MPEG Signals (PSI/SI, NIT, EPG)

Transcription

1 MPEG Signals (PSI/SI, NIT, EPG) 17.February.2010 Satoshi ASAMI TV Asahi 1

2 Purview of this seminar This seminar Video Signal Audio Signal Video Coding Audio Coding Packetizing Packetizing Multiplexing Modulation Transmission PSI/SI data Receiver : TV set / Mobile(one-seg) Display De-Coding De-Multiplexing De-Modulation 2

3 Goal of this seminar How does Receiver tune a specific channel? How does Receiver show EPG? What is PSI/SI ( MPEG2-Systems, NIT etc.)? 3

4 Purview of this seminar from the Viewpoint of Standard MPEG2-Systems Video Signal Audio Signal Video Coding Audio Coding Packetizing Packetizing Multiplexing Modulation Transmission ARIB STD-B10 ARIB TR-B14 Vol.#4 PSI/SI data Receiver PSI/SI Video, Audio Display De-Coding De-Multiplexing De-Modulation 4

5 Overview of related Standard What is MPEG2-Systems? - International Standard for multiplexing ( ISO/IEC / ITU-T Rec H.222 ) - MPEG2-Systems specifies Transport Stream (TS) and PSI (Program Specific Information) 5

6 Overview of related Standard What is ARIB STD-B10? - Japanese Standard for multiplexing & PSI/SI for Digital Broadcasting ( not only Terrestrial but also Satellite service ) - SI (Service Information) is Information for EPG 6

7 Overview of related Standard What is ARIB TR-B14 Vol.#4? - ARIB TR-B14 is Operational Standard for Digital Terrestrial Broadcasting service in Japan - ARIB TR-B14 Vol.#4 is PSI/SI part which specifies Operational rules regarding PSI/SI 7

8 What is PSI/SI? Transport Stream (TS) Video Signal Audio Signal Video Coding Audio Coding Packetizing Packetizing Multiplexing Modulation Transmission Coding & Packetizing & Multiplexing How Receivers get packets they need? :Video packet :Audio packet :other packet Transport Stream (TS) PSI!! 8

9 What is PSI/SI? PSI : Program Specific Information - Information for Channel Selection - PSI consists of PAT, CAT, PMT, NIT which are Tables used to get specific packets (ex. Video packets) - These Tables are conveyed by packets 9

10 What is PSI/SI? SI : Service Information - Information for EPG and others - SI consists of SDT, EIT, BIT, TOT etc which are Tables carrying EPG information and Date & Time information etc - These Tables are conveyed by packets 10

11 How Receiver tune to channel? 20ch 21ch 22ch 23ch 24ch 25ch 26ch 27ch 28ch Tokyo area UHF band Broadcaster (Station name) MX TV CX TBS TX EX TV Asahi NTV NHK -E NHK -G UD No.# on Remote Control Frequency channel ( = n ) Central Frequency x (n 13) + 1/7 [MHz] No.# on Remote Control is not Frequency channel. How Receiver knows which channel is which frequency? 11

12 How Receiver tune to channel? NIT : Network Information Table - NIT conveys information relating to the physical transmission ( Frequency etc ), characteristics ( Station name, TS info. etc ) of the network. - Receivers can know tuning information from NIT. - Receiver memories information of NIT 12

13 How Receiver tune to channel? Structure of NIT NIT - table_id - network_id - version_number - network name - transport_stream_id - Service List Descriptor( ) service_id, service_type x N - Terrestrial Delivery System Descriptor( ) area code, transmission mode, frequency, - TS Information Descriptor( ) remote_control_key_id TS name transmission type info. 13

14 How Receiver tune to channel? By getting NITs of all broadcasters, Receiver can have channel & frequency tables. channel & frequency tables of Tokyo area (Example) Broadcaster (Station name) MX TV CX TBS TX EX TV Asahi NTV NHK -E NHK -G UD No.# on Remote Control Frequency range 512~ ~ ~ ~ ~ ~ ~ ~ ~ 566 Central Frequency x (Channel # 13) + 1/7 [MHz] Network ID 7E87 7FE4 7FE3 7FE6 7FE5 7FE2 7FE1 7FE0 7FE8 List of Service ID 0428,... 05A8 A primary service is described first in service list and assigned Remote Control Key. 14

