[FFmpeg-cvslog] drawtext: make x and y parametric
Luca Barbato
git at videolan.org
Sun Dec 4 01:09:27 CET 2011
ffmpeg | branch: master | Luca Barbato <lu_zero at gentoo.org> | Thu Dec 1 11:43:11 2011 +0100| [2cf74eca70759320200f06efe4a09bd69e169dec] | committer: Luca Barbato
drawtext: make x and y parametric
Introduce variables "E", "PHI", "PI", "main_w"/"W", "main_h"/"H",
"text_w"/"w", "text_h"/"h", "x", "y", "n" and "t" in line with
vf_overlay and refactor the code accordingly.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=2cf74eca70759320200f06efe4a09bd69e169dec
---
doc/filters.texi | 27 +++++++++
libavfilter/vf_drawtext.c | 133 ++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 152 insertions(+), 8 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 4b38813..101bec6 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -505,6 +505,32 @@ If both text and textfile are specified, an error is thrown.
@item x, y
The offsets where text will be drawn within the video frame.
Relative to the top/left border of the output image.
+They accept expressions similar to the @ref{overlay} filter:
+ at table @option
+
+ at item x, y
+the computed values for @var{x} and @var{y}. They are evaluated for
+each new frame.
+
+ at item main_w, main_h
+main input width and height
+
+ at item W, H
+same as @var{main_w} and @var{main_h}
+
+ at item text_w, text_h
+rendered text width and height
+
+ at item w, h
+same as @var{text_w} and @var{text_h}
+
+ at item n
+the number of frames processed, starting from 0
+
+ at item t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+ at end table
The default value of @var{x} and @var{y} is 0.
@@ -1048,6 +1074,7 @@ other parameters is 0.
These parameters correspond to the parameters assigned to the
libopencv function @code{cvSmooth}.
+ at anchor{overlay}
@section overlay
Overlay one video on top of another.
diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
index 06b5dc0..b7ba89c 100644
--- a/libavfilter/vf_drawtext.c
+++ b/libavfilter/vf_drawtext.c
@@ -31,7 +31,9 @@
#include "libavutil/colorspace.h"
#include "libavutil/file.h"
+#include "libavutil/eval.h"
#include "libavutil/opt.h"
+#include "libavutil/mathematics.h"
#include "libavutil/parseutils.h"
#include "libavutil/pixdesc.h"
#include "libavutil/tree.h"
@@ -45,6 +47,36 @@
#include FT_FREETYPE_H
#include FT_GLYPH_H
+static const char *var_names[] = {
+ "E",
+ "PHI",
+ "PI",
+ "main_w", "W", ///< width of the main video
+ "main_h", "H", ///< height of the main video
+ "text_w", "w", ///< width of the overlay text
+ "text_h", "h", ///< height of the overlay text
+ "x",
+ "y",
+ "n", ///< number of processed frames
+ "t", ///< timestamp expressed in seconds
+ NULL
+};
+
+enum var_name {
+ VAR_E,
+ VAR_PHI,
+ VAR_PI,
+ VAR_MAIN_W, VAR_MW,
+ VAR_MAIN_H, VAR_MH,
+ VAR_TEXT_W, VAR_TW,
+ VAR_TEXT_H, VAR_TH,
+ VAR_X,
+ VAR_Y,
+ VAR_N,
+ VAR_T,
+ VAR_VARS_NB
+};
+
typedef struct {
const AVClass *class;
