbf table_id_extension 2 16 uimsbf reserved 2 11 version_number 1 5 uimsbf current_next_indicator 6 1 bslbf section_number 1 8 uimsbf last_section_number 1 8 uimsbf protocol_version 1 8 uimsbf actual_table_data N 8*N CRC_ rpchof

16 Table Header and Trailer Summary Fields that are variable or peculiar to a specific table are highlighted Syntax Bytes STT table_id 1 0xCD section_syntax_indicator 1 private_indicator reserved 11 section_length (allowed values) table_id_extension 2 0x0000 reserved 11 version_number 1 0 current_next_indicator 6 1 section_number 1 0 last_section_number 1 0 protocol_version 1 0 actual_table_data N CRC_ rpchof MGT 0xC x rpchof TVCT 0xC TSID rpchof RRT 0xCA rating_region rpchof EIT-j 0xCB source_id rpchof ETT-k 0xCC x rpchof

17 Other Table Parameters Parameter STT MGT TVCT RRT EIT-j ETT-k Maximum Section Size (bytes) Maximum Sections per Table Maximum Table Size (bytes) * * Typical Table Size (bytes) per per chan chan or event Maximum Cycle Time (msec) (rec EIT-0) Maximum Bit Rate (kbps) sb_leak_rate sb_size (bytes)

18 Maximum Cycle Times MGT TVCT EIT-0 STT RRT 150 ms 400 ms 500 ms (recommended) 1 s 60 s t (sec)

19 STT Format daylight savings Syntax of STT Table Bytes Bits Format or Note STT Header 9 9*8 STT Header system_time 32 Number of GPS seconds since 12 am, 1/6/80 Must be accurate to ± 4 sec GPS_UTC_offset 8 UTC = GPS - GPS_UTC_offset DS_status = Not in DST; 1 = In DST reserved 2 11 DS_day_of_month 5 Day of month in which transition occurs (1-31) DS_hour 8 Local hour at which transition occurs (0-18) descriptors D 8*D Descriptor data CRC_ bit Cyclic Redundancy Check In order to calculate correct local time, receiver must: calculate UTC (local time in Greenwich, England) adjust for local time zone difference adjust for daylight savings time (if applicable) convert to date and time format for display

20 What is GPS? Global Positioning System (GPS) units are used for System Time (current date and time of day) in STT and event start times in EIT s. GPS time begins at midnight, January 6 th, GPS time is related to Coordinated Universal Time (UTC), which is the current local time at Greenwich, England. UTC = GPS - GPS_UTC_offset (offset = 13 leap seconds as of Jan. 1, 1999) Example: UTC = 599,320, = 599,320,800 = 2:00:00 PM, Jan 2 nd, 1999 For more info, see

21 Master Guide Table (MGT) Lists key information about all other PSIP tables (except STT): version numbers table sizes PID s Allows simpler decoder designs since any change in PSIP status is flagged in this table. Only the base PID (0x1FFB) needs to be monitored to detect change in PSIP status

22 MGT Format Syntax of MGT Table Bytes Bits Format or Note MGT Header 9 9*8 MGT Header tables_defined 16 Number of tables in loop (6-370) for each table table_type x0000: TVCT with current_next_indicator=1 0x0001: TVCT with current_next_indicator=0 0x0002: CVCT with current_next_indicator=1 0x0003: CVCT with current_next_indicator=0 0x0004: Channel ETT 0x0100-0x017F: EIT-0 to EIT-127 0x0200-0x027F: Event ETT-0 to Event ETT-127 0x0301-0x03FF: RRT with rating_region reserved table_type_pid 13 PID for table_type in field above reserved table_type_version_number 5 Must be the same as version number in actual table number_bytes 32 Total number of bytes used for this table reserved table_type_descriptors_length 12 Total length (in bytes) of event descriptors descriptors D1 8*D1 Descriptor data reserved descriptors_length 12 Total length (in bytes) of event descriptors descriptors D2 8*D2 Descriptor data CRC_ bit Cyclic Redundancy Check

23 MGT Example: Time T 0 MGT tables_defined = 6; version = 8 Type Name PID Version Bytes 0x0000 TVCT (current_next = 1) 0x1FFB x0100 EIT-0 0x1AA x0101 EIT-1 0x1AA x0102 EIT-2 0x1AA x0103 EIT-3 0x1AA x0301 RRT (rating_region = 1) 0x1FFB Note: Underlined values are variable from station to station

24 MGT Example: EIT-1 Content Changes MGT tables_defined = 6; version = 9* Type Name PID Version Bytes 0x0000 TVCT (current_next = 1) 0x1FFB x0100 EIT-0 0x1AA x0101 EIT-1 0x1AA1 3* 73* 0x0102 EIT-2 0x1AA x0103 EIT-3 0x1AA x0301 RRT (rating_region = 1) 0x1FFB Note: Asterisks indicate changed values

25 MGT Example: Just prior to EIT Cross-over MGT tables_defined = 6; version = 9 Type Name PID Version Bytes 0x0000 TVCT (current_next = 1) 0x1FFB x0100 EIT-0 0x1AA x0101 EIT-1 0x1AA x0102 EIT-2 0x1AA x0103 EIT-3 0x1AA x0301 RRT (rating_region = 1) 0x1FFB Note: EIT content shifts every three hours. EIT PID shifting is an easy way to implement this (but not required)

