Method and apparatus for correcting corrupted digital video transport streams

• US 20020087995A1
• Filed: 06/14/2001
• Published: 07/04/2002
• Est. Priority Date: 06/14/2000
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Pedlow, Leo Mark Jr.
• Granted Patent: US 7,657,913 B2
• Time in Patent Office: Days
• US Class Current: 725/87
• CPC Class Codes: H04N 19/89 involving methods or arrangements for detection of transmission errors at the decoder
• CPC Class Codes: H04N 21/2181 comprising remotely distributed storage units, e.g. when movies are replicated over a plurality of video servers distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097
• CPC Class Codes: H04N 21/2225 Local VOD servers
• CPC Class Codes: H04N 21/238 Interfacing the downstream path of the transmission network, e.g. adapting the transmission rate of a video stream to network bandwidth; Processing of multiplex streams hybrid fiber coaxial [HFC] networks for downstream channel allocation for video distribution H04L12/2801; flow control in packet networks H04L47/10; real-time communication protocols in data switching networks H04L65/00; scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/2393 involving handling client requests scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/2402 Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/2404 Monitoring of server processing errors or hardware failure error or fault detection G06F11/07; monitoring in general G06F11/30

Abstract

A digital video system, method, and computer program product for correcting corrupted digital video transport streams is described. The digital video system may include a digital cable, digital broadcast satellite (DBS), high definition television (HDTV), or video-on demand (VOD) system. In a VOD system, a VOD client at each receiver is capable of subscribing to one or more VOD sessions. The headend includes a video server and a control server that is coupled to the video server. The video server transmits one or more VOD sessions to one or more receivers over a transport stream. The control server can also cause the video server to transmit one or more dummy sessions to maintain a predetermined minimum bandwidth of content over the transport stream. Alternatively, the headend can transmit one or more null packets having a randomized payload, as necessary, to maintain a constant bit rate over the transport stream.

Claims

1. A video-on-demand (VOD) system, comprising:

a transmission channel;

a plurality of receivers coupled to the transmission channel, a VOD client at each receiver capable of subscribing to one or more VOD sessions over a transport stream; and

a headend coupled to the transmission channel, said headend including a video server than can transmit one or more VOD sessions to one or more receivers, and a control server coupled to the video server, the control server to dynamically allocate and terminate VOD sessions over the transport stream as VOD clients are added and terminated, and, if necessary, to cause the video server to transmit one or more dummy sessions over the transport stream to maintain a predetermined minimum bandwidth of content over the transport stream.

2. The VOD system of claim 1, wherein the control server to prevent each receiver from decoding the dummy sessions.

3. The VOD system of claim 1, wherein the control server, if necessary, to transmit one or more dummy sessions over the transport stream to maintain a minimum bandwidth of content over the transport stream to ensure that each receiver can synchronize to a subscribed VOD session.

4. The VOD system of claim 1, wherein the control server to determine whether the bandwidth of content over the transport stream is below a predetermined threshold, and to cause the video server to transmit one or more dummy sessions, as necessary, to maintain the bandwidth of content at or above the predetermined threshold.

5. The VOD system of claim 1 wherein each receiver includes a demodulator, decoder, and an MPEG frame synchronizer.

6. The VOD system of claim 1 wherein said headend includes a transmitter having an MPEG frame synchronizer, encoder, and modulator.

7. The VOD system of claim 1 wherein the transport stream is transmitted over a radio frequency channel.

8. The VOD system of claim 1 wherein the video server can transmit one or more VOD sessions over one or more radio frequency (RF) channels each associated with a transport stream, and wherein said control server, if necessary, to cause the video server to transmit one or more dummy sessions over each transport stream, as necessary, to maintain a predetermined minimum bandwidth of content over each of the one or more transport streams.

9. The VOD system of claim 1 wherein when the control server receives a request for a new VOD session from a VOD client, the control server terminates one or more of the one or more dummy sessions, and causes transmission of the new VOD session over the transport stream.

10. A video-on-demand (VOD) server, comprising:

a server that receives requests from one or more VOD clients for one or more VOD sessions, causes transmission of one or more VOD sessions over a transport stream to the one or more VOD clients, determines whether the number of VOD sessions transmitted over the transport stream is below a minimum threshold, and causes transmission of one or more padding sessions over the transport stream if the number of VOD sessions transmitted over the transport stream is below the minimum threshold to maintain the number of VOD sessions at or above the minimum threshold.

