Streaming to Wireless and Mobile Devices

2008-07-13T03:27:31Z

Yliu:

Wireless networks offer convenience,mobility, and low cost infrastructure. As wireless networks provide higher throughput and quality-of-service (QoS), video streaming over wireless networks has become an important application. The optimization of video streaming over wireless networks, however, is a challenging task because of the heterogeneity and dynamic nature of the channels among wireless nodes. In this project, we seek to optimize the quality of video streaming in wireless networks with energy-constrained devices. We consider a general wireless network model, in which there are multiple wireless stations sharing a common wireless medium. These wireless stations can, for example, be notebook computers, PDAs, or video sensors. The wireless media can include cellular networks, IEEE 802.16 WiMAX networks, and IEEE 802.11 WLANs. The wireless stations can be sending and/or receiving video streams to/from the video server through a wireless base station. For example, in video surveillance systems, video sensors captures and transmit their streams over a WLAN to a processing server for further analysis. As another example, wireless stations can be receiving video tutorials, demos, or movies from a video-on-demand streaming server over a WiMAX network.

We consider battery-powered wireless stations that have power constraints. To cope with the power constraints, stations employ complexity scalable video coders that may selectively skip some encoding optimization modules to save power. To maximize quality at a given power budget, we employ models that relate power consumption, encoding bit rate, and resulting distortion. Power considerations are critical in wireless devices. Previous measurement studies indicate that modern video coders consume about two-thirds of the system power in video wireless communication systems

We are also interested in video broadcasting to mobile devices in systems such as DVB-H (Digital Video Broadcast--Handheld). These systems provide TV services to mobile devices. We are working on algorithms to broadcast IP packets to mobile devices such that their wireless reception components can sleep for the longest possible period of time (and hence save energy) while maintaining good video quality.

== People ==

* [http://www.cs.sfu.ca/~mhefeeda/ Mohamed Hefeeda]

* Cheng-Hsin Hsu (PhD student)

* Yi Liu (MSc student)

== Publications ==

* C. Hsu, M. Hefeeda, Power-aware Video Streaming in 802.11 Wireless LANs, under review.

== Mobile TV (DVB-H) Testbed and Experiments ==

This testbed is used to evaluate several of our algorithms that aim to improve mobile TV quality and usability. We configure a commodity Linux workstation as our streaming server as well as IP encapsulator that converts a video over IP stream into a MPEG-2 transport stream. This Linux workstation also hosts a PCI-based DVB-H modulator card that is connected to an in-door antenna. We currently use Nokia N92 mobile phone as TV receivers, which enables us to gather several performance metrics such as video quality, CPU loads, and energy consumption (battery-life). In particular, this testbed consists of:

* An Intel Quad-Core Xeon E5420 (2.5 GHz) PC running Ubuntu Linux.
* A Dektec DTA-110T DVB-T/H Modulator and UHF Upconverter for PCI Bus.
* A Nokia N-92 mobile TV phone.
* Open source IP encapsulator software from http://amuse.ftw.at/downloads/encapsulator .

[[Image:MobileTV2.jpg|center|frame|Mobile TV Testbed]]

== Discussion and Ideas ==

* Extend power awareness to WiMax and TDMA networks.

* [[Private:mobile_streaming_ideas|Underinvestigated ideas of streaming to mobile devices (login required)]].

* [[Time slicing in DVB-H]]

*[[PSI_SI_DVB-H]]

*[[ESG_DVB-H]]

*[[FLUTE_DVB-H]]

== References and Links ==

* [http://www.dvb-h.org/ The official Mobile TV website maintained by the DVB Project Office.]

* [http://projects.celtic-initiative.org/WING-TV/ Wing-TV Project:] Docs to test and to verify in detail the DVB-H specification.

* J. Wang, M. Venkatachalam, and Y. Fang, [http://www.fang.ece.ufl.edu/mypaper/jsac07wang.pdf System Architecture and Cross-Layer Optimization of Video Broadcast over WiMAX], IEEE JSAC 25(4), pp. 712--721, MAY 2007. (Check this special issue of JSAC as well.)

* G. Gardikis, G. Xilouris, C. Skianis, [http://www.springerlink.com/content/a32p21815h46n12q/ Broadband multimedia on the move with DVB-H], Multimedia Tools and Applications, 36(1-2), January 2008. (DVB-H tutorial in inter-active mode.)

