In order to display the output lines, you need to set the loglevel at
least to the AV_LOG_INFO value.
-The filter accepts the syntax:
-@example
-blackframe[=@var{amount}:[@var{threshold}]]
-@end example
+The filter accepts parameters as a list of @var{key}=@var{value}
+pairs, separated by ":". If the key of the first options is omitted,
+the arguments are interpreted according to the syntax
+blackframe[=@var{amount}[:@var{threshold}]].
-@var{amount} is the percentage of the pixels that have to be below the
-threshold, and defaults to 98.
+A description of the accepted options follows.
+
+@table @option
+@item amount
+Set the percentage of pixels that have to be below the
+threshold to enable black detection. Default value is 98.
-@var{threshold} is the threshold below which a pixel value is
-considered black, and defaults to 32.
+@item threshold
+Set the threshold below which a pixel value is considered
+black. Default value is 32.
+@end table
@section blend
#include <inttypes.h>
#include "libavutil/internal.h"
+#include "libavutil/opt.h"
#include "avfilter.h"
#include "internal.h"
#include "formats.h"
#include "video.h"
typedef struct {
+ const AVClass *class;
unsigned int bamount; ///< black amount
unsigned int bthresh; ///< black threshold
unsigned int frame; ///< frame number
unsigned int last_keyframe; ///< frame number of the last received key-frame
} BlackFrameContext;
+#define OFFSET(x) offsetof(BlackFrameContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption blackframe_options[] = {
+ { "amount", "set least percentual amount of pixels below the black threshold enabling black detection", OFFSET(bamount), AV_OPT_TYPE_INT, {.i64=98}, 0, 100, FLAGS },
+ { "thresh", "set threshold below which a pixel value is considered black", OFFSET(bthresh), AV_OPT_TYPE_INT, {.i64=32}, 0, 255, FLAGS },
+ { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(blackframe);
+
static int query_formats(AVFilterContext *ctx)
{
static const enum AVPixelFormat pix_fmts[] = {
static av_cold int init(AVFilterContext *ctx, const char *args)
{
BlackFrameContext *blackframe = ctx->priv;
+ static const char *shorthand[] = { "amount", "thresh", NULL };
+ int ret;
- blackframe->bamount = 98;
- blackframe->bthresh = 32;
- blackframe->nblack = 0;
- blackframe->frame = 0;
- blackframe->last_keyframe = 0;
+ blackframe->class = &blackframe_class;
+ av_opt_set_defaults(blackframe);
- if (args)
- sscanf(args, "%u:%u", &blackframe->bamount, &blackframe->bthresh);
+ if ((ret = av_opt_set_from_string(blackframe, args, shorthand, "=", ":")) < 0)
+ return ret;
av_log(ctx, AV_LOG_VERBOSE, "bamount:%u bthresh:%u\n",
blackframe->bamount, blackframe->bthresh);
- if (blackframe->bamount > 100 || blackframe->bthresh > 255) {
- av_log(ctx, AV_LOG_ERROR, "Too big value for bamount (max is 100) or bthresh (max is 255)\n");
- return AVERROR(EINVAL);
- }
-
return 0;
}
+static av_cold void uninit(AVFilterContext *ctx)
+{
+ BlackFrameContext *blackframe = ctx->priv;
+ av_opt_free(blackframe);
+}
+
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
{
AVFilterContext *ctx = inlink->dst;
.priv_size = sizeof(BlackFrameContext),
.init = init,
+ .uninit = uninit,
.query_formats = query_formats,
.inputs = avfilter_vf_blackframe_inputs,
.outputs = avfilter_vf_blackframe_outputs,
+
+ .priv_class = &blackframe_class,
};