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lavfi/overlay: add dynamic expression evaluation support

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Add support for dynamic x, y expressions evaluation.

Also add support for an evaluation mode which allows to disable per-frame
evaluation, so that there is no speedloss in case the expression does not
depend on frame variables.
This commit is contained in:
Stefano Sabatini 2013-02-19 20:10:02 +01:00
parent 8afcaaeb75
commit cc3edd99a6
3 changed files with 150 additions and 51 deletions
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81
doc/filters.texi
View File

@ -4260,26 +4260,31 @@ arguments are interpreted according to the syntax @var{x}:@var{y}.
A description of the accepted options follows.
@table @option
@item x, y
@item x
@item y
Set the expression for the x and y coordinates of the overlayed video
on the main video. Default value is 0.
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).
The @var{x} and @var{y} expressions can contain the following
parameters:
@table @option
@item main_w, main_h
main input width and height
@item eval
Set when the expressions for @option{x} and @option{y} are evaluated.
@item W, H
same as @var{main_w} and @var{main_h}
It accepts the following values:
@table @samp
@item init
only evaluate expressions once during the filter initialization
@item overlay_w, overlay_h
overlay input width and height
@item w, h
same as @var{overlay_w} and @var{overlay_h}
@item frame
evaluate expressions for each incoming frame
@end table
Default value is @samp{frame}.
@item shortest
If set to 1, force the output to terminate when the shortest input
terminates. Default value is 0.
@item format
Set the format for the output video.
@ -4301,12 +4306,45 @@ Default value is @samp{yuv420}.
If set to 1, force the filter to accept inputs in the RGB
color space. Default value is 0. This option is deprecated, use
@option{format} instead.
@item shortest
If set to 1, force the output to terminate when the shortest input
terminates. Default value is 0.
@end table
The @option{x}, and @option{y} expressions can contain the following
parameters.
@table @option
@item main_w, W
@item main_h, H
main input width and height
@item overlay_w, w
@item overlay_h, h
overlay input width and height
@item x
@item y
the computed values for @var{x} and @var{y}. They are evaluated for
each new frame.
@item hsub
@item vsub
horizontal and vertical chroma subsample values of the output
format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
@var{vsub} is 1.
@item n
the number of input frame, starting from 0
@item pos
the position in the file of the input frame, NAN if unknown
@item t
timestamp expressed in seconds, NAN if the input timestamp is unknown
@end table
Note that the @var{n}, @var{pos}, @var{t} variables are available only
when evaluation is done @emph{per frame}, and will evaluate to NAN
when @option{eval} is set to @samp{init}.
Be aware that frames are taken from each input video in timestamp
order, hence, if their initial timestamps differ, it is a a good idea
to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
@ -4364,6 +4402,13 @@ The above command is the same as:
ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
@end example
@item
Make a sliding overlay appearing from the left to the right top part of the
screen starting since time 2:
@example
overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
@end example
@item
Compose output by putting two input videos side to side:
@example

2
libavfilter/version.h
View File

@ -30,7 +30,7 @@
#define LIBAVFILTER_VERSION_MAJOR 3
#define LIBAVFILTER_VERSION_MINOR 50
#define LIBAVFILTER_VERSION_MICRO 100
#define LIBAVFILTER_VERSION_MICRO 101
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
LIBAVFILTER_VERSION_MINOR, \