26 MGT Example: Just after EIT Cross-over MGT tables_defined = 6; version = 10* Type Name PID Version Bytes 0x0000 TVCT (current_next = 1) 0x1FFB x0100 EIT-0 0x1AA x0101 EIT-1 0x1AA x0102 EIT-2 0x1AA x0103 EIT-3 0x1AA0* x0301 RRT (rating_region = 1) 0x1FFB Note: EIT-0 content is shifted out. EIT-1 becomes EIT-0, etc. PID s may cycle through a fixed pool as shown, but this is not required

27 Virtual Channel Table (VCT) Contains list of channels in the Transport Stream. May also include broadcaster s analog channel and digital channels in other Transport Streams. TVCT = Terrestrial VCT; CVCT = Cable VCT Key info in VCT: short name major and minor channel numbers modulation mode and carrier frequency Transport Stream ID (TSID) and program number source ID, service type, access controlled and hidden flags Service Location Descriptor: contains list of PID s for elementary streams

28 Major and Minor Channel Numbers major_channel_number is used to group all services associated with a broadcaster s NTSC brand minor_channel_number specifies a particular channel within that group. 0 is reserved for analog service. All other values (1-999) are allowed for digital services. One suggestion is to start with 1 and to continue numerically. A/65, Annex B assigns major_channel_numbers as follows: for existing NTSC broadcasters, major_channel_number is the same as the current NTSC RF channel number (2-69) for new DTV broadcasters, major_channel_number is the same as the new DTV RF channel number (2-69) major_channel_numbers in range may be used to identify groups of digital services carried separately

29 Major-Minor Channel Number Example RF Ch. 2 RF Ch RF Ch WXYZ WXYZ-DT WPQR-DT analog digital digital An existing analog broadcaster with a second digital channel. Branding is preserved. The DTV RF channel number is hidden from the viewer! A digital-only broadcaster (no analog channel)

30 Which Delimiter? None specified. All shown are legal. Dots and commas may not reproduce well in printed program guides. Dashes are popular. May become de facto standard

31 Channel TSID - What and Why? Channel TSID is a 16-bit number that stands for Transport Stream ID (digital) Transmission Signal ID (analog ) The receiver may use the Channel TSID to verify that the Transport Stream acquired at the referenced carrier frequency is actually the desired multiplex. Can help resolve co-channel issues and instances where a DTV signal frequency is translated without modification of listed carrier frequency

32 Channel TSID For digital programs contained in this Transport Stream, the Channel TSID must match this Transport Stream ID. For digital programs contained in other Transport Streams, the Channel TSID must match the Transport ID of the other streams. For analog programs, the Channel TSID must match the Transmission Signal ID, or must contain 0xFFFF if unknown. TSID Assignments proposed by MSTV ( NTSC = even TSID, DTV = odd TSID Example WNBC (Ch. 4) = 0x086E WNBC-DT (Ch. 28) = 0x086F

33 Proposed TSID s for New York City NTSC Chan Dec Hex x086C 0x086E 0x0870 0x0872 0x0874 0x0876 0x0878 DTV Chan Dec Hex x086D 0x086F 0x0871 0x0873 0x0875 0x0877 0x0879 Transmission Signal ID (TSID) Transport Stream ID (TSID)

34 TSID Issues If a broadcaster is transmitting the same signal in different channels, each TSID should be unique. If a signal is frequency translated without other modification, then the TSID will remain the same, but the carrier frequency listed in the VCT will be wrong. In this case, receiver should match channel_tsid s with actual TSID s to ensure correct presentation. A receiver should minimize reliance on carrier frequencies listed in the VCT. Instead, a receiver should associate the TSID with the carrier frequency at which it is found

35 PAT and PMT The Program Association Table (PAT) associates MPEG-2 Program Numbers with Program Map Table (PMT) PID s The PMT associates program elements with PID s These tables are required for MPEG-2 compliance Program Program Association Association Table Table (PAT) (PAT) table_id table_id = = 0x00 0x00 transport_stream_id transport_stream_id = = 0x0AA1 0x0AA1 Program Program Number Number PMT PMT PID PID 0x00F1 0x00F1 0x0100 0x0100 0x00C2 0x00C2 0x0440 0x0440 0x00B3 0x00B3 0x0301 0x0301 Example PAT Program Program Number Number 0x00B3 0x00B3 Stream Stream Type Type PID PID PCR PCR 0x0303 0x0303 Video Video 0x0303 0x0303 Audio Audio 0x0206 0x0206 Example PMT at PID 0x

36 TSID and Program Number Transport Stream ID and Program Numbers in the VCT and PAT must match Program Program Association Association Table Table (PAT) (PAT) table_id table_id = = 0x00 0x00 transport_stream_id transport_stream_id = = 0x0AA1 0x0AA1 Program Program Number Number PMT PMT PID PID 0x00F1 0x00F1 0x0100 0x0100 0x00C2 0x00C2 0x0440 0x0440 0x00B3 0x00B3 0x0301 0x0301 Example PAT Terrestrial Terrestrial Virtual Virtual Channel Channel Table Table (TVCT) (TVCT) table_id table_id = = 0xC8 0xC8 transport_stream_id transport_stream_id = = 0x0AA1 0x0AA1 Program Program Number Number Channel Channel TSID TSID Descriptor Descriptor 0x00F1 0x00F1 0x0AA1 0x0AA1 Service Service Location Location 0x00C2 0x00C2 0x0AA1 0x0AA1 Service Service Location Location 0x00B3 0x00B3 0x0AA1 0x0AA1 Service Service Location Location 0x0AA0 0x0AA0 0x0AA0 0x0AA0 Analog Analog program program 0x00F4 0x00F4 0x0AA3 0x0AA3 Service Service Location Location 0x00E5 0x00E5 0x0AA3 0x0AA3 Service Service Location Location Corresponding TVCT

