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| 1 | +/* |
| 2 | + * This file is part of FFmpeg. |
| 3 | + * |
| 4 | + * FFmpeg is free software; you can redistribute it and/or |
| 5 | + * modify it under the terms of the GNU Lesser General Public |
| 6 | + * License as published by the Free Software Foundation; either |
| 7 | + * version 2.1 of the License, or (at your option) any later version. |
| 8 | + * |
| 9 | + * FFmpeg is distributed in the hope that it will be useful, |
| 10 | + * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | + * Lesser General Public License for more details. |
| 13 | + * |
| 14 | + * You should have received a copy of the GNU Lesser General Public |
| 15 | + * License along with FFmpeg; if not, write to the Free Software |
| 16 | + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 17 | + */ |
| 18 | + |
| 19 | +#include "libavutil/opt.h" |
| 20 | +#include "libavutil/imgutils.h" |
| 21 | +#include "avfilter.h" |
| 22 | +#include "formats.h" |
| 23 | +#include "internal.h" |
| 24 | +#include "video.h" |
| 25 | + |
| 26 | +typedef struct BackgroundkeyContext { |
| 27 | + const AVClass *class; |
| 28 | + |
| 29 | + float threshold; |
| 30 | + float similarity; |
| 31 | + float blend; |
| 32 | + int max; |
| 33 | + |
| 34 | + int nb_threads; |
| 35 | + int hsub_log2; |
| 36 | + int vsub_log2; |
| 37 | + |
| 38 | + int64_t max_sum; |
| 39 | + int64_t *sums; |
| 40 | + |
| 41 | + AVFrame *background; |
| 42 | + |
| 43 | + int (*do_slice)(AVFilterContext *avctx, void *arg, |
| 44 | + int jobnr, int nb_jobs); |
| 45 | +} BackgroundkeyContext; |
| 46 | + |
| 47 | +static int do_backgroundkey_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs) |
| 48 | +{ |
| 49 | + BackgroundkeyContext *s = avctx->priv; |
| 50 | + AVFrame *frame = arg; |
| 51 | + const int slice_start = (frame->height * jobnr) / nb_jobs; |
| 52 | + const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs; |
| 53 | + const int min_diff = (255 + 255 + 255) * s->similarity; |
| 54 | + const float blend = s->blend; |
| 55 | + const int hsub = s->hsub_log2; |
| 56 | + const int vsub = s->vsub_log2; |
| 57 | + int64_t sum = 0; |
| 58 | + |
| 59 | + for (int y = slice_start; y < slice_end; y++) { |
| 60 | + const uint8_t *srcy = frame->data[0] + frame->linesize[0] * y; |
| 61 | + const uint8_t *srcu = frame->data[1] + frame->linesize[1] * (y >> vsub); |
| 62 | + const uint8_t *srcv = frame->data[2] + frame->linesize[2] * (y >> vsub); |
| 63 | + const uint8_t *bsrcy = s->background->data[0] + s->background->linesize[0] * y; |
| 64 | + const uint8_t *bsrcu = s->background->data[1] + s->background->linesize[1] * (y >> vsub); |
| 65 | + const uint8_t *bsrcv = s->background->data[2] + s->background->linesize[2] * (y >> vsub); |
| 66 | + uint8_t *dst = frame->data[3] + frame->linesize[3] * y; |
| 67 | + for (int x = 0; x < frame->width; x++) { |
| 68 | + const int xx = x >> hsub; |
| 69 | + const int diff = FFABS(srcy[x] - bsrcy[x]) + |
| 70 | + FFABS(srcu[xx] - bsrcu[xx]) + |
| 71 | + FFABS(srcv[xx] - bsrcv[xx]); |
| 72 | + int A; |
| 73 | + |
| 74 | + sum += diff; |
| 75 | + if (blend > 0.f) { |
| 76 | + A = 255 - av_clipf((min_diff - diff) / blend, 0.f, 255.f); |
| 77 | + } else { |
| 78 | + A = (diff > min_diff) ? 255 : 0; |
| 79 | + } |
| 80 | + |
| 81 | + dst[x] = A; |
| 82 | + } |
| 83 | + } |
| 84 | + |
| 85 | + s->sums[jobnr] = sum; |
| 86 | + |
| 87 | + return 0; |
| 88 | +} |
| 89 | + |