118
libavfilter/vf_overlay.c
View File

@ -47,6 +47,13 @@ static const char *const var_names[] = {
"main_h", "H", ///< height of the main video
"overlay_w", "w", ///< width of the overlay video
"overlay_h", "h", ///< height of the overlay video
"hsub",
"vsub",
"x",
"y",
"n", ///< number of frame
"pos", ///< position in the file
"t", ///< timestamp expressed in seconds
NULL
};
@ -55,6 +62,13 @@ enum var_name {
VAR_MAIN_H, VAR_MH,
VAR_OVERLAY_W, VAR_OW,
VAR_OVERLAY_H, VAR_OH,
VAR_HSUB,
VAR_VSUB,
VAR_X,
VAR_Y,
VAR_N,
VAR_POS,
VAR_T,
VAR_VARS_NB
};
@ -84,6 +98,7 @@ typedef struct {
uint8_t overlay_rgba_map[4];
uint8_t overlay_has_alpha;
enum OverlayFormat { OVERLAY_FORMAT_YUV420, OVERLAY_FORMAT_YUV444, OVERLAY_FORMAT_RGB, OVERLAY_FORMAT_NB} format;
enum EvalMode { EVAL_MODE_INIT, EVAL_MODE_FRAME, EVAL_MODE_NB } eval_mode;
AVFrame *overpicref;
struct FFBufQueue queue_main;
@ -94,7 +109,9 @@ typedef struct {
int hsub, vsub; ///< chroma subsampling values
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;
} OverlayContext;
#define OFFSET(x) offsetof(OverlayContext, x)
@ -103,6 +120,11 @@ 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 },
{ "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" },
{ "frame", "eval expressions per-frame", 0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_FRAME}, .flags = FLAGS, .unit = "eval" },
{ "rgb", "force packed RGB in input and output (deprecated)", OFFSET(allow_packed_rgb), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS },
{ "shortest", "force termination when the shortest input terminates", OFFSET(shortest), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, FLAGS },
@ -135,6 +157,8 @@ static av_cold void uninit(AVFilterContext *ctx)
av_frame_free(&over->overpicref);
ff_bufqueue_discard_all(&over->queue_main);
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;
}
static int query_formats(AVFilterContext *ctx)
@ -217,12 +241,29 @@ static int config_input_main(AVFilterLink *inlink)
return 0;
}
static inline int normalize_xy(double d, int chroma_sub)
{
if (isnan(d))
return INT_MAX;
return (int)d & ~((1 << chroma_sub) - 1);
}
static void eval_expr(AVFilterContext *ctx)
{
OverlayContext *over = ctx->priv;
over->var_values[VAR_X] = av_expr_eval(over->x_pexpr, over->var_values, NULL);
over->var_values[VAR_Y] = av_expr_eval(over->y_pexpr, over->var_values, NULL);
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);
}
static int config_input_overlay(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
OverlayContext *over = inlink->dst->priv;
char *expr;
double var_values[VAR_VARS_NB], res;
int ret;
const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
@ -230,53 +271,49 @@ static int config_input_overlay(AVFilterLink *inlink)
/* Finish the configuration by evaluating the expressions
now when both inputs are configured. */
var_values[VAR_MAIN_W ] = var_values[VAR_MW] = ctx->inputs[MAIN ]->w;
var_values[VAR_MAIN_H ] = var_values[VAR_MH] = ctx->inputs[MAIN ]->h;
var_values[VAR_OVERLAY_W] = var_values[VAR_OW] = ctx->inputs[OVERLAY]->w;
var_values[VAR_OVERLAY_H] = var_values[VAR_OH] = ctx->inputs[OVERLAY]->h;
over->var_values[VAR_MAIN_W ] = over->var_values[VAR_MW] = ctx->inputs[MAIN ]->w;
over->var_values[VAR_MAIN_H ] = over->var_values[VAR_MH] = ctx->inputs[MAIN ]->h;
over->var_values[VAR_OVERLAY_W] = over->var_values[VAR_OW] = ctx->inputs[OVERLAY]->w;
