Pixel Mapping on AXI4-Stream Interface - 2.1 English - PG199

DisplayPort 1.2 TX Subsystem LogiCORE IP Product Guide (PG199)
Document ID
PG199
Release Date
2024-12-11
Version
2.1 English

By default, the pixel mode is selected based on Pixel Frequency in the subsystem driver. The following shows the different Pixel per Clock (PPC) for each pixel frequency:

  • For 1 PPC, Pixel Frequency < 75 MHz.
  • For 2 PPC, Pixel Frequency ≥ 75 and < 300 MHz.
  • For 4 PPC, Pixel Frequency ≥ 300 MHz.

Also, you can override the pixel width dynamically. For example, if the driver selects a 2 pixel mode as default, you can change the pixel mode to 1.

  • For pixel mode of 1, valid pixels are available only in pixel 0 position.
  • For pixel mode of 2, valid pixels are available only in pixel 0 and pixel 1 position.
  • For pixel mode of 4, valid pixels are available only in pixel 0, pixel 1, pixel 2, and pixel 3 position.

The data width of the AXI4-Stream interface depends on different parameters of the core.

Pixel_Width = MAX_BPC × 3

Interface Width = Pixel Width × LANE_COUNT

For example, if the system is generated using four lanes with MAX_BPC of 16, the data width of the AXI4-Stream interface is 16 × 4 × 3 = 192.

The following table shows the pixel mapping examples for an AXI4-Stream interface implemented in the DisplayPort TX Subsystem.

Table 1. Pixel Mapping Examples on AXI4-Stream Interface
MAX_BPC LANES Pixel Width Interface Width Video BPC Pixel 3 Pixel 2 Pixel 1 Pixel 0
16 4 48 192 16 191:176 175:160 159:144 143:128 127:112 111:96 95:80 79:64 63:48 47:32 31:16 15:0
2 48 96 – – – – – – 95:80 79:64 63:48 47:32 31:16 15:0
1 48 48 – – – – – – – – – 47:32 31:16 15:0
12 4 36 144 12 143:132 131:120 119:108 107:96 95:84 83:72 71:60 59:48 47:36 35:24 23:12 11:0
2 36 72 – – – – – – 71:60 59:48 47:36 35:24 23:12 11:0
1 36 36 – – – – – – – – – 35:24 23:12 11:0
10 4 30 120 10 119:110 109:100 99:90 89:80 79:70 69:60 59:50 49:40 39:30 29:20 19:10 9:0
2 30 60 – – – – – – 59:50 49:40 39:30 29:20 19:10 9:0
1 30 30 – – – – – – – – – 29:20 19:10 9:0
8 4 24 96 8 95:88 87:80 79:72 71:64 63:56 55:48 47:40 39:32 31:24 23:16 15:8 7:0
2 24 48 – – – – – – 47:40 39:32 31:24 23:16 15:8 7:0
1 24 24 – – – – – – – – – 23:16 15:8 7:0
16 4 48 192 12 191:180 175:164 159:148 143:132 127:116 111:100 95:84 79:68 63:52 47:36 31:20 15:4
2 48 96 – – – – – – 95:84 79:68 63:52 47:36 31:20 15:4
1 48 48 – – – – – – – – – 47:36 31:20 15:4
12 4 36 144 10 143:134 131:122 119:110 107:98 95:86 83:74 71:62 59:50 47:38 35:26 23:14 11:2
2 36 72 – – – – – – 71:62 59:50 47:38 35:26 23:14 11:2
1 36 36 – – – – – – – – – 35:26 23:14 11:2
10 4 30 120 8 119:112 109:102 99:92 89:82 79:72 69:62 59:52 49:42 39:32 29:22 19:12 9:2
2 30 60 – – – – – – 59:52 49:42 39:32 29:22 19:12 9:2
1 30 30 – – – – – – – – – 29:22 19:12 9:2
8 4 24 96 6 95:90 87:82 79:74 71:66 63:58 55:50 47:42 39:34 31:26 23:18 15:10 7:2
2 24 48 – – – – – – 47:42 39:34 31:26 23:18 15:10 7:2
1 24 24 – – – – – – – – – 23:18 15:10 7:2
16 4 48 192 10 191:182 175:166 159:150 143:134 127:118 111:102 95:86 79:70 63:54 47:38 31:22 15:6
2 48 96 – – – – – – 95:86 79:70 63:54 47:38 31:22 15:6
1 48 48 – – – – – – – – – 47:38 31:22 15:6
12 4 36 144 8 143:136 131:124 119:112 107:100 95:88 83:76 71:64 59:52 47:40 35:28 23:16 11:4
2 36 72 – – – – – – 71:64 59:52 47:40 35:28 23:16 11:4
1 36 36 – – – – – – – – – 35:28 23:16 11:4
10 4 30 120 6 119:114 109:104 99:94 89:84 79:74 69:64 59:54 49:44 39:34 29:24 19:14 9:4
2 30 60 – – – – – – 59:54 49:44 39:34 29:24 19:14 9:4
1 30 30 – – – – – – – – – 29:24 19:14 9:4
16 4 48 192 8 191:184 175:168 159:152 143:136 127:120 111:104 95:88 79:72 63:56 47:40 31:24 15:8
2 48 96 – – – – – – 95:88 79:72 63:56 47:40 31:24 15:8
1 48 48 – – – – – – – – – 47:40 31:24 15:8
12 4 36 144 6 143:138 131:126 119:114 107:102 95:90 83:78 71:66 59:54 47:42 35:30 23:18 11:6
2 36 72 – – – – – – 71:66 59:54 47:42 35:30 23:18 11:6
1 36 36 – – – – – – – – – 35:30 23:18 11:6
16 4 48 192 6 191:186 175:170 159:154 143:138 127:122 111:106 95:90 79:74 63:58 47:42 31:26 15:10
2 48 96 – – – – – – 95:90 79:74 63:58 47:42 31:26 15:10
1 48 48 – – – – – – – – – 47:42 31:26 15:10
  1. The padding bits are zeros.

