Transmitting digital video signals over an IP network

• US 20030126294A1
• Filed: 11/19/2002
• Published: 07/03/2003
• Est. Priority Date: 11/19/2001
• Status: Abandoned Application

• Current Assignee: Electronics and Telecommunications Research Institute, Linear Systems Incorporated
• Original Assignee: Electronics and Telecommunications Research Institute, Linear Systems Incorporated
• Inventors: Cosens, George F., Shimizu, David Tadashi, Nikkel, Steven A., Rueda, Jose Alejandro, Thorsteinson, Thomas M.
• Application Number:
  US10/299,000
• Publication Number:
  US 20030126294A1
• Time in Patent Office: Days
• US Class Current: 709/247
• CPC Class Codes: H04L 41/0213 Standardised network management protocols, e.g. simple network management protocol [SNMP]
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/1108 Web based protocols, e.g. webRTC
• CPC Class Codes: H04L 65/765 intermediate
• CPC Class Codes: H04N 21/222 Secondary servers, e.g. proxy server, cable television Head-end provisioning of proxy services in data packet switching networks H04L67/56
• CPC Class Codes: H04N 21/2221 being a cable television head-end CATV in broadcast systems H04H20/78
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/2381 Adapting the multiplex stream to a specific network, e.g. an Internet Protocol [IP] network transmission of MPEG streams over ATM H04L12/5601
• CPC Class Codes: H04N 21/2383 Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/6125 involving transmission via Internet transmission by internet of broadcast information H04H60/82
• CPC Class Codes: H04N 21/6437 Real-time Transport Protocol [RTP]

Abstract

The device disclosed is capable of accepting and transmitting multiplexed compressed digital video, (Digital TV DTV/HDTV), in a MPEG2 Transport Stream (TS) form, from various devices and sources. It is intended to be used by broadcasting companies to leverage high-speed networks, for point to point and point to multipoint transmissions. The disclosure includes methods for Supporting DHCP and DNS. The processing of the received signals provides a Constant Delay for synchronization. This is obtained by providing at the receiving node provides buffering for accommodating network jitter and lost packages and for controlling the output bit rate. The buffering includes a buffer for retaining a predetermined quantity of data the effective size of which before the data is released is changed depending upon bit rate and the output bit rate is controlled by varying the amount of data retained. Remote Management and Monitoring function is provided based on the SNMP protocol and a remote management and monitoring function via the WWW and HTTP protocol. A design is provided for Point to Multipoint multicast Transmissions.

Claims

1. A method for transmitting digital video signals comprising:

providing a transmitter node and a receiver node each connected to an IP network;

providing at the transmitter node an input for receiving multiplexed compressed digital video in a MPEG2 Transport Stream form containing MPEG2 Transport Stream packets from a source;

providing at the receiver node an output for transmitting multiplexed compressed digital video in a MPEG2 Transport Stream form to a receiver;

at the transmitter node, extracting the data from the MPEG2 Transport Stream, encapsulating that data in IP network packets each containing the data from a plurality of MPEG2 Transport Stream packets and transmitting the IP network packets addressed to the receiver node over the IP network from the transmitter node to the receiver node;

at the receiver node, receiving the IP network packets, extracting the data therein, encapsulating the data into a MPEG2 Transport Stream and transmitting the MPEG2 Transport Stream to the receiver;

wherein the receiving node transmits the MPEG2 Transport Stream at a predetermined required output bit rate equal to the bit rate of the stream from the source;

and wherein the IP network packets are jumbo ethernet frames.

2. The method according to claim 1 wherein the jumbo ethernet frame size is at least 1501 bytes.

3. The method according to claim 1 wherein the transmitting node selects a jumbo ethernet frame format from a plurality of different available formats depending upon the frame format which can be accepted by the IP network.

4. The method according to claim 1 wherein the transmitting node selects a format in response to an automatic detection of the available format on the network.

5. A method for transmitting digital video signals comprising:

providing a transmitter node and a plurality of receiver nodes each connected to an IP network;

providing at the transmitter node an input for receiving multiplexed compressed digital video in a MPEG2 Transport Stream form containing MPEG2 Transport Stream packets from a source;

providing at each of the receiver nodes an output for transmitting multiplexed compressed digital video in a MPEG2 Transport Stream form to a respective receiver;

at the transmitter node, extracting the data from the MPEG2 Transport Stream, encapsulating that data in IP network packets each containing the data from a plurality of MPEG2 Transport Stream packets and transmitting the IP network packets over the IP network from the transmitter node to the receiver node;

at the receiver nodes, receiving the IP network packets, extracting the data therein, encapsulating the data into a MPEG2 Transport Stream, and transmitting the MPEG2 Transport Stream to the respective receiver;

wherein the receiving node transmits the MPEG2 Transport Stream at a predetermined required output bit rate equal to the bit rate of the stream from the source;

and wherein the transmitter node is arranged to address the IP network packages such that each transmitted packet is directed by the network to each of the receiver nodes in a multicast arrangement.

