/* * Copyright (c) 2011 Smartjog S.A.S, Clément Bœsch <clement.boesch@smartjog.com> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * Potential thumbnail lookup filter to reduce the risk of an inappropriate * selection (such as a black frame) we could get with an absolute seek. * * Simplified version of algorithm by Vadim Zaliva <lord@crocodile.org>. * @see http://notbrainsurgery.livejournal.com/29773.html */ #include "libavutil/opt.h" #include "libavutil/pixdesc.h" #include "avfilter.h" #include "internal.h" #define HIST_SIZE (3*256) struct thumb_frame { AVFrame *buf; ///< cached frame int histogram[HIST_SIZE]; ///< RGB color distribution histogram of the frame }; typedef struct ThumbContext { const AVClass *class; int n; ///< current frame int loglevel; int n_frames; ///< number of frames for analysis struct thumb_frame *frames; ///< the n_frames frames AVRational tb; ///< copy of the input timebase to ease access int nb_threads; int *thread_histogram; int planewidth[4]; int planeheight[4]; } ThumbContext; #define OFFSET(x) offsetof(ThumbContext, x) #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM static const AVOption thumbnail_options[] = { { "n", "set the frames batch size", OFFSET(n_frames), AV_OPT_TYPE_INT, {.i64=100}, 2, INT_MAX, FLAGS }, { "log", "force stats logging level", OFFSET(loglevel), AV_OPT_TYPE_INT, {.i64 = AV_LOG_INFO}, INT_MIN, INT_MAX, FLAGS, "level" }, { "quiet", "logging disabled", 0, AV_OPT_TYPE_CONST, {.i64 = AV_LOG_QUIET}, 0, 0, FLAGS, "level" }, { "info", "information logging level", 0, AV_OPT_TYPE_CONST, {.i64 = AV_LOG_INFO}, 0, 0, FLAGS, "level" }, { "verbose", "verbose logging level", 0, AV_OPT_TYPE_CONST, {.i64 = AV_LOG_VERBOSE}, 0, 0, FLAGS, "level" }, { NULL } }; AVFILTER_DEFINE_CLASS(thumbnail); static av_cold int init(AVFilterContext *ctx) { ThumbContext *s = ctx->priv; s->frames = av_calloc(s->n_frames, sizeof(*s->frames)); if (!s->frames) { av_log(ctx, AV_LOG_ERROR, "Allocation failure, try to lower the number of frames\n"); return AVERROR(ENOMEM); } av_log(ctx, AV_LOG_VERBOSE, "batch size: %d frames\n", s->n_frames); return 0; } /** * @brief Compute Sum-square deviation to estimate "closeness". * @param hist color distribution histogram * @param median average color distribution histogram * @return sum of squared errors */ static double frame_sum_square_err(const int *hist, const double *median) { int i; double err, sum_sq_err = 0; for (i = 0; i < HIST_SIZE; i++) { err = median[i] - (double)hist[i]; sum_sq_err += err*err; } return sum_sq_err; } static AVFrame *get_best_frame(AVFilterContext *ctx) { AVFrame *picref; ThumbContext *s = ctx->priv; int i, j, best_frame_idx = 0; int nb_frames = s->n; double avg_hist[HIST_SIZE] = {0}, sq_err, min_sq_err = -1; // average histogram of the N frames for (j = 0; j < FF_ARRAY_ELEMS(avg_hist); j++) { for (i = 0; i < nb_frames; i++) avg_hist[j] += (double)s->frames[i].histogram[j]; avg_hist[j] /= nb_frames; } // find the frame closer to the average using the sum of squared errors for (i = 0; i < nb_frames; i++) { sq_err = frame_sum_square_err(s->frames[i].histogram, avg_hist); if (i == 0 || sq_err < min_sq_err) best_frame_idx = i, min_sq_err = sq_err; } // free and reset everything (except the best frame buffer) for (i = 0; i < nb_frames; i++) { memset(s->frames[i].histogram, 0, sizeof(s->frames[i].histogram)); if (i != best_frame_idx) av_frame_free(&s->frames[i].buf); } s->n = 0; // raise the chosen one picref = s->frames[best_frame_idx].buf; if (s->loglevel != AV_LOG_QUIET) av_log(ctx, s->loglevel, "frame id #%d (pts_time=%f) selected " "from a set of %d images\n", best_frame_idx, picref->pts * av_q2d(s->tb), nb_frames); s->frames[best_frame_idx].buf = NULL; return picref; } static int do_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs) { ThumbContext *s = ctx->priv; AVFrame *frame = arg; int *hist = s->thread_histogram + HIST_SIZE * jobnr; const int h = frame->height; const int w = frame->width; const int slice_start = (h * jobnr) / nb_jobs; const int slice_end = (h * (jobnr+1)) / nb_jobs; const uint8_t *p = frame->data[0] + slice_start * frame->linesize[0]; memset(hist, 0, sizeof(*hist) * HIST_SIZE); switch (frame->format) { case AV_PIX_FMT_RGB24: case AV_PIX_FMT_BGR24: for (int j = slice_start; j < slice_end; j++) { for (int i = 0; i < w; i++) { hist[0*256 + p[i*3 ]]++; hist[1*256 + p[i*3 + 1]]++; hist[2*256 + p[i*3 + 2]]++; } p += frame->linesize[0]; } break; case AV_PIX_FMT_RGB0: case AV_PIX_FMT_BGR0: case AV_PIX_FMT_RGBA: case AV_PIX_FMT_BGRA: for (int j = slice_start; j < slice_end; j++) { for (int i = 0; i < w; i++) { hist[0*256 + p[i*4 ]]++; hist[1*256 + p[i*4 + 1]]++; hist[2*256 + p[i*4 + 2]]++; } p += frame->linesize[0]; } break; case AV_PIX_FMT_0RGB: case AV_PIX_FMT_0BGR: case AV_PIX_FMT_ARGB: case AV_PIX_FMT_ABGR: for (int j = slice_start; j < slice_end; j++) { for (int i = 0; i < w; i++) { hist[0*256 + p[i*4 + 1]]++; hist[1*256 + p[i*4 + 2]]++; hist[2*256 + p[i*4 + 3]]++; } p += frame->linesize[0]; } break; default: for (int plane = 0; plane < 3; plane++) { const int slice_start = (s->planeheight[plane] * jobnr) / nb_jobs; const int slice_end = (s->planeheight[plane] * (jobnr+1)) / nb_jobs; const uint8_t *p = frame->data[plane] + slice_start * frame->linesize[plane]; const ptrdiff_t linesize = frame->linesize[plane]; const int planewidth = s->planewidth[plane]; int *hhist = hist + 256 * plane; for (int j = slice_start; j < slice_end; j++) { for (int i = 0; i < planewidth; i++) hhist[p[i]]++; p += linesize; } } break; } return 0; } static int filter_frame(AVFilterLink *inlink, AVFrame *frame) { AVFilterContext *ctx = inlink->dst; ThumbContext *s = ctx->priv; AVFilterLink *outlink = ctx->outputs[0]; int *hist = s->frames[s->n].histogram; // keep a reference of each frame s->frames[s->n].buf = frame; ff_filter_execute(ctx, do_slice, frame, NULL, FFMIN(frame->height, s->nb_threads)); // update current frame histogram for (int j = 0; j < FFMIN(frame->height, s->nb_threads); j++) { int *thread_histogram = s->thread_histogram + HIST_SIZE * j; for (int i = 0; i < HIST_SIZE; i++) hist[i] += thread_histogram[i]; } // no selection until the buffer of N frames is filled up s->n++; if (s->n < s->n_frames) return 0; return ff_filter_frame(outlink, get_best_frame(ctx)); } static av_cold void uninit(AVFilterContext *ctx) { int i; ThumbContext *s = ctx->priv; for (i = 0; i < s->n_frames && s->frames && s->frames[i].buf; i++) av_frame_free(&s->frames[i].buf); av_freep(&s->frames); av_freep(&s->thread_histogram); } static int request_frame(AVFilterLink *link) { AVFilterContext *ctx = link->src; ThumbContext *s = ctx->priv; int ret = ff_request_frame(ctx->inputs[0]); if (ret == AVERROR_EOF && s->n) { ret = ff_filter_frame(link, get_best_frame(ctx)); if (ret < 0) return ret; ret = AVERROR_EOF; } if (ret < 0) return ret; return 0; } static int config_props(AVFilterLink *inlink) { AVFilterContext *ctx = inlink->dst; ThumbContext *s = ctx->priv; const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format); s->nb_threads = ff_filter_get_nb_threads(ctx); s->thread_histogram = av_calloc(HIST_SIZE, s->nb_threads * sizeof(*s->thread_histogram)); if (!s->thread_histogram) return AVERROR(ENOMEM); s->tb = inlink->time_base; s->planewidth[1] = s->planewidth[2] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w); s->planewidth[0] = s->planewidth[3] = inlink->w; s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h); s->planeheight[0] = s->planeheight[3] = inlink->h; return 0; } static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24, AV_PIX_FMT_RGBA, AV_PIX_FMT_BGRA, AV_PIX_FMT_RGB0, AV_PIX_FMT_BGR0, AV_PIX_FMT_ABGR, AV_PIX_FMT_ARGB, AV_PIX_FMT_0BGR, AV_PIX_FMT_0RGB, AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA444P, AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP, AV_PIX_FMT_NONE }; static const AVFilterPad thumbnail_inputs[] = { { .name = "default", .type = AVMEDIA_TYPE_VIDEO, .config_props = config_props, .filter_frame = filter_frame, }, }; static const AVFilterPad thumbnail_outputs[] = { { .name = "default", .type = AVMEDIA_TYPE_VIDEO, .request_frame = request_frame, }, }; const AVFilter ff_vf_thumbnail = { .name = "thumbnail", .description = NULL_IF_CONFIG_SMALL("Select the most representative frame in a given sequence of consecutive frames."), .priv_size = sizeof(ThumbContext), .init = init, .uninit = uninit, FILTER_INPUTS(thumbnail_inputs), FILTER_OUTPUTS(thumbnail_outputs), FILTER_PIXFMTS_ARRAY(pix_fmts), .priv_class = &thumbnail_class, .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS, };