Streaming to Wireless and Mobile Devices

2008-06-02T21:49:15Z

Yliu:

Wireless networks offer convenience,mobility, and low cost infrastructure. As wireless networks provide higher throughput and quality-of-service (QoS), video streaming over wireless networks has become an important application. The optimization of video streaming over wireless networks, however, is a challenging task because of the heterogeneity and dynamic nature of the channels among wireless nodes. In this project, we seek to optimize the quality of video streaming in wireless networks with energy-constrained devices. We consider a general wireless network model, in which there are multiple wireless stations sharing a common wireless medium. These wireless stations can, for example, be notebook computers, PDAs, or video sensors. The wireless media can include cellular networks, IEEE 802.16 WiMAX networks, and IEEE 802.11 WLANs. The wireless stations can be sending and/or receiving video streams to/from the video server through a wireless base station. For example, in video surveillance systems, video sensors captures and transmit their streams over a WLAN to a processing server for further analysis. As another example, wireless stations can be receiving video tutorials, demos, or movies from a video-on-demand streaming server over a WiMAX network.

We consider battery-powered wireless stations that have power constraints. To cope with the power constraints, stations employ complexity scalable video coders that may selectively skip some encoding optimization modules to save power. To maximize quality at a given power budget, we employ models that relate power consumption, encoding bit rate, and resulting distortion. Power considerations are critical in wireless devices. Previous measurement studies indicate that modern video coders consume about two-thirds of the system power in video wireless communication systems

We are also interested in video broadcasting to mobile devices in systems such as DVB-H (Digital Video Broadcast--Handheld). These systems provide TV services to mobile devices. We are working on algorithms to broadcast IP packets to mobile devices such that their wireless reception components can sleep for the longest possible period of time (and hence save energy) while maintaining good video quality.

== People ==

* [http://www.cs.sfu.ca/~mhefeeda/ Mohamed Hefeeda]

* Cheng-Hsin Hsu (PhD student)

* Yi Liu (MSc student)

== Publications ==

* C. Hsu, M. Hefeeda, Power-aware Video Streaming in 802.11 Wireless LANs, under review.

== Mobile TV (DVB-H) Testbed and Experiments ==

This testbed is used to evaluate several of our algorithms that aim to improve mobile TV quality and usability. We configure a commodity Linux workstation as our streaming server as well as IP encapsulator that converts a video over IP stream into a MPEG-2 transport stream. This Linux workstation also hosts a PCI-based DVB-H modulator card that is connected to an in-door antenna. We currently use Nokia N92 mobile phone as TV receivers, which enables us to gather several performance metrics such as video quality, CPU loads, and energy consumption (battery-life). In particular, this testbed consists of:

* An Intel Quad-Core Xeon E5420 (2.5 GHz) PC running Ubuntu Linux.
* A Dektec DTA-110T DVB-T/H Modulator and UHF Upconverter for PCI Bus.
* A Nokia N-92 mobile TV phone.
* Open source IP encapsulator software from http://amuse.ftw.at/downloads/encapsulator .

[[Image:MobileTV.jpg|center|frame|Mobile TV Testbed]]

== Discussion and Ideas ==

* Extend power awareness to WiMax and TDMA networks.

* [[Time slicing in DVB-H]]

*[[PSI_SI_DVB-H]]

*[[ESG_DVB-H]]

*[[FLUTE_DVB-H]]

== References and Links ==

* [http://www.dvb-h.org/ The official Mobile TV website maintained by the DVB Project Office.]

* [http://projects.celtic-initiative.org/WING-TV/ Wing-TV Project:] Docs to test and to verify in detail the DVB-H specification.

* J. Wang, M. Venkatachalam, and Y. Fang, [http://www.fang.ece.ufl.edu/mypaper/jsac07wang.pdf System Architecture and Cross-Layer Optimization of Video Broadcast over WiMAX], IEEE JSAC 25(4), pp. 712--721, MAY 2007. (Check this special issue of JSAC as well.)

* G. Gardikis, G. Xilouris, C. Skianis, [http://www.springerlink.com/content/a32p21815h46n12q/ Broadband multimedia on the move with DVB-H], Multimedia Tools and Applications, 36(1-2), January 2008. (DVB-H tutorial in inter-active mode.)

