464 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			464 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2011 Stefano Sabatini
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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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| /**
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|  * @file
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|  * filter for selecting which frame passes in the filterchain
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|  */
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| 
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| #include "libavutil/eval.h"
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| #include "libavutil/fifo.h"
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| #include "libavutil/internal.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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| 
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| #if CONFIG_AVCODEC
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| #include "libavcodec/dsputil.h"
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| #endif
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| 
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| static const char *const var_names[] = {
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|     "TB",                ///< timebase
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| 
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|     "pts",               ///< original pts in the file of the frame
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|     "start_pts",         ///< first PTS in the stream, expressed in TB units
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|     "prev_pts",          ///< previous frame PTS
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|     "prev_selected_pts", ///< previous selected frame PTS
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| 
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|     "t",                 ///< first PTS in seconds
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|     "start_t",           ///< first PTS in the stream, expressed in seconds
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|     "prev_t",            ///< previous frame time
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|     "prev_selected_t",   ///< previously selected time
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| 
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|     "pict_type",         ///< the type of picture in the movie
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|     "I",
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|     "P",
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|     "B",
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|     "S",
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|     "SI",
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|     "SP",
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|     "BI",
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| 
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|     "interlace_type",    ///< the frame interlace type
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|     "PROGRESSIVE",
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|     "TOPFIRST",
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|     "BOTTOMFIRST",
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| 
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|     "n",                 ///< frame number (starting from zero)
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|     "selected_n",        ///< selected frame number (starting from zero)
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|     "prev_selected_n",   ///< number of the last selected frame
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| 
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|     "key",               ///< tell if the frame is a key frame
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|     "pos",               ///< original position in the file of the frame
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| 
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|     "scene",
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| 
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|     NULL
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| };
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| 
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| enum var_name {
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|     VAR_TB,
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| 
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|     VAR_PTS,
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|     VAR_START_PTS,
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|     VAR_PREV_PTS,
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|     VAR_PREV_SELECTED_PTS,
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| 
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|     VAR_T,
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|     VAR_START_T,
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|     VAR_PREV_T,
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|     VAR_PREV_SELECTED_T,
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| 
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|     VAR_PICT_TYPE,
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|     VAR_PICT_TYPE_I,
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|     VAR_PICT_TYPE_P,
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|     VAR_PICT_TYPE_B,
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|     VAR_PICT_TYPE_S,
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|     VAR_PICT_TYPE_SI,
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|     VAR_PICT_TYPE_SP,
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|     VAR_PICT_TYPE_BI,
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| 
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|     VAR_INTERLACE_TYPE,
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|     VAR_INTERLACE_TYPE_P,
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|     VAR_INTERLACE_TYPE_T,
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|     VAR_INTERLACE_TYPE_B,
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| 
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|     VAR_N,
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|     VAR_SELECTED_N,
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|     VAR_PREV_SELECTED_N,
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| 
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|     VAR_KEY,
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|     VAR_POS,
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| 
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|     VAR_SCENE,
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| 
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|     VAR_VARS_NB
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| };
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| 
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| #define FIFO_SIZE 8
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| 
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| typedef struct {
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|     AVExpr *expr;
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|     double var_values[VAR_VARS_NB];
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|     int do_scene_detect;            ///< 1 if the expression requires scene detection variables, 0 otherwise
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| #if CONFIG_AVCODEC
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|     AVCodecContext *avctx;          ///< codec context required for the DSPContext (scene detect only)
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|     DSPContext c;                   ///< context providing optimized SAD methods   (scene detect only)
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|     double prev_mafd;               ///< previous MAFD                             (scene detect only)
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| #endif
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|     AVFilterBufferRef *prev_picref; ///< previous frame                            (scene detect only)
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|     double select;
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|     int cache_frames;
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|     AVFifoBuffer *pending_frames; ///< FIFO buffer of video frames
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| } SelectContext;
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| 
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| static av_cold int init(AVFilterContext *ctx, const char *args)
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| {
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|     SelectContext *select = ctx->priv;
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|     int ret;
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| 
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|     if ((ret = av_expr_parse(&select->expr, args ? args : "1",