uint8_t *fontfile; ///< font to be used
@@ -81,6 +113,10 @@ typedef struct {
int pixel_step[4]; ///< distance in bytes between the component of each pixel
uint8_t rgba_map[4]; ///< map RGBA offsets to the positions in the packed RGBA format
uint8_t *box_line[4]; ///< line used for filling the box background
+ char *x_expr, *y_expr;
+ AVExpr *x_pexpr, *y_pexpr; ///< parsed expressions for x and y
+ double var_values[VAR_VARS_NB];
+ int draw; ///< set to zero to prevent drawing
} DrawTextContext;
#define OFFSET(x) offsetof(DrawTextContext, x)
@@ -94,8 +130,8 @@ static const AVOption drawtext_options[]= {
{"shadowcolor", "set shadow color", OFFSET(shadowcolor_string), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX },
{"box", "set box", OFFSET(draw_box), AV_OPT_TYPE_INT, {.dbl=0}, 0, 1 },
{"fontsize", "set font size", OFFSET(fontsize), AV_OPT_TYPE_INT, {.dbl=16}, 1, 72 },
-{"x", "set x", OFFSET(x), AV_OPT_TYPE_INT, {.dbl=0}, 0, INT_MAX },
-{"y", "set y", OFFSET(y), AV_OPT_TYPE_INT, {.dbl=0}, 0, INT_MAX },
+{"x", "set x", OFFSET(x_expr), AV_OPT_TYPE_STRING, {.str="0"}, CHAR_MIN, CHAR_MAX },
+{"y", "set y", OFFSET(y_expr), AV_OPT_TYPE_STRING, {.str="0"}, CHAR_MIN, CHAR_MAX },
{"shadowx", "set x", OFFSET(shadowx), AV_OPT_TYPE_INT, {.dbl=0}, INT_MIN, INT_MAX },
{"shadowy", "set y", OFFSET(shadowy), AV_OPT_TYPE_INT, {.dbl=0}, INT_MIN, INT_MAX },
{"tabsize", "set tab size", OFFSET(tabsize), AV_OPT_TYPE_INT, {.dbl=4}, 0, INT_MAX },
@@ -374,7 +410,7 @@ static inline int is_newline(uint32_t c)
return (c == '\n' || c == '\r' || c == '\f' || c == '\v');
}
-static int dtext_prepare_text(AVFilterContext *ctx, int width, int height)
+static int dtext_prepare_text(AVFilterContext *ctx)
{
DrawTextContext *dtext = ctx->priv;
uint32_t code = 0, prev_code = 0;
@@ -387,6 +423,8 @@ static int dtext_prepare_text(AVFilterContext *ctx, int width, int height)
FT_Vector delta;
Glyph *glyph = NULL, *prev_glyph = NULL;
Glyph dummy = { 0 };
+ int width = ctx->inputs[0]->w;
+ int height = ctx->inputs[0]->h;
#if HAVE_LOCALTIME_R
time_t now = time(0);
@@ -504,6 +542,27 @@ static int config_input(AVFilterLink *inlink)
dtext->hsub = pix_desc->log2_chroma_w;
dtext->vsub = pix_desc->log2_chroma_h;
+ dtext->var_values[VAR_E ] = M_E;
+ dtext->var_values[VAR_PHI] = M_PHI;
+ dtext->var_values[VAR_PI ] = M_PI;
+
+ dtext->var_values[VAR_MAIN_W] =
+ dtext->var_values[VAR_MW] = ctx->inputs[0]->w;
+ dtext->var_values[VAR_MAIN_H] =
+ dtext->var_values[VAR_MH] = ctx->inputs[0]->h;
+
+ dtext->var_values[VAR_X] = 0;
+ dtext->var_values[VAR_Y] = 0;
+ dtext->var_values[VAR_N] = 0;
+ dtext->var_values[VAR_T] = NAN;
+
+
+ if ((ret = av_expr_parse(&dtext->x_pexpr, dtext->x_expr, var_names,
+ NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||
+ (ret = av_expr_parse(&dtext->y_pexpr, dtext->y_expr, var_names,
+ NULL, NULL, NULL, NULL, 0, ctx)) < 0)
+ return AVERROR(EINVAL);
+
if ((ret =
ff_fill_line_with_color(dtext->box_line, dtext->pixel_step,
