IMAGE ENCODING DEVICE AND IMAGE DECODING DEVICE

• US 20140056349A1
• Filed: 06/08/2012
• Published: 02/27/2014
• Est. Priority Date: 06/28/2011
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Aoki, Hirofumi, Chono, Keiichi, Senda, Yuzo
• Granted Patent: US 10,432,934 B2
• Time in Patent Office: Days
• US Class Current: 375/240.12
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/50 using predictive coding H04N19/61 takes precedence
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution

Abstract

A video encoding device includes: a quantization step size encoding unit 11 for encoding a quantization step size for controlling quantization granularity; and a quantization step size downsampling unit 12 for downsampling one or more encoded quantization step sizes to generate a quantization step size representative value. The quantization step size encoding unit 11 predicts the quantization step size using the quantization step size representative value.

Claims

1. A video encoding device for dividing input video data into blocks of a predetermined size and applying quantization to each image block obtained by division, to perform a compression-encoding process, comprising:

a quantization step size encoding unit which encodes a quantization step size for controlling granularity of the quantization; and

a quantization step size downsampling unit which downsamples one or more encoded quantization step sizes to generate a quantization step size representative value,

wherein the quantization step size encoding unit predicts the quantization step size using the quantization step size representative value.

2. The video encoding device according to claim 1, wherein the quantization step size encoding unit uses, as the quantization step size representative value, a quantization step size representative value generated using at least an encoded quantization step size in the current frame.

3. The video encoding device according to claim 1, wherein the quantization step size encoding unit uses, as the quantization step size representative value, a quantization step size representative value generated using at least an encoded quantization step size in a different frame.

4. The video encoding device according to claim 1, comprising:

a quantization step size downsampling control unit which controls an operation of the quantization step size downsampling unit based on a predetermined operation parameter; and

a multiplexer which multiplexes at least a part of the operation parameter of the quantization step size downsampling unit, in a compression-encoded video bitstream.

5. The video encoding device according to claim 4, wherein the operation parameter includes at least a downsampling factor.

6. A video decoding device for decoding image blocks by applying inverse quantization to input compressed video data, to perform a generation process of video data as a set of the image blocks, comprising:

a quantization step size decoding unit which decodes quantization step size for controlling granularity of the inverse quantization; and

a quantization step size downsampling unit which downsamples one or more decoded quantization step sizes to generate a quantization step size representative value,

wherein the quantization step size decoding unit predicts the quantization step size using the quantization step size representative value.

7. The video decoding device according to claim 6, wherein the quantization step size decoding unit uses, as the quantization step size representative value, a quantization step size representative value generated using at least a decoded quantization step size in the current frame.

8. The video decoding device according to claim 6, wherein the quantization step size decoding unit uses, as the quantization step size representative value, a quantization step size representative value generated using at least a decoded quantization step size in a different frame.

9. The video decoding device according to claim 6, comprising:

a quantization step size downsampling control unit which controls an operation of the quantization step size downsampling unit based on a predetermined operation parameter; and

a de-multiplexer which de-multiplexes a bitstream including at least a part of the operation parameter of the quantization step size downsampling unit.

10. The video decoding device according to claim 9, wherein the operation parameter includes at least a downsampling factor.