Digital television systems - (DTS) Lectures DVB transport stream Technical Univ. of Kosice Faculty of Electrical Engineering and Informatics Lˇ. Maceková, 2017

DVB - coding – tables of transport stream

Example: Calculate the bit rate at 4:2:2 sampling scheme [ITU-T B.601], at: a)8 bit per sample for each, Y, CR, CB sample, b) 10 bit per sample for each, Y, CR, CB sample, Solution: a) luminance: 13,5 MHz x 8 bits = 108 Mbps each color difference signals: 6,5 MHz x 8 bits x 2 = 108 Mbps ------ Together: 108 + 108 = 216 Mbps b) luminance: 13,5 MHz x 10 bits = 135 Mbps each color difference signals: 6,5 MHz x 10 bits x 2 = 135 Mbps Together: 135 + 135 = 270 Mbps This is the basic data rate for SDI (Serial Digital Interface) for digital component signal transmission.

Data Bits Reduction Methods Why? because of data speed requirements reduction because of data storage volume reduction compressing data – high effective compression methods to 100-times decreasing of the data amount (1 to 6 Mbps per program) compression standards (MPEG-2, MPEG-4): removing of redundancy (DPCM, DCT-transformation, prediction methods in the GOPs – Groups-of-Pictures I,P,B, VLC (Variable Length Coding)

In the opposite side, there are effective transmission methods developed. Why? - for data speed increasing How? using of multiple carriers system (OFDM, COFDM) digital modulations QAM, QPSK (multistate modulation of each carrier) error prevent and correction methods (channel coding - FEC - RS code, convolution codes, inter-bit and inter-symbol interleaving)

The MPEG-2 tables Program Service Information (PSI) Program allocation table (PAT) always present (packets PID = 0×0000). indication (for each program in the transport multiplex) = “interconnections” between program number (from 0 to 65535) and PID of packets which transmits the program map (Program Map Table—PMT). Conditional access table (CAT) It is present once at least 1 program in the multiplex has conditional access It is transported by packets PID = 0×0001. It indicates PID of the packets of EMM (EMM is one of 2 information required for descrambling of coded program) Program map table (PMT) 1 x PMT for each program in multiplex PID of elementary stream (coded program and alternatively other privat information relevant to program, e.g.ECM for the descrambling)

Tab. Illustration of PAT Field (PAT) Comment No. of bits Table_id (00) Always 00 for the PAT 8 Section_syntax_indicator 0 Always 1 Always 0 1 Reserved 2 Section_length Max. value 1021 (2 MSB = 0) 12 Transport_stream_id Stream identification (in a network) 16 Version_number Incremented at every PAT modification 5 Current_next_indicator 1 = current PAT, 0 = next Section_number Number of current section (1st = 00) Last_section_number Number of last section (JVtot−1) .... ... CRC_32 CRC on 32 bits 32

Transport stream description table (TSDT) description of the multiplex content PID = 0×0002 packets Others privat tables .... DVB-SI Table (DVB – Service Information): - allows automatic configuration of the receiver - allows user access to a lot of programs and services - 4 mandatory and 3 optional ones: Network information Table (NIT) the frequencies and No. of channels (for receiver configuration) PID = 0×0010 Service description table (SDT) list of the names and parameters of other services in multiplex PID = 0×0011. Event information table (EIT), present/following information about events present or incoming by actual transport multiplex PID = 0×0012. Time and date table (TDT) - for the update of internal time/clock of set-top-box - PID = 0×0014.

Optional tables in DVB-SI Bouquet association table (BAT) Running status table (RST) Time offset table (TOT) Stuffing tables (ST) PID hex (13 b) Table ID hex (8b) Repetition Min Max Table PSI PAT 0000 00 25 ms 100 ms CAT 0001 01 PMT 0020 to 1FFE 02 NIT 0010 40 to 41 10 s Table SI 10 to 41 SDT 0011 42, 46 2 s BAT 4A EIT 0012 4E to 6F RST 0013 71 - TDT 0014 70 30 s TOT 73 ST 0010 to 001F 72 the tables are repeated very often for quick access of the decodes to information in the case of the channel change ETSI TR 101 290

RTCP-protocol (Real-time Transport Control Protocol) Unicast RTCP-protocol (Real-time Transport Control Protocol) user affects the transport (the content, start, stop, interruption) example: YouTube, Video-archive higher demands on transport capacity/ throughput of lines routers, switchs Multicast RTP-protocol (Real-time Transport Protocol) 1 directional communication the user can not affect the communication example: IPTV TV JOJ , 6 Mbps 6 Mbps

S = shift register length R = m/n = code ratio < 1 Convolution coder e.g.: =1 =2 =1/2 =3 m = inputs number n = outputs number S = shift register length R = m/n = code ratio < 1 K = (S+1). m = length of State diagram The generating polynomial: G1=x2+x+1=78, G2= x2+1=58, hence [7,5]8 or [111, 102]2 if ip = 0 if ip = 1 current state next state (op) 00 00 (00) 10 (11) 01 00 (11) 10 (00) 10 01 (10) 11 (01) 11 01 (01) 11 (10) Table of transitions between states http://www.dsplog.com/2009/01/04/convolutional-code/