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|                              var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
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|         av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
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|         return ret;
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|     }
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| 
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|     select->pending_frames = av_fifo_alloc(FIFO_SIZE*sizeof(AVFilterBufferRef*));
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|     if (!select->pending_frames) {
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|         av_log(ctx, AV_LOG_ERROR, "Failed to allocate pending frames buffer.\n");
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|         return AVERROR(ENOMEM);
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|     }
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| 
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|     select->do_scene_detect = args && strstr(args, "scene");
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|     if (select->do_scene_detect && !CONFIG_AVCODEC) {
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|         av_log(ctx, AV_LOG_ERROR, "Scene detection is not available without libavcodec.\n");
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|         return AVERROR(EINVAL);
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|     }
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|     return 0;
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| }
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| 
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| #define INTERLACE_TYPE_P 0
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| #define INTERLACE_TYPE_T 1
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| #define INTERLACE_TYPE_B 2
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| 
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| static int config_input(AVFilterLink *inlink)
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| {
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|     SelectContext *select = inlink->dst->priv;
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| 
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|     select->var_values[VAR_N]          = 0.0;
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|     select->var_values[VAR_SELECTED_N] = 0.0;
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| 
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|     select->var_values[VAR_TB] = av_q2d(inlink->time_base);
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| 
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|     select->var_values[VAR_PREV_PTS]          = NAN;
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|     select->var_values[VAR_PREV_SELECTED_PTS] = NAN;
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|     select->var_values[VAR_PREV_SELECTED_T]   = NAN;
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|     select->var_values[VAR_START_PTS]         = NAN;
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|     select->var_values[VAR_START_T]           = NAN;
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| 
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|     select->var_values[VAR_PICT_TYPE_I]  = AV_PICTURE_TYPE_I;
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|     select->var_values[VAR_PICT_TYPE_P]  = AV_PICTURE_TYPE_P;
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|     select->var_values[VAR_PICT_TYPE_B]  = AV_PICTURE_TYPE_B;
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|     select->var_values[VAR_PICT_TYPE_SI] = AV_PICTURE_TYPE_SI;
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|     select->var_values[VAR_PICT_TYPE_SP] = AV_PICTURE_TYPE_SP;
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| 
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|     select->var_values[VAR_INTERLACE_TYPE_P] = INTERLACE_TYPE_P;
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|     select->var_values[VAR_INTERLACE_TYPE_T] = INTERLACE_TYPE_T;
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|     select->var_values[VAR_INTERLACE_TYPE_B] = INTERLACE_TYPE_B;
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| 
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|     if (CONFIG_AVCODEC && select->do_scene_detect) {
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|         select->avctx = avcodec_alloc_context3(NULL);
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|         if (!select->avctx)
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|             return AVERROR(ENOMEM);
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|         dsputil_init(&select->c, select->avctx);
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|     }
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|     return 0;
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| }
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| 
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| #if CONFIG_AVCODEC
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| static double get_scene_score(AVFilterContext *ctx, AVFilterBufferRef *picref)
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| {
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|     double ret = 0;
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|     SelectContext *select = ctx->priv;
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|     AVFilterBufferRef *prev_picref = select->prev_picref;
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| 
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|     if (prev_picref &&
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|         picref->video->h    == prev_picref->video->h &&
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|         picref->video->w    == prev_picref->video->w &&
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|         picref->linesize[0] == prev_picref->linesize[0]) {
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|         int x, y, nb_sad = 0;
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|         int64_t sad = 0;
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|         double mafd, diff;
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|         uint8_t *p1 =      picref->data[0];
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|         uint8_t *p2 = prev_picref->data[0];
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|         const int linesize = picref->linesize[0];
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| 
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|         for (y = 0; y < picref->video->h - 8; y += 8) {
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|             for (x = 0; x < picref->video->w*3 - 8; x += 8) {
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|                 sad += select->c.sad[1](select, p1 + x, p2 + x,
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|                                         linesize, 8);
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|                 nb_sad += 8 * 8;
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|             }
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|             p1 += 8 * linesize;
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|             p2 += 8 * linesize;
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|         }
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|         emms_c();
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|         mafd = nb_sad ? sad / nb_sad : 0;
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|         diff = fabs(mafd - select->prev_mafd);
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|         ret  = av_clipf(FFMIN(mafd, diff) / 100., 0, 1);
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|         select->prev_mafd = mafd;
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|         avfilter_unref_buffer(prev_picref);
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|     }
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|     select->prev_picref = avfilter_ref_buffer(picref, ~0);
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|     return ret;
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| }
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| #endif
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| 
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| #define D2TS(d)  (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
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| #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
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| 
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| static int select_frame(AVFilterContext *ctx, AVFilterBufferRef *picref)
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| {
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|     SelectContext *select = ctx->priv;
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|     AVFilterLink *inlink = ctx->inputs[0];
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|     double res;
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| 
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|     if (CONFIG_AVCODEC && select->do_scene_detect) {
