yading@10: /*
yading@10:  * Copyright (c) 2010 Stefano Sabatini
yading@10:  * Copyright (c) 2006 Ivo van Poorten
yading@10:  * Copyright (c) 2006 Julian Hall
yading@10:  * Copyright (c) 2002-2003 Brian J. Murrell
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or modify
yading@10:  * it under the terms of the GNU General Public License as published by
yading@10:  * the Free Software Foundation; either version 2 of the License, or
yading@10:  * (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
yading@10:  * GNU General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU General Public License along
yading@10:  * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
yading@10:  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Search for black frames to detect scene transitions.
yading@10:  * Ported from MPlayer libmpcodecs/vf_blackframe.c.
yading@10:  */
yading@10: 
yading@10: #include <stdio.h>
yading@10: #include <inttypes.h>
yading@10: 
yading@10: #include "libavutil/internal.h"
yading@10: #include "libavutil/opt.h"
yading@10: #include "avfilter.h"
yading@10: #include "internal.h"
yading@10: #include "formats.h"
yading@10: #include "internal.h"
yading@10: #include "video.h"
yading@10: 
yading@10: typedef struct {
yading@10:     const AVClass *class;
yading@10:     int bamount;          ///< black amount
yading@10:     int bthresh;          ///< black threshold
yading@10:     unsigned int frame;   ///< frame number
yading@10:     unsigned int nblack;  ///< number of black pixels counted so far
yading@10:     unsigned int last_keyframe; ///< frame number of the last received key-frame
yading@10: } BlackFrameContext;
yading@10: 
yading@10: static int query_formats(AVFilterContext *ctx)
yading@10: {
yading@10:     static const enum AVPixelFormat pix_fmts[] = {
yading@10:         AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NV12,
yading@10:         AV_PIX_FMT_NV21, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
yading@10:         AV_PIX_FMT_NONE
yading@10:     };
yading@10: 
yading@10:     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
yading@10: {
yading@10:     AVFilterContext *ctx = inlink->dst;
yading@10:     BlackFrameContext *blackframe = ctx->priv;
yading@10:     int x, i;
yading@10:     int pblack = 0;
yading@10:     uint8_t *p = frame->data[0];
yading@10: 
yading@10:     for (i = 0; i < frame->height; i++) {
yading@10:         for (x = 0; x < inlink->w; x++)
yading@10:             blackframe->nblack += p[x] < blackframe->bthresh;
yading@10:         p += frame->linesize[0];
yading@10:     }
yading@10: 
yading@10:     if (frame->key_frame)
yading@10:         blackframe->last_keyframe = blackframe->frame;
yading@10: 
yading@10:     pblack = blackframe->nblack * 100 / (inlink->w * inlink->h);
yading@10:     if (pblack >= blackframe->bamount)
yading@10:         av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pts:%"PRId64" t:%f "
yading@10:                "type:%c last_keyframe:%d\n",
yading@10:                blackframe->frame, pblack, frame->pts,
yading@10:                frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base),
yading@10:                av_get_picture_type_char(frame->pict_type), blackframe->last_keyframe);
yading@10: 
yading@10:     blackframe->frame++;
yading@10:     blackframe->nblack = 0;
yading@10:     return ff_filter_frame(inlink->dst->outputs[0], frame);
yading@10: }
yading@10: 
yading@10: #define OFFSET(x) offsetof(BlackFrameContext, x)
yading@10: #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
yading@10: static const AVOption blackframe_options[] = {
yading@10:     { "amount", "Percentage of the pixels that have to be below the threshold "
yading@10:         "for the frame to be considered black.", OFFSET(bamount), AV_OPT_TYPE_INT, { .i64 = 98 }, 0, 100,     FLAGS },
yading@10:     { "threshold", "threshold below which a pixel value is considered black",
yading@10:                                                  OFFSET(bthresh), AV_OPT_TYPE_INT, { .i64 = 32 }, 0, 255,     FLAGS },
yading@10:     { "thresh", "threshold below which a pixel value is considered black",
yading@10:                                                  OFFSET(bthresh), AV_OPT_TYPE_INT, { .i64 = 32 }, 0, 255,     FLAGS },
yading@10:     { NULL },
yading@10: };
yading@10: 
yading@10: AVFILTER_DEFINE_CLASS(blackframe);
yading@10: 
yading@10: static const AVFilterPad avfilter_vf_blackframe_inputs[] = {
yading@10:     {
yading@10:         .name             = "default",
yading@10:         .type             = AVMEDIA_TYPE_VIDEO,
yading@10:         .get_video_buffer = ff_null_get_video_buffer,
yading@10:         .filter_frame     = filter_frame,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: static const AVFilterPad avfilter_vf_blackframe_outputs[] = {
yading@10:     {
yading@10:         .name = "default",
yading@10:         .type = AVMEDIA_TYPE_VIDEO
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: AVFilter avfilter_vf_blackframe = {
yading@10:     .name        = "blackframe",
yading@10:     .description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
yading@10: 
yading@10:     .priv_size = sizeof(BlackFrameContext),
yading@10:     .priv_class = &blackframe_class,
yading@10: 
yading@10:     .query_formats = query_formats,
yading@10: 
yading@10:     .inputs    = avfilter_vf_blackframe_inputs,
yading@10: 
yading@10:     .outputs   = avfilter_vf_blackframe_outputs,
yading@10: };