11. The VOD server of claim 10 wherein the server causes transmission of VOD sessions over a plurality of radio frequency channels each associated with a transport stream, the server determines, for each transport stream, whether the number of VOD sessions is below the minimum threshold, and, for each transport stream, causes transmission of one or more padding sessions if the number of VOD sessions transmitted over the respective transport stream is below the minimum threshold to maintain the number of VOD sessions at or above the minimum threshold.

12. The VOD server of claim 10 wherein when the server receives a request for a new VOD session from a VOD client, the control server terminates one or more of the one or more padding sessions, and causes transmission of the new VOD session.

14. The VOD system of claim 13 wherein the headend generates the one or more randomized payloads using one of a random number generator, pseudo-random number generator, and predetermined static payload.

15. The VOD system of claim 13 wherein the video server can transmit one or more VOD sessions over one or more radio frequency (RF) channels each associated with a transport stream, and wherein said headend to transmit one or more stuffing packets for each transport stream, as necessary, to maintain the constant bit rate over the one or more transport streams, said one or more stuffing packets including a randomized payload.

16. The VOD system of claim 15 wherein the headend includes a random number generator that generates a plurality of random numbers, said plurality of random numbers being used to fill the payloads of the one or more stuffing packets.

18. The VOD method of claim 17, wherein transmitting one or more null packets comprises transmitting one or more null packets, as necessary, to maintain the constant bit rate over the transport stream, said null packets each including a randomized payload populated using one of a pseudo-random number generator, random number generator, and one of a plurality of predetermined static payloads.

19. The VOD method of claim 17, further comprising dynamically allocating and terminating VOD sessions over the transport stream as VOD clients are added and terminated, respectively.

13. A video-on-demand (VOD) system, comprising:

a transmission channel;

a plurality of receivers coupled to the transmission channel, a VOD client at each receiver capable of subscribing to one or more VOD sessions over a transport stream; and

a headend coupled to the transmission channel, said headend including a video server than can transmit one or more VOD sessions to one or more receivers, and a control server coupled to the video server, the control server to dynamically allocate and terminate VOD sessions over the transport stream as VOD clients are added and terminated, said headend to transmit one or more stuffing packets, as necessary, to maintain a constant bit rate over the transport stream, said one or more stuffing packets including a randomized payload.

17. A video on demand (VOD) method, comprising:

receiving requests from one or more VOD clients for one or more VOD sessions;

transmitting one or more VOD sessions to the one or more VOD clients over a transport stream having a constant bit rate; and

transmitting one or more null packets, as necessary, to maintain the constant bit rate over the transport stream, said null packets including a randomized payload.

20. A digital video system, comprising:

a transmission channel;

a plurality of receivers coupled to the transmission channel, a client at each receiver capable of subscribing to one or more video sessions over a transport stream; and

a headend coupled to the transmission channel, said headend including a video server than can transmit one or more video sessions to one or more receivers, and a control server coupled to the video server, the control server to cause the video server to transmit one or more dummy sessions over the transport stream to maintain a predetermined minimum bandwidth of content over the transport stream.

21. The digital video system of claim 20, wherein the control server to determine whether the bandwidth of content over the transport stream is below a predetermined threshold, and to cause the video server to transmit one or more dummy sessions, as necessary, to maintain the bandwidth of content at or above the predetermined threshold.

22. The digital video system of claim 20, wherein the headend transmits digital video programming in accordance to one of a digital broadcast satellite (DBS) system, digital cable system, high definition television (HDTV) system, and video-on-demand (VOD) system.

24. The computer program product of claim 23, wherein the first computer readable program code comprises first computer readable program code to transmit one or more video sessions in accordance to one of a digital broadcast satellite (DBS) system, digital cable system, high definition television (HDTV) system, and video-on-demand (VOD) system.

23. A computer program product, comprising:

a computer usable medium having computer readable program code embodied therein to minimize a possibility of an erroneous MPEG frame synchronization in a digital video receiver, the computer readable program code in said computer program product comprising;

first computer readable program code to transmit one or more video sessions to the one or more clients over a transport stream having a constant bit rate; and

second computer readable program code to transmit one or more null packets, as necessary, to maintain the constant bit rate over the transport stream, said null packets including a randomized payload.

25. A digital video receiver, comprising:

a demodulator to demodulate analog signals received over a transmission channel;

a decoder to decode signals from the demodulator;

an MPEG framer to synchronize to a video session in a transport stream;

a memory including one or more instructions;

a processor, coupled to the memory, demodulator, decoder, and framer, the processor, in response to the one or more instructions, to,

detect a checksum error from the MPEG framer indicative of a false synchronization to the video session, and

responsive to detecting a checksum error, resynchronize the MPEG framer to the transport stream.