The preceding table shows the pixel mapping on an AXI4-Stream interface for all video sampling modes (4:4:4, 4:2:2, and Y-only). Implementation of 4:2:2 and Y-only sampling mode pixel mapping is different from the UG934 guidelines ( see the AXI4-Stream Video IP and System Design Guide (UG934))).

The following table shows the color component mapping for different video sampling modes for the AXI4-Stream pixel mapping shown in the preceding table. The 422 and Y-only sampling modes are shown to highlight the difference between video sampling mode mappings. In the following table, MAX_BPC is 16, LANES=4 and Video BPC=16.

Table 2. Color Component Mapping for Different Video Sampling Modes
Pixel Width Interface Width Video Sampling Mode Pixel 3 Pixel 2 Pixel 1 Pixel 0
48 192 444 191:176 175:160 159:144 143:128 127:112 111:96 95:80 79:64 63:48 47:32 31:16 15:0
32 128 422

V2

[191:176]

Y3

[175:160]

 –

U2

[143:128]

Y2

[127:112]

 –

V0

[95:80]

Y1

[79:64]

 –

U0

[47:32]

Y0

[31:16]

 –
16 64 Y-Only

Y2

[191:176]

 – –

Y2

[143:128]

 – –

Y1

[95:80]

 – –

Y0

[47:32]

 – –

The following table shows UG934-compliant pixel mapping examples over an AXI4-Stream interface.

Table 3. Pixel Mapping Examples on AXI4-Stream Interface (UG934-Compliant Mode)
MAX_BPC LANES Pixel Width Interface Width Video BPC

Video Sampling

Mode

 Pixel 3 Pixel 2 Pixel 1 Pixel 0
8 4 24 96 8 444 95:88 87:80 79:72 71:64 63:56 55:48 47:40 39:32 31:24 23:16 15:8 7:0
4 16 64 422 63:56 55:48 47:40 39:32 31:24 23:16 15:8 7:0
4 8 32 Y-Only 31:24 23:16 15:8 7:0
2 24 48 444 – – – – – – 47:40 39:32 31:24 23:16 15:8 7:0
2 16 32 422 – – – – 31:24 23:16 15:8 7:0
2 8 16 Y-Only – – 15:8 7:0
1 24 24 444 – – – – – – – – – 23:16 15:8 7:0
1 16 16 422 – – – – – – 15:8 7:0
1 8 8 Y-Only – – – 7:0
10 4 30 120 8 444 119:112 109:102 99:92 89:82 79:72 69:62 59:52 49:42 39:32 29:22 19:12 9:2
4 20 80 422 79:72 69:62 59:52 49:42 39:32 29:22 19:12 9:2
4 10 40 Y-Only 39:32 29:22 19:12 9:2
2 30 60 444 – – – – – – 59:52 49:42 39:32 29:22 19:12 9:2
2 20 40 422 – – – – 39:32 29:22 19:12 9:2
2 10 20 Y-Only – – 19:12 9:2
1 30 30 444 – – – – – – – – – 29:22 19:12 9:2
1 20 20 422 – – – – – – 19:12 9.2
1 10 10 Y-Only – – – 9:2
12 4 36 144 8 444 143:136 131:124 119:112 107:100 95:88 83:76 71:64 59:52 47:40 35:28 23:16 11:4
4 24 96 422 95:88 83:76 71:64 59:52 47:40 35:28 23:16 11:4
4 12 48 Y-Only 47:40 35:28 23:16 11:4
2 36 72 444 – – – – – – 71:64 59:52 47:40 35:28 23:16 11:4
2 24 48 422 – – – – 47:40 35:28 23:16 11:4
2 12 24 Y-Only – – 23:16 11:4
1 36 36 444 – – – – – – – – – 35:28 23:16 11:4
1 24 24 422 – – – – – – 23:16 11:4
1 12 12 Y-Only – – – 11:4
16 4 48 192 8 444 191:184 175:168 159:152 143:136 127:120 111:104 95:88 79:72 63:56 47:40 31:24 15:8
4 32 128 422 127:120 111:104 95:88 79:72 63:56 47:40 31:24 15:8
4 16 64 Y-Only 63:56 47:40 31:24 15:8
2 48 96 444 – – – – – – 95:88 79:72 63:56 47:40 31:24 15:8
2 32 64 422 – – – – 63:56 47:40 31:24 15:8
2 16 32 Y-Only – – 31:24 15:8
1 48 48 444 – – – – – – – – – 47:40 31:24 15:8
1 32 32 422 – – – – – – 31:24 15:8
1 16 16 Y-Only – – – 15:8