37 Service Location Descriptor The PID s in the Service Location Descriptor and in the PMT must match Program Program Association Association Table Table (PAT) (PAT) table_id table_id = = 0x00 0x00 transport_stream_id transport_stream_id = = 0x0AA1 0x0AA1 Program Program Number Number PMT PMT PID PID 0x00F1 0x00F1 0x0100 0x0100 0x00C2 0x00C2 0x0440 0x0440 0x00B3 0x00B3 0x0301 0x0301 Example PAT Example PMT Stream Stream Type Type PCR PCR Video Video Audio Audio PID PID 0x0303 0x0303 0x0303 0x0303 0x0206 0x0206 Terrestrial Terrestrial Virtual Virtual Channel Channel Table Table (TVCT) (TVCT) table_id table_id = = 0xC8 0xC8 transport_stream_id transport_stream_id = = 0x0AA1 0x0AA1 Program Program Number Number Channel Channel TSID TSID Descriptor Descriptor 0x00F1 0x00F1 0x0AA1 0x0AA1 Service Service Location Location 0x00C2 0x00C2 0x0AA1 0x0AA1 Service Service Location Location 0x00B3 0x00B3 0x0AA1 0x0AA1 Service Service Location Location Corresponding TVCT Corresponding Service Location Descriptor Stream Stream Type Type PCR PCR Video Video Audio Audio PID PID 0x0303 0x0303 0x0303 0x0303 0x0206 0x

38 TVCT Format (1) Syntax of TVCT Table Bytes Bits Format or Note TVCT Header 9 9*8 transport_stream_id is in table_id_extension num_channels_in_section 8 Number of channels in loop (0-31) for each channel short_name BMP Unicode characters reserved major_channel_number 10 First part of virtual channel number (1-99) minor_channel_number 10 Last part of virtual channel number (0-999) 27 modulation_mode 8 0x01: analog 0x02: SCTE_mode_1 0x03: SCTE_mode_2 0x04: ATSC (8 VSB) 0x05: ATSC (16 VSB) 0x80: Defined by private descriptor carrier_frequency 32 In Hz. Pilot tone for VSB; Pix carrier for analog channel_tsid 16 MPEG-2 TSID or Analog Transmission Signal ID program_number 16 MPEG-2 PAT/PMT number or 0xFFFF for analog continued on next slide

39 TVCT Format (cont d) for each channel (cont d) ETM_location 2 access_controlled 1 1 = events for this virtual channel may be access controlled hidden 1 1 = virtual channel cannot be accessed by direct user entry reserved service_type 6 6 source_id 16 0x00: No ETM 0x01: ETM located in the PTC carrying this PSIP 0x02: ETM located in the PTC specified by the channel_tsid 0x01: analog television 0x02: ATSC_digital_television 0x03: ATSC_audio_only (audio and data, no video) 0x04: ATSC_data_broadcast_service (T3/S13) Uniquely identifies programming source. 0x0000: reserved 0x0001-0x0FFF: must be unique within this TS 0x1000-0xFFFF: must be unique at regional level reserved descriptors_length 10 Length (in bytes) of descriptors that follow descriptors D1 8*D1 Descriptor data reserved additional_descriptors_length 10 Length (in bytes) of additional descriptors additional_descriptors D2 8*D2 Additional descriptor data CRC_ bit Cyclic Redundancy Check This is where the Service Location Descriptor appears

40 The Program Number Myth MPEG-2 Program Numbers are not related to Major-Minor Channel Numbers! MPEG-2 Program Numbers are hidden from the viewer and serve to link MPEG-2 data structures (PAT and PMT). Major-Minor channels numbers are what viewers tune to! Terrestrial Terrestrial Virtual Virtual Channel Channel Table Table (TVCT) (TVCT) Major-Minor Major-Minor Number Number Program Program Number Number Channel Channel TSID TSID Descriptor Descriptor x00F1 0x00F1 0x0AA1 0x0AA1 Service Service Location Location x00C2 0x00C2 0x0AA1 0x0AA1 Service Service Location Location x00B3 0x00B3 0x0AA1 0x0AA1 Service Service Location Location What the viewer tunes to Hidden from the viewer Tells the receiver where to find PID s

41 TVCT Example TVCT number_channels_in_section = 5; TSID = 0x0AA1 Major Num. Minor Num. Short Name Carrier Freq (MHz) Channel TSID Program Number Service Type Source ID Descriptors 12 0 NBZ x0AA0 0xFFFF analog 20 ch name NBZ-D NBZ-S NBZ-M NBZ-H x0AA1 0x0AA1 0x0AA1 0x0AA1 0x0F21 0x00B2 0x0CC7 0x0CD0 digital digital digital digital ch name; serv loc ch name; serv loc ch name; serv loc ch name; serv loc Adapted from A/

42 Event Information Tables Each EIT spans 3 hours Start time for each EIT is constrained to be one of the following UTC times: 0:00 (midnight), 3:00, 6:00, 9:00 12:00 (noon), 15:00, 18:00, 21:00 EIT-0 represents the current 3 hours of programming For terrestrial PSIP, first 4 EIT s (EIT-0, -1, -2, -3), representing 12 hours, are required Maximum number of EIT s = 128 (16 days)