| 90 | +static int do_backgroundkey16_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs) |
| 91 | +{ |
| 92 | + BackgroundkeyContext *s = avctx->priv; |
| 93 | + AVFrame *frame = arg; |
| 94 | + const int slice_start = (frame->height * jobnr) / nb_jobs; |
| 95 | + const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs; |
| 96 | + const int hsub = s->hsub_log2; |
| 97 | + const int vsub = s->vsub_log2; |
| 98 | + const int max = s->max; |
| 99 | + const int min_diff = s->similarity * (s->max + s->max + s->max); |
| 100 | + const float blend = s->blend; |
| 101 | + int64_t sum = 0; |
| 102 | + |
| 103 | + for (int y = slice_start; y < slice_end; y++) { |
| 104 | + const uint16_t *srcy = (const uint16_t *)(frame->data[0] + frame->linesize[0] * y); |
| 105 | + const uint16_t *srcu = (const uint16_t *)(frame->data[1] + frame->linesize[1] * (y >> vsub)); |
| 106 | + const uint16_t *srcv = (const uint16_t *)(frame->data[2] + frame->linesize[2] * (y >> vsub)); |
| 107 | + const uint16_t *bsrcy = (const uint16_t *)(s->background->data[0] + s->background->linesize[0] * y); |
| 108 | + const uint16_t *bsrcu = (const uint16_t *)(s->background->data[1] + s->background->linesize[1] * (y >> vsub)); |
| 109 | + const uint16_t *bsrcv = (const uint16_t *)(s->background->data[2] + s->background->linesize[2] * (y >> vsub)); |
| 110 | + uint16_t *dst = (uint16_t *)(frame->data[3] + frame->linesize[3] * y); |
| 111 | + for (int x = 0; x < frame->width; x++) { |
| 112 | + const int xx = x >> hsub; |
| 113 | + const int diff = FFABS(srcy[x] - bsrcy[x] ) + |
| 114 | + FFABS(srcu[xx] - bsrcu[xx]) + |
| 115 | + FFABS(srcv[xx] - bsrcv[xx]); |
| 116 | + int A; |
| 117 | + |
| 118 | + sum += diff; |
| 119 | + if (blend > 0.f) { |
| 120 | + A = max - av_clipf((min_diff - diff) / blend, 0.f, max); |
| 121 | + } else { |
| 122 | + A = (diff > min_diff) ? max : 0; |
| 123 | + } |
| 124 | + |
| 125 | + dst[x] = A; |
| 126 | + } |
| 127 | + } |
| 128 | + |
| 129 | + s->sums[jobnr] = sum; |
| 130 | + |
| 131 | + return 0; |
| 132 | +} |
| 133 | + |
| 134 | +static int filter_frame(AVFilterLink *link, AVFrame *frame) |
| 135 | +{ |
| 136 | + AVFilterContext *avctx = link->dst; |
| 137 | + BackgroundkeyContext *s = avctx->priv; |
| 138 | + int64_t sum = 0; |
| 139 | + int ret = 0; |
| 140 | + |
| 141 | + if (!s->background) { |
| 142 | + s->background = ff_get_video_buffer(link, frame->width, frame->height); |
| 143 | + if (!s->background) { |
| 144 | + ret = AVERROR(ENOMEM); |
| 145 | + goto fail; |
| 146 | + } |
| 147 | + ret = av_frame_copy(s->background, frame); |
| 148 | + if (ret < 0) |
| 149 | + goto fail; |
| 150 | + } |
| 151 | + |
| 152 | + if (ret = ff_filter_execute(avctx, s->do_slice, frame, NULL, |
| 153 | + FFMIN(frame->height, s->nb_threads))) |
| 154 | + goto fail; |
| 155 | + |
| 156 | + for (int n = 0; n < s->nb_threads; n++) |
| 157 | + sum += s->sums[n]; |
| 158 | + if (s->max_sum * s->threshold < sum) { |
| 159 | + ret = av_frame_copy(s->background, frame); |
| 160 | + if (ret < 0) |
| 161 | + goto fail; |
| 162 | + } |
| 163 | + |
| 164 | + return ff_filter_frame(avctx->outputs[0], frame); |
| 165 | +fail: |
| 166 | + av_frame_free(&frame); |
| 167 | + return ret; |
| 168 | +} |
| 169 | + |
| 170 | +static av_cold int config_output(AVFilterLink *outlink) |
| 171 | +{ |
| 172 | + const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format); |
| 173 | + AVFilterContext *avctx = outlink->src; |
| 174 | + AVFilterLink *inlink = avctx->inputs[0]; |
