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libavfilter/vf_blackframe.c

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00001 /*
00002  * Copyright (c) 2010 Stefano Sabatini
00003  * Copyright (c) 2006 Ivo van Poorten
00004  * Copyright (c) 2006 Julian Hall
00005  * Copyright (c) 2002-2003 Brian J. Murrell
00006  *
00007  * This file is part of FFmpeg.
00008  *
00009  * FFmpeg is free software; you can redistribute it and/or modify
00010  * it under the terms of the GNU General Public License as published by
00011  * the Free Software Foundation; either version 2 of the License, or
00012  * (at your option) any later version.
00013  *
00014  * FFmpeg is distributed in the hope that it will be useful,
00015  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00016  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00017  * GNU General Public License for more details.
00018  *
00019  * You should have received a copy of the GNU General Public License along
00020  * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
00021  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00022  */
00023 
00030 #include "avfilter.h"
00031 
00032 typedef struct {
00033     unsigned int bamount; 
00034     unsigned int bthresh; 
00035     unsigned int frame;   
00036     unsigned int nblack;  
00037     unsigned int last_keyframe; 
00038 } BlackFrameContext;
00039 
00040 static int query_formats(AVFilterContext *ctx)
00041 {
00042     static const enum PixelFormat pix_fmts[] = {
00043         PIX_FMT_YUV410P, PIX_FMT_YUV420P, PIX_FMT_GRAY8, PIX_FMT_NV12,
00044         PIX_FMT_NV21, PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV411P,
00045         PIX_FMT_NONE
00046     };
00047 
00048     avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));
00049     return 0;
00050 }
00051 
00052 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00053 {
00054     BlackFrameContext *blackframe = ctx->priv;
00055 
00056     blackframe->bamount = 98;
00057     blackframe->bthresh = 32;
00058     blackframe->nblack = 0;
00059     blackframe->frame = 0;
00060     blackframe->last_keyframe = 0;
00061 
00062     if (args)
00063         sscanf(args, "%u:%u", &blackframe->bamount, &blackframe->bthresh);
00064 
00065     av_log(ctx, AV_LOG_INFO, "bamount:%u bthresh:%u\n",
00066            blackframe->bamount, blackframe->bthresh);
00067 
00068     if (blackframe->bamount > 100 || blackframe->bthresh > 255) {
00069         av_log(ctx, AV_LOG_ERROR, "Too big value for bamount (max is 100) or bthresh (max is 255)\n");
00070         return AVERROR(EINVAL);
00071     }
00072 
00073     return 0;
00074 }
00075 
00076 static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
00077 {
00078     AVFilterContext *ctx = inlink->dst;
00079     BlackFrameContext *blackframe = ctx->priv;
00080     AVFilterBufferRef *picref = inlink->cur_buf;
00081     int x, i;
00082     uint8_t *p = picref->data[0] + y * picref->linesize[0];
00083 
00084     for (i = 0; i < h; i++) {
00085         for (x = 0; x < inlink->w; x++)
00086             blackframe->nblack += p[x] < blackframe->bthresh;
00087         p += picref->linesize[0];
00088     }
00089 
00090     avfilter_draw_slice(ctx->outputs[0], y, h, slice_dir);
00091 }
00092 
00093 static void end_frame(AVFilterLink *inlink)
00094 {
00095     AVFilterContext *ctx = inlink->dst;
00096     BlackFrameContext *blackframe = ctx->priv;
00097     AVFilterBufferRef *picref = inlink->cur_buf;
00098     int pblack = 0;
00099 
00100     if (picref->video->key_frame)
00101         blackframe->last_keyframe = blackframe->frame;
00102 
00103     pblack = blackframe->nblack * 100 / (inlink->w * inlink->h);
00104     if (pblack >= blackframe->bamount)
00105         av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pos:%"PRId64" pts:%"PRId64" t:%f "
00106                "type:%c last_keyframe:%d\n",
00107                blackframe->frame, pblack, picref->pos, picref->pts,
00108                picref->pts == AV_NOPTS_VALUE ? -1 : picref->pts * av_q2d(inlink->time_base),
00109                av_get_picture_type_char(picref->video->pict_type), blackframe->last_keyframe);
00110 
00111     blackframe->frame++;
00112     blackframe->nblack = 0;
00113     avfilter_end_frame(inlink->dst->outputs[0]);
00114 }
00115 
00116 AVFilter avfilter_vf_blackframe = {
00117     .name        = "blackframe",
00118     .description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
00119 
00120     .priv_size = sizeof(BlackFrameContext),
00121     .init      = init,
00122 
00123     .query_formats = query_formats,
00124 
00125     .inputs    = (const AVFilterPad[]) {{ .name       = "default",
00126                                     .type             = AVMEDIA_TYPE_VIDEO,
00127                                     .draw_slice       = draw_slice,
00128                                     .get_video_buffer = avfilter_null_get_video_buffer,
00129                                     .start_frame      = avfilter_null_start_frame,
00130                                     .end_frame        = end_frame, },
00131                                   { .name = NULL}},
00132 
00133     .outputs   = (const AVFilterPad[]) {{ .name       = "default",
00134                                     .type             = AVMEDIA_TYPE_VIDEO },
00135                                   { .name = NULL}},
00136 };
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