Direct memory access execution engine with indirect addressing of circular queues in addition to direct memory addressing

• US 6,463,059 B1
• Filed: 12/04/1998
• Issued: 10/08/2002
• Est. Priority Date: 12/04/1998
• Status: Expired due to Term

• Current Assignee: MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Lai, Brian, Puttaswamy, Niranjan A., Hoem, Robert H., Movshovich, Alek
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Elallam, Ahmed
• Application Number:
  US09/205,480
• Time in Patent Office: 1,404 Days
• Field of Search: 370/312, 370/352, 370/358, 370/360, 370/366, 370/389, 370/390, 370/392, 370/412, 370/413, 370/420, 370/421, 370/428, 370/429, 370/474, 370/493, 370/535, 370/536, 370/542, 725/143, 725/151, 725/153
• US Class Current: 370/389
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/566 Routing instructions carried by the data packet, e.g. active networks
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/764 at the destination reformatting of additional data in video clients H04N21/4355

Abstract

A method for enhancing transport packet demultiplexing and distribution in a digital transport demultiplexing system that inputs a stream of digital multimedia transport packets is provided. Each of the transport packets includes a packet identifier (PID) to identify the digital program or elementary stream to which it corresponds. Local packet information is generated for each of the transport packets, which is used in identifying and distributing the transport packets. A local header is created that includes the generated local packet information, and the local header is linked to its corresponding transport packet to create a modified transport packet. In this manner, each of the modified transport packets represents a self-contained digital transport packet having local distribution information contained therein. A transport stream demultiplexing apparatus for use in a digital transmission system capable of providing a plurality of digital transport packets to a digital program presentation device is provided. The demulitplexing apparatus performs the demultiplexing operation by creating a set of direct memory access (DMA) instructions for a DMA engine to execute when transferring the transport packets to one or more output queues. The DMA engine is also configured to descramble the contents of the transport packets while the DMA operation occurs.

Claims

1. A method for managing digital transport packet distribution in a transport packet demultiplexing system, wherein the transport packet demultiplexing system receives a transport stream including digital transport packets each identified by a packet identifier (PID), the method comprising:

generating an address index for each of the transport packets based on the PID, wherein the address index corresponds to a memory queue address;

generating a local header incorporating the address index for each of the transport packets;

adding the local headers to their corresponding transport packets; and

distributing the modified transport packet to corresponding memory queues based on their associated one of the memory queue addresses in the local header.

2. A method for managing digital transport packet distribution in a transport packet demultiplexing system, wherein the transport packet demultiplexing system receives a transport stream including digital transport packets each identified by a packet identifier (PID), the method comprising:

generating an address index for each of the transport packets based on the PID, wherein the address index corresponds to a memory queue address;

generating a local header incorporating the address index for each of the transport packets;

adding the local headers to their corresponding transport packets; and

distributing the modified transport packet to corresponding memory queues based on their associated one of the memory queue addresses in the local header, including

reading the local headers of the transport packets,

generating direct memory access (DMA) instructions indicating where the transport packet is to be distributed,

storing the DMA instructions in memory, and

transferring the transport packets using a DMA transport engine which executes the DMA instructions directly from memory.

3. The method according to claim 2, wherein the DMA transport engine transfers the transport packets as a memory-to-memory operation.

4. The method according to claim 3, wherein the memory-to-memory operation is specified using an absolute source address.

5. The method according to claim 3, wherein the memory-to-memory operation is specified using an absolute destination address.

6. The method according to claim 3, wherein the memory-to-memory operation is specified using a queue number to specify a source address.

7. The method according to claim 3, wherein the memory-to-memory operation is specified using a queue number to specify a destination address.

8. The method according to claim 3, wherein the memory-to-memory operation comprises a de-scrambling operation as the data transfer occurs.

9. The method according to claim 8, wherein the memory-to-memory operation is specified using an absolute source address.

10. The method according to claim 8, wherein the memory-to-memory operation is specified using an absolute destination address.

11. The method according to claim 8, wherein the memory-to-memory operation is specified using a queue number to specify a source address.

12. The method according to claim 8, wherein the memory-to-memory operation is specified using a queue number to specify a destination address.

13. The method according to claim 8, wherein the de-scrambling operation uses a key stored within a key table.

14. The method according to claim 13, wherein the key used in a de-scrambling operation is selected by a key pointer.

15. The method according to claim 3, wherein the memory-to memory operation comprises:

a memory read operation from a source address;

a first memory write to a first destination address; and

a second memory write to a Sky Queue using a second destination address.

16. The method according to claim 15, wherein the memory-to-memory operation further comprises a de-scrambling as the data transfer occurs using a key stored in a key table, the key is selected using a key pointer.

17. The method according to claim 16, wherein the source address is an absolute memory address.

18. The method according to claim 16, wherein the source address is a queue number.

19. The method according to claim 16, wherein the first destination address is an absolute memory address.

20. The method according to claim 16, wherein the first destination address is a queue number.

21. The method according to claim 16, wherein the second destination address is an absolute memory address.

22. The method according to claim 16, wherein the second destination address is a queue number.

23. The method according to claim 3, wherein the completion of the memory-to-memory operation comprises a interrupt service request be sent to a host processor.

24. A method for managing digital transport packet distribution in a transport packet demultiplexing system, wherein the transport packet demultiplexing system receives a transport stream including digital transport packets each identified by a packet identifier (PID), the method comprising:

generating an address index for each of the transport packets based on the PID, wherein the address index corresponds to a memory queue address;

generating a local header incorporating the address index for each of the transport packets;

adding the local headers to their corresponding transport packets; and

distributing the modified transport packet to corresponding memory queues based on their associated one of the memory queue addresses in the local header;

wherein the distributing step comprises;

reading the local headers of the transport packets;

generating direct memory access (DMA) instructions indicating where the transport packet is to be distributed;

storing the DMA instructions in memory; and

transferring the transport packets using a DMA transport engine which executes the DMA instructions directly from memory; and

the DMA transport engine transfers the transport packets as a memory-to-memory operation, the memory-to-memory operation selectively comprises a de-scrambling as the data transfer occurs using a key stored in a key table, the key is selected using a key pointer.

25. An apparatus for managing digital transport packet distribution in a transport packet demultiplexing system, wherein the transport packet demultiplexing system receives a transport stream including digital transport packets each identified by a packet identifier (PID), the apparatus comprising:

means for generating an address index for each of the transport packets based on the PID, wherein the address index corresponds to a memory queue address;

means for generating a local header incorporating the address index for each of the transport packets;

means for adding the local headers to their corresponding transport packets; and

means for distributing the modified transport packet to corresponding memory queues based on their associated one of the memory queue addresses in the local header;

wherein the distributing means comprises;

means for reading the local headers of the transport packets;

means for generating direct memory access (DMA) instructions indicating where the transport packet is to be distributed;

means for storing the DMA instructions in memory; and

means for transferring the transport packets using a DMA transport engine which executes the DMA instructions directly from memory; and

the DMA transport engine transfers the transport packets as a memory-to-memory operation and the memory-to-memory operation selectively comprises a de-scrambling means using a key stored in a key table.