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