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libavfilter/vf_settb.c

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00001 /*
00002  * Copyright (c) 2010 Stefano Sabatini
00003  *
00004  * This file is part of FFmpeg.
00005  *
00006  * FFmpeg is free software; you can redistribute it and/or
00007  * modify it under the terms of the GNU Lesser General Public
00008  * License as published by the Free Software Foundation; either
00009  * version 2.1 of the License, or (at your option) any later version.
00010  *
00011  * FFmpeg is distributed in the hope that it will be useful,
00012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014  * Lesser General Public License for more details.
00015  *
00016  * You should have received a copy of the GNU Lesser General Public
00017  * License along with FFmpeg; if not, write to the Free Software
00018  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00019  */
00020 
00026 #include "libavutil/avstring.h"
00027 #include "libavutil/eval.h"
00028 #include "libavutil/rational.h"
00029 #include "avfilter.h"
00030 #include "internal.h"
00031 
00032 static const char *var_names[] = {
00033     "E",
00034     "PHI",
00035     "PI",
00036     "AVTB",   /* default timebase 1/AV_TIME_BASE */
00037     "intb",   /* input timebase */
00038     NULL
00039 };
00040 
00041 enum var_name {
00042     VAR_E,
00043     VAR_PHI,
00044     VAR_PI,
00045     VAR_AVTB,
00046     VAR_INTB,
00047     VAR_VARS_NB
00048 };
00049 
00050 typedef struct {
00051     char tb_expr[256];
00052     double var_values[VAR_VARS_NB];
00053 } SetTBContext;
00054 
00055 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00056 {
00057     SetTBContext *settb = ctx->priv;
00058     av_strlcpy(settb->tb_expr, "intb", sizeof(settb->tb_expr));
00059 
00060     if (args)
00061         sscanf(args, "%255[^:]", settb->tb_expr);
00062 
00063     return 0;
00064 }
00065 
00066 static int config_output_props(AVFilterLink *outlink)
00067 {
00068     AVFilterContext *ctx = outlink->src;
00069     SetTBContext *settb = ctx->priv;
00070     AVFilterLink *inlink = ctx->inputs[0];
00071     AVRational time_base;
00072     int ret;
00073     double res;
00074 
00075     settb->var_values[VAR_E]    = M_E;
00076     settb->var_values[VAR_PHI]  = M_PHI;
00077     settb->var_values[VAR_PI]   = M_PI;
00078     settb->var_values[VAR_AVTB] = av_q2d(AV_TIME_BASE_Q);
00079     settb->var_values[VAR_INTB] = av_q2d(inlink->time_base);
00080 
00081     outlink->w = inlink->w;
00082     outlink->h = inlink->h;
00083 
00084     if ((ret = av_expr_parse_and_eval(&res, settb->tb_expr, var_names, settb->var_values,
00085                                       NULL, NULL, NULL, NULL, NULL, 0, NULL)) < 0) {
00086         av_log(ctx, AV_LOG_ERROR, "Invalid expression '%s' for timebase.\n", settb->tb_expr);
00087         return ret;
00088     }
00089     time_base = av_d2q(res, INT_MAX);
00090     if (time_base.num <= 0 || time_base.den <= 0) {
00091         av_log(ctx, AV_LOG_ERROR,
00092                "Invalid non-positive values for the timebase num:%d or den:%d.\n",
00093                time_base.num, time_base.den);
00094         return AVERROR(EINVAL);
00095     }
00096 
00097     outlink->time_base = time_base;
00098     av_log(outlink->src, AV_LOG_INFO, "tb:%d/%d -> tb:%d/%d\n",
00099            inlink ->time_base.num, inlink ->time_base.den,
00100            outlink->time_base.num, outlink->time_base.den);
00101 
00102     return 0;
00103 }
00104 
00105 static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
00106 {
00107     AVFilterContext *ctx = inlink->dst;
00108     AVFilterLink *outlink = ctx->outputs[0];
00109     AVFilterBufferRef *picref2 = picref;
00110 
00111     if (av_cmp_q(inlink->time_base, outlink->time_base)) {
00112         picref2 = avfilter_ref_buffer(picref, ~0);
00113         picref2->pts = av_rescale_q(picref->pts, inlink->time_base, outlink->time_base);
00114         av_log(ctx, AV_LOG_DEBUG, "tb:%d/%d pts:%"PRId64" -> tb:%d/%d pts:%"PRId64"\n",
00115                inlink ->time_base.num, inlink ->time_base.den, picref ->pts,
00116                outlink->time_base.num, outlink->time_base.den, picref2->pts);
00117         avfilter_unref_buffer(picref);
00118     }
00119 
00120     avfilter_start_frame(outlink, picref2);
00121 }
00122 
00123 AVFilter avfilter_vf_settb = {
00124     .name      = "settb",
00125     .description = NULL_IF_CONFIG_SMALL("Set timebase for the output link."),
00126     .init      = init,
00127 
00128     .priv_size = sizeof(SetTBContext),
00129 
00130     .inputs    = (AVFilterPad[]) {{ .name             = "default",
00131                                     .type             = AVMEDIA_TYPE_VIDEO,
00132                                     .get_video_buffer = avfilter_null_get_video_buffer,
00133                                     .start_frame      = start_frame,
00134                                     .end_frame        = avfilter_null_end_frame },
00135                                   { .name = NULL }},
00136 
00137     .outputs   = (AVFilterPad[]) {{ .name            = "default",
00138                                     .type            = AVMEDIA_TYPE_VIDEO,
00139                                     .config_props    = config_output_props, },
00140                                   { .name = NULL}},
00141 };

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