43 EIT Format Syntax of EIT Table Bytes Bits Format or Note EIT Header 9 9*8 EIT Header num_events_in_section 1 8 Number of events in this EIT section for each event: reserved 2 11 event_id 14 Event ID. Also part of ETM_id start_time 32 In units of GPS seconds since 12 am, 1/6/80 reserved = No ETM = ETM in PTC carrying this PSIP ETM_location 2 10 = ETM in PTC carrying this event 11 = [reserved for future ATSC use] length_in_seconds 20 Duration of event in seconds title_length 8 Length (in bytes) of title_text title_text T 8*T Event title (multiple string structure format) reserved descriptors_length 12 Total length (in bytes) of event descriptors descriptors D 8*D Descriptor data CRC_ bit Cyclic Redundancy Check

44 EIT Example EIT-0 source_id = 22 num_events_in _section = 3 Event ID Local Start Time 12:30 14:30 15:30 Length (seconds) ETM Location 01 (this PTC) 00 (no ETM) 01 (this PTC) Title Soccer Live Golf Report Car Racing Descriptors content_ advisory closed_ caption content_ advisory Adapted from A/

45 Source ID s and Event ID s VCT Channel A source_id_a Channel B source_id_b Channel C source_id_c Event B1 source_id_b event_id_b1 EIT-0 18:00-19:00 19:00-20:00 20:00-21:00 Event A1 source_id_a event_id_a1 Event A2 source_id_a event_id_a2 Event C1 source_id_c event_id_c1 Event A3 source_id_a event_id_a3 Event B2 source_id_b event_id_b2 Source ID s link events to virtual channels. 0x0001-0x0FFF are unique within this Transport Stream; 0x1000-0xFFFF are unique at the regional level. Event ID s are unique within this Transport Stream

46 Events that Span EIT Boundaries EIT-0 EIT-1 VCT 18:00-19:00 19:00-20:00 20:00-21:00 21:00-22:00 22:00-23:00 23:00-0:00 Channel A source_id_a Event A1 event_id_a1 Event A2 event_id_a2 Event A3 event_id_a3 Event A4 event_id_a4 Event A5 event_id_a5 Event A6 event_id_a6 Channel B source_id_b Event B1 event_id_b1 Event B2 event_id_b2 Event B3 event_id_b3 Event B4 event_id_b4 Channel C source_id_c Event C1 event_id_c1 Event C2 event_id_c2 Event C3 event_id_c3 Event C2 spans an EIT time interval. It must appear in both EIT s, with the same event ID

47 ETT Format Syntax of ETT Table Bytes Bits Format or Note ETT Header 9 9*8 ETT Header ETM_id 4 32 channel ETM_id = source_id event ETM_id = source_id + event_id + 10 extended_text_message M 8*M Multiple string structure message CRC_ bit Cyclic Redundancy Check The Extended Text Table (optional) is used to provide detailed descriptions of virtual channels or events. These descriptions are called Extended Text Messages (ETM s). The format of the 32-bit ETM_id tells the receiver whether the ETM describes a channel or and event This format allows the receiver to search for a single description quickly without having to parse the payload of a large table

48 Rating Region Table The RRT defines the rating standard for a particular geographic region and/or country Each RRT instance is identified by the rating_region field in the table_id_extension Only one rating region is currently defined: US (50 states + possessions) The Content Advisory Descriptor, which may appear in the EIT and PMT, indicates, for a given event, the ratings for any or all of the rating dimensions defined in the RRT. Full implementation in the U.S. requires document EIA-766: U.S. Region Rating Table (RRT) and Content Advisory Descriptor for Transport of Content Advisory Information Using ATSC A/65 Program and System Information Protocol (PSIP), September

49 RRT Format Syntax of RRT Table Bytes Bits Format or Note RRT Header 9 9*8 rating_region is LS byte of table_id_extension 0x00: Forbidden 0x01: US (50 states + possessions) 0x02-0xFF: Reserved rating_region_name_length 8 Length (in bytes) of next field rating_region_name_text var Multiple string structure dimensions_defined 8 Number of rating dimensions (1-255) for each dimension dimension_name_length 8 Length (in bytes) of next field dimension_name_text var Multiple string structure reserved graduated scale 1 1 if higher values means higher rated content values_defined var 4 Number of values for this dimension (1-15) for each value abbrev_rating_value_length 8 Length (in bytes) of next field abbrev_rating_value_text var Multiple string structure rating_value_length 8 Length (in bytes) of next field rating_value_text var Multiple string structure reserved descriptors_length 10 Total length (in bytes) of event descriptors descriptors 8*D Descriptor data CRC_ bit Cyclic Redundancy Check

50 RRT Information for U.S. To date, the U.S. is the only rating region that has been defined This is documented in EIA-766, Sept and summarized below and in the following slides: Syntax Element Value rating_region 0x01 version_number rating_region_name_text() US (50 states + possessions) dimensions_defined 0x08 Text Formatting ISO_639_language_code compression_type mode number_strings number_segments Value 0x656E67 0x00 0x00 0x01 0x

51 RRT Information for U.S. RRT rating_region = 1 (first instance) rating_region_name_text = US (50 states + possessions) dimension_name = Entire Audience ; dimension index = 0; grad = 1 index abbrev value 0 1 None None 2 TV-G TV-G 3 TV-PG TV-PG 4 TV-14 TV-14 5 TV-MA TV-MA From EIA-766, Sept

