Programmable quantization dead zone and threshold for standard-based H.264 and/or VC1 video encoding

• US 7,620,103 B2
• Filed: 12/10/2004
• Issued: 11/17/2009
• Est. Priority Date: 12/10/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: LSI Corporation (Broadcom, Inc.)
• Inventors: Linzer, Elliot N., Winger, Lowell L., Cote, Guy
• Primary Examiner(s): Rao; Andy S
• Assistant Examiner(s): Werner; David N
• Application Number:
  US11/010,029
• Publication Number:
  US 20060126724A1
• Time in Patent Office: 1,803 Days
• Field of Search: 375/240.03
• US Class Current: 375/240.03
• CPC Class Codes: H04B 1/66 for reducing bandwidth of signals; for improving efficiency of transmission H04B1/68 takes precedence
• CPC Class Codes: H04N 19/126 Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/42 characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation H04N19/635 takes precedence
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards

Abstract

A video encoder is disclosed that includes an encoder circuit, a quantizer circuit and a control circuit. The encoder circuit may be configured to generate a number of coefficient values in response to a video stream and a number of quantized values. The quantizer circuit may be configured to generate the number of quantized values in response to the coefficient values, two or more quantization dead zones and two or more offsets. The control circuit may be configured to set the two or more quantization dead zones and the two or more offsets to different values. The two or more quantization dead zones and the two or more offsets are independently programmable.

Claims

1. An apparatus comprising:

an encoder circuit configured to generate a plurality of coefficient values and motion vectors in response to a video stream, a first control signal selecting between intra and inter modes, a second control signal selecting between a plurality of transforms, and a number of quantized values;

a quantizer circuit configured to generate said number of quantized values in response to said coefficient values, a quantizer index signal, two or more quantization dead zones and two or more offsets, wherein a first coefficient value is quantized using a first quantization dead zone and a first offset, a second coefficient value is quantized using a second quantization dead zone and a second offset, said first and second quantization dead zones have different values and said first and second offsets have different values;

a control circuit configured to (i) generate said first control signal, said second control signal, said quantizer index signal, and a status signal indicating a transmission status and (ii) set said two or more quantization dead zones and said two or more offsets to different values, wherein said quantization dead zones and said offsets are independently programmable; and

an entropy encoder circuit configured to generate a compressed bit stream in response to the first control signal, the quantizer index signal, the status signal, the quantized values and the motion vectors, wherein

4×

4 luma and chroma quantization is performed according to a first equation comprising

2. The apparatus according to claim 1, wherein said encoder circuit is compliant with one or more encoding standards selected from the group consisting of MPEG1, MPEG2, MPEG4, WMV, VC9, VC1, H.262, H.263, H.264, H.264/JVC/AV/MPEG4 part 10, and AVS 1.0.

3. The apparatus according to claim 1, wherein said control circuit is further configured to provide a plurality of dead zone threshold values and offset threshold values.

4. The apparatus according to claim 1, wherein said control circuit is configured to provide a plurality of parameter sets.

5. The apparatus according to claim 4, wherein said plurality of parameter sets comprises a plurality of parameter pairs.

6. The apparatus according to claim 5, wherein said plurality of parameter pairs each comprise an offset parameter and a dead zone parameter.

7. The apparatus according to claim 4, wherein said plurality of parameter sets comprises 16 parameter sets configured for either 8×

8 or 4×

4 luma and chroma quantization, one parameter set configured for 2×

2 chroma DC quantization and one parameter set configured for 4×

4 luma DC quantization.

8. The apparatus according to claim 1, wherein said encoder circuit comprises a VC1 compliant encoder/decoder (CODEC) and said quantizer circuit is configured to implement a variable dead zone comprising a rounding factor configured to vary between a first predetermined value and a second predetermined value.

9. The apparatus according to claim 1, wherein said quantizer circuit is further configured to implement a programmable offset for standard-based VC1 encoding, wherein a forward quantization matrix parameter is variable between a first predetermined value and a second predetermined value.

21. The apparatus according to claim 1, wherein said entropy encoder circuit uses one or more of variable length codes (VLC), context-adaptive variable length coding (CAVLC) and context-adaptive binary arithmetic coding (CABAC).