over->var_values[VAR_OVERLAY_H] = over->var_values[VAR_OH] = ctx->inputs[OVERLAY]->h;
over->var_values[VAR_HSUB] = 1<<pix_desc->log2_chroma_w;
over->var_values[VAR_VSUB] = 1<<pix_desc->log2_chroma_h;
over->var_values[VAR_X] = NAN;
over->var_values[VAR_Y] = NAN;
over->var_values[VAR_N] = 0;
over->var_values[VAR_T] = NAN;
over->var_values[VAR_POS] = NAN;
if ((ret = av_expr_parse_and_eval(&res, (expr = over->x_expr), var_names, var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
expr = over->x_expr;
if ((ret = av_expr_parse(&over->x_pexpr, expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0)
goto fail;
over->x = res;
if ((ret = av_expr_parse_and_eval(&res, (expr = over->y_expr), var_names, var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)))
expr = over->y_expr;
if ((ret = av_expr_parse(&over->y_pexpr, expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0)
goto fail;
over->y = res;
/* x may depend on y */
if ((ret = av_expr_parse_and_eval(&res, (expr = over->x_expr), var_names, var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
goto fail;
over->x = res;
over->overlay_is_packed_rgb =
ff_fill_rgba_map(over->overlay_rgba_map, inlink->format) >= 0;
over->overlay_has_alpha = ff_fmt_is_in(inlink->format, alpha_pix_fmts);
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",
over->var_values[VAR_X], over->x,
over->var_values[VAR_Y], over->y);
}
av_log(ctx, AV_LOG_VERBOSE,
"main w:%d h:%d fmt:%s overlay x:%d y:%d w:%d h:%d fmt:%s\n",
"main w:%d h:%d fmt:%s overlay w:%d h:%d fmt:%s\n",
ctx->inputs[MAIN]->w, ctx->inputs[MAIN]->h,
av_get_pix_fmt_name(ctx->inputs[MAIN]->format),
over->x, over->y,
ctx->inputs[OVERLAY]->w, ctx->inputs[OVERLAY]->h,
av_get_pix_fmt_name(ctx->inputs[OVERLAY]->format));
if (over->x < 0 || over->y < 0 ||
over->x + var_values[VAR_OVERLAY_W] > var_values[VAR_MAIN_W] ||
over->y + var_values[VAR_OVERLAY_H] > var_values[VAR_MAIN_H]) {
av_log(ctx, AV_LOG_WARNING,
"Overlay area with coordinates x1:%d y1:%d x2:%d y2:%d "
"is not completely contained within the output with size %dx%d\n",
over->x, over->y,
(int)(over->x + var_values[VAR_OVERLAY_W]),
(int)(over->y + var_values[VAR_OVERLAY_H]),
(int)var_values[VAR_MAIN_W], (int)var_values[VAR_MAIN_H]);
}
return 0;
fail:
av_log(NULL, AV_LOG_ERROR,
"Error when evaluating the expression '%s'\n", expr);
"Error when parsing the expression '%s'\n", expr);
return ret;
}
@ -495,6 +532,7 @@ static void blend_image(AVFilterContext *ctx,
static int try_filter_frame(AVFilterContext *ctx, AVFrame *mainpic)
{
OverlayContext *over = ctx->priv;
AVFilterLink *inlink = ctx->inputs[0];
AVFrame *next_overpic;
int ret;
@ -526,8 +564,24 @@ static int try_filter_frame(AVFilterContext *ctx, AVFrame *mainpic)
av_ts2str(over->overpicref->pts), av_ts2timestr(over->overpicref->pts, &ctx->inputs[OVERLAY]->time_base));
av_dlog(ctx, "\n");
if (over->overpicref)
if (over->overpicref) {
if (over->eval_mode == EVAL_MODE_FRAME) {
int64_t pos = av_frame_get_pkt_pos(mainpic);
over->var_values[VAR_T] = mainpic->pts == AV_NOPTS_VALUE ?
NAN : mainpic->pts * av_q2d(inlink->time_base);
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",
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);
}
blend_image(ctx, mainpic, over->overpicref, over->x, over->y);
over->var_values[VAR_N] += 1.0;
}
ret = ff_filter_frame(ctx->outputs[0], mainpic);
av_assert1(ret != AVERROR(EAGAIN));
over->frame_requested = 0;