Memory Format - 2020.2 English

H.264/H.265 Video Codec Unit v1.2 Solutions LogiCORE IP Product Guide (PG252)
Document ID
PG252
Release Date
2020-11-24
Version
2020.2 English

The decoded picture buffer contains the decoded pixels. It contains two parts: luminance pixels (Luma) followed by chrominance pixels (Chroma). Luma pixels are stored in pixel raster scan order. Chroma pixels are stored in U/V-interleaved pixel raster scan order, hence the Chroma part is half the size of the Luma part when using a 4:2:0 format and the same size as the Luma part when using a 4:2:2 format. The decoded picture buffer must be one contiguous memory region.

Note: Decoder output buffers width are in multiple of 256 byte. Height is in multiples of 64. For example: for 1920x1080 resolution, Decoder output is 2048x1088.

Two packing formats are supported in external memory: eight bits per component or 10 bits per component, shown in the following tables, respectively. The 8-bit format can only be used for an 8-bit component depth and the 10-bit format can only be used for a 10-bit component depth. The following tables show the raster scan format supported by the decoder block for 8-bit and 10-bit color depth.

Table 1. Source Frame Buffer Format with 8-bit Component Format
255 248 ... 31 24 23 16 15 8 7 0
Yx+31,y ... Yx+3,y Yx+2,y Yx+1,y Yx,y
...(all Luma in pixel raster scan order)...
255 248 247 240 ... 31 24 23 16 15 8 7 0
Vx+15,y Ux+15,y ... Vx+1,y Ux+1,y Vx,y Ux,y
...(all interleaved Chroma in pixel raster scan order)...
Table 2. Source Frame Buffer Format with 10-bit Component Format
255 254 253 244             31 30 29 20 19 10 9 0
0 0 Vx+23,y   0 0 Yx+2,y Yx+1,y Yx,y
...(all Luma in pixel raster scan order)...
255 254 253 244 ... 63 62 61 52 51 42 41 32 31 30 29 20 19 10 9 0
0 0 Vx+11,y ... 0 0 Vx+2,y Ux+2,y Vx+1,y 0 0 Ux+1,y Vx,y Ux,y
...(all interleaved Chroma in pixel raster scan order)...

The frame buffer width (pitch) may be larger than the frame width so that there are (pitch - width) ignored values between consecutive pixel lines.