inlink->w, dtext->boxcolor,
@@ -524,7 +583,9 @@ static int config_input(AVFilterLink *inlink)
dtext->shadowcolor[3] = rgba[3];
}
- return dtext_prepare_text(ctx, ctx->inputs[0]->w, ctx->inputs[0]->h);
+ dtext->draw = 1;
+
+ return dtext_prepare_text(ctx);
}
#define GET_BITMAP_VAL(r, c) \
@@ -697,15 +758,71 @@ static int draw_text(AVFilterContext *ctx, AVFilterBufferRef *picref,
static void null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir) { }
+static inline int normalize_double(int *n, double d)
+{
+ int ret = 0;
+
+ if (isnan(d)) {
+ ret = AVERROR(EINVAL);
+ } else if (d > INT_MAX || d < INT_MIN) {
+ *n = d > INT_MAX ? INT_MAX : INT_MIN;
+ ret = AVERROR(EINVAL);
+ } else
+ *n = round(d);
+
+ return ret;
+}
+
+static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
+{
+ AVFilterContext *ctx = inlink->dst;
+ DrawTextContext *dtext = ctx->priv;
+
+ if (dtext_prepare_text(ctx) < 0) {
+ av_log(ctx, AV_LOG_ERROR, "Can't draw text\n");
+ dtext->draw = 0;
+ }
+
+ dtext->var_values[VAR_T] = inpicref->pts == AV_NOPTS_VALUE ?
+ NAN : inpicref->pts * av_q2d(inlink->time_base);
+ dtext->var_values[VAR_X] =
+ av_expr_eval(dtext->x_pexpr, dtext->var_values, NULL);
+ dtext->var_values[VAR_Y] =
+ av_expr_eval(dtext->y_pexpr, dtext->var_values, NULL);
+ dtext->var_values[VAR_X] =
+ av_expr_eval(dtext->x_pexpr, dtext->var_values, NULL);
+
+ normalize_double(&dtext->x, dtext->var_values[VAR_X]);
+ normalize_double(&dtext->y, dtext->var_values[VAR_Y]);
+
+ if (dtext->x < 0) dtext->x = 0;
+ if (dtext->y < 0) dtext->y = 0;
+ if ((unsigned)dtext->x + (unsigned)dtext->w > inlink->w)
+ dtext->x = inlink->w - dtext->w;
+ if ((unsigned)dtext->y + (unsigned)dtext->h > inlink->h)
+ dtext->y = inlink->h - dtext->h;
+
+ dtext->x &= ~((1 << dtext->hsub) - 1);
+ dtext->y &= ~((1 << dtext->vsub) - 1);
+
+ av_dlog(ctx, "n:%d t:%f x:%d y:%d x+w:%d y+h:%d\n",
+ (int)dtext->var_values[VAR_N], dtext->var_values[VAR_T],
+ dtext->x, dtext->y, dtext->x+dtext->w, dtext->y+dtext->h);
+
+ avfilter_start_frame(inlink->dst->outputs[0], inpicref);
+}
+
static void end_frame(AVFilterLink *inlink)
{
AVFilterLink *outlink = inlink->dst->outputs[0];
AVFilterBufferRef *picref = inlink->cur_buf;
- int err = dtext_prepare_text(inlink->dst,
- picref->video->w, picref->video->h);
- if (!err)
+ DrawTextContext *dtext = inlink->dst->priv;
+
+ if (dtext->draw)
draw_text(inlink->dst, picref, picref->video->w, picref->video->h);
+ dtext->var_values[VAR_N] += 1.0;
+
avfilter_draw_slice(outlink, 0, picref->video->h, 1);
avfilter_end_frame(outlink);
}
@@ -721,7 +838,7 @@ AVFilter avfilter_vf_drawtext = {
.inputs = (AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.get_video_buffer = avfilter_null_get_video_buffer,
- .start_frame = avfilter_null_start_frame,
+ .start_frame = start_frame,
.draw_slice = null_draw_slice,
.end_frame = end_frame,
.config_props = config_input,
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