15 How Receiver tune to channel? To making the table, Receiver have a function of Initial Scan & Re-scan. 1) Receiver search through all receivable channel at the location. 2) And get all NITs in the area. 3) Receiver memories NIT information in NVRAM. 4) Receiver uses this information to tune to aiming channel next time. demonstration 15

16 Network of terrestrial broadcasting Structure of Network of terrestrial broadcasting is different with satellite broadcasting. - In terrestrial broadcasting, Network = Broadcaster One network includes only one TV broadcaster s signal (TS). - In satellite broadcasting, Network consists of several TV broadcaster s signals (TS). 16

17 Network of terrestrial broadcasting Satellite broadcasting SI gathering center Broadcaster#1 Uplink center Broadcaster#2 Broadcaster#3 - Satellite service covers all areas of Japan. - All broadcasters send their TS to Uplink center. (All broadcasters are located in Tokyo area.) - Each broadcaster s EPG data is sent to SI gathering center and merged. 17

18 Network of terrestrial broadcasting Satellite broadcasting - Satellite Network includes all broadcaster s TS. - NIT has all broadcaster s information. - Only one network exists in the Satellite Service. - Receiver can know all tuning info. by getting one NIT. - Receiver can have all EPG data without tuning all channels (all transponders). Network_01 EPG data (all broadcaster) Broadcaster_01 ( = TS_01 ) - HDTV Broadcaster_02 ( = TS_02 ) - HDTV Broadcaster_03 ( = TS_03 ) - SDTV#1 - SDTV#2 18

19 Network of terrestrial broadcasting Terrestrial broadcasting Broadcaster#A1, #A2, #A3 area-a Broadcaster#B1, #B2, #B3 area-b Broadcaster#C1, #C2, #C3 area-c - Terrestrial TV service covers only a certain area. - NIT of area-a does not need info of area-b, C. - Broadcaster transmits only own NIT and EPG data in licensed area. 19

20 Network of terrestrial broadcasting Terrestrial broadcasting - NIT has one broadcaster s information. - Receiver can know all tuning info it needs by scanning and getting all NITs of receivable area. - Receiver can have all EPG data it needs by scanning and getting all EPG data of receivable area. Broadcaster#A1 Broadcaster#A2 Broadcaster#A3 area-a Network_01 ( = TS_01 ) - HDTV - one-seg Network_02 ( = TS_02 ) - HDTV - one-seg Network_03 ( = TS_03 ) - SDTV#1 - SDTV#2 - one-seg 20

21 Network of terrestrial broadcasting Terrestrial broadcasting - One Network is one Broadcaster ( one TS ). - Network_id and TS_id are unique value in Japan. ( network_id = TS_id ) - Remote Control No. ( remote_control_key_id ) is unique value in the area. 21

22 Channel Selection How Receivers identify packets they need? Transport Stream Video_01 ( packet_id = 01 ) Video_02 ( packet_id = 02 ) Audio_03 ( packet_id = 03 ) Audio_04 ( packet_id = 04 )? Audio_05 ( packet_id = 05 ) 22

23 Channel Selection PMT : Program Map Table - PMT specifies the PID ( Packet ID ) of each program - Receiver uses the newest PMT - PMT also conveys copy protection information of a current program PMT - program_number - version_number - PID & stream_type(video, audio, data ) x N - PCR_PID & ECM_PID - copy control info. ( copy once) 23

24 Channel Selection Transport Stream Video_01 ( packet_id = 01 ) PMT#1 of service[1] - Video_PID = 01 - Audio#1_PID = 04 - Audio#2_PID = 05 Video_02 ( packet_id = 02 ) Audio_03 ( packet_id = 03 ) Audio_04 ( packet_id = 04 ) Audio_05 ( packet_id = 05 ) PMT#2 of service[2] - Video_PID = 02 - Audio#1_PID = 03 How Receivers get a PMT packet they need? 24

25 Channel Selection PAT : Program Association Table - PAT specifies the PID of PMT in Transport Stream - PID of PAT is fixed number ( PID = 0x0000, table_id = 0x00 ) PAT (PID=0x0000) - version_number - network_id - [ each program info. ] x N program_number PID of PMT 25