52 RRT Information for U.S. RRT rating_region = 1 (first instance) rating_region_name_text = US (50 states + possessions) dimension_name = Dialogue ; dimension index = 1; grad = 0 index abbrev value 0 1 D D dimension_name = Language ; dimension index = 2; grad = 0 index abbrev value 0 1 L L dimension_name = Sex ; dimension index = 3; grad = 0 index abbrev value 0 1 S S From EIA-766, Sept

53 RRT Information for U.S. RRT rating_region = 1 (first instance) rating_region_name_text = US (50 states + possessions) dimension_name = Violence ; dimension index = 4; grad = 0 index abbrev value 0 1 V V dimension_name = Children ; dimension index = 5; grad = 1 index abbrev value 0 1 TV-Y TV-Y 2 TV-Y7 TV-Y7 dimension_name = Fantasy Violence ; dimension index = 6; grad = 0 index abbrev value 0 1 FV FV From EIA-766, Sept

54 RRT Information for U.S. RRT rating_region = 1 (first instance) rating_region_name_text = US (50 states + possessions) dimension_name = MPAA ; dimension index = 7; grad = 0 index abbrev value 0 1 N/A MPAA Rating Not Applicable 2 G Suitable for All Ages 3 PG Parental Guidance Suggested 4 PG-13 Parents Strongly Cautioned 5 R Restricted, under 17 must be accompanied by adult 6 NC-17 No One 17 and Under Admitted 7 X No One 17 and Under Admitted 8 NR Not Rated by MPAA From EIA-766, Sept

55 PSIP Descriptors Descriptor Name Tag Terrestrial Cable PMT CAT MGT VCT EIT PMT MGT VCT EIT stuffing 0x80 * * * * * * * * * AC-3 audio 0x81 M M M O caption service 0x86 O M M O content advisory 0x87 O M M O ATSC_CA (cond. access) 0x88 O O extended channel name 0xA0 M M service location 0xA1 S M time-shifted service 0xA2 M M component name 0xA3 M M user private 0xC0-0xFE * * * * * * * * * Legend * M O S descriptor may appear without restrictions when present, descriptor must appear in location shown when present, descriptor may optionally appear in second location shown the service location descriptor must be present in the location shown

56 AC-3 Audio Descriptor Syntax Bytes Bits Format or Note descriptor_tag 8 0x81 2 descriptor_length 8 Number of bytes following this field sample_rate_code 3 Sample rate of encoded audio bsid 5 Same as bsid field in AC-3 stream bit_rate_code 6 Indicates bit rate (exact or upper limit) surround_mode 2 Same as dsurmod field in AC-3 stream 4 bsmod 3 Same as bsmod field in AC-3 stream num_channels 4 Indicates audio coding or number of channels full_svc 1 Indicates full or partial audio service langcod 8 Same as langcod field in AC-3 stream if num_channels = 0 langcod2 1 8 Same as langcod2 field in AC-3 stream if bsmod<2 mainid reserved 3 5 Identifies main audio service else asvcflags 2 8 Links main and associated services textlen text_code text additional_info T A 7 Length of text field that follows 1 1 = ISO Latin-1; 0 = 16-bit Unicode 8*T Brief description of audio service 8*A Additional description (not currently defined)

57 Caption Service Descriptor Syntax Bytes Bits Format or Note descriptor_tag 8 0x86 2 descriptor_length 8 Number of bytes following this field reserved number_of_services 5 Number of closed caption services (1-16) for each service language 24 3-byte language code (ISO 639.2/B) cc_type 1 1 = DTV caption; 0 = line21 caption reserved 1 1 if cc_type==line21 reserved line21_field easy_reader wide_aspect_ratio reserved = field 2; 0 = field 1 else caption_service_number 6 Service number for this closed caption stream 1 1 = text tailored to needs of beginning readers 1 1 = text formatted for 16:9 displays For implementation details, see: EIA-708-B, Digital Television (DTV) Closed Captioning

58 Content Advisory Descriptor Syntax Bytes Bits Format or Note descriptor_tag 8 0x87 2 descriptor_length 8 Number of bytes following this field reserved rating_region_count 6 Number of rating regions (1-8) for each rating region rating_region 8 Rating region number 2 rated_dimensions 8 Number of rated dimensions for each rated dimension rating_dimension_j reserved Index into the RRT instance for this region 1111 rating_value 4 Rating value of this dimension and region rating_description_length rating_description_text 1 T 8 Length of text that follows (1-80) 8*T Text in multiple string structure format Used to describe the content advisory rating value for an event

59 Content Advisory Information for U.S. To date, the U.S. is the only rating region that has been defined This is documented in EIA-766, Sept and summarized below and in the following slides: Syntax Element rating_region rated_dimensions rating_dimension rating_value rating_description_length rating_description_text Value 0x01 [0x01, 0x08] (program specific) [0x00, 0x07] (signifies dimension) Index into Rating Message Table 0x00 None From EIA-766, Sept

