[FFmpeg-devel] [PATCH] lavfi/overlay: add dynamic x/y expression evaluation support
Stefano Sabatini
stefasab at gmail.com
Tue Feb 19 20:10:50 CET 2013
TODO: bump micro
---
doc/filters.texi | 59 ++++++++++++++++++++--------
libavfilter/vf_overlay.c | 98 +++++++++++++++++++++++++++++++---------------
2 files changed, 109 insertions(+), 48 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 7b45ba4..5dd7404 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -3854,33 +3854,53 @@ arguments are interpreted according to the syntax @var{x}:@var{y}.
A description of the accepted options follows.
@table @option
- at item x, y
+ at item x
+ at 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. These values are evaluated for each new output
+frame. 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).
+
+ at item rgb
+If set to 1, force the filter to accept inputs in the RGB
+color space. Default value is 0.
+
+ at item shortest
+If set to 1, force the output to terminate when the shortest input
+terminates. Default value is 0.
+ at end table
The @var{x} and @var{y} expressions can contain the following
parameters:
@table @option
- at item main_w, main_h
+ at item main_w, W
+ at item main_h, H
main input width and height
- at item W, H
-same as @var{main_w} and @var{main_h}
-
- at item overlay_w, overlay_h
+ at item overlay_w, w
+ at item overlay_h, h
overlay input width and height
- at item w, h
-same as @var{overlay_w} and @var{overlay_h}
- at end table
+ at item x
+ at item y
+the computed values for @var{x} and @var{y}. They are evaluated for
+each new frame.
- at item rgb
-If set to 1, force the filter to accept inputs in the RGB
-color space. Default value is 0.
+ at item hsub
+ at item vsub
+horizontal and vertical chroma subsample values of the output
+format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
+ at var{vsub} is 1.
- at item shortest
-If set to 1, force the output to terminate when the shortest input
-terminates. Default value is 0.
+ at item n
+the number of input frame, starting from 0
+
+ at item pos
+the position in the file of the input frame, NAN if unknown
+
+ at item t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
@end table
Be aware that frames are taken from each input video in timestamp
@@ -3941,6 +3961,13 @@ 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:
+ at example
+overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
+ at end example
+
+ at item
Create a side by side video, combining left and right videos side to side:
@example
ffmpeg -i left.avi -i right.avi -filter_complex "
diff --git a/libavfilter/vf_overlay.c b/libavfilter/vf_overlay.c
index 607c02d..166c376 100644
--- a/libavfilter/vf_overlay.c
+++ b/libavfilter/vf_overlay.c
@@ -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
};
@@ -93,7 +107,9 @@ 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)
@@ -126,6 +142,9 @@ static av_cold void uninit(AVFilterContext *ctx)
av_opt_free(over);
+ av_expr_free(over->x_pexpr); over->x_pexpr = NULL;
+ av_expr_free(over->y_pexpr); over->y_pexpr = NULL;
+
avfilter_unref_bufferp(&over->overpicref);
ff_bufqueue_discard_all(&over->queue_main);
ff_bufqueue_discard_all(&over->queue_over);
@@ -194,7 +213,6 @@ 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);
@@ -202,48 +220,37 @@ 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;
-
- 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;
- if ((ret = av_expr_parse_and_eval(&res, (expr = over->y_expr), var_names, var_values,
- NULL, NULL, NULL, NULL, NULL, 0, ctx)))
+ 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;
+
+ 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->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)
+ 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->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);
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:
@@ -450,6 +457,7 @@ static int try_filter_frame(AVFilterContext *ctx, AVFilterBufferRef *mainpic)
{
OverlayContext *over = ctx->priv;
AVFilterLink *outlink = ctx->outputs[0];
+ AVFilterLink *inlink = ctx->inputs[0];
AVFilterBufferRef *next_overpic;
int ret;
@@ -481,8 +489,34 @@ static int try_filter_frame(AVFilterContext *ctx, AVFilterBufferRef *mainpic)
av_ts2str(over->overpicref->pts), av_ts2timestr(over->overpicref->pts, &outlink->time_base));
av_dlog(ctx, "\n");
- if (over->overpicref)
+ if (over->overpicref) {
+ over->var_values[VAR_T] = mainpic->pts == AV_NOPTS_VALUE ?
+ NAN : mainpic->pts * av_q2d(inlink->time_base);
+ over->var_values[VAR_POS] = mainpic->pos == -1 ? NAN : mainpic->pos;
+ 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);
+
+ if (isnan(over->var_values[VAR_X])) {
+ over->x = INT_MAX;
+ } else {
+ over->x = over->var_values[VAR_X];
+ over->x &= ~((1 << over->hsub) - 1);
+ }
+ if (isnan(over->var_values[VAR_Y])) {
+ over->y = INT_MAX;
+ } else {
+ over->y = over->var_values[VAR_Y];
+ over->y &= ~((1 << over->vsub) - 1);
+ }
+ 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;
--
1.7.9.5
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