• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1@TEMPLATE encoder_tmpl.c
2VP8 Set Active and ROI Maps
3===========================
4~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION
5This is an example demonstrating how to control the VP8 encoder's
6ROI and Active maps.
7
8ROI (Reigon of Interest) maps are a way for the application to assign
9each macroblock in the image to a region, and then set quantizer and
10filtering parameters on that image.
11
12Active maps are a way for the application to specify on a
13macroblock-by-macroblock basis whether there is any activity in that
14macroblock.
15~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION
16
17
18Configuration
19-------------
20An ROI map is set on frame 22. If the width of the image in macroblocks
21is evenly divisble by 4, then the output will appear to have distinct
22columns, where the quantizer, loopfilter, and static threshold differ
23from column to column.
24
25An active map is set on frame 33. If the width of the image in macroblocks
26is evenly divisble by 4, then the output will appear to have distinct
27columns, where one column will have motion and the next will not.
28
29The active map is cleared on frame 44.
30~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  PER_FRAME_CFG
31if(frame_cnt + 1 == 22) {
32    vpx_roi_map_t  roi;
33    int            i;
34
35    roi.rows = cfg.g_h/16;
36    roi.cols = cfg.g_w/16;
37
38    roi.delta_q[0] = 0;
39    roi.delta_q[1] = -2;
40    roi.delta_q[2] = -4;
41    roi.delta_q[3] = -6;
42
43    roi.delta_lf[0] = 0;
44    roi.delta_lf[1] = 1;
45    roi.delta_lf[2] = 2;
46    roi.delta_lf[3] = 3;
47
48    roi.static_threshold[0] = 1500;
49    roi.static_threshold[1] = 1000;
50    roi.static_threshold[2] =  500;
51    roi.static_threshold[3] =    0;
52
53    /* generate an ROI map for example */
54    roi.roi_map = malloc(roi.rows * roi.cols);
55    for(i=0;i<roi.rows*roi.cols;i++)
56        roi.roi_map[i] = i & 3;
57
58    if(vpx_codec_control(&codec, VP8E_SET_ROI_MAP, &roi))
59        die_codec(&codec, "Failed to set ROI map");
60
61    free(roi.roi_map);
62} else if(frame_cnt + 1 == 33) {
63    vpx_active_map_t  active;
64    int               i;
65
66    active.rows = cfg.g_h/16;
67    active.cols = cfg.g_w/16;
68
69    /* generate active map for example */
70    active.active_map = malloc(active.rows * active.cols);
71    for(i=0;i<active.rows*active.cols;i++)
72        active.active_map[i] = i & 1;
73
74    if(vpx_codec_control(&codec, VP8E_SET_ACTIVEMAP, &active))
75        die_codec(&codec, "Failed to set active map");
76
77    free(active.active_map);
78} else if(frame_cnt + 1 == 44) {
79    vpx_active_map_t  active;
80
81    active.rows = cfg.g_h/16;
82    active.cols = cfg.g_w/16;
83
84    /* pass in null map to disable active_map*/
85    active.active_map = NULL;
86
87    if(vpx_codec_control(&codec, VP8E_SET_ACTIVEMAP, &active))
88        die_codec(&codec, "Failed to set active map");
89}
90~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  PER_FRAME_CFG
91
92
93Observing The Effects
94---------------------
95Use the `simple_decoder` example to decode this sample, and observe
96the change in the image at frames 22, 33, and 44.
97