6. The method according to claim 5 wherein the receiver node requests participation in the multicast arrangement.

7. A method for transmitting digital video signals comprising:

providing a transmitter node and a receiver node each connected to an IP network;

providing at the transmitter node an input for receiving multiplexed compressed digital video in a MPEG2 Transport Stream form containing MPEG2 Transport Stream packets from a source;

providing at the receiver node an output for transmitting multiplexed compressed digital video in a MPEG2 Transport Stream form to a receiver;

at the transmitter node, extracting the data from the MPEG2 Transport Stream, encapsulating that data in IP network packets each containing the data from a plurality of MPEG2 Transport Stream packets and transmitting the IP network packets addressed to the receiver node over the IP network from the transmitter node to the receiver node;

at the receiver node, receiving the IP network packets, extracting the data therein, encapsulating the data into a MPEG2 Transport Stream and transmitting the MPEG2 Transport Stream to the receiver;

wherein the receiving node transmits the MPEG2 Transport Stream at a predetermined required output bit rate equal to the bit rate of the stream from the source;

wherein the receiver node and the transmitter node are arranged to support DHCP configuration of its network interfaces to improve the manageability and to support DNS name resolution to improve the configurability of the operation.

8. A method for transmitting digital video signals comprising:

providing a transmitter node and a receiver node each connected to an IP network;

providing at the transmitter node an input for receiving multiplexed compressed digital video in an input MPEG2 Transport Stream form containing MPEG2 Transport Stream packets from a source;

providing at the receiver node an output for transmitting multiplexed compressed digital video in an output MPEG2 Transport Stream form to a receiver;

at the transmitter node, extracting the data from the MPEG2 Transport Stream, encapsulating that data in IP network packets each containing the data from a plurality of MPEG2 Transport Stream packets and transmitting the IP network packets addressed to the receiver node over the IP network from the transmitter node to the receiver node;

at the receiver node, receiving the IP network packets, extracting the data therein, encapsulating the data into a MPEG2 Transport Stream and transmitting the MPEG2 Transport Stream to the receiver;

wherein the receiving node transmits the MPEG2 Transport Stream at a predetermined required output bit rate equal to the bit rate of the stream from the source;

wherein the receiving node provides buffering for accommodating network jitter and lost packages and for controlling the output bit rate;

and wherein the buffering is controlled to provide a predetermined constant time delay between the input stream and the output stream.

9. The method according to claim 8 wherein the delay is of the order of 0.5 secs.

10. The method according to claim 8 wherein the transmitter node is arranged for receiving different input streams at different bit rates and the buffering is arranged to maintain the same delay for different bit rates.

11. The method according to claim 8 wherein the buffering includes a buffer for retaining a predetermined quantity of data the effective size of which before the data is released is changed depending upon bit rate.

12. The method according to claim 11 wherein the output bit rate is controlled by varying the amount of data retained.

13. The method according to claim 8 wherein at the transmitter node there is applied to each transmitted packet an accurate time stamp and wherein the input rate is determined at the receiver node by detecting the time stamp of a plurality of sequential packets and the quantity of data therein.

14. The method according to claim 13 wherein the input rate is determined taking into account lost and erroneous packets.

15. The method according to claim 14 wherein the buffering includes a buffer for retaining a predetermined quantity of data the effective size of which before the data is released is changed depending upon bit rate and wherein the lost and erroneous packets are replaced by null packets prior to inputting the packets into the buffer.

16. The method according to claim 11 wherein the buffer size is maintained at substantially a minimum so as to minimize the delay.

17. The method according to claim 11 wherein:

each time a network packet is received, the software checks the RTP timestamp to see if its sampling interval has elapsed where the interval should be much longer than the difference between consecutive RTP timestamps, such that the actual sampling intervals are almost uniform;

the variation in the RTP packet arrival times is ignored;

if the sampling interval has passed, the software compares the actual circular buffer level to the desired half-full level and uses this difference as the error signal for a digital feedback control system;

this error signal is applied to a proportional-integral (PI) compensator whose output is the bit rate;

the gains of the proportional and integral blocks are set such that the control loop is stable and highly damped, to reject variations in the RTP packet arrival times;

the bit rate is applied to the circular buffer, which acts as a second integrator and produces the actual buffer level used in the error signal calculation;

each time the sampling interval elapses, the bit rate of the DVB ASI interface is updated;

since the actual output bit rate is controlled by the hardware interface, it is very stable; and

the control loop makes minor changes to the bit rate over long periods of time, resulting in an overall bit rate within tolerances of transport stream standards for jitter and drift.

