Method and circuitry for compressing and decompressing digital video data

• US 6,204,780 B1
• Filed: 06/16/1998
• Issued: 03/20/2001
• Est. Priority Date: 10/31/1996
• Status: Expired due to Term

• Current Assignee: STMicroelectronics Limited (STMicroelectronics NV)
• Original Assignee: SGS-Thomson Microelectronics (STMicroelectronics NV)
• Inventors: Cole, Anthony James Carvallo
• Primary Examiner(s): Tokar, Michael
• Assistant Examiner(s): JEAN PIERRE, PEGUY
• Application Number:
  US09/091,600
• Time in Patent Office: 1,008 Days
• Field of Search: 341/50, 341/65, 341/67, 348/408, 348/405, 358/433, 382/251
• US Class Current: 341/50
• CPC Class Codes: H04N 19/423 characterised by memory arrangements H04N19/433 takes precedence
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

According to the present invention circuitry is provided for processing digital data items. The circuitry comprises compression and decompression circuitry. The compression circuitry further comprises: a circuit for transforming M number of data items into N number of data items; a circuit for quantising P number of data items and producing Q number of data items; and a circuit for appropriately storing in memory and/or transferring R number of data items. The decompression circuitry comprises: a circuit for appropriately retrieving from memory and/or receiving S number of data items; a circuit for dequantising T number of data items and producing U number of dequantised data items; and a circuit for receiving and inverse transforming V number of data items into W number of data items, said W data items being representative of said M data items.

Claims

1. Circuitry for processing digital data items, including compression circuitry and decompression circuitry, wherein said compression circuitry comprises:

a circuit for receiving and transforming a plurality of M first data items into a group of N second data items, where M is an integer greater than or equal to two and where N is an integer less than or equal to M;

a circuit for receiving and quantising a set of P said second data items and producing a group of Q third data items, where P is an integer less than or equal to N and where Q is an integer less than or equal to P;

a circuit for range clamping the group of Q third data items and producing a group of Q′

third range clamped data items, wherein the circuitry for range clamping is arranged to convert signed data to unsigned data comprising fewer buts such that Q′

is an integer less than Q and

a circuit for appropriately storing in memory and/or transferring a set of R said third range clamped data items;

where the integer R is less than or equal to Q,

said decompression circuitry comprises;

a circuit for appropriately retrieving from memory and/or receiving a group of S first stored or transferred data items, where S is greater than or equal to R;

a circuit for receiving and dequantising a set of T said first stored or transferred data items and producing a group of U dequantised second data items, where T is greater than or equal to S and U is greater than or equal to T; and

a circuit for receiving and inverse transforming a group of V second data items into a group of W third data items, where V is greater than or equal to U and where W is greater than or equal to V, said a group of W third data items being representative of said plurality M of first data items.

2. Circuitry according to claim 1, wherein the compression circuitry further comprises a circuit for truncating the group of the N second data items and producing the group of N′

second truncated data items, where N′

is an integer less than or equal to N and where the integer P is less than or equal to N′

.

3. Circuitry according to claim 1, wherein the decompression circuitry further comprises a circuit for range clamping the group of W third data items and producing a group of W′

third range clamped data items, where W′

is an integer less than or equal to W, said W′

third range clamped data items being representative of said M first data items.

4. Circuitry according to claim 1, wherein the number M of first data items equals 2^Y, where Y is an integer greater than or equal to one.

5. Circuitry according to claim 1, wherein the group of P second data items are quantised independently of each other and the group of T first data items are dequantised independently of each other.

6. Circuitry according to claim 1, wherein it is incorporated or used in a system or apparatus.

7. A system or apparatus according to claim 6, wherein it is, or that it is incorporated within, or that it is used in conjunction with, a computer.

8. A system or apparatus according to claim 6, wherein it is, or it is incorporated within, or it is used in conjunction with, a domestic or consumer appliance.

9. A system or apparatus according to claim 6, wherein it is incorporated within, or that it is used in conjunction with, a vehicle.

10. A system or apparatus according to claim 6, wherein it is, or it is incorporated within, or it is used in conjunction with, a telephone or a telephone network.

11. An MPEG decoder for processing digital video/image data items, including compression circuitry and decompression circuitry, said compression circuitry comprising:

a circuit for receiving and transforming a plurality of M first video/image data items into a group of N second video/image data items, where M is an integer greater than or equal to two and where N is an integer less than or equal to M;

a circuit for receiving and quantising a set of P second video/image data items and producing a group of Q third video/image data items, where P is an integer less than or equal to N and where Q is an integer less than or equal to P;

a circuit for range clamping the group of Q third video/image data items and producing a group of Q′

third range clamped video/image data items, wherein the circuit for range clamping is arranged to convert signed data to unsigned data comprising fewer bits such that Q′

is an integer less than Q; and

a circuit for appropriately storing in memory and/or transferring a set of R said third range clamped video/image data items;

where the integer R is less than or equal to Q′

,

said decompression circuitry comprising;

a circuit for appropriately retrieving from memory and/or receiving a group of S first stored or transferred video/image data items, where S is greater than or equal to R;

a circuit for receiving and dequantising a set of T said first stored or transferred video/image data items and producing a group of U dequantised second video/image data items, where T is greater than or equal to S and U is greater than or equal to T; and

a circuit for receiving and inverse transforming a group of V second video/image data items into a group of W third video/image data items, where V is greater than or equal to U and where W is greater than or equal to V,

said group of W third video/image data items being representative of said plurality M of first video/image data items.

