Apparatus and method for encoding and decoding moving picture using adaptive scanning
Provided is an apparatus and method for encoding/decoding a moving picture based on adaptive scanning. The moving picture apparatus and method can increase a compression rate based on adaptive scanning by performing intra prediction onto blocks of a predetermined size, and scanning coefficients acquired from Discrete Cosine Transform (DCT) of a residue signal and quantization differently according to the intra prediction mode. The moving picture encoding apparatus includes: a mode selector for selecting and outputting a prediction mode; a predictor for predicting pixel values of pixels to be encoded of an input video based on the prediction mode to thereby output a residue signal block; a transform/quantization unit for performing DCT onto the residue signal block and quantizing the transformed residue signal block; and an encoder for adaptively scanning and encoding the quantized residue signal block based on the prediction mode.
1. A method of decoding motion pictures based on adaptive scanning, the method comprising:
determining a prediction mode; and
reconstructing a block using entropy-decoded signals and a scanning method determined based on the prediction mode,
wherein the scanning method comprises:
scanning entropy-decoded signals of a first row with priority so that all of the entropy-decoded signals of the first row are scanned prior to scanning entropy-decoded signals of any other row in response to the prediction mode being a first mode; and
scanning entropy-decoded signals of a first column with priority so that all of the entropy-decoded signals of the first column are scanned prior to scanning entropy-decoded signals of any other column in response to the prediction mode being a second mode.
2. The method of claim 1 , wherein the method further comprises dequantizing and inverse-transforming the entropy-decoded signals after determining the scanning method.
3. The method of claim 1 , wherein each of the entropy-decoded signals is a transformed and quantized residue signal representing a difference between a pixel value and a predicted pixel value.
4. The method of claim 1 , wherein the first mode is a vertical intra prediction mode and the second mode is a horizontal intra prediction mode.
5. A method of encoding images, the method comprising:
generating a transformed and quantized residue signal block; and
performing an adaptive scan on the transformed and quantized residue signal block based on a prediction mode,
wherein the performing of the adaptive scan comprises:
scanning all coefficients of a first row of the transformed and quantized residue signal block before scanning any coefficient in any other row of the transformed and quantized residue signal block in response to the prediction mode being a first mode; and
scanning all coefficients of a first column of the transformed and quantized residue signal block before scanning any coefficient in any other column of the transformed and quantized residue signal block in response to the prediction mode being a second mode.
6. The method of claim 5 , further comprising performing entropy encoding of coefficients of the transformed and quantized residue signal block acquired and arrayed by the adaptive scan performed on the transformed and quantized residue signal block.
7. The method of claim 5 , wherein the first mode is a vertical intra prediction mode and the second mode is a horizontal intra prediction mode.
8. A non-transitory computer-readable medium storing a bitstream which is decoded by a processor of an entropy decoder, the bitstream comprising:
block information; and
a prediction mode indicator,
wherein the block information is used by the entropy decoder to produce entropy-decoded signals for a block;
wherein the prediction mode indicator is used by the entropy decoder to determine a prediction mode for the block
wherein the entropy decoder scans entropy-decoded signals of a first row are scanned with priority so that all of the entropy-decoded signals of the first row are scanned prior to scanning entropy-decoded signals of any other row in response to the prediction mode for the block being a first mode; and
wherein the entropy decoder scans entropy-decoded signals of a first column are scanned with priority so that all of the entropy-decoded signals of the first column are scanned prior to scanning entropy-decoded signals of any other column in response to the prediction mode for the block being a second mode.
9. The non-transitory computer-readable medium of claim 8 , wherein the entropy-decoded signals are dequantized and inverse-transformed after a scanning method for the entropy-decoded signals is determined.
10. The non-transitory computer-readable medium of claim 8 , wherein each of the entropy-decoded signals is a transformed and quantized residue signal representing a difference between a pixel value and a predicted pixel value.
11. The non-transitory computer-readable medium of claim 8 , wherein the first mode is a vertical intra prediction mode and the second mode is a horizontal intra prediction mode.