IP broadcast system, and multiplexer, receiving apparatus and method used in IP broadcast system

• US 8,483,239 B2
• Filed: 03/14/2008
• Issued: 07/09/2013
• Est. Priority Date: 03/20/2007
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Osaki, Yoshiro, Satoh, Naoko, Kimiyama, Kenji, Maeda, Tetsuo
• Primary Examiner(s): Rinehart, Mark
• Assistant Examiner(s): KHIRODHAR, MAHARISHI V
• Application Number:
  US12/049,081
• Publication Number:
  US 20080232361A1
• Time in Patent Office: 1,943 Days
• Field of Search: 370/471, 370/514, 370/474, 370/467, 370/473, 370/470, 370/477
• US Class Current: 370/471
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06
• CPC Class Codes: H04L 65/65 Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
• CPC Class Codes: H04L 65/762 at the source reformatting of additional data in video distribution servers H04N21/2355
• CPC Class Codes: H04L 65/764 at the destination reformatting of additional data in video clients H04N21/4355

Abstract

According to one embodiment, an IP broadcast system includes a transmitting side and a receiving side connected to the transmitting side through a broadcast network on an IP network. The transmitting side includes a multiplexer which generates a standardized multiplex frame including at least a header field and an information field by multiplexing a plurality of RTP packets. The receiving side includes a buffer which temporarily holds the multiplex frame from the broadcast network and a program reproducer which retrieves and analyzes the multiplex frame from the buffer, extracts a reproduction clock shared by a plurality of programs, demultiplexes a plurality of TSs for each program from the multiplex frame, and based on the reproduction clock, reproduces the programs from each TS.

Claims

1. An internet protocol (IP) broadcast system comprising:

a transmitting side which converts a plurality of transport streams (TSs) into a plurality of real-time transport protocol (RTP) packets for IP network transmission, and transmits the converted plurality of RTP packets to a broadcast network on an IP network, the TS including packet structures different in program and reproduction clock, wherein the transmitting side comprises a multiplexer which multiplexes the converted plurality of RTP packets to generate a standardized multiplex frame including at least a header field and an information field, and wherein the multiplexer comprises;

a plurality of input buffers configured to temporarily store the plurality of RTP packets for each program;

a rate detector which detects a transmission rate of each of the plurality of RTP packets;

an arithmetic unit to determine a delay amount based on a buffer occupation amount of each of the plurality of input buffers, and read out the plurality of RTP packets from the corresponding plurality of input buffers based on the delay amount, wherein the arithmetic unit determines a program including the highest transmission rate as a master program among the plurality of programs based on a detection result of the rate detector, and multiplexes a plurality of corresponding RTP packets at a rate equal to a product of the transmission rate of the master program and the number of programs;

a header generator which generates data of the header field of the multiplex frame based on the plurality of RTP packets; and

an output buffer which stores the plurality of RTP packets and the data in the header field of the multiplex frame to output the multiplex frame; and

a receiving side which receives the plurality of RTP packets from the broadcast network, extracts a reproduction clock from each of the plurality of RTP packets, and reproduces a program from the TS in each of the plurality of RTP packets based on the reproduction clock, wherein the receiving side comprises;

a buffer which temporarily holds the multiplex frame received from the broadcast network; and

a program reproducer which retrieves and analyzes the multiplex frame from the buffer, extracts the reproduction clock shared by the plurality of programs, demultiplexes a plurality of TSs for each program from the multiplex frame and reproduces the program from each TS based on the reproduction clock.

2. The IP broadcast system according to claim 1,

wherein the program reproducer executes a reproduction process by extracting the reproduction clock of the master program.

3. The IP broadcast system according to claim 1,

wherein the multiplexer changes the combination of a plurality of programs to be multiplexed, in accordance with a receiving area.

