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FFmpeg/libavfilter/vsrc_nullsrc.c
Reinhard Tartler 737eb5976f Merge libavcore into libavutil
It is pretty hopeless that other considerable projects will adopt
libavutil alone in other projects. Projects that need small footprint
are better off with more specialized libraries such as gnulib or rather
just copy the necessary parts that they need. With this in mind, nobody
is helped by having libavutil and libavcore split. In order to ease
maintenance inside and around FFmpeg and to reduce confusion where to
put common code, avcore's functionality is merged (back) to avutil.

Signed-off-by: Reinhard Tartler <siretart@tauware.de>
2011-02-15 16:18:21 +01:00

130 lines
3.3 KiB
C

/*
* 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/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}
},
};