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|         char buf[32];
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|         select->var_values[VAR_SCENE] = get_scene_score(ctx, picref);
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|         // TODO: document metadata
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|         snprintf(buf, sizeof(buf), "%f", select->var_values[VAR_SCENE]);
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|         av_dict_set(&picref->metadata, "lavfi.scene_score", buf, 0);
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|     }
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|     if (isnan(select->var_values[VAR_START_PTS]))
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|         select->var_values[VAR_START_PTS] = TS2D(picref->pts);
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|     if (isnan(select->var_values[VAR_START_T]))
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|         select->var_values[VAR_START_T] = TS2D(picref->pts) * av_q2d(inlink->time_base);
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| 
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|     select->var_values[VAR_PTS] = TS2D(picref->pts);
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|     select->var_values[VAR_T  ] = TS2D(picref->pts) * av_q2d(inlink->time_base);
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|     select->var_values[VAR_POS] = picref->pos == -1 ? NAN : picref->pos;
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|     select->var_values[VAR_PREV_PTS] = TS2D(picref ->pts);
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| 
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|     select->var_values[VAR_INTERLACE_TYPE] =
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|         !picref->video->interlaced     ? INTERLACE_TYPE_P :
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|         picref->video->top_field_first ? INTERLACE_TYPE_T : INTERLACE_TYPE_B;
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|     select->var_values[VAR_PICT_TYPE] = picref->video->pict_type;
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| 
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|     res = av_expr_eval(select->expr, select->var_values, NULL);
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|     av_log(inlink->dst, AV_LOG_DEBUG,
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|            "n:%d pts:%d t:%f pos:%d interlace_type:%c key:%d pict_type:%c "
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|            "-> select:%f\n",
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|            (int)select->var_values[VAR_N],
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|            (int)select->var_values[VAR_PTS],
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|            select->var_values[VAR_T],
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|            (int)select->var_values[VAR_POS],
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|            select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_P ? 'P' :
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|            select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_T ? 'T' :
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|            select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_B ? 'B' : '?',
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|            (int)select->var_values[VAR_KEY],
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|            av_get_picture_type_char(select->var_values[VAR_PICT_TYPE]),
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|            res);
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| 
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|     select->var_values[VAR_N] += 1.0;
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| 
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|     if (res) {
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|         select->var_values[VAR_PREV_SELECTED_N]   = select->var_values[VAR_N];
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|         select->var_values[VAR_PREV_SELECTED_PTS] = select->var_values[VAR_PTS];
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|         select->var_values[VAR_PREV_SELECTED_T]   = select->var_values[VAR_T];
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|         select->var_values[VAR_SELECTED_N] += 1.0;
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|     }
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|     return res;
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| }
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| 
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| static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
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| {
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|     SelectContext *select = inlink->dst->priv;
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| 
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|     select->select = select_frame(inlink->dst, picref);
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|     if (select->select) {
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|         AVFilterBufferRef *buf_out;
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|         /* frame was requested through poll_frame */
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|         if (select->cache_frames) {
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|             if (!av_fifo_space(select->pending_frames))
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|                 av_log(inlink->dst, AV_LOG_ERROR,
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|                        "Buffering limit reached, cannot cache more frames\n");
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|             else
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|                 av_fifo_generic_write(select->pending_frames, &picref,
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|                                       sizeof(picref), NULL);
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|             return 0;
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|         }
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|         buf_out = avfilter_ref_buffer(picref, ~0);
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|         if (!buf_out)
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|             return AVERROR(ENOMEM);
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|         return ff_start_frame(inlink->dst->outputs[0], buf_out);
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|     }
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| 
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|     return 0;
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| }
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| 
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| static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
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| {
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|     SelectContext *select = inlink->dst->priv;
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| 
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|     if (select->select && !select->cache_frames)
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|         return ff_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
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|     return 0;
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| }
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| 
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| static int end_frame(AVFilterLink *inlink)
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| {
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|     SelectContext *select = inlink->dst->priv;
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| 
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|     if (select->select) {
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|         if (select->cache_frames)
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|             return 0;
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|         return ff_end_frame(inlink->dst->outputs[0]);
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|     }
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|     return 0;
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| }
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| 
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| static int request_frame(AVFilterLink *outlink)
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| {
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|     AVFilterContext *ctx = outlink->src;
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|     SelectContext *select = ctx->priv;
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|     AVFilterLink *inlink = outlink->src->inputs[0];
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|     select->select = 0;
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| 
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|     if (av_fifo_size(select->pending_frames)) {
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|         AVFilterBufferRef *picref;