12. Circuitry according to claim 11, wherein the compression circuitry further comprises a circuit for truncating the group of N second video/image data items and producing a group of N′

second truncated video/image data items, where N′

is an integer less than or equal to N and where the integer P is less than or equal to N′

.

13. Circuitry according to claim 11, wherein the decompression circuitry further comprises a circuit for range clamping the group of W third video/image data items and producing a group of W′

third range clamped video/image data items, where W′

is an integer less than or equal to W, said group of W′

third range clamped video/image data items being representative of said group of M first video/image data items.

14. Circuitry according to claim 11, wherein the number M of first video/image data items equals 2Y, where Y is an integer greater than or equal to one.

15. Circuitry according to claim 11, wherein the group of P second video/image data items are quantised independently of each other and the group of T first video/image data items are dequantised independently of each other.

16. A method for processing digital data items, including the steps of compressing and decompressing the digital data items, said compression comprising the steps of:

receiving and transforming a plurality of M first data items into a group of N second data items, where M is an integer greater than or equal to two and where N is an integer less than or equal to M;

receiving and quantising a set of P said second data items and producing Q a group of third data items, where P is an integer less than or equal to N and where Q is an integer less than or equal to P;

range clamping the group of Q third data items and producing a group of Q′

third range clamped data items, wherein the circuit for range clamping is arranged to convert signed data to unsigned data comprising fewer bits such that Q′

is an integer less than Q; and

appropriately storing in memory and/or transferring a set of R said third range clamped data items;

where the integer R is less than or equal to Q′

,

said decompression comprising the steps of;

appropriately retrieving from memory and/or receiving a group of S first stored or transferred data items, where S is greater than or equal to R;

receiving and dequantising a set of T said first stored or transferred data items and producing a group of U dequantised second data items, where T is greater than or equal to S and U is greater than or equal to T; and

receiving and inverse transforming a group of V second data items into a group of W third data items, where V is greater than or equal to U and where W is greater than or equal to V,

said group of W third data items being representative of said plurality M of first data items.

17. A method according to claim 16, wherein the compression step further comprises a step for truncating the group of N second data items and producing a group of N′

second truncated data items, where N′

is an integer less than or equal to N and where the integer P is less than or equal to N′

.

18. A method according to claim 16, wherein the decompression step further comprises a step for range clamping the group of W third data items and producing a group of W′

third range clamped data items, where W′

is an integer less than or equal to W, said W′

third range clamped data items being representative of said M first data items.

19. A method according to claim 16, wherein the number M of first data items equals 2^Y, where Y is an integer greater than or equal to one.

20. A method according to claim 16, wherein the group of P second data items are quantised independently of each other and the group of T first data items are dequantised independently of each other.

21. A method according to claim 16, wherein it is incorporated or used in a system or apparatus.

22. A system or apparatus according to claim 21, characterised in that it is, or that it is incorporated within, or that it is used in conjunction with, a computer.

23. A system or apparatus according to claim 21, characterised in that it is, or that it is incorporated within, or that it is used in conjunction with, a domestic or consumer appliance.

24. A system or apparatus according to claim 21, characterised in that it is incorporated within, or that it is used in conjunction with, a vehicle.

25. A system or apparatus according to claim 21, characterised in that it is, or that it is incorporated within, or that it is used in conjunction with, a telephone or a telephone network.

27. A method according to claim 19, wherein the compression step further comprises a step for truncating the group of N second video/image data items and producing a group of N′

second truncated video/image data items, where N′

is an integer less than or equal to N and where the integer P is less than or equal to N′

.

26. A method for processing digital video/image data items in an MPEG decoder, including the steps of compressing and decompressing the digital video/image data items, said compression comprising the steps of:

receiving and transforming a plurality of M first video/image data items into a group of N second video/image data items, where M is an integer greater than or equal to two and where N is an integer less than or equal to M;

receiving and quantising a set of P said second video/image data items and producing a group of Q third video/image data items, where P is an integer less than or equal to N and where Q is an integer less than or equal to P;

range clamping the a group of Q third video/image data items and producing a group of Q′

third range clamped video/image data items, wherein the circuit for range clamping is arranged to convert signed data to unsigned data comprising fewer bits such that Q′

is an integer less than Q; and

appropriately storing in memory and/or transferring a set of R said third range clamped video/image data items;

where the integer R is less than or equal to Q′

,

said decompression step comprising the steps of;

appropriately retrieving from memory and/or receiving a group of S first stored or transferred video/image data items, where S is greater than or equal to R;

receiving and dequantising a set of T said first stored or transferred video/image data items and producing a group of U dequantised second video/image data items, where T is greater than or equal to S and U is greater than or equal to T; and

receiving and inverse transforming a group of V second video/image data items into a group of W third video/image data items, where V is greater than or equal to U and where W is greater than or equal to V,

said group of W third video/image data items being representative of said plurality M of first video/image data items.

28. A method according to claim 26, wherein the decompression step further comprises a step for range clamping the group of W third video/image data items and producing a group of W′

third range clamped video/image data items, where W′

is an integer less than or equal to W, said group of W′

third range clamped video/image data items being representative of said group of M first video/image data items.

29. A method according to claim 26, wherein the number M of first video/image data items equals 2Y, where Y is at integer greater than or equal to one.

30. A method according to claim 26, wherein the group of P second video/image data items are quantised independently of each other and the group of T first video/image data items are dequantised independently of each other.