Low complexity video decoder

• US 8,259,808 B2
• Filed: 03/25/2010
• Issued: 09/04/2012
• Est. Priority Date: 03/25/2010
• Status: Active Grant

• Current Assignee: Xueshan Technologies Inc. (Wi-LAN Inc.)
• Original Assignee: MediaTek, Inc.
• Inventors: Lin, Jian-Liang, Chang, Shen-Kai, Lei, Shaw-Min, Hsieh, Fang-Yi
• Primary Examiner(s): DIEP, NHON THANH
• Application Number:
  US12/732,177
• Publication Number:
  US 20110235712A1
• Time in Patent Office: 894 Days
• Field of Search: None
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/156 Availability of hardware or computational resources, e.g. encoding based on power-saving criteria
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/48 using compressed domain processing techniques other than decoding, e.g. modification of transform coefficients, variable length coding [VLC] data or run-length data motion estimation in a transform domain H04N19/547; processing of decoded motion vectors H04N19/513
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/234363 by altering the spatial resolution, e.g. for clients with a lower screen resolution
• CPC Class Codes: H04N 21/43637 involving a wireless protocol, e.g. Bluetooth, RF or wireless LAN [IEEE 802.11] arrangements for wireless networking or broadcasting of information in indoor or near-field type systems H04B10/114

Abstract

A low complexity video decoder includes: a fast variable length decoding (VLD) and inverse quantization module arranged to perform fast VLD and inverse quantization on an input bit stream to generate inverse quantization results; an inverse transform unit arranged to perform inverse transform on the inverse quantization results to generate inverse transform results; a motion compensation module arranged to perform motion compensation according to the input bit stream and generate associated prediction outputs, wherein the motion compensation module includes a temporal/spatial prediction unit arranged to perform temporal/spatial prediction to generate at least a portion of the prediction outputs; an arithmetic unit arranged to sum up the inverse transform results and the prediction outputs to generate compensated outputs; a reconstructed frame output unit arranged to generate reconstructed frames according to the compensated outputs; and a frame storage arranged to store some reconstructed frames.

Claims

1. A low complexity video decoder, comprising:

a fast variable length decoding (VLD) and inverse quantization module arranged to perform fast VLD and inverse quantization on an input bit stream to generate inverse quantization results;

an inverse transform unit arranged to perform inverse transform on the inverse quantization results to generate inverse transform results;

a motion compensation module arranged to perform motion compensation according to the input bit stream and generate associated prediction outputs, wherein the motion compensation module comprises;

a temporal prediction unit arranged to perform temporal prediction to generate at least a portion of the prediction outputs; and

a spatial prediction unit arranged to perform spatial prediction to generate at least a portion of the prediction outputs;

an arithmetic unit arranged to sum up the inverse transform results and the prediction outputs to generate compensated outputs;

a reconstructed frame output unit arranged to generate a plurality of reconstructed frames according to the compensated outputs, wherein the spatial prediction unit performs spatial prediction according to a current reconstructed frame of the reconstructed frames; and

a frame storage arranged to temporarily store at least one portion of the reconstructed frames, wherein the temporal prediction unit performs temporal prediction according to the at least one portion of the reconstructed frames;

wherein the temporal prediction unit operates in accordance with a resolution of the reconstructed frames, rather than a resolution of a plurality of original frames represented by the input bit stream, in order to reduce complexity of performing temporal prediction;

and the temporal prediction unit further estimates at least a portion of partial information that has been omitted, in order to perform sub-pixel interpolation for use of performing temporal prediction.

2. The low complexity video decoder of claim 1, wherein the resolution of the reconstructed frames is less than the resolution of the original frames.

3. The low complexity video decoder of claim 2, wherein for every W by W pixels of an original frame, the low complexity video decoder utilizes at least a bottom right pixel of the W by W pixels for an associated reconstructed frame;

and W represents an integer that is greater than one.

4. The low complexity video decoder of claim 3, wherein the low complexity video decoder stores pixel values of all boundary pixels of a bottom boundary and a right boundary within a current macroblock, and stores pixel values of all boundary pixels of a bottom boundary within an upper macroblock and pixel values of all boundary pixels of a right boundary within a left macroblock, for use of intra prediction.

5. The low complexity video decoder of claim 1, wherein the temporal prediction unit estimates at least the portion of the partial information that has been omitted, in order to perform sub-pixel interpolation for use of performing temporal prediction.

