| /* |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| /** |
| * @file |
| * null video source |
| */ |
| |
| #include "libavutil/avstring.h" |
| #include "libavutil/eval.h" |
| #include "libavutil/mathematics.h" |
| #include "libavutil/parseutils.h" |
| #include "avfilter.h" |
| |
| static const char *var_names[] = { |
| "E", |
| "PHI", |
| "PI", |
| "AVTB", /* default timebase 1/AV_TIME_BASE */ |
| NULL |
| }; |
| |
| enum var_name { |
| VAR_E, |
| VAR_PHI, |
| VAR_PI, |
| VAR_AVTB, |
| VAR_VARS_NB |
| }; |
| |
| typedef struct { |
| int w, h; |
| char tb_expr[256]; |
| double var_values[VAR_VARS_NB]; |
| } NullContext; |
| |
| static int init(AVFilterContext *ctx, const char *args, void *opaque) |
| { |
| NullContext *priv = ctx->priv; |
| |
| priv->w = 352; |
| priv->h = 288; |
| av_strlcpy(priv->tb_expr, "AVTB", sizeof(priv->tb_expr)); |
| |
| if (args) |
| sscanf(args, "%d:%d:%255[^:]", &priv->w, &priv->h, priv->tb_expr); |
| |
| if (priv->w <= 0 || priv->h <= 0) { |
| av_log(ctx, AV_LOG_ERROR, "Non-positive size values are not acceptable.\n"); |
| return AVERROR(EINVAL); |
| } |
| |
| return 0; |
| } |
| |
| static int config_props(AVFilterLink *outlink) |
| { |
| AVFilterContext *ctx = outlink->src; |
| NullContext *priv = ctx->priv; |
| AVRational tb; |
| int ret; |
| double res; |
| |
| priv->var_values[VAR_E] = M_E; |
| priv->var_values[VAR_PHI] = M_PHI; |
| priv->var_values[VAR_PI] = M_PI; |
| priv->var_values[VAR_AVTB] = av_q2d(AV_TIME_BASE_Q); |
| |
| if ((ret = av_expr_parse_and_eval(&res, priv->tb_expr, var_names, priv->var_values, |
| NULL, NULL, NULL, NULL, NULL, 0, NULL)) < 0) { |
| av_log(ctx, AV_LOG_ERROR, "Invalid expression '%s' for timebase.\n", priv->tb_expr); |
| return ret; |
| } |
| tb = av_d2q(res, INT_MAX); |
| if (tb.num <= 0 || tb.den <= 0) { |
| av_log(ctx, AV_LOG_ERROR, |
| "Invalid non-positive value for the timebase %d/%d.\n", |
| tb.num, tb.den); |
| return AVERROR(EINVAL); |
| } |
| |
| outlink->w = priv->w; |
| outlink->h = priv->h; |
| outlink->time_base = tb; |
| |
| av_log(outlink->src, AV_LOG_INFO, "w:%d h:%d tb:%d/%d\n", priv->w, priv->h, |
| tb.num, tb.den); |
| |
| return 0; |
| } |
| |
| static int request_frame(AVFilterLink *link) |
| { |
| return -1; |
| } |
| |
| AVFilter avfilter_vsrc_nullsrc = { |
| .name = "nullsrc", |
| .description = NULL_IF_CONFIG_SMALL("Null video source, never return images."), |
| |
| .init = init, |
| .priv_size = sizeof(NullContext), |
| |
| .inputs = (AVFilterPad[]) {{ .name = NULL}}, |
| |
| .outputs = (AVFilterPad[]) { |
| { |
| .name = "default", |
| .type = AVMEDIA_TYPE_VIDEO, |
| .config_props = config_props, |
| .request_frame = request_frame, |
| }, |
| { .name = NULL} |
| }, |
| }; |