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lavfi/curves: add plot option

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This commit is contained in:
Clément Bœsch 2016-07-22 01:17:44 +02:00
parent 5c14018fc4
commit 4a8f5f1fd8
2 changed files with 74 additions and 0 deletions
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10
doc/filters.texi
View File

@ -5750,6 +5750,8 @@ options. In this case, the unset component(s) will fallback on this
@option{all} setting.
@item psfile
Specify a Photoshop curves file (@code{.acv}) to import the settings from.
@item plot
Save Gnuplot script of the curves in specified file.
@end table
To avoid some filtergraph syntax conflicts, each key points list need to be
@ -5796,6 +5798,14 @@ Use a Photoshop preset and redefine the points of the green component:
@example
curves=psfile='MyCurvesPresets/purple.acv':green='0/0 0.45/0.53 1/1'
@end example
@item
Check out the curves of the @code{cross_process} profile using @command{ffmpeg}
and @command{gnuplot}:
@example
ffmpeg -f lavfi -i color -vf curves=cross_process:plot=/tmp/curves.plt -frames:v 1 -f null -
gnuplot -p /tmp/curves.plt
@end example
@end itemize
@section datascope

64
libavfilter/vf_curves.c
View File

@ -67,6 +67,7 @@ typedef struct {
char *psfile;
uint8_t rgba_map[4];
int step;
char *plot_filename;
} CurvesContext;
typedef struct ThreadData {
@ -98,6 +99,7 @@ static const AVOption curves_options[] = {
{ "b", "set blue points coordinates", OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
{ "all", "set points coordinates for all components", OFFSET(comp_points_str_all), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
{ "psfile", "set Photoshop curves file name", OFFSET(psfile), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
{ "plot", "save Gnuplot script of the curves in specified file", OFFSET(plot_filename), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
{ NULL }
};
@ -377,6 +379,65 @@ end:
return ret;
}
static int dump_curves(const char *fname, uint8_t graph[NB_COMP + 1][256],
struct keypoint *comp_points[NB_COMP + 1])
{
int i;
AVBPrint buf;
static const char * const colors[] = { "red", "green", "blue", "#404040", };
FILE *f = av_fopen_utf8(fname, "w");
av_assert0(FF_ARRAY_ELEMS(colors) == NB_COMP + 1);
if (!f) {
int ret = AVERROR(errno);
av_log(NULL, AV_LOG_ERROR, "Cannot open file '%s' for writing: %s\n",
fname, av_err2str(ret));
return ret;
}
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
av_bprintf(&buf, "set xtics 0.1\n");
av_bprintf(&buf, "set ytics 0.1\n");
av_bprintf(&buf, "set size square\n");
av_bprintf(&buf, "set grid\n");
for (i = 0; i < FF_ARRAY_ELEMS(colors); i++) {
av_bprintf(&buf, "%s'-' using 1:2 with lines lc '%s' title ''",
i ? ", " : "plot ", colors[i]);
if (comp_points[i])
av_bprintf(&buf, ", '-' using 1:2 with points pointtype 3 lc '%s' title ''",
colors[i]);
}
av_bprintf(&buf, "\n");
for (i = 0; i < FF_ARRAY_ELEMS(colors); i++) {
int x;
/* plot generated values */
for (x = 0; x < 256; x++)
av_bprintf(&buf, "%f %f\n", x/255., graph[i][x]/255.);
av_bprintf(&buf, "e\n");
/* plot user knots */
if (comp_points[i]) {
const struct keypoint *point = comp_points[i];
while (point) {
av_bprintf(&buf, "%f %f\n", point->x, point->y);
point = point->next;
}
av_bprintf(&buf, "e\n");
}
}
fwrite(buf.str, 1, buf.len, f);
fclose(f);
av_bprint_finalize(&buf, NULL);
return 0;
}
static av_cold int init(AVFilterContext *ctx)
{
int i, j, ret;
@ -448,6 +509,9 @@ static av_cold int init(AVFilterContext *ctx)
}
}
if (curves->plot_filename)
dump_curves(curves->plot_filename, curves->graph, comp_points);
for (i = 0; i < NB_COMP + 1; i++) {
struct keypoint *point = comp_points[i];
while (point) {