6. A low complexity video decoder, comprising:

a fast variable length decoding (VLD) and inverse quantization module arranged to perform fast VLD and inverse quantization on an input bit stream to generate inverse quantization results;

an inverse transform unit arranged to perform inverse transform on the inverse quantization results to generate inverse transform results;

a motion compensation module arranged to perform motion compensation according to the input bit stream and generate associated prediction outputs, wherein the motion compensation module comprises;

a temporal prediction unit arranged to perform temporal prediction to generate at least a portion of the prediction outputs; and

a spatial prediction unit arranged to perform spatial prediction to generate at least a portion of the prediction outputs;

an arithmetic unit arranged to sum up the inverse transform results and the prediction outputs to generate compensated outputs;

a reconstructed frame output unit arranged to generate a plurality of reconstructed frames according to the compensated outputs, wherein the spatial prediction unit performs spatial prediction according to a current reconstructed frame of the reconstructed frames; and

a frame storage arranged to temporarily store at least one portion of the reconstructed frames, wherein the temporal prediction unit performs temporal prediction according to the at least one portion of the reconstructed frames;

wherein the spatial prediction unit operates in accordance with a resolution of the reconstructed frames, rather than a resolution of a plurality of original frames represented by the input bit stream, in order to reduce complexity of performing spatial prediction; and

the spatial prediction unit further estimates at least a portion of partial information that has been omitted, in order to perform sub-pixel interpolation for use of performing spatial prediction.

7. The low complexity video decoder of claim 6, wherein the resolution of the reconstructed frames is less than the resolution of the original frames.

8. The low complexity video decoder of claim 7, wherein for every W by W pixels of an original frame, the low complexity video decoder utilizes at least a bottom right pixel of the W by W pixels to generate a corresponding pixel of an associated reconstructed frame;

and W represents an integer that is greater than one.

9. The low complexity video decoder of claim 8, wherein the low complexity video decoder stores pixel values of all boundary pixels of a bottom boundary and a right boundary within a current macroblock, and stores pixel values of all boundary pixels of a bottom boundary within an upper macroblock and pixel values of all boundary pixels of a right boundary within a left macroblock, for use of intra prediction.

10. The low complexity video decoder of claim 6, wherein the spatial prediction unit estimates at least the portion of the partial information that has been omitted, in order to perform sub-pixel interpolation for use of performing spatial prediction.

11. A low complexity video decoder, comprising:

a fast variable length decoding (VLD) and inverse quantization module arranged to perform fast VLD and inverse quantization on an input bit stream to generate inverse quantization results;

an inverse transform unit arranged to perform inverse transform on inverse quantization results to generate inverse transform results;

a motion compensation module arranged to perform motion compensation according to the input bit stream and generate associated prediction outputs, wherein the motion compensation module comprises;

a temporal prediction unit arranged to perform temporal prediction to generate at least a portion of the prediction outputs; and

a spatial prediction unit arranged to perform spatial prediction to generate at least a portion of the prediction outputs;

an arithmetic unit arranged to sum up the inverse transform results and the prediction outputs to generate compensated outputs;

a reconstructed frame output unit arranged to generate a plurality of reconstructed frames according to the compensated outputs, wherein the spatial prediction unit performs spatial prediction according to a current reconstructed frame of the reconstructed frames; and

a frame storage arranged to temporarily store at least one portion of the reconstructed frames, wherein the temporal prediction unit performs temporal prediction according to the at least one portion of the reconstructed frames;

wherein the inverse transform unit operates in accordance with a resolution of the reconstructed frames, rather than a resolution of a plurality of original frames represented by the input bit stream, in order to reduce complexity of performing the inverse transform; and

the inverse transform unit omits a portion of calculations of the inverse transform.

12. The low complexity video decoder of claim 11, wherein the resolution of the reconstructed frames is less than the resolution of the original frames.

13. The low complexity video decoder of claim 12, wherein for every W by W pixels of an original frame, the low complexity video decoder utilizes at least a bottom right pixel of the W by W pixels to generate a corresponding pixel of an associated reconstructed frame;

and W represents an integer that is greater than one.

14. The low complexity video decoder of claim 13, wherein the low complexity video decoder stores pixel values of all boundary pixels of a bottom boundary and a right boundary within a current macroblock, and stores pixel values of all boundary pixels of a bottom boundary within an upper macroblock and pixel values of all boundary pixels of a right boundary within a left macroblock, for use of intra prediction.

15. The low complexity video decoder of claim 11, wherein at least a portion of the predetermined inverse transform functions comprises at least one zero transform coefficient, or the inverse transform unit drops at least a portion of transform coefficients of the selected one of the predetermined inverse transform functions.

16. The low complexity video decoder of claim 11, wherein the inverse transform unit omits a portion of calculations of the inverse transform by analyzing the input bit stream and selecting one of a plurality of predetermined inverse transform functions according to the analyzing result.

17. The low complexity video decoder of claim 11, wherein the fast VLD and inverse quantization module operates in accordance with the resolution of the reconstructed frames, rather than the resolution of the original frames, in order to reduce complexity of performing the fast VLD and inverse quantization;

and the fast VLD and inverse quantization module performs the fast VLD and inverse quantization by performing merged operations that are merged from both VLD operations and inverse quantization operations.