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|         int ret;
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| 
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|         av_fifo_generic_read(select->pending_frames, &picref, sizeof(picref), NULL);
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|         if ((ret = ff_start_frame(outlink, picref)) < 0 ||
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|             (ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 ||
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|             (ret = ff_end_frame(outlink)) < 0);
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| 
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|         return ret;
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|     }
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| 
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|     while (!select->select) {
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|         int ret = ff_request_frame(inlink);
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|         if (ret < 0)
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|             return ret;
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|     }
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| 
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|     return 0;
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| }
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| 
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| static int poll_frame(AVFilterLink *outlink)
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| {
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|     SelectContext *select = outlink->src->priv;
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|     AVFilterLink *inlink = outlink->src->inputs[0];
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|     int count, ret;
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| 
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|     if (!av_fifo_size(select->pending_frames)) {
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|         if ((count = ff_poll_frame(inlink)) <= 0)
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|             return count;
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|         /* request frame from input, and apply select condition to it */
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|         select->cache_frames = 1;
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|         while (count-- && av_fifo_space(select->pending_frames)) {
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|             ret = ff_request_frame(inlink);
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|             if (ret < 0)
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|                 break;
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|         }
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|         select->cache_frames = 0;
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|     }
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| 
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|     return av_fifo_size(select->pending_frames)/sizeof(AVFilterBufferRef *);
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| }
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| 
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| static av_cold void uninit(AVFilterContext *ctx)
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| {
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|     SelectContext *select = ctx->priv;
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|     AVFilterBufferRef *picref;
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| 
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|     av_expr_free(select->expr);
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|     select->expr = NULL;
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| 
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|     while (select->pending_frames &&
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|            av_fifo_generic_read(select->pending_frames, &picref, sizeof(picref), NULL) == sizeof(picref))
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|         avfilter_unref_buffer(picref);
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|     av_fifo_free(select->pending_frames);
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|     select->pending_frames = NULL;
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| 
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|     if (select->do_scene_detect) {
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|         avfilter_unref_bufferp(&select->prev_picref);
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|         if (select->avctx) {
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|             avcodec_close(select->avctx);
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|             av_freep(&select->avctx);
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|         }
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|     }
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| }
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| 
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| static int query_formats(AVFilterContext *ctx)
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| {
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|     SelectContext *select = ctx->priv;
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| 
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|     if (!select->do_scene_detect) {
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|         return ff_default_query_formats(ctx);
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|     } else {
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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_NONE
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|         };
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|         ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
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|     }
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|     return 0;
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| }
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| 
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| static const AVFilterPad avfilter_vf_select_inputs[] = {
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|     {
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|         .name             = "default",
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|         .type             = AVMEDIA_TYPE_VIDEO,
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|         .get_video_buffer = ff_null_get_video_buffer,
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|         .min_perms        = AV_PERM_PRESERVE,
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|         .config_props     = config_input,
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|         .start_frame      = start_frame,
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|         .draw_slice       = draw_slice,
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|         .end_frame        = end_frame
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|     },
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|     { NULL }
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| };
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| 
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| static const AVFilterPad avfilter_vf_select_outputs[] = {
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|     {
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|         .name          = "default",
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|         .type          = AVMEDIA_TYPE_VIDEO,
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|         .poll_frame    = poll_frame,
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|         .request_frame = request_frame,
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|     },
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|     { NULL }
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| };
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| 
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| AVFilter avfilter_vf_select = {
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|     .name      = "select",
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|     .description = NULL_IF_CONFIG_SMALL("Select frames to pass in output."),
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|     .init      = init,
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|     .uninit    = uninit,
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|     .query_formats = query_formats,
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| 
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|     .priv_size = sizeof(SelectContext),
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| 
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|     .inputs    = avfilter_vf_select_inputs,
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|     .outputs   = avfilter_vf_select_outputs,
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| };
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