Libav 0.7.1
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00001 /* 00002 * Copyright (c) 2010 Stefano Sabatini 00003 * 00004 * This file is part of Libav. 00005 * 00006 * Libav 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 * Libav 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 Libav; 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 };