97 lines
3.0 KiB
Plaintext
97 lines
3.0 KiB
Plaintext
@TEMPLATE encoder_tmpl.c
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VP8 Set Active and ROI Maps
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===========================
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION
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This is an example demonstrating how to control the VP8 encoder's
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ROI and Active maps.
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ROI (Reigon of Interest) maps are a way for the application to assign
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each macroblock in the image to a region, and then set quantizer and
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filtering parameters on that image.
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Active maps are a way for the application to specify on a
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macroblock-by-macroblock basis whether there is any activity in that
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macroblock.
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION
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Configuration
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-------------
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An ROI map is set on frame 22. If the width of the image in macroblocks
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is evenly divisble by 4, then the output will appear to have distinct
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columns, where the quantizer, loopfilter, and static threshold differ
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from column to column.
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An active map is set on frame 33. If the width of the image in macroblocks
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is evenly divisble by 4, then the output will appear to have distinct
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columns, where one column will have motion and the next will not.
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The active map is cleared on frame 44.
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PER_FRAME_CFG
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if(frame_cnt + 1 == 22) {
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vpx_roi_map_t roi;
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int i;
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roi.rows = cfg.g_h/16;
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roi.cols = cfg.g_w/16;
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roi.delta_q[0] = 0;
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roi.delta_q[1] = -2;
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roi.delta_q[2] = -4;
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roi.delta_q[3] = -6;
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roi.delta_lf[0] = 0;
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roi.delta_lf[1] = 1;
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roi.delta_lf[2] = 2;
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roi.delta_lf[3] = 3;
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roi.static_threshold[0] = 1500;
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roi.static_threshold[1] = 1000;
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roi.static_threshold[2] = 500;
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roi.static_threshold[3] = 0;
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/* generate an ROI map for example */
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roi.roi_map = malloc(roi.rows * roi.cols);
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for(i=0;i<roi.rows*roi.cols;i++)
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roi.roi_map[i] = i & 3;
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if(vpx_codec_control(&codec, VP8E_SET_ROI_MAP, &roi))
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die_codec(&codec, "Failed to set ROI map");
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free(roi.roi_map);
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} else if(frame_cnt + 1 == 33) {
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vpx_active_map_t active;
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int i;
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active.rows = cfg.g_h/16;
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active.cols = cfg.g_w/16;
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/* generate active map for example */
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active.active_map = malloc(active.rows * active.cols);
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for(i=0;i<active.rows*active.cols;i++)
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active.active_map[i] = i & 1;
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if(vpx_codec_control(&codec, VP8E_SET_ACTIVEMAP, &active))
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die_codec(&codec, "Failed to set active map");
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free(active.active_map);
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} else if(frame_cnt + 1 == 44) {
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vpx_active_map_t active;
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active.rows = 240/16;
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active.cols = 320/16;
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/* pass in null map to disable active_map*/
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active.active_map = NULL;
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if(vpx_codec_control(&codec, VP8E_SET_ACTIVEMAP, &active))
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die_codec(&codec, "Failed to set active map");
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}
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PER_FRAME_CFG
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Observing The Effects
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---------------------
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Use the `simple_decoder` example to decode this sample, and observe
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the change in the image at frames 22, 33, and 44.
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