Libav 0.7.1
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 Libav.
00006  *
00007  * Libav 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  * Libav 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 Libav; 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 "avfilter.h"
00031 
00032 static const char *var_names[] = {
00033     "E",           
00034     "INTERLACED",  
00035     "N",           
00036     "PHI",         
00037     "PI",          
00038     "POS",         
00039     "PREV_INPTS",  
00040     "PREV_OUTPTS", 
00041     "PTS",         
00042     "STARTPTS",   
00043     "TB",          
00044     NULL
00045 };
00046 
00047 enum var_name {
00048     VAR_E,
00049     VAR_INTERLACED,
00050     VAR_N,
00051     VAR_PHI,
00052     VAR_PI,
00053     VAR_POS,
00054     VAR_PREV_INPTS,
00055     VAR_PREV_OUTPTS,
00056     VAR_PTS,
00057     VAR_STARTPTS,
00058     VAR_TB,
00059     VAR_VARS_NB
00060 };
00061 
00062 typedef struct {
00063     AVExpr *expr;
00064     double var_values[VAR_VARS_NB];
00065 } SetPTSContext;
00066 
00067 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00068 {
00069     SetPTSContext *setpts = ctx->priv;
00070     int ret;
00071 
00072     if ((ret = av_expr_parse(&setpts->expr, args ? args : "PTS",
00073                              var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
00074         av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
00075         return ret;
00076     }
00077 
00078     setpts->var_values[VAR_E          ] = M_E;
00079     setpts->var_values[VAR_N          ] = 0.0;
00080     setpts->var_values[VAR_PHI        ] = M_PHI;
00081     setpts->var_values[VAR_PI         ] = M_PI;
00082     setpts->var_values[VAR_PREV_INPTS ] = NAN;
00083     setpts->var_values[VAR_PREV_OUTPTS] = NAN;
00084     setpts->var_values[VAR_STARTPTS   ] = NAN;
00085     return 0;
00086 }
00087 
00088 static int config_input(AVFilterLink *inlink)
00089 {
00090     SetPTSContext *setpts = inlink->dst->priv;
00091 
00092     setpts->var_values[VAR_TB] = av_q2d(inlink->time_base);
00093 
00094     av_log(inlink->src, AV_LOG_INFO, "TB:%f\n", setpts->var_values[VAR_TB]);
00095     return 0;
00096 }
00097 
00098 #define D2TS(d)  (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
00099 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
00100 
00101 static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
00102 {
00103     SetPTSContext *setpts = inlink->dst->priv;
00104     double d;
00105     AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
00106 
00107     if (isnan(setpts->var_values[VAR_STARTPTS]))
00108         setpts->var_values[VAR_STARTPTS] = TS2D(inpicref->pts);
00109 
00110     setpts->var_values[VAR_INTERLACED] = inpicref->video->interlaced;
00111     setpts->var_values[VAR_PTS       ] = TS2D(inpicref->pts);
00112     setpts->var_values[VAR_POS       ] = inpicref->pos == -1 ? NAN : inpicref->pos;
00113 
00114     d = av_expr_eval(setpts->expr, setpts->var_values, NULL);
00115     outpicref->pts = D2TS(d);
00116 
00117 #ifdef DEBUG
00118     av_log(inlink->dst, AV_LOG_DEBUG,
00119            "n:%"PRId64" interlaced:%d pos:%"PRId64" pts:%"PRId64" t:%f -> pts:%"PRId64" t:%f\n",
00120            (int64_t)setpts->var_values[VAR_N],
00121            (int)setpts->var_values[VAR_INTERLACED],
00122            inpicref ->pos,
00123            inpicref ->pts, inpicref ->pts * av_q2d(inlink->time_base),
00124            outpicref->pts, outpicref->pts * av_q2d(inlink->time_base));
00125 #endif
00126 
00127     setpts->var_values[VAR_N] += 1.0;
00128     setpts->var_values[VAR_PREV_INPTS ] = TS2D(inpicref ->pts);
00129     setpts->var_values[VAR_PREV_OUTPTS] = TS2D(outpicref->pts);
00130     avfilter_start_frame(inlink->dst->outputs[0], outpicref);
00131 }
00132 
00133 static av_cold void uninit(AVFilterContext *ctx)
00134 {
00135     SetPTSContext *setpts = ctx->priv;
00136     av_expr_free(setpts->expr);
00137     setpts->expr = NULL;
00138 }
00139 
00140 AVFilter avfilter_vf_setpts = {
00141     .name      = "setpts",
00142     .description = NULL_IF_CONFIG_SMALL("Set PTS for the output video frame."),
00143     .init      = init,
00144     .uninit    = uninit,
00145 
00146     .priv_size = sizeof(SetPTSContext),
00147 
00148     .inputs    = (AVFilterPad[]) {{ .name             = "default",
00149                                     .type             = AVMEDIA_TYPE_VIDEO,
00150                                     .get_video_buffer = avfilter_null_get_video_buffer,
00151                                     .config_props     = config_input,
00152                                     .start_frame      = start_frame, },
00153                                   { .name = NULL }},
00154     .outputs   = (AVFilterPad[]) {{ .name             = "default",
00155                                     .type             = AVMEDIA_TYPE_VIDEO, },
00156                                   { .name = NULL}},
00157 };