| 175 | + BackgroundkeyContext *s = avctx->priv; |
| 176 | + int depth; |
| 177 | + |
| 178 | + s->nb_threads = ff_filter_get_nb_threads(avctx); |
| 179 | + depth = desc->comp[0].depth; |
| 180 | + s->do_slice = depth <= 8 ? do_backgroundkey_slice : do_backgroundkey16_slice; |
| 181 | + s->max = (1 << depth) - 1; |
| 182 | + s->hsub_log2 = desc->log2_chroma_w; |
| 183 | + s->vsub_log2 = desc->log2_chroma_h; |
| 184 | + s->max_sum = (int64_t)(inlink->w) * inlink->h * s->max; |
| 185 | + s->max_sum += 2LL * (inlink->w >> s->hsub_log2) * (inlink->h >> s->vsub_log2) * s->max; |
| 186 | + |
| 187 | + s->sums = av_calloc(s->nb_threads, sizeof(*s->sums)); |
| 188 | + if (!s->sums) |
| 189 | + return AVERROR(ENOMEM); |
| 190 | + |
| 191 | + return 0; |
| 192 | +} |
| 193 | + |
| 194 | +static av_cold void uninit(AVFilterContext *ctx) |
| 195 | +{ |
| 196 | + BackgroundkeyContext *s = ctx->priv; |
| 197 | + |
| 198 | + av_frame_free(&s->background); |
| 199 | + av_freep(&s->sums); |
| 200 | +} |
| 201 | + |
| 202 | +static const AVFilterPad backgroundkey_inputs[] = { |
| 203 | + { |
| 204 | + .name = "default", |
| 205 | + .type = AVMEDIA_TYPE_VIDEO, |
| 206 | + .flags = AVFILTERPAD_FLAG_NEEDS_WRITABLE, |
| 207 | + .filter_frame = filter_frame, |
| 208 | + }, |
| 209 | +}; |
| 210 | + |
| 211 | +static const AVFilterPad backgroundkey_outputs[] = { |
| 212 | + { |
| 213 | + .name = "default", |
| 214 | + .type = AVMEDIA_TYPE_VIDEO, |
| 215 | + .config_props = config_output, |
| 216 | + }, |
| 217 | +}; |
| 218 | + |
| 219 | +#define OFFSET(x) offsetof(BackgroundkeyContext, x) |
| 220 | +#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM |
| 221 | + |
| 222 | +static const AVOption backgroundkey_options[] = { |
| 223 | + { "threshold", "set the scene change threshold", OFFSET(threshold), AV_OPT_TYPE_FLOAT, { .dbl = 0.08}, 0.0, 1.0, FLAGS }, |
| 224 | + { "similarity", "set the similarity", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.1 }, 0.0, 1.0, FLAGS }, |
| 225 | + { "blend", "set the blend value", OFFSET(blend), AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS }, |
| 226 | + { NULL } |
| 227 | +}; |
| 228 | + |
| 229 | +static const enum AVPixelFormat backgroundkey_fmts[] = { |
| 230 | + AV_PIX_FMT_YUVA420P, |
| 231 | + AV_PIX_FMT_YUVA422P, |
| 232 | + AV_PIX_FMT_YUVA444P, |
| 233 | + AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA444P9, |
| 234 | + AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA444P10, |
| 235 | + AV_PIX_FMT_YUVA422P12, AV_PIX_FMT_YUVA444P12, |
| 236 | + AV_PIX_FMT_YUVA420P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA444P16, |
| 237 | + AV_PIX_FMT_GBRAP, |
| 238 | + AV_PIX_FMT_GBRAP10, AV_PIX_FMT_GBRAP12, AV_PIX_FMT_GBRAP16, |
| 239 | + AV_PIX_FMT_NONE |
| 240 | +}; |
| 241 | + |
| 242 | +AVFILTER_DEFINE_CLASS(backgroundkey); |
| 243 | + |
| 244 | +const AVFilter ff_vf_backgroundkey = { |
| 245 | + .name = "backgroundkey", |
| 246 | + .description = NULL_IF_CONFIG_SMALL("Turns a static background into transparency."), |
| 247 | + .priv_size = sizeof(BackgroundkeyContext), |
| 248 | + .priv_class = &backgroundkey_class, |
| 249 | + .uninit = uninit, |
| 250 | + FILTER_INPUTS(backgroundkey_inputs), |
| 251 | + FILTER_OUTPUTS(backgroundkey_outputs), |
| 252 | + FILTER_PIXFMTS_ARRAY(backgroundkey_fmts), |
| 253 | + .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS, |
| 254 | + .process_command = ff_filter_process_command, |
| 255 | +}; |