GPU Pro 4

352 VI GPGPU

Chroma subsampling mode

4:4:4 Y

0

C

b0

C

r0

Y

1

C

b1

C

r1

...N

4:2:2 Y

0

Y

1

C

b0

C

r0

Y

2

Y

3

...N

4:2:0 Y

0

Y

1

Y

2

Y

3

C

b0

C

r0

...N

Copy GPU result to CPU

CPU

Final JPEG dataJFIF header

EOI

Figure 2.7. GPU to CPU process showing thread group output order based on chroma

subsampling mode.

2.3 Performance

Performance tests were performed by compressing back-buffer data into JPEG

data. Two source images, of dimensions 2,268 × 1,512 pixels, were encoded with

different settings using the presented technique and libjpeg-turbo version 1.2.0.

1

The back buffer has the relevant flags to be treated as a shader resource. The

source

Texture2D resource is created by loadingRGBdatafromafile. T