18. A method for transmitting digital video signals comprising:

providing a transmitter node and a receiver node each connected to an IP network;

providing at the transmitter node an input for receiving multiplexed compressed digital video in an input MPEG2 Transport Stream form containing MPEG2 Transport Stream packets from a source;

providing at the receiver node an output for transmitting multiplexed compressed digital video in an output MPEG2 Transport Stream form to a receiver;

at the transmitter node, extracting the data from the MPEG2 Transport Stream, encapsulating that data in IP network packets each containing the data from a plurality of MPEG2 Transport Stream packets and transmitting the IP network packets addressed to the receiver node over the IP network from the transmitter node to the receiver node;

at the receiver node, receiving the IP network packets, extracting the data therein, encapsulating the data into a MPEG2 Transport Stream and transmitting the MPEG2 Transport Stream to the receiver;

wherein the receiving node transmits the MPEG2 Transport Stream at a predetermined required output bit rate equal to the bit rate of the stream from the source;

wherein the receiving node provides buffering for accommodating network jitter and lost packages and for controlling the output bit rate;

wherein the buffering includes a buffer for retaining a predetermined quantity of data the effective size of which before the data is released is changed depending upon bit rate;

and wherein the output bit rate is controlled by varying the amount of data retained.

19. The method according to claim 18 wherein at the transmitter node there is applied to each transmitted packet an accurate time stamp and wherein the input rate is determined at the receiver node by detecting the time stamp of a plurality of sequential packets and the quantity of data therein.

20. The method according to claim 19 wherein the input rate is determined taking into account lost and erroneous packets.

21. The method according to claim 20 wherein the lost and erroneous packets are replaced by null packets prior to inputting the packets into the buffer.

22. The method according to claim 18 wherein the buffer size is maintained at substantially a minimum so as to minimize the delay.

23. The method according to claim 18 wherein:

each time a network packet is received, the software checks the RTP timestamp to see if its sampling interval has elapsed where the interval should be much longer than the difference between consecutive RTP timestamps, such that the actual sampling intervals are almost uniform;

the variation in the RTP packet arrival times is ignored;

if the sampling interval has passed, the software compares the actual circular buffer level to the desired half-full level and uses this difference as the error signal for a digital feedback control system;

this error signal is applied to a proportional-integral (PI) compensator whose output is the bit rate;

the gains of the proportional and integral blocks are set such that the control loop is stable and highly damped, to reject variations in the RTP packet arrival times;

the bit rate is applied to the circular buffer, which acts as a second integrator and produces the actual buffer level used in the error signal calculation;

each time the sampling interval elapses, the bit rate of the DVB ASI interface is updated;

since the actual output bit rate is controlled by the hardware interface, it is very stable; and

the control loop makes minor changes to the bit rate over long periods of time, resulting in an overall bit rate within tolerances of transport stream standards for jitter and drift.

24. A method for transmitting digital video signals comprising:

providing a transmitter node and a receiver node each connected to an IP network;

providing at the transmitter node an input for receiving multiplexed compressed digital video in an input MPEG2 Transport Stream form containing MPEG2 Transport Stream packets from a source;

providing at the receiver node an output for transmitting multiplexed compressed digital video in an output MPEG2 Transport Stream form to a receiver;

at the transmitter node, extracting the data from the MPEG2 Transport Stream, encapsulating that data in IP network packets each containing the data from a plurality of MPEG2 Transport Stream packets and transmitting the IP network packets addressed to the receiver node over the IP network from the transmitter node to the receiver node;

at the receiver node, receiving the IP network packets, extracting the data therein, encapsulating the data into a MPEG2 Transport Stream and transmitting the MPEG2 Transport Stream to the receiver;

wherein the receiving node transmits the MPEG2 Transport Stream at a predetermined required output bit rate equal to the bit rate of the stream from the source;

wherein the receiver and transmitter nodes include a remote monitoring function based on the SNMP protocol and a remote management and monitoring function via the WWW and HTTP protocol.

25. The method according to claim 24 wherein both the SNMP and WWW interfaces obtain the monitoring information from several variables recorded by the software of the node and stored in a shared memory location of the node.

26. The method according to claim 24 wherein access control is implemented on the shared memory location to maintain accuracy of information.

27. The method according to claim 24 wherein the SNMP protocol utilizes a MIB specification to implement the function.

28. The method according to claim 24 wherein the WWW interface also links directly to the configuration and log files and system software for management functions.

29. The method according to claim 24 wherein the WWW interface is implemented in industry standard HTML and PHP software.