135 lines
4.5 KiB
C
135 lines
4.5 KiB
C
/*
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* Copyright (c) 2010 Stefano Sabatini
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* Copyright (c) 2006 Ivo van Poorten
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* Copyright (c) 2006 Julian Hall
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* Copyright (c) 2002-2003 Brian J. Murrell
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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 modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with FFmpeg; if not, write to the Free Software Foundation, Inc.,
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* 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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* Search for black frames to detect scene transitions.
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* Ported from MPlayer libmpcodecs/vf_blackframe.c.
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*/
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#include <stdio.h>
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#include <inttypes.h>
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#include "libavutil/internal.h"
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#include "libavutil/opt.h"
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#include "avfilter.h"
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#include "formats.h"
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#include "internal.h"
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#include "video.h"
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typedef struct BlackFrameContext {
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const AVClass *class;
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int bamount; ///< black amount
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int bthresh; ///< black threshold
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unsigned int frame; ///< frame number
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unsigned int nblack; ///< number of black pixels counted so far
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unsigned int last_keyframe; ///< frame number of the last received key-frame
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} BlackFrameContext;
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static const enum AVPixelFormat pix_fmts[] = {
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AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NV12,
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AV_PIX_FMT_NV21, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
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AV_PIX_FMT_NONE
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};
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#define SET_META(key, format, value) \
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snprintf(buf, sizeof(buf), format, value); \
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av_dict_set(metadata, key, buf, 0)
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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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BlackFrameContext *s = ctx->priv;
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int x, i;
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int pblack = 0;
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uint8_t *p = frame->data[0];
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AVDictionary **metadata;
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char buf[32];
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for (i = 0; i < frame->height; i++) {
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for (x = 0; x < inlink->w; x++)
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s->nblack += p[x] < s->bthresh;
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p += frame->linesize[0];
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}
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if (frame->flags & AV_FRAME_FLAG_KEY)
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s->last_keyframe = s->frame;
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pblack = s->nblack * 100 / (inlink->w * inlink->h);
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if (pblack >= s->bamount) {
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metadata = &frame->metadata;
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av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pts:%"PRId64" t:%f "
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"type:%c last_keyframe:%d\n",
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s->frame, pblack, frame->pts,
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frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base),
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av_get_picture_type_char(frame->pict_type), s->last_keyframe);
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SET_META("lavfi.blackframe.pblack", "%u", pblack);
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}
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s->frame++;
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s->nblack = 0;
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return ff_filter_frame(inlink->dst->outputs[0], frame);
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}
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#define OFFSET(x) offsetof(BlackFrameContext, x)
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#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
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static const AVOption blackframe_options[] = {
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{ "amount", "percentage of the pixels that have to be below the threshold "
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"for the frame to be considered black", OFFSET(bamount), AV_OPT_TYPE_INT, { .i64 = 98 }, 0, 100, FLAGS },
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{ "threshold", "threshold below which a pixel value is considered black",
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OFFSET(bthresh), AV_OPT_TYPE_INT, { .i64 = 32 }, 0, 255, FLAGS },
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{ "thresh", "threshold below which a pixel value is considered black",
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OFFSET(bthresh), AV_OPT_TYPE_INT, { .i64 = 32 }, 0, 255, FLAGS },
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{ NULL }
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};
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AVFILTER_DEFINE_CLASS(blackframe);
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static const AVFilterPad avfilter_vf_blackframe_inputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_VIDEO,
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.filter_frame = filter_frame,
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},
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};
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static const AVFilterPad avfilter_vf_blackframe_outputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_VIDEO
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},
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};
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const AVFilter ff_vf_blackframe = {
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.name = "blackframe",
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.description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
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.priv_size = sizeof(BlackFrameContext),
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.priv_class = &blackframe_class,
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.flags = AVFILTER_FLAG_METADATA_ONLY,
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FILTER_INPUTS(avfilter_vf_blackframe_inputs),
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FILTER_OUTPUTS(avfilter_vf_blackframe_outputs),
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FILTER_PIXFMTS_ARRAY(pix_fmts),
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};
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