Time slicing in DVB-H

2008-06-02T07:45:03Z

Yliu:

== Four components of Testbed: ==

Just-DVB Open source software --- used to get DVB-T signal

FATCAPS DVB-H IP-Encapsulator --- used to get DVB-H signal based on the DVB-T signal

DTA-110T PCI card ---send the DVB-H signal to the target client (Nokia N92)

Nokia N92 --- the receiving device

== What does FATCPAS do? ==

Reads IP data from configurable sources via one or more instances of the dataaggregator tool
Organizes the data in a MPE-FEC frame as specified in the DVB-H standard and optionally computes the MPE forward error correction (MPE-FEC)
Creates a stream of MPEG-2 TS packets of 188B size and outputs them to a configurable output FIFO or a file
Outputs timesliced MPEG2 transport stream data
All files located under /DVB-H/DVBH_Encapsulator

== What does Just-IT do? ==

JustDVB just replaces nullpackets by configurable PSI/SI which is mandatory for a regular DVB-H stream.
All files located under /DVB-H/DVBH_Encapsulator/python-config-dvbh

== DTA-110T PCI Card ==

Start the card:
/DVB-H/Dta1xx/Dta1xxInit start
Stop the card:
/DVB-H/Dta1xx/Dta1xxInit stop

== Two Tools from FATCAPS ==
'''1) Dataaggregator (Encapsulator + sec2ts )'''
collects IP packets matching a given filter expression
yliu1@cs-nsl-11:/DVB-H/DVBH_Encapsulator$ ./dataaggregator -h
Usage: dataaggregator [-h] capture -o <file> -e <string> [-c <string>] [-s <string>] [-d <string>]
-o, --outfile=<file> Filename to write to.
-e, --filterexp=<string> Filter expression, libpcap style
-c, --capturedevice=<string> Capture device
-s, --srcaddr=<string> Source IP address to be set
-d, --dstaddr=<string> Destination IP address to be set
-h, --help print this help and exit

Sample usage
./dataaggregator capture -e 'port 1110 || port 1120' -o /tmp/capturedpackets &

'''2) Timeslicer'''
reads the MPE sections and MPE-FEC sections output by the encapsulator and creates corresponding MPEG2 transport stream packets

outputs timesliced MPEG2 transport stream data
For the above file run by dataaggregator, it also need to be run by timeslicer
./timeslicer -n 1024 -g 8 -b 8 -d 100 -c 3 -o qpsk -p my_program_name:/tmp/captured/packetѕ > /tmp/myfifo &
Also we need to manually specify several parameters such as delta-T, the number of rows of the MPE-FEC frame and whether to use MPE-FEC or not.
yliu1@cs-nsl-11:/DVB-H/DVBH_Encapsulator$ ./timeslicer -h
Usage: timeslicer [-h] [--fec] [-n [256, 512, 768, 1024 (default)]] -g [4, 8, 16, 32] -b [5, 7, 8] -d <int> -c [1, 2, 3, 5, 7] -o [qpsk, 16qam, 64qam] [-r <double>] -p [name:inputfile:PID] [-p [name:inputfile:PID]]... [-f <file>]
--fec Use MPE-FEC
-n, --numRows=[256, 512, 768, 1024 (default)] define number of rows in MPE-FEC frame
-g, --guardInt=[4, 8, 16, 32] OFDM guard interval
-b, --bandwidth=[5, 7, 8] OFDM bandwidth
-d, --deltat=<int> delta-T value for *all* programs
-c, --coderate=[1, 2, 3, 5, 7] coderate
-o, --constellation=[qpsk, 16qam, 64qam] constellation
-r, --nullrate=<double> the rate at which we insert nullpackets in the Ñtream. Defaults to 0.1.
-p, --program=[name:inputfile:PID] add a timesliced program
-f, --outfile=<file> the file to write the output to. Defaults to stdout
-h, --help print this help and exit

Example:
timeslicer -n 1024 -g 8 -b 8 -d 90 -c 3 -o qpsk -r 0.1 -p myprog:mydir/myinputfile:0x666
This command starts a timeslicer with the following OFDM transmission parameters: guard interval is 1/8, bandwidth is 8 MHz, constellation is qpsk and code rate is 3/4. The DVB-H encapsulator creates MPE-FEC frames with 1024 rows and with a delta-T of 0.9 seconds. For every 10 data packets, 1 nullpacket is inserted (nullrate=0.1). There's one program named myprog. The data for this program is read from /mydir/myinputfile. This program uses PID 0x666.