26 Channel Selection Basic process of Receivers ( Get all NITs at the location by Scanning ) 1. Tune to aiming frequency and get TS 2. Get PAT and know PID of PMT 3. Get PMT and know PIDs of Video stream, Audio stream, PCR, ECM. 4. Get specific packets from TS (Filtering) 5. ( Descramble Video & Audio stream by using Scramble Key conveyed by ECM ) 6. Show Video & Audio 26

27 Transmission cycles and Speed of channel selection - When users change station channel, Receivers get PSI from new TS - Transmission cycle of PSI relates with speed of channel selection - Transmitting PSI faster needs more bandwidth [ Case of Japan ] PAT PMT (fixed service) PMT (one-seg) Transmission cycle 100 msec 100 msec 200 msec Transmission cycle NIT 1.0 sec ECM* 100 msec * : not use in one-seg demonstration 27

28 SI (Service Information) & EPG SI : Service Information - SI is Information for EPG and others - SI consists of SDT, EIT, BIT, TOT etc which are Tables carrying EPG information and Date & Time information etc 28

29 SI (Service Information) & EPG EIT : Event Information Table - EIT specifies the program related information; program title, start date & time, description of the program (explanation), ID of the program (event_id) - Receivers use information of EIT to display EPG and program recording - two types of EIT EIT[p/f] and EIT[schedule] ( or EIT[p/f after] ) 29

30 SI (Service Information) & EPG Structure of EIT EIT - table_id - service_id - version_number - [ each program info. ] x N event_id start time duration program title program description copy control info. ( copy once) genre component info. (Video&Audio stream info.) event_id identifies program (event) event_id has to be unique in the service channel 30

31 SI (Service Information) & EPG EIT[schedule] event_id has to be unique in the service channel within 8 days - EIT[schedule] table has information of all programs within 8 days - EIT[schedule] is used for service for fixed TV For one-seg service, EIT[p/f after] is used instead of EIT[schedule] - Receiver can set VCR to record programs in advance 31

32 SI (Service Information) & EPG EIT[p/f] : EIT present / following - EIT[p/f] table has information of current program (on-air now!) and next program - When current program ends and next program starts, EIT[p/f] will be renewed (version up! ) - Receiver can start VCR recoding by watching EIT[p/f] status 32

33 SI (Service Information) & EPG EIT[p/f] : EIT present / following Program [A] Program [B] EIT[p/f] Version = 01 <present event> Program [A] event_id = 0x 010F start time = 13:20 duration = 40 min <next event> Program [B] event_id = 0x 0110 start time = 14:00 duration = 90 min 14:00 EIT[p/f] Version = 02 <present event> Program [B] event_id = 0x 0110 start time = 14:00 duration = 90 min <next event> Program [C] event_id = 0x 0111 start time = 15:30 duration = 30 min time 33

34 SI (Service Information) & EPG Categories of EIT Service for Fixed TV Mobile Portable (one-seg) Name of EIT H-EIT M-EIT L-EIT Type of EIT H-EIT[p/f] M-EIT[p/f] L-EIT[p/f] H-EIT[schedule] M-EIT[p/f after] L-EIT[p/f after] M-EIT is not used in Japan currently. EIT type PID EIT type Table_id H-EIT 0x0012 H-EIT[p/f] 0x4E M-EIT 0x0026 H-EIT[schedule] 0x50~0x5F L-EIT 0x0027 M-EIT 0x4E L-EIT 0x4E 34

35 SI (Service Information) & EPG SDT : Service Description Table - SDT describes information on service channels in TS; service channel name, service_id, logo info. information of EIT transmitting SDT - table_id - version_number - [ each service info. ] x N service_id service name service logo info. EIT transmitting info. Logo bitmap data is sent by CDT(Common Data Table) 35

36 SI (Service Information) & EPG BIT : Broadcaster Information Table - BIT describes terrestrial TV broadcaster related information station grouping info, parameter of SI transmitting TOT: Time Offset Table - TOT conveys current date and time demonstration 36

37 Facilities of PSI/SI ExampleStructure Data Input Data Server SI production SW er Controller ENC/MUX Controller PSI data SI Encoder SW er Encoder Multiplexer TS Encoder 37

38 Thank you for your attention! 38