Video encoding apparatus, video decoding apparatus, video compression and transmission system, video encoding method, video decoding method, and computer readable storage medium
A video encoding apparatus that encodes a video having a plurality of color components includes: a linear prediction unit configured to perform linear prediction of reference pixels of a prediction target color component using reference pixels that are used in intra prediction for a color component other than the prediction target color component among the plurality of color components; and an intra prediction unit configured to perform intra prediction of a prediction target block of the prediction target color component using the reference pixels of the prediction target color component that have been obtained through the linear prediction performed by the linear prediction unit.
1. A video encoding apparatus that encodes a video having a plurality of color components, the video encoding apparatus comprising:
a processor; and
a memory including a program,
wherein the program, when executed by the processor, causes the processor to execute:
deriving a prediction coefficient based on first reference pixels of a luminance component of the plurality of color components and second reference pixels of a chrominance component of the plurality of color components, wherein the second reference pixels are included in a block different from a prediction target block, and the first reference pixels are included in a block corresponding to the block including the second reference pixels;
generating third reference pixels of the chrominance component based on the prediction coefficient and the first reference pixels using a predetermined equation; and
performing intra prediction of the prediction target block of the chrominance component using the third reference pixels as chrominance intra reference pixels of the intra prediction,
wherein
the second reference pixels are left of the prediction target block, left of and above the prediction target block, and above the prediction target block, and
the first reference pixels are corresponding pixels of the second reference pixels.
2. The video encoding apparatus according to claim 1 ,
wherein the program further causes the processor to execute reference possibility verification processing for confirming a local-decoded state of pixels corresponding to first pixel positions, and
padding processing for generating fourth reference pixels from pixel positions different from the first pixel positions, and smoothing processing of the fourth reference pixels when reference has been determined to be impossible in the reference possibility verification processing.
3. The video encoding apparatus according to claim 1 , wherein
the prediction coefficient is selected from among a plurality of preset prediction coefficients.
4. The video encoding apparatus according to claim 1 ,
wherein the program further causes the processor to execute:
determining whether linear prediction of the prediction target block is to be performed in a video decoding apparatus, and sending a signal indicating a result of determination as one of chrominance intra prediction modes to the video decoding apparatus, and
when determining that the linear prediction of the prediction target block is to be performed in the video decoding apparatus, making an arrangement so that a prediction mode for the chrominance component is the same as a prediction mode for the luminance component after sending the signal indicating the result of determination.
5. The video encoding apparatus according to claim 1 , wherein, when a prediction mode for the chrominance component is the same as a prediction mode for the luminance component, determining whether linear prediction of the prediction target block is to be performed in a video decoding apparatus, and sending a signal indicating a result of determination to the video decoding apparatus.
6. A video decoding apparatus that decodes a video having a plurality of color components, the video decoding apparatus comprising:
a processor; and
a memory including a program,
wherein the program, when executed by the processor, causes the processor to execute:
deriving a prediction coefficient based on first reference pixels of a luminance component of the plurality of color components and second reference pixels of a chrominance component of the plurality of color components, wherein the second reference pixels are included in a block different from a prediction target block, and the first reference pixels are included in a block corresponding to the block including the second reference pixels;
generating third reference pixels of the chrominance component based on the prediction coefficient and the first reference pixels using a predetermined equation; and
performing intra prediction of the prediction target block of the chrominance component using the third reference pixels as chrominance intra reference pixels of the intra prediction,
wherein
the second reference pixels are left of the prediction target block, left of and above the prediction target block, and above the prediction target block, and
the first reference pixels are corresponding pixels of the second reference pixels.
7. The video decoding apparatus according to claim 6 ,
wherein the program further causes the processor to execute:
reference possibility verification processing for confirming a local-decoded state of pixels corresponding to first pixel positions of the first reference pixels, and
padding processing for generating fourth reference pixels from pixel positions different from the first pixel positions, and smoothing processing of the fourth reference pixels when reference has been determined to be impossible in the reference possibility verification processing.