== Configure PSI/SI table ==
FATCAPS provides some basic code in Python for configuring PSI/SI table.
Suppose we want to create a new PSI/SI, we need to do the following:

'''1) Create a new python file under /DVB-H/DVBH_Encapsulator/python-config-dvbh'''

Example: Suppose the file is called pat.py
import os
from dvbobjects.PSI.PAT import *
from dvbobjects.DVB.Descriptors import *
import psimain
sec = program_association_section(
transport_stream_id = psimain.transport_stream1.transport_stream_id,
program_loop = [
psimain.program1,
psimain.program2,
psimain.program3,
psimain.program4,
psimain.int_program,
],
version_number = 1,
section_number = 0,
last_section_number = 0,
elementary_PID = 0,
filename = "pat",
repeat_time = "40", #milliseconds
)

'''2) Modify /DVB-H/DVBH_Encapsulator/python-config-dvbh/startgenerator.py to process the new python file'''
Add the following code:
import pat
UpdateSection(pat.sec)
justdvbit.AddTableToNullShaper(pat.sec)

Global variables go to /DVB-H/DVBH_Encapsulator/python-config-dvbh/psimain.py.
/DVB-H/DVBH_Encapsulator/python-config-dvbh/justdvbit.py is the central file that determines the order in which the
single tools are called, we should normally not need to change this.

2008-06-02T06:19:14Z

Yliu:

FLUTE DVB-H

2008-06-02T06:09:10Z

Yliu:

File:l21.jpg

2008-06-02T06:06:15Z

Yliu:

FLUTE DVB-H

2008-06-02T06:05:00Z

Yliu:

PSI SI DVB-H

2008-05-27T16:50:39Z

Yliu:

== What is PSI/SI in DVB-H: ==
PSI (Program Specific Information) consists of data enabling a decoder to demultiplex DVB-H services. It contains the following table: PAT, PMT, NIT, CAT

SI provides information on DVB-H services carried by different multiplexes, it contains the following table: SDT, EIT, RST, TDT, TOT, ST

== Is PSI/SI mandatory in DVB-H? ==
Yes, in order for cell phones to receive DVB-H programs, Timeslicing, MPE-FEC, PSI/SI and ESG are all needed.
To get the DVB-H service correctly for the cell phone, server must insert the associated information into the TS stream, that is PSI and SI.

== PSI/SI and receiver (cell phone) ==
When the cell phone starts to receive DVB-H program, it actually starts with receiving PSI/SI. They are in the table format, no encryption and directly built in the TS datagram.

From PSI/SI information, the cell phone knows the program list and the PID of each program in the received TS. After that the cell phone can start to receive the particular PID of the target program and ignore all PIDs of all other programs in the same TS.

== DVB-H network layer ==
[[Image:newlayer1.jpg]]

For higher resolution picture, please go to [http://www.sfu.ca/~yliu1/layer1.jpg]

A DVB network is uniquely identified by a network_id. A DVB network consist of one or more Transport Streams
(TS), each carrying a multiplex and being transmitted by one or more Services.

TS use transport_stream_id & original_network_id for identification, these info are saved in PAT table

Service use service_id & transport_stream_id & original_network_id for identification. these info are saved in PMT table

ES (elementary stream) use component_tag or the PID in TS for identification.

== PSI contains the following tables: ==
PAT（Program Association Table）:The PAT lists PIDs for all PMTs in the stream. TS Packets containing PAT information always have PID 0x0.

PMT（Program Map Table）:contain information about programs. For each program, there is a PMT.

NIT（Network Information Table）: provides information about the multiplexes and transport streams on a given network. Information about the current network uses table_id of 0x40, that about other networks uses table_id of 0x41

CAT（Conditional Access Table）:This table is used for conditional access to the streams. This table provides association with EMM stream.

The releationship between PAT and PMT are:

[[Image:newlayer3.jpg]]

For higher resolution picture, please go to [http://www.sfu.ca/~yliu1/layer3.jpg]

== SI contains the following tables: ==
INT : (IP/MAC Notification Table): in an IP platform, contains all the IP address of the services and the corresponding service_id of each IP. We can get the PID of a particular service in TS with the help of PAT and PMT. Very important.

SDT (service description table) : used to descript service name, service provider, the description of the TS.

EIT (event information table) : the corresponding audio stream, file stream and the propsed program start time and end time. Eg. 2008-May-27 0:27am, Yi Liu is writting this wiki page.

RST (runtime status table): provide one or more events status and time, e.g whether or not an event is running or not running.