60 Content Advisory Descriptor Examples Example 1: TV - Y rating_region 0x01 Rating region = US rated_dimensions 0x01 Number of rated dimensions rating_dimension_0 0x05 Signifies dimension Children rating_value 1 Signifies TV-Y Example 2: TV - PG rating_region 0x01 Rating region = US rated_dimensions 0x01 Number of rated dimensions rating_dimension_0 0x00 Signifies dimension Entire Audience rating_value 3 Signifies TV-PG Example 3: MPAA - PG13 rating_region 0x01 Rating region = US rated_dimensions 0x01 Number of rated dimensions rating_dimension_0 0x07 Signifies dimension MPAA rating_value 4 Signifies MPAA-PG13 From EIA-766, Sept

61 Content Advisory Descriptor Examples Example 4: TV V rating_region 0x01 Rating region = US rated_dimensions 0x02 Number of rated dimensions rating_dimension_0 0x00 Signifies dimension Entire Audience rating_value 4 Signifies TV-14 rating_dimension_1 0x04 Signifies dimension Violence rating_value 1 With Above, Signifies TV-14-V Example 5: TV - MA - L - S rating_region 0x01 Rating region = US rated_dimensions 0x03 Number of rated dimensions rating_dimension_0 0x00 Signifies dimension Entire Audience rating_value 5 Signifies TV-MA rating_dimension_1 0x02 Signifies dimension Language rating_value 1 With Above, Signifies TV-MA-L rating_dimension_2 0x03 Signifies dimension Sex rating_value 1 With Above, Signifies TV-MA-L-S From EIA-766, Sept

62 ATSC Conditional Access Descriptor Syntax Bytes Bits Format or Note descriptor_tag 8 0x88 2 descriptor_length 8 Number of bytes following this field Conditional Access System ID CA_system_ID 2 16 (privately defined) private_data_byte T 8*T Private CA info The ATSC Conditional Access System (A/70) requires PSIP in order to be implemented. However, PSIP does not require CA descriptors. If present in the VCT, the CA descriptor is applicable to all events on that virtual channel. The CA descriptor can be made event-specific by placing it in the EIT

63 Extended Channel Name Descriptor Syntax Bytes Bits Format or Note descriptor_tag 8 0xA0 2 descriptor_length 8 Number of bytes following this field long_channel_name_text T 8*T Text in multiple string structure format The short name for a virtual channel is limited to 7 Unicode characters. This descriptor is used to provide a longer name for a virtual channel

64 Service Location Descriptor Syntax Bytes Bits Format or Note descriptor_tag 8 0xA1 2 descriptor_length 8 Number of bytes following this field reserved PCR_PID 3 13 PID of TS packets containing PCR for this program number_elements 8 Number of PID s used for this program for each element stream_type 8 6 0x00: ITU-T/ISO/IEC reserved 0x01-0x7F: As specified in Table 2.29 (stream type assignments) of MPEG-2 Systems, ISO/IEC x80: Used in other systems 0x81: ATSC A/53 audio 0x82-0x84: Used in other systems 0x85: UPID (ATSC A/57) 0x86-0xBF: Reserved 0xC0-0xFF: User private reserved elementary_pid 13 PID for this elementary stream ISO_639_language_code 24 Language used for this elementary stream Note: this descriptor must be present in the TVCT!

65 Time Shifted Service Descriptor Syntax Bytes Bits Format or Note descriptor_tag 8 0xA2 2 descriptor_length 8 Number of bytes following this field reserved number_of_servcies 5 Number of time-shifted services (1-20) for each service reserved time_shift 10 Number of minutes this service is shifted (1-720) reserved major_channel_number 10 Major channel number (1-99) of time shifted service minor_channel_number 10 Minor channel number (0-999) of time shifted service This descriptor can be used for Near Video On Demand (NVOD) services, in which the same event is repeated, usually at regular intervals, on different virtual channels

66 Component Name Descriptor (in PMT) Syntax Bytes Bits Format or Note descriptor_tag 8 0xA3 2 descriptor_length 8 Number of bytes following this field component_name_string T 8*T Name in multiple string structure format This descriptor can be used to provide a name for a component listed in the Program Map Table (PMT). If used, it must appear in the PMT

67 Multiple String Structure Format Syntax Bytes Bits Format or Note number_strings 1 8 Number of strings in the following data for each string ISO_639_language_code 24 Language used for this string 4 number_segments 8 Number of segments in the following data for each segment compression_type mode x00: No compression 0x01: Huffman coding using standard encode/ decode defined in Table C.4 and C.5 in A/65 Annex C. 0x02: Huffman coding using standard encode/ decode defined in Table C.6 and C.7 in A/65 Annex C. 0x03-0xAF: Reserved 0xB0-0xFF: User private 0x00-0x3E: 8-bit Unicode 0x3F: 16-bit Unicode 0x40-0xDF: Reserved for future ATSC use 0xE0-0xFE: User private 0xFF: Text mode is not applicable number_bytes 8 Number of bytes in field that follows compressed_string_byte S 8*S A byte of this segment

68 Huffman-Based Text Compression First-order (two-character) Huffman coding may be used for text compression Receivers must support Huffman decoding (requires less than 2KB of storage) Optimized Huffman tables for Titles and Program Descriptions are provided Example: <term> assumed T h e n e x t <term> Uncompressed: 9 bytes = 72 bits 010 T followed by an h is much more likely than e followed by x followed by an n uses an 8-bit escape sequence followed by the ASCII code for n Compressed: 39 bits