10. A video encoder comprising;

means for generating a plurality of coefficient values and motion vectors in response to a video stream, a first control signal selecting between intra and inter modes, a second control signal selecting between a plurality of transforms, and a number of quantized values;

means for generating said number of quantized values in response to said coefficient values, a quantizer index signal, two or more quantization dead zones and two or more offsets, wherein a first coefficient value is quantized using a first quantization dead zone and a first offset, a second coefficient value is quantized using a second quantization dead zone and a second offset, said first and second quantization dead zones have different values and said first and second offsets have different values;

means for (i) generating said first control signal, said second control signal, said quantizer index signal, and a status signal indicating a transmission status and (ii) setting said two or more quantization dead zones and said two or more offsets to different values, wherein said two or more quantization dead zones and said two or more offsets are independently programmable; and

means for generating a compressed bit stream using entropy encoding in response to the first control signal, the quantizer index signal, the status signal, the quantized values and the motion vectors, wherein

4×

4 luma and chroma quantization is performed according to a first equation comprising

11. A method for encoding video comprising:

generating a plurality of coefficient values and motion vectors with a video encoder in response to a video stream, a first control signal selecting between intra and inter modes, a second control signal selecting between a plurality of transforms, and a number of quantized values;

generating said number of quantized values with said video encoder in response to said coefficient values, a quantizer index signal, two or more quantization dead zones and two or more offsets, wherein a first coefficient value is quantized using a first quantization dead zone and a first offset, a second coefficient value is quantized using a second quantization dead zone and a second offset, said first and second quantization dead zones have different values and said first and second offsets have different values;

generating said first control signal, said second control signal, said quantizer index signal, and a status signal indicating a transmission status;

setting said two or more quantization dead zones and said two or more offsets to different values, wherein said two or more quantization dead zones and said two or more offsets are independently programmable; and

generating a compressed bit stream with said video encoder using entropy encoding in response to the first control signal, the quantizer index signal, the status signal, the quantized values and the motion vectors, wherein

4×

4 luma and chroma quantization is performed according to a first equation comprising

12. The method according to claim 11, further comprising:

implementing said video encoder as an encoder circuit compliant with one or more encoding standards selected from the group consisting of MPEG1, MPEG2, MPEG4, WMVI VC9, VC1, H.262, H.263, H.264, H.264/JVC/AV/MPEG4 part 10, and AVS 1.0.

13. The method according to claim 11, further comprising:

providing a plurality of dead zone threshold values and offset threshold values.

14. The method according to claim 11, further comprising:

providing a plurality of parameter sets.

15. The method according to claim 14, wherein said plurality of parameter sets comprises a plurality of parameter pairs.

16. The method according to claim 15, wherein said plurality of parameter pairs each comprise an offset parameter and a dead zone parameter.

17. The method according to claim 14, wherein said plurality of parameter sets comprises 16 parameter sets configured for either 8×

8 or 4×

4 luma and chroma quantization, one parameter set configured for 2×

2 chroma DC quantization and one parameter set configured for 4×

4 luma DC quantization.

18. The method according to claim 11, further comprising:

implementing said video encoder as a VC1 compliant encoder/decoder (CODEC) and a quantizer circuit configured to implement a variable dead zone comprising a rounding factor configured to vary between a first predetermined value and a second predetermined value.

19. The method according to claim 11, further comprising:

implementing said video encoder as a VC1 compliant encoder/decoder (CODEC) and a quantizer circuit configured to implement a programmable offset for standard-based VC1 encoding, wherein a forward quantization matrix parameter is variable between a first predetermined value and a second predetermined value.

20. The method according to claim 11, further comprising:

implementing said video encoder as a VC1 compliant encoder/decoder (CODEC) and a quantizer circuit configured to implement (i) a variable dead zone comprising a rounding factor configured to vary between a first predetermined value and a second predetermined value and (ii) a programmable offset for standard base VC1 encoding, wherein a forward quantization matrix parameter is variable between a third predetermined value and a fourth predetermined value.

22. The method according to claim 11, wherein:

sixteen 3-bit programmable offsets O_ij for 4×

4 luma and chroma quantization are utilized according to a first equation

23. The method according to claim 11, wherein:

sixteen 3-bit programmable offsets O_ij for 8×

8 luma and chroma quantization are utilized according to a third equation

24. The method according to claim 11, wherein values of the quantization dead zones and offsets are variable for each macroblock.