TDT : record the current date, time info for the server

TOT : record the current time difference between server and local time

== How a mobile TV receiver using PSI/SI table to find the first time-slicing bursts ==
EIT table can tell the receiver the start time of the program. And whenever the program starts, the first burst session occurs.

== How a mobile TV receiver switch channels ==
channel switch request is initiated via a user interface. This causes a mobile broadcast receiver to switch from the first channel to the second channel. It is actually switching to another PID. We can use NIT, PAT, PMT, INT tables to trace that PID (get it from PMT). See following session for tracing service_id

== To trace service_id ==
This procedure is called INT discovery, the goal is to get service_id and IP of all programs, and the ESG service IP and service_id.

The procedure is:

Frequency tuning --> locate and read INT table from IP datagram, find platform_id and service_id --> Locate PAT, based on service_id to find PMT_pid in PAT --> Locate PMT, analyze the program PID --> Locate INT, get program name and service provider name --> Locate SDT, get the program broadcase address

The complete programs and program list is contains in INT and SDT. Note: ESG address is described in the INT table

File:newlayer3.jpg

2008-05-27T16:49:31Z

Yliu:

File:newlayer1.jpg

2008-05-27T16:48:57Z

Yliu:

PSI SI DVB-H

2008-05-27T16:48:39Z

Yliu:

== What is PSI/SI in DVB-H: ==
PSI (Program Specific Information) consists of data enabling a decoder to demultiplex DVB-H services. It contains the following table: PAT, PMT, NIT, CAT

SI provides information on DVB-H services carried by different multiplexes, it contains the following table: SDT, EIT, RST, TDT, TOT, ST

== Is PSI/SI mandatory in DVB-H? ==
Yes, in order for cell phones to receive DVB-H programs, Timeslicing, MPE-FEC, PSI/SI and ESG are all needed.
To get the DVB-H service correctly for the cell phone, server must insert the associated information into the TS stream, that is PSI and SI.

== PSI/SI and receiver (cell phone) ==
When the cell phone starts to receive DVB-H program, it actually starts with receiving PSI/SI. They are in the table format, no encryption and directly built in the TS datagram.

From PSI/SI information, the cell phone knows the program list and the PID of each program in the received TS. After that the cell phone can start to receive the particular PID of the target program and ignore all PIDs of all other programs in the same TS.

== DVB-H network layer ==
[[Image:newlayer1.jpg]]

A DVB network is uniquely identified by a network_id. A DVB network consist of one or more Transport Streams
(TS), each carrying a multiplex and being transmitted by one or more Services.

TS use transport_stream_id & original_network_id for identification, these info are saved in PAT table

Service use service_id & transport_stream_id & original_network_id for identification. these info are saved in PMT table

ES (elementary stream) use component_tag or the PID in TS for identification.

== PSI contains the following tables: ==
PAT（Program Association Table）:The PAT lists PIDs for all PMTs in the stream. TS Packets containing PAT information always have PID 0x0.

PMT（Program Map Table）:contain information about programs. For each program, there is a PMT.

NIT（Network Information Table）: provides information about the multiplexes and transport streams on a given network. Information about the current network uses table_id of 0x40, that about other networks uses table_id of 0x41

CAT（Conditional Access Table）:This table is used for conditional access to the streams. This table provides association with EMM stream.

The releationship between PAT and PMT are:
[[Image:newlayer3.jpg]]

== SI contains the following tables: ==
INT : (IP/MAC Notification Table): in an IP platform, contains all the IP address of the services and the corresponding service_id of each IP. We can get the PID of a particular service in TS with the help of PAT and PMT. Very important.

SDT (service description table) : used to descript service name, service provider, the description of the TS.

EIT (event information table) : the corresponding audio stream, file stream and the propsed program start time and end time. Eg. 2008-May-27 0:27am, Yi Liu is writting this wiki page.

RST (runtime status table): provide one or more events status and time, e.g whether or not an event is running or not running.

TDT : record the current date, time info for the server

TOT : record the current time difference between server and local time

== How a mobile TV receiver using PSI/SI table to find the first time-slicing bursts ==
EIT table can tell the receiver the start time of the program. And whenever the program starts, the first burst session occurs.

== How a mobile TV receiver switch channels ==
channel switch request is initiated via a user interface. This causes a mobile broadcast receiver to switch from the first channel to the second channel. It is actually switching to another PID. We can use NIT, PAT, PMT, INT tables to trace that PID (get it from PMT). See following session for tracing service_id

== To trace service_id ==
This procedure is called INT discovery, the goal is to get service_id and IP of all programs, and the ESG service IP and service_id.