69 Program Guide Formation STT April 8, :11 pm Chan Name 6:00 pm 6:30 pm 7:00 pm 7:30 pm 8:00 pm 8:30 pm 12-0 NBZ Local News Dino World NBZ News & Movies NBZ-S Local News Soccer - World Cup Subscription Only Dino World (1997) Harrison Pontiac, Peg O Ryan Dinosaurs eat Newark, NJ in this Francis Ford Spielberg oscar-winning film. PG-13 Golf CC (Eng, Fr) Table Tennis VCT ETT-V EIT-0 Conditional ETT-0 Access RRT & Content Advisory Caption Service

70 Interra MProbe Demo

71 Example: Sarnoff s Lipsync4 Bitstream TVCT PID = 0x1FFB EIT-0 PID = 0x1FFA source1 6-1 source_id = 4092 source2 6-2 source_id = 4091 source3 6-3 source_id = 4090 source4 6-4 source_id = x480 source1 source_id = 4092; event_id = 192 start_time = ; length_in_seconds = x480 source2 source_id = 4091; event_id = 256 start_time = ; length_in_seconds = x480 source3 source_id = 4090; event_id = 320 start_time = ; length_in_seconds = x480 source4 source_id = 4089; event_id = 384 start_time = ; length_in_seconds = 300 Service Location Descriptor: PCR PID 0x61 MPEG-2 Video PID 0x61 AC-3 Audio PID 0x64 Note: TSID = all channel_tsid s =

72 Forming PSIP Packets PSIP tables can start at any byte in a Transport Packet except for MGT, whose first byte must be the first payload byte. For MGT packets carrying the table_id field: payload_unit_start_indicator = 1 pointer_field = 0x00. Table sections may span packet boundaries. More than one PSIP table may be present within a single Transport Packet. pointer_field used to indicate offset of first table header subsequent table locations found by section_length fields If packet payload does not include start of any PSIP table: payload_unit_start_indicator = 0 pointer_field not present

73 Forming PSIP Packets Generic PSIP Transport Packet Format sync_byte (8 bits) transport error indicator (1 bit) payload unit start indicator (1 bit) transport priority (1 bit) PID (13 bits) transport scrambling control (2 bits) adaptation field control (2 bits) continuity counter (4 bits) pointer field (8 bits) 0x or 1 0 PID CC PF Payload For MGT packet carrying table_id: PSIP requires 1 for this field and 0x00 for pointer field. If other tables start in this packet, PSIP requires 1 for this field, and a valid number for the pointer field. If no tables start in this packet, PSIP requires 0 for this field and no pointer field PSIP requires 01 for this field, meaning no adaptation field, payload only PSIP requires 00 for this field, meaning payload not scrambled PSIP requires 0x1FFB for STT, MGT, VCT and RRT. EIT and ETT PID s are defined in the MGT

74 Example PSIP Packets 188 bytes MGT & STT sync tei pusi tpi PID tsc afc cont pointer 0x x1FFB CC 0x00 MGT STT stuffing VCT & RRT 0x x1FFB CC 0x80 End of VCT RRT EIT-0 0x x1FD CC Middle of EIT-0 Section (PID pointed to by MGT) (no pointer field)

75 PSIP Generation/Insertion NTSC INPUT NTSC PLANT [24] Etc. DATA EXTRACTOR [31] DATA INSERTER [33] NTSC OUTPUT TOP-DOWN DATA PLANE (taken from ATSC Implementation Subcommittee s Top Down Report) M DATA BRIDGE [32] DATA SERVER [88] M PSIP, UPID and PSI GENERATOR Ensures consistency between PAT/PMT & PSIP data. A T S C DIGITAL OUTPUT Management and Control Plane Interface M WAN [89] DATA EXTRACTOR [77] M U X [90] DIGITAL INPUT DEMUX [50] [57] DECODERS [52-53] Etc. Copyright 1998 by the Advanced Television Systems Committee. DIGITAL PLANT [70] Etc. VIDEO ENCODER [79] AUDIO ENCODER MUX [81] 75 [80]

76 Relevant PSIP Documents PSIP Standard (A/65) Program and System Information Protocol for Terrestrial Broadcast and Cable, ATSC Document A/65, 23 Dec Available at PSIP Corrigendum 1 (A/66) Technical Corrigendum No. 1 to ATSC Standard: Program and System Information Protocol for Terrestrial Broadcast and Cable Doc. A/65 (23 Dec 97), ATSC Document A/66, 17 Dec Flips polarity of 2 reserved bits in the tables Revises core descriptor table Adds Informative Annex G (PSIP for Cable) Available at

77 Relevant PSIP Documents (cont d) PSIP Amendment 1 (A/67) Amendment No. 1 to ATSC Standard: Program and System Information Protocol for Terrestrial Broadcast and Cable Doc. A/65 (23 Dec 97), ATSC Document A/67, 17 Dec 99. Provides a means to deal with currently inactive channels Available at Conditional Access System for Terrestrial B cast (A/70) Defines ATSC_CA_descriptor for VCT and EIT U.S. Region Rating Table (RRT) and Content Advisory Descriptor for Transport of Content Advisory Information Using ATSC A/65 Program and System Information Protocol (PSIP), September 1998 (EIA-766) Used for rating and content advisory in the U.S

78 PSIP and Data Services (T3/S13) The Draft ATSC Data Broadcast Standard lists several requirements for PSIP: Each virtual channel in the VCT shall include no more than one data service The data elementary stream is listed in the Service Location Descriptor The Data Event Table (DET) announces data services. DET s are similar to EIT s in structure, time span and other constraints. Long Term Service Table (LTST) can announce data events far into the future

