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lavfi/overlay: add enable expression

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This expression is useful to enable/disable overlaying on the fly.

Note that this can't be easily done relying on the filtergraph structure,
since this implies caching issues or a null frame overlaying in the best
case, which is better avoided for performance and convenience reasons.
This commit is contained in:
Stefano Sabatini 2013-04-08 12:22:48 +02:00
parent cc3edd99a6
commit 006e20bd36
3 changed files with 28 additions and 11 deletions
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12
doc/filters.texi
View File

@ -4267,8 +4267,14 @@ on the main video. Default value is "0" for both expressions. In case
the expression is invalid, it is set to a huge value (meaning that the
overlay will not be displayed within the output visible area).
@item enable
Set the expression which enables the overlay. If the evaluation is
different from 0, the overlay is displayed on top of the input
frame. By default it is "1".
@item eval
Set when the expressions for @option{x} and @option{y} are evaluated.
Set when the expressions for @option{x}, @option{y}, and
@option{enable} are evaluated.
It accepts the following values:
@table @samp
@ -4308,8 +4314,8 @@ color space. Default value is 0. This option is deprecated, use
@option{format} instead.
@end table
The @option{x}, and @option{y} expressions can contain the following
parameters.
The @option{x}, @option{y}, and @option{enable} expressions can
contain the following parameters.
@table @option
@item main_w, W

2
libavfilter/version.h
View File

@ -30,7 +30,7 @@
#define LIBAVFILTER_VERSION_MAJOR 3
#define LIBAVFILTER_VERSION_MINOR 50
#define LIBAVFILTER_VERSION_MICRO 101
#define LIBAVFILTER_VERSION_MICRO 102
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
LIBAVFILTER_VERSION_MINOR, \

25
libavfilter/vf_overlay.c
View File

@ -87,6 +87,7 @@ enum var_name {
typedef struct {
const AVClass *class;
int x, y; ///< position of overlayed picture
double enable; ///< tells if blending is enabled
int allow_packed_rgb;
uint8_t frame_requested;
@ -110,8 +111,8 @@ typedef struct {
int shortest; ///< terminate stream when the shortest input terminates
double var_values[VAR_VARS_NB];
char *x_expr, *y_expr;
AVExpr *x_pexpr, *y_pexpr;
char *x_expr, *y_expr, *enable_expr;
AVExpr *x_pexpr, *y_pexpr, *enable_pexpr;
} OverlayContext;
#define OFFSET(x) offsetof(OverlayContext, x)
@ -120,6 +121,7 @@ typedef struct {
static const AVOption overlay_options[] = {
{ "x", "set the x expression", OFFSET(x_expr), AV_OPT_TYPE_STRING, {.str = "0"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "y", "set the y expression", OFFSET(y_expr), AV_OPT_TYPE_STRING, {.str = "0"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "enable", "set expression which enables overlay", OFFSET(enable_expr), AV_OPT_TYPE_STRING, {.str = "1"}, .flags = FLAGS },
{ "eval", "specify when to evaluate expressions", OFFSET(eval_mode), AV_OPT_TYPE_INT, {.i64 = EVAL_MODE_FRAME}, 0, EVAL_MODE_NB-1, FLAGS, "eval" },
{ "init", "eval expressions once during initialization", 0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_INIT}, .flags = FLAGS, .unit = "eval" },
@ -159,6 +161,7 @@ static av_cold void uninit(AVFilterContext *ctx)
ff_bufqueue_discard_all(&over->queue_over);
av_expr_free(over->x_pexpr); over->x_pexpr = NULL;
av_expr_free(over->y_pexpr); over->y_pexpr = NULL;
av_expr_free(over->enable_pexpr); over->enable_pexpr = NULL;
}
static int query_formats(AVFilterContext *ctx)
@ -257,6 +260,7 @@ static void eval_expr(AVFilterContext *ctx)
over->var_values[VAR_X] = av_expr_eval(over->x_pexpr, over->var_values, NULL);
over->x = normalize_xy(over->var_values[VAR_X], over->hsub);
over->y = normalize_xy(over->var_values[VAR_Y], over->vsub);
over->enable = av_expr_eval(over->enable_pexpr, over->var_values, NULL);
}
static int config_input_overlay(AVFilterLink *inlink)
@ -291,6 +295,10 @@ static int config_input_overlay(AVFilterLink *inlink)
if ((ret = av_expr_parse(&over->y_pexpr, expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0)
goto fail;
expr = over->enable_expr;
if ((ret = av_expr_parse(&over->enable_pexpr, expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0)
goto fail;
over->overlay_is_packed_rgb =
ff_fill_rgba_map(over->overlay_rgba_map, inlink->format) >= 0;
@ -298,9 +306,10 @@ static int config_input_overlay(AVFilterLink *inlink)
if (over->eval_mode == EVAL_MODE_INIT) {
eval_expr(ctx);
av_log(ctx, AV_LOG_VERBOSE, "x:%f xi:%d y:%f yi:%d\n",
av_log(ctx, AV_LOG_VERBOSE, "x:%f xi:%d y:%f yi:%d enable:%f\n",
over->var_values[VAR_X], over->x,
over->var_values[VAR_Y], over->y);
over->var_values[VAR_Y], over->y,
over->enable);
}
av_log(ctx, AV_LOG_VERBOSE,
@ -573,12 +582,14 @@ static int try_filter_frame(AVFilterContext *ctx, AVFrame *mainpic)
over->var_values[VAR_POS] = pos == -1 ? NAN : pos;
eval_expr(ctx);
av_log(ctx, AV_LOG_DEBUG, "n:%f t:%f pos:%f x:%f xi:%d y:%f yi:%d\n",
av_log(ctx, AV_LOG_DEBUG, "n:%f t:%f pos:%f x:%f xi:%d y:%f yi:%d enable:%f\n",
over->var_values[VAR_N], over->var_values[VAR_T], over->var_values[VAR_POS],
over->var_values[VAR_X], over->x,
over->var_values[VAR_Y], over->y);
over->var_values[VAR_Y], over->y,
over->enable);
}
blend_image(ctx, mainpic, over->overpicref, over->x, over->y);
if (over->enable)
blend_image(ctx, mainpic, over->overpicref, over->x, over->y);
over->var_values[VAR_N] += 1.0;
}