The procedure is:

Frequency tuning --> locate and read INT table from IP datagram, find platform_id and service_id --> Locate PAT, based on service_id to find PMT_pid in PAT --> Locate PMT, analyze the program PID --> Locate INT, get program name and service provider name --> Locate SDT, get the program broadcase address

The complete programs and program list is contains in INT and SDT. Note: ESG address is described in the INT table

2008-05-27T08:04:21Z

Yliu:

== What is PSI/SI in DVB-H: ==
PSI (Program Specific Information) consists of data enabling a decoder to demultiplex DVB-H services. It contains the following table: PAT, PMT, NIT, CAT
SI provides information on DVB-H services carried by different multiplexes, it contains the following table: SDT, EIT, RST, TDT, TOT, ST

== Is PSI/SI mandatory in DVB-H? ==
Yes, in order for cell phones to receive DVB-H programs, Timeslicing, MPE-FEC, PSI/SI and ESG are all needed.
To get the DVB-H service correctly for the cell phone, server must insert the associated information into the TS stream, that is PSI and SI.

== PSI/SI and receiver (cell phone) ==
When the cell phone starts to receive DVB-H program, it actually starts with receiving PSI/SI. They are in the table format, no encryption and directly built in the TS datagram.

From PSI/SI information, the cell phone knows the program list and the PID of each program in the received TS. After that the cell phone can start to receive the particular PID of the target program and ignore all PIDs of all other programs in the same TS.

== DVB-H network layer ==
This is a very important picture, my account can not upload picture to this wiki, have to put it on my SFU webpage.
[http://www.sfu.ca/~yliu1/layer1.jpg]

A DVB network is uniquely identified by a network_id. A DVB network consist of one or more Transport Streams
(TS), each carrying a multiplex and being transmitted by one or more Services.

TS use transport_stream_id & original_network_id for identification, these info are saved in PAT table

Service use service_id & transport_stream_id & original_network_id for identification. these info are saved in PMT table

ES (elementary stream) use component_tag or the PID in TS for identification.

== PSI contains the following tables: ==
PAT（Program Association Table）:The PAT lists PIDs for all PMTs in the stream. TS Packets containing PAT information always have PID 0x0.

PMT（Program Map Table）:contain information about programs. For each program, there is a PMT.

NIT（Network Information Table）: provides information about the multiplexes and transport streams on a given network. Information about the current network uses table_id of 0x40, that about other networks uses table_id of 0x41

CAT（Conditional Access Table）:This table is used for conditional access to the streams. This table provides association with EMM stream.

The releationship between PAT and PMT are:
[http://www.sfu.ca/~yliu1/layer3.jpg]

== SI contains the following tables: ==
INT : (IP/MAC Notification Table): in an IP platform, contains all the IP address of the services and the corresponding service_id of each IP. We can get the PID of a particular service in TS with the help of PAT and PMT. Very important.

SDT (service description table) : used to descript service name, service provider, the description of the TS.

EIT (event information table) : the corresponding audio stream, file stream and the propsed program start time and end time. Eg. 2008-May-27 0:27am, Yi Liu is writting this wiki page.

RST (runtime status table): provide one or more events status and time, e.g whether or not an event is running or not running.

TDT : record the current date, time info for the server

TOT : record the current time difference between server and local time

== How a mobile TV receiver using PSI/SI table to find the first time-slicing bursts ==
EIT table can tell the receiver the start time of the program. And whenever the program starts, the first burst session occurs.

== How a mobile TV receiver switch channels ==
channel switch request is initiated via a user interface. This causes a mobile broadcast receiver to switch from the first channel to the second channel. It is actually switching to another PID. We can use NIT, PAT, PMT, INT tables to trace that PID (get it from PMT). See following session for tracing service_id

== To trace service_id ==
This procedure is called INT discovery, the goal is to get service_id and IP of all programs, and the ESG service IP and service_id.

The procedure is:

Frequency tuning --> locate and read INT table from IP datagram, find platform_id and service_id --> Locate PAT, based on service_id to find PMT_pid in PAT --> Locate PMT, analyze the program PID --> Locate INT, get program name and service provider name --> Locate SDT, get the program broadcase address

The complete programs and program list is contains in INT and SDT. Note: ESG address is described in the INT table