8. The video decoding apparatus according to claim 6 , wherein
the prediction coefficient is selected from among a plurality of preset prediction coefficients.
9. The video decoding apparatus according to claim 6 ,
wherein the program further causes the processor to execute:
determining whether to perform the linear prediction based on a signal from a video encoding apparatus, the linear prediction being one of prediction modes for the chrominance component, and
when having determined that the linear prediction is to be performed, making an arrangement so that a prediction mode for the chrominance component is the same as a prediction mode for the first color component.
10. The video decoding apparatus according to claim 6 , wherein
when a prediction mode for the chrominance component is the same as a prediction mode for the luminance component, determining whether to perform the linear prediction based on a signal from a video encoding apparatus.
11. A video encoding method of a video encoding apparatus that encodes a video having a plurality of color components, the video encoding method comprising:
deriving a prediction coefficient based on first reference pixels of a luminance component of the plurality of color components and second reference pixels of a chrominance component of the plurality of color components, wherein the second reference pixels are included in a block different from a prediction target block, and the first reference pixels are included in a block corresponding to the block including the second reference pixels;
generating third reference pixels of the chrominance component based on the prediction coefficient and the first reference pixels using a predetermined equation; and
performing intra prediction of the prediction target block of the chrominance component using the third reference pixels as chrominance intra reference pixels of the intra prediction,
wherein
the second reference pixels are left of the prediction target block, left of and above the prediction target block, and above the prediction target block, and
the first reference pixels are corresponding pixels of the second reference pixels.
12. A video decoding method of a video decoding apparatus that decodes a video having a plurality of color components, the video decoding method comprising:
deriving a prediction coefficient based on first reference pixels of a luminance component of the plurality of color components and second reference pixels of a chrominance component of the plurality of color components, wherein the second reference pixels are included in a block different from a prediction target block, and the first reference pixels are included in the block corresponding to the block including the second reference pixels;
generating third reference pixels of the chrominance component based on the prediction coefficient and the first reference pixels using a predetermined equation; and
performing intra prediction of the prediction target block of the chrominance component using the third reference pixels as chrominance intra reference pixels of the intra prediction,
wherein
the second reference pixels are left of the prediction target block, left of and above the prediction target block, and above the prediction target block, and
the first reference pixels are corresponding pixels of the second reference pixels.
13. A non-transitory computer readable storage medium including program for causing a computer to execute a video encoding method of a video encoding apparatus that encodes a video having a plurality of color components, the program causing the computer to execute:
deriving a prediction coefficient based on first reference pixels of a luminance component of the plurality of color components and second reference pixels of a chrominance component of the plurality of color components, wherein the second reference pixels are included in a block different from a prediction target block, and the first reference pixels are included in a block corresponding to the block including the second reference pixels;
generating third reference pixels of the chrominance component based on the prediction coefficient and the first reference pixels using a predetermined equation; and
performing intra prediction of the prediction target block of the chrominance component using the third reference pixels as chrominance intra reference pixels of the intra prediction,
wherein
the second reference pixels are left of the prediction target block, left of and above the prediction target block, and above the prediction target block, and
the first reference pixels are corresponding pixels of the second reference pixels.
14. A non-transitory computer readable storage medium including program for causing a computer to execute a video decoding method of a video decoding apparatus that decodes a video having a plurality of color components, the program causing the computer to execute:
deriving a prediction coefficient based on first reference pixels of a luminance component of the plurality of color components and second reference pixels of a chrominance component of the plurality of color components, wherein the second reference pixels are included in a block different from a prediction target block, and the first reference pixels are included in the block corresponding to the block including the second reference pixels;
generating third reference pixels of the chrominance component based on the prediction coefficient and the first reference pixels using a predetermined equation; and
performing intra prediction of the prediction target block of the chrominance component using the third reference pixels as chrominance intra reference pixels of the intra prediction,
wherein
the second reference pixels are left of the prediction target block, left of and above the prediction target block, and above the prediction target block, and
the first reference pixels are corresponding pixels of the second reference pixels.