4. A multiplexer used on a transmitting side of an internet protocol (IP) broadcast system, the transmitting side converts a plurality of transport streams (TSs) into a plurality of real-time transport protocol (RTP) packets for IP network transmission, and transmits the plurality of RTP packets to a broadcast network on an IP network, the plurality of TSs including packet structures different in program and reproduction clock, the multiplexer comprising:

a frame generator which generates a standardized multiplex frame including at least a header field and an information field by multiplexing the plurality of RTP packets,

wherein the frame generator comprises;

a plurality of input buffers which temporarily hold the plurality of RTP packets for each program;

a rate detector which detects a transmission rate of each of the plurality of RTP packets;

an arithmetic unit to determine a delay amount based on a buffer occupation amount of each of the plurality of input buffers, and read out the plurality of RTP packets from the plurality of corresponding input buffers based on the determined delay amount, wherein the arithmetic unit determines a program including the highest transmission rate as a master program among the plurality of programs based on a detection result of the rate detector, and multiplexes a plurality of corresponding RTP packets at a rate equal to a product of the transmission rate of the master program and the number of programs;

a header generator which generates data of the header field of the multiplex frame based on the plurality of RTP packets; and

an output buffer which stores the plurality of RTP packets and the data in the header field of the multiplex frame, to output the multiplex frame.

5. The multiplexer according to claim 4,

wherein the frame generator changes the combination of a plurality of programs to be multiplexed, in accordance with a receiving area.

6. A receiving apparatus used on a receiving side of an internet protocol (IP) broadcast system, the IP broadcast system converts a plurality of transport streams (TSs) into a plurality of real-time transport protocol (RTP) packets for IP network transmission, and transmits the plurality of RTP packets to a broadcast network on an IP network, the TS including packet structures different in program and reproduction clock, wherein a transmitting side of the IP broadcast system comprises a multiplexer which multiplexes the converted plurality of RTP packets to generate a standardized multiplex frame including at least a header field and an information field, and wherein the multiplexer comprises:

a plurality of input buffers configured to temporarily store the plurality of RTP packets for each program;

a rate detector which detects a transmission rate of each of the plurality of RTP packets;

an arithmetic unit to determine a delay amount based on a buffer occupation amount of each of the plurality of input buffers, and read out the plurality of RTP packets from the corresponding plurality of input buffers based on the delay amount, wherein the arithmetic unit determines a program including the highest transmission rate as a master program among the plurality of programs based on a detection result of the rate detector, and multiplexes a plurality of corresponding RTP packets at a rate equal to a product of the transmission rate of the master program and the number of programs;

a header generator which generates data of the header field of the multiplex frame based on the plurality of RTP packets; and

an output buffer which stores the plurality of RTP packets and the data in the header field of the multiplex frame to output the multiplex frame;

the receiving apparatus comprising;

a receiving unit to receive a multiplex frame from the broadcast network, the multiplex frame including at least a header field and an information field by multiplexing the plurality of RTP packets in a multiplexer in a transmitting side of the IP broadcast system, wherein the multiplexer includes a plurality of input buffers, which temporarily hold the plurality of RTP packets for each program, and an arithmetic unit which determines a delay amount from a buffer occupation amount of each of the plurality of input buffers, and reads out the plurality of RTP packets from the plurality of corresponding input buffers based on the delay amount;

a buffer which temporarily holds the multiplex frame; and

a program reproducer which retrieves and analyzes the multiplex frame from the buffer, extracts a reproduction clock shared by the plurality of programs, demultiplexes the plurality of TSs for each program from the multiplex frame, and reproduces the program from each TS based on the reproduction clock.

7. The receiving apparatus according to claim 6,

wherein the program reproducer executes a reproduction process by extracting the reproduction clock for the master program designated by the transmitting side.

8. A method of converting a plurality of transport streams (TSs) into real-time transport protocol (RTP) packets for internet protocol IP network transmission and transmitting the converted RTP packets to a broadcast network on the IP network, the TS including packet structures different in program and reproduction clock, the method comprising:

designating a program including the highest transmission rate as a master program among a plurality of programs to be transmitted to the broadcast network;

detecting a transmission rate of each of the plurality of RTP packets;

determining a delay amount for the master program and for each of a plurality of programs following the master program, wherein the determining comprises determining a program including the highest transmission rate as a master program among the plurality of programs based on a detection result of the detecting, and multiplexing a plurality of corresponding RTP packets at a rate equal to a product of the transmission rate of the master program and the number of programs;

judging whether the delay amount is larger than a target delay amount;

storing the plurality of the corresponding RTP packets in an output buffer with regard to the program including a delay amount larger than the target delay amount;

storing the plurality of the corresponding RTP packets and dummy data for a deficient part in the output buffer with regard to the program including a delay amount not larger than the target delay amount; and

generating and outputting a standardized multiplex frame including at least a header field and an information field based on the plurality of RTP packets stored in the output buffer.