79 Data Event Table Format (draft) Syntax of DET Table Bytes Bits Format or Note DET Header 9 9*8 DET Header (table_id = 0xCE) num_data_in_section 1 8 Number of events in this DET section for each data: reserved 2 11 data_id 14 Data ID. Also part of ETM_id start_time 32 In units of GPS seconds since 12 am, 1/6/80 reserved = No ETM = ETM in PTC carrying this PSIP ETM_location 2 10 = ETM in PTC carrying this event 11 = [reserved for future ATSC use] length_in_seconds 20 Duration of data in sec (unbounded = 0xFFFFF) title_length 8 Length (in bytes) of title_text (0 = no title) title_text T 8*T Data title (multiple string structure format) reserved descriptors_length 12 Total length (in bytes) of data descriptors descriptors D 8*D Descriptor data CRC_ bit Cyclic Redundancy Check

80 DET Example DET-0 source_id = 22 num_data_in _section = 3 Data ID Local Start Time 12:30 14:30 15:30 Length (seconds) ETM Location 01 (this PTC) 00 (no ETM) 01 (this PTC) Title Oodles o bits Solitaire Game Pak Descriptors data_ service data_ service data_service, PID_count Adapted from draft ATSC Data Broadcasting Standard

81 Data Service Descriptor Syntax Bytes Bits Format or Note descriptor_tag 8 0xA4 2 descriptor_length 8 Number of bytes following this field data_service_profile 1 data_service_level x00: reserved 0x01: ATSC Data Bcast Service Profile G1 0x02: ATSC Data Bcast Service Profile G2 0x03: ATSC Data Bcast Service Profile G2 0x04: ATSC Data Bcast Service Profile A1 0x05-0xFF: ATSC reserved 0x00: no synchronized stream in service 0x01: Data Service Level 1 (DBESn = B) 0x02-0x03: ATSC reserved 0x04: Data Service Level 4 (DBESn = B) 0x05-0x0F: ATSC reserved 0x10: Data Service Level 16 (DBESn = B) 0x11-0x3F: ATSC reserved 0x40: Data Service Level 64 (DBESn = B) 0x41-0xFF: ATSC reserved private_data_length 1 8 Length in bytes of field that follows for each byte private_data_byte 1 8 Private data Note: a Data Service Descriptor is required for every data event

82 Data Profile Attributes (draft) Guranteed BW Opportunistic BW Attributes Profile G1 Profile G2 Profile G3 Profile A1 Max Terrestrial Data Rate 383,896 b/s 3,838,960 b/s 19.2 Mb/s 19.2 Mb/s System Latency (seconds) N/A sb_leak (x 400 b/s) ,000 48,000 sb_size (bytes) ,000 10,

83 PID Count Descriptor (draft) Syntax Bytes Bits Format or Note descriptor_tag 8 0xA5 2 descriptor_length 8 Number of bytes following this field reserved Max number of concurrent PID s for the 2 total_number_of_pids 13 data services. Shall include PID s for Data Service Table and Network Resources Table reserved Minimum number of PID s that a receiver must min_number_of_pids 2 acquire simultaneously to provide a meaningful rendition of the service. 0 means the 13 minimum number is unspecified. This optional descriptor can help the receiver determine resources required for PID handling

84 Long Term Service Table (draft) Syntax of LTST Table Bytes Bits Format or Note LTST Header 9 9*8 LTST Header (table_id = 0xD2) num_data_in_section 1 8 Number of events in this DET section for each data: reserved 1 1 AV_association_flag 1 1 means the data is associated with AV event data_id 14 Data ID. start_time 32 In units of GPS seconds since 12 am, 1/6/80 10 length_in_seconds 16 Duration of data in sec (unbounded = 0xFFFFF) reserved ETM_flag 1 Indicates whether ETM is available title_length 8 Length (in bytes) of title_text (0 = no title) title_text T 8*T Data title (multiple string structure format) reserved descriptors_length 12 Total length (in bytes) of data descriptors descriptors D 8*D Descriptor data CRC_ bit Cyclic Redundancy Check This is a special Data Event Table that can announce data services beyond the currently defined time period (far into the future)

85 Relevant Committee Work T3/S8 PSIP Ad Hoc Groups PSIP Ad Hoc Group (Art Allison, chair) Directed Channel Change: Provides a means to enable directed channel change, either by direct viewer selection or automatically (Merrill Weiss, chair) Extensions to Accommodate Non-Alphabetic Characters: needed to support PSIP in other ATSC countries, such as Korea and Taiwan. Draft Recommended Practice has been prepared. (Chao Yang, chair) Advanced EPG Functionality: Looking at content-based description of events to allow improved browsing (Regis Crinon and Paul Martinez, chairs)

86 Relevant Committee Work (cont d) Update Other Topics (closed): GPS Time Annex NVOD clarification ETT table_id_extension Unicode issues Clarify events that cannot overlap Correct private indicator bit in Table 4.1 Other Topics (still open) VCT scaling Transmission of VCT s with different branding (cable/air) Private descriptors Single-part channel numbers (cable) Version management of shifting EIT s Clarify situations where analog pointer is to be believed

87 Thank you! And thanks to the following for reviewing and improving this presentation: Art Allison (NAB) Jean-Louis Diascorn (Thomson Consumer Electronics) Art Greenberg (formerly of Sarnoff) Tom Gurley (MSTV) Bernie Lechner (Consultant, T3/S8 chair) Gomer Thomas (LGERCA)