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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 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 "libavutil/mathematics.h"
00031 #include "avfilter.h"
00032 
00033 static const char *var_names[] = {
00034     "E",           
00035     "INTERLACED",  
00036     "N",           
00037     "PHI",         
00038     "PI",          
00039     "POS",         
00040     "PREV_INPTS",  
00041     "PREV_OUTPTS", 
00042     "PTS",         
00043     "STARTPTS",   
00044     "TB",          
00045     NULL
00046 };
00047 
00048 enum var_name {
00049     VAR_E,
00050     VAR_INTERLACED,
00051     VAR_N,
00052     VAR_PHI,
00053     VAR_PI,
00054     VAR_POS,
00055     VAR_PREV_INPTS,
00056     VAR_PREV_OUTPTS,
00057     VAR_PTS,
00058     VAR_STARTPTS,
00059     VAR_TB,
00060     VAR_VARS_NB
00061 };
00062 
00063 typedef struct {
00064     AVExpr *expr;
00065     double var_values[VAR_VARS_NB];
00066 } SetPTSContext;
00067 
00068 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00069 {
00070     SetPTSContext *setpts = ctx->priv;
00071     int ret;
00072 
00073     if ((ret = av_expr_parse(&setpts->expr, args ? args : "PTS",
00074                              var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
00075         av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
00076         return ret;
00077     }
00078 
00079     setpts->var_values[VAR_E          ] = M_E;
00080     setpts->var_values[VAR_N          ] = 0.0;
00081     setpts->var_values[VAR_PHI        ] = M_PHI;
00082     setpts->var_values[VAR_PI         ] = M_PI;
00083     setpts->var_values[VAR_PREV_INPTS ] = NAN;
00084     setpts->var_values[VAR_PREV_OUTPTS] = NAN;
00085     setpts->var_values[VAR_STARTPTS   ] = NAN;
00086     return 0;
00087 }
00088 
00089 static int config_input(AVFilterLink *inlink)
00090 {
00091     SetPTSContext *setpts = inlink->dst->priv;
00092 
00093     setpts->var_values[VAR_TB] = av_q2d(inlink->time_base);
00094 
00095     av_log(inlink->src, AV_LOG_INFO, "TB:%f\n", setpts->var_values[VAR_TB]);
00096     return 0;
00097 }
00098 
00099 #define D2TS(d)  (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
00100 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
00101 
00102 static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
00103 {
00104     SetPTSContext *setpts = inlink->dst->priv;
00105     double d;
00106     AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
00107 
00108     if (isnan(setpts->var_values[VAR_STARTPTS]))
00109         setpts->var_values[VAR_STARTPTS] = TS2D(inpicref->pts);
00110 
00111     setpts->var_values[VAR_INTERLACED] = inpicref->video->interlaced;
00112     setpts->var_values[VAR_PTS       ] = TS2D(inpicref->pts);
00113     setpts->var_values[VAR_POS       ] = inpicref->pos == -1 ? NAN : inpicref->pos;
00114 
00115     d = av_expr_eval(setpts->expr, setpts->var_values, NULL);
00116     outpicref->pts = D2TS(d);
00117 
00118 #ifdef DEBUG
00119     av_log(inlink->dst, AV_LOG_DEBUG,
00120            "n:%"PRId64" interlaced:%d pos:%"PRId64" pts:%"PRId64" t:%f -> pts:%"PRId64" t:%f\n",
00121            (int64_t)setpts->var_values[VAR_N],
00122            (int)setpts->var_values[VAR_INTERLACED],
00123            inpicref ->pos,
00124            inpicref ->pts, inpicref ->pts * av_q2d(inlink->time_base),
00125            outpicref->pts, outpicref->pts * av_q2d(inlink->time_base));
00126 #endif
00127 
00128     setpts->var_values[VAR_N] += 1.0;
00129     setpts->var_values[VAR_PREV_INPTS ] = TS2D(inpicref ->pts);
00130     setpts->var_values[VAR_PREV_OUTPTS] = TS2D(outpicref->pts);
00131     avfilter_start_frame(inlink->dst->outputs[0], outpicref);
00132 }
00133 
00134 static av_cold void uninit(AVFilterContext *ctx)
00135 {
00136     SetPTSContext *setpts = ctx->priv;
00137     av_expr_free(setpts->expr);
00138     setpts->expr = NULL;
00139 }
00140 
00141 AVFilter avfilter_vf_setpts = {
00142     .name      = "setpts",
00143     .description = NULL_IF_CONFIG_SMALL("Set PTS for the output video frame."),
00144     .init      = init,
00145     .uninit    = uninit,
00146 
00147     .priv_size = sizeof(SetPTSContext),
00148 
00149     .inputs    = (AVFilterPad[]) {{ .name             = "default",
00150                                     .type             = AVMEDIA_TYPE_VIDEO,
00151                                     .get_video_buffer = avfilter_null_get_video_buffer,
00152                                     .config_props     = config_input,
00153                                     .start_frame      = start_frame, },
00154                                   { .name = NULL }},
00155     .outputs   = (AVFilterPad[]) {{ .name             = "default",
00156                                     .type             = AVMEDIA_TYPE_VIDEO, },
00157                                   { .name = NULL}},
00158 };
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