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libavfilter/vf_setpts.c

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00001 /*
00002  * Copyright (c) 2010 Stefano Sabatini
00003  * Copyright (c) 2008 Victor Paesa
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00027 /* #define DEBUG */
00028 
00029 #include "libavutil/eval.h"
00030 #include "libavutil/mathematics.h"
00031 #include "avfilter.h"
00032 
00033 static const char * const var_names[] = {
00034     "INTERLACED",  
00035     "N",           
00036     "POS",         
00037     "PREV_INPTS",  
00038     "PREV_OUTPTS", 
00039     "PTS",         
00040     "STARTPTS",   
00041     "TB",          
00042     NULL
00043 };
00044 
00045 enum var_name {
00046     VAR_INTERLACED,
00047     VAR_N,
00048     VAR_POS,
00049     VAR_PREV_INPTS,
00050     VAR_PREV_OUTPTS,
00051     VAR_PTS,
00052     VAR_STARTPTS,
00053     VAR_TB,
00054     VAR_VARS_NB
00055 };
00056 
00057 typedef struct {
00058     AVExpr *expr;
00059     double var_values[VAR_VARS_NB];
00060 } SetPTSContext;
00061 
00062 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00063 {
00064     SetPTSContext *setpts = ctx->priv;
00065     int ret;
00066 
00067     if ((ret = av_expr_parse(&setpts->expr, args ? args : "PTS",
00068                              var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
00069         av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
00070         return ret;
00071     }
00072 
00073     setpts->var_values[VAR_N          ] = 0.0;
00074     setpts->var_values[VAR_PREV_INPTS ] = NAN;
00075     setpts->var_values[VAR_PREV_OUTPTS] = NAN;
00076     setpts->var_values[VAR_STARTPTS   ] = NAN;
00077     return 0;
00078 }
00079 
00080 static int config_input(AVFilterLink *inlink)
00081 {
00082     SetPTSContext *setpts = inlink->dst->priv;
00083 
00084     setpts->var_values[VAR_TB] = av_q2d(inlink->time_base);
00085 
00086     av_log(inlink->src, AV_LOG_INFO, "TB:%f\n", setpts->var_values[VAR_TB]);
00087     return 0;
00088 }
00089 
00090 #define D2TS(d)  (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
00091 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
00092 
00093 static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
00094 {
00095     SetPTSContext *setpts = inlink->dst->priv;
00096     double d;
00097     AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
00098 
00099     if (isnan(setpts->var_values[VAR_STARTPTS]))
00100         setpts->var_values[VAR_STARTPTS] = TS2D(inpicref->pts);
00101 
00102     setpts->var_values[VAR_INTERLACED] = inpicref->video->interlaced;
00103     setpts->var_values[VAR_PTS       ] = TS2D(inpicref->pts);
00104     setpts->var_values[VAR_POS       ] = inpicref->pos == -1 ? NAN : inpicref->pos;
00105 
00106     d = av_expr_eval(setpts->expr, setpts->var_values, NULL);
00107     outpicref->pts = D2TS(d);
00108 
00109 #ifdef DEBUG
00110     av_log(inlink->dst, AV_LOG_DEBUG,
00111            "n:%"PRId64" interlaced:%d pos:%"PRId64" pts:%"PRId64" t:%f -> pts:%"PRId64" t:%f\n",
00112            (int64_t)setpts->var_values[VAR_N],
00113            (int)setpts->var_values[VAR_INTERLACED],
00114            inpicref ->pos,
00115            inpicref ->pts, inpicref ->pts * av_q2d(inlink->time_base),
00116            outpicref->pts, outpicref->pts * av_q2d(inlink->time_base));
00117 #endif
00118 
00119     setpts->var_values[VAR_N] += 1.0;
00120     setpts->var_values[VAR_PREV_INPTS ] = TS2D(inpicref ->pts);
00121     setpts->var_values[VAR_PREV_OUTPTS] = TS2D(outpicref->pts);
00122     avfilter_start_frame(inlink->dst->outputs[0], outpicref);
00123 }
00124 
00125 static av_cold void uninit(AVFilterContext *ctx)
00126 {
00127     SetPTSContext *setpts = ctx->priv;
00128     av_expr_free(setpts->expr);
00129     setpts->expr = NULL;
00130 }
00131 
00132 AVFilter avfilter_vf_setpts = {
00133     .name      = "setpts",
00134     .description = NULL_IF_CONFIG_SMALL("Set PTS for the output video frame."),
00135     .init      = init,
00136     .uninit    = uninit,
00137 
00138     .priv_size = sizeof(SetPTSContext),
00139 
00140     .inputs    = (const AVFilterPad[]) {{ .name       = "default",
00141                                     .type             = AVMEDIA_TYPE_VIDEO,
00142                                     .get_video_buffer = avfilter_null_get_video_buffer,
00143                                     .config_props     = config_input,
00144                                     .start_frame      = start_frame, },
00145                                   { .name = NULL }},
00146     .outputs   = (const AVFilterPad[]) {{ .name       = "default",
00147                                     .type             = AVMEDIA_TYPE_VIDEO, },
00148                                   { .name = NULL}},
00149 };
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