18. A low complexity video decoder, comprising:

a fast variable length decoding (VLD) and inverse quantization module arranged to perform fast VLD and inverse quantization on an input bit stream to generate inverse quantization results;

an inverse transform unit arranged to perform inverse transform on the inverse quantization results to generate inverse transform results;

a motion compensation module arranged to perform motion compensation according to the input bit stream and generate associated prediction outputs, wherein the motion compensation module comprises;

a temporal prediction unit arranged to perform temporal prediction to generate at least a portion of the prediction outputs; and

a spatial prediction unit arranged to perform spatial prediction to generate at least a portion of the prediction outputs;

an arithmetic unit arranged to sum up the inverse transform results and the prediction outputs to generate compensated outputs;

a reconstructed frame output unit arranged to generate a plurality of reconstructed frames according to the compensated outputs, wherein the spatial prediction unit performs spatial prediction according to a current reconstructed frame of the reconstructed frames; and

a frame storage arranged to temporarily store at least one portion of the reconstructed frames, wherein the temporal prediction unit performs temporal prediction according to the at least one portion of the reconstructed frames;

wherein the reconstructed frame output unit operates in accordance with a resolution of the reconstructed frames, rather than a resolution of a plurality of original frames represented by the input bit stream, in order to reduce complexity of generating the reconstructed frames; and

the reconstructed frame output unit comprises a low complexity de-blocking filter.

19. The low complexity video decoder of claim 18, wherein the resolution of the reconstructed frames is less than the resolution of the original frames.

20. The low complexity video decoder of claim 19, wherein for every W by W pixels of an original frame, the low complexity video decoder utilizes at least a bottom right pixel of the W by W pixels to generate a corresponding pixel of an associated reconstructed frame;

and W represents an integer that is greater than one.

21. The low complexity video decoder of claim 20, wherein the low complexity video decoder stores pixel values of all boundary pixels of a bottom boundary and a right boundary within a current macroblock, and stores pixel values of all boundary pixels of a bottom boundary within an upper macroblock and pixel values of all boundary pixels of a right boundary within a left macroblock, for use of intra prediction.

22. The low complexity video decoder of claim 19, wherein the low complexity de-blocking filter performs filtering by adjusting a value of existing pixel values that are regarded as down sampled values, rather than discarded pixel values, according to a difference between two of the existing pixel values, in order to generate a de-blocking filtered value.

23. The low complexity video decoder of claim 18, wherein the low complexity de-blocking filter performs low complexity de-blocking according to a quantization step size, a macroblock (MB) type, and edge strength.

24. A low complexity video decoder, comprising:

a fast variable length decoding (VLD) and inverse quantization module arranged to perform fast VLD and inverse quantization on an input bit stream to generate inverse quantization results;

an inverse transform unit arranged to perform inverse transform on the inverse quantization results to generate inverse transform results;

a motion compensation module arranged to perform motion compensation according to the input bit stream and generate associated prediction outputs, wherein the motion compensation module comprises;

a temporal prediction unit arranged to perform temporal prediction to generate at least a portion of the prediction outputs; and

a spatial prediction unit arranged to perform spatial prediction to generate at least a portion of the prediction outputs;

an arithmetic unit arranged to sum up the inverse transform results and the prediction outputs to generate compensated outputs;

a reconstructed frame output unit arranged to generate a plurality of reconstructed frames according to the compensated outputs, wherein the spatial prediction unit performs spatial prediction according to a current reconstructed frame of the reconstructed frames; and

a frame storage arranged to temporarily store at least one portion of the reconstructed frames, wherein the temporal prediction unit performs temporal prediction according to the at least one portion of the reconstructed frames;

wherein the fast VLD and inverse quantization module operates in accordance with a resolution of the reconstructed frames, rather than a resolution of a plurality of original frames represented by the input bit stream, in order to reduce complexity of performing fast VLD and inverse quantization; and

the fast VLD and inverse quantization module utilizes a lookup table comprising a main table and at least one sub-table during fast VLD, and a probability of utilizing the main table is greater than that of the at least one sub-table.

25. The low complexity video decoder of claim 24, wherein the resolution of the reconstructed frames is less than the resolution of the original frames.

26. The low complexity video decoder of claim 25, wherein for every W by W pixels of an original frame, the low complexity video decoder utilizes at least a bottom right pixel of the W by W pixels to generate a corresponding pixel of an associated reconstructed frame;

and W represents an integer that is greater than one.

27. The low complexity video decoder of claim 26, wherein the low complexity video decoder stores pixel values of all boundary pixels of a bottom boundary and a right boundary within a current macroblock, and stores pixel values of all boundary pixels of a bottom boundary within an upper macroblock and pixel values of all boundary pixels of a right boundary within a left macroblock, for use of intra prediction.

28. The low complexity video decoder of claim 24, wherein each entry of the main table and the sub-table comprises a symbol and/or a codeword length;

and each entry occupies at least a storage space of a size of one word.

29. The low complexity video decoder of claim 24, wherein in a situation where a codeword length of a codeword exceeds a predetermined bit size, the fast VLD and inverse quantization module utilizes the at least one sub-table to store associated information of the codeword.

30. The low complexity video decoder of claim 24, wherein the fast VLD and inverse quantization module performs fast VLD and inverse quantization by performing merged operations that are merged from both VLD operations and inverse quantization operations.