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vf_select: switch to an AVOptions-based system.

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This commit is contained in:
Anton Khirnov 2013-02-25 21:21:29 +01:00
parent 40c885c589
commit 95f1f56a21
2 changed files with 34 additions and 8 deletions
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19
doc/filters.texi
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@ -1742,9 +1742,16 @@ scale=w='min(500\, iw*3/2):h=-1'
@section select
Select frames to pass in output.
It accepts in input an expression, which is evaluated for each input
frame. If the expression is evaluated to a non-zero value, the frame
is selected and passed to the output, otherwise it is discarded.
This filter accepts the following options:
@table @option
@item expr
An expression, which is evaluated for each input frame. If the expression is
evaluated to a non-zero value, the frame is selected and passed to the output,
otherwise it is discarded.
@end table
The expression can contain the following constants:
@ -1831,13 +1838,13 @@ Some examples follow:
select
# the above is the same as:
select=1
select=expr=1
# skip all frames:
select=0
select=expr=0
# select only I-frames
select='eq(pict_type\,I)'
select='expr=eq(pict_type\,I)'
# select one frame every 100
select='not(mod(n\,100))'

23
libavfilter/vf_select.c
View File

@ -27,6 +27,7 @@
#include "libavutil/fifo.h"
#include "libavutil/internal.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "avfilter.h"
#include "internal.h"
#include "video.h"
@ -115,6 +116,8 @@ enum var_name {
#define FIFO_SIZE 8
typedef struct {
const AVClass *class;
char *expr_str;
AVExpr *expr;
double var_values[VAR_VARS_NB];
double select;
@ -127,9 +130,10 @@ static av_cold int init(AVFilterContext *ctx, const char *args)
SelectContext *select = ctx->priv;
int ret;
if ((ret = av_expr_parse(&select->expr, args ? args : "1",
if ((ret = av_expr_parse(&select->expr, select->expr_str,
var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n",
select->expr_str);
return ret;
}
@ -309,6 +313,20 @@ static av_cold void uninit(AVFilterContext *ctx)
select->pending_frames = NULL;
}
#define OFFSET(x) offsetof(SelectContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM
static const AVOption options[] = {
{ "expr", "An expression to use for selecting frames", OFFSET(expr_str), AV_OPT_TYPE_STRING, { .str = "1" }, .flags = FLAGS },
{ NULL },
};
static const AVClass select_class = {
.class_name = "select",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
static const AVFilterPad avfilter_vf_select_inputs[] = {
{
.name = "default",
@ -337,6 +355,7 @@ AVFilter avfilter_vf_select = {
.uninit = uninit,
.priv_size = sizeof(SelectContext),
.priv_class = &select_class,
.inputs = avfilter_vf_select_inputs,
.outputs = avfilter_vf_select_outputs,