[FFmpeg-devel] [PATCH 4/4] lavfi/drawtext: implement more generic expansion.
Nicolas George
nicolas.george at normalesup.org
Thu Nov 15 17:13:58 CET 2012
The new expansion mechanism uses the %{...} notation.
For compatibility reasons, it must be enabled explicitly,
but a warning is printed if a change is likely to happen.
TODO micro bump
Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
---
Changelog | 1 +
doc/filters.texi | 55 ++++++++++++++-
libavfilter/vf_drawtext.c | 167 +++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 214 insertions(+), 9 deletions(-)
Implement Clément and Stefano's comments.
diff --git a/Changelog b/Changelog
index 9ef12b8..8fe99af 100644
--- a/Changelog
+++ b/Changelog
@@ -23,6 +23,7 @@ version <next>:
- field filter ported from libmpcodecs
- AVR demuxer
- geq filter ported from libmpcodecs
+- new expansion syntax for drawtext
version 1.0:
diff --git a/doc/filters.texi b/doc/filters.texi
index b86b146..e75cd15 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -1844,8 +1844,7 @@ libfreetype library.
To enable compilation of this filter you need to configure FFmpeg with
@code{--enable-libfreetype}.
-The filter also recognizes strftime() sequences in the provided text
-and expands them accordingly. Check the documentation of strftime().
+ at subsection Syntax
The filter accepts parameters as a list of @var{key}=@var{value} pairs,
separated by ":".
@@ -1875,6 +1874,12 @@ Default value is "1".
See below for the list of accepted constants and functions.
+ at item expand
+Select how the @var{text} is expanded. Can be either @code{none},
+ at code{strftime} (default for compatibity reasons but deprecated) or
+ at code{expand}. See the @ref{drawtext_expansion, Text expansion} section
+below for details.
+
@item fix_bounds
If true, check and fix text coords to avoid clipping.
@@ -2039,6 +2044,46 @@ each other, so you can for example specify @code{y=x/dar}.
If libavfilter was built with @code{--enable-fontconfig}, then
@option{fontfile} can be a fontconfig pattern or omitted.
+ at anchor{drawtext_expansion}
+ at subsection Text expansion
+
+If @option{expand} is set to @code{strftime} (which is the default for now),
+the filter recognizes strftime() sequences in the provided text and expands
+them accordingly. Check the documentation of strftime(). This feature is
+deprecated.
+
+If @option{expand} is set to @code{none}, the text is printed verbatim.
+
+If @option{expand} is set to @code{expand} (which will be the default), the
+following expansion mechanism is used.
+
+The backslash character '\', followed by any character, always expand to the
+second character.
+
+Sequence of the form @code{%@{...@}} are expanded. The text between the
+braces is a function name, possibly followed by arguments separated by ':'.
+If the arguments contain special characters or delimiters (':' or '@}'),
+they should be escaped. Note that they probably must also be escaped as the
+value for the @option{text} option in the filter argument string and as the
+filter argument in the filter graph description, and possibly also for the
+shell, that makes up to four levels of escaping; using a text file avoids
+these problems.
+
+The following functions are available:
+
+ at table @command
+
+ at item localtime
+The time at which the filter is running, expressed in the local time zone.
+It can accept an argument: a strftime() format string.
+
+ at item pts
+The timestamp of the current frame, in seconds, with microsecond accuracy.
+
+ at end table
+
+ at subsection Examples
+
Some examples follow.
@itemize
@@ -2104,6 +2149,12 @@ Use fontconfig to set the font. Note that the colons need to be escaped.
drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
@end example
+ at item
+Print the date of a real-time encoding (see strftime(3)):
+ at example
+drawtext='fontfile=FreeSans.ttf:expand=expand:text=%@{localtime:%a %b %d %Y@}'
+ at end example
+
@end itemize
For more information about libfreetype, check:
diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
index f9c69ae..54c303c 100644
--- a/libavfilter/vf_drawtext.c
+++ b/libavfilter/vf_drawtext.c
@@ -113,8 +113,15 @@ enum var_name {
VAR_VARS_NB
};
+enum expansion_mode {
+ EXP_NONE,
+ EXP_EXPAND,
+ EXP_STRFTIME,
+};
+
typedef struct {
const AVClass *class;
+ enum expansion_mode exp_mode; ///< use old strftime-style expand
int reinit; ///< tells if the filter is being reinited
uint8_t *fontfile; ///< font to be used
uint8_t *text; ///< text to be drawn
@@ -181,6 +188,10 @@ static const AVOption drawtext_options[]= {
{"tabsize", "set tab size", OFFSET(tabsize), AV_OPT_TYPE_INT, {.i64=4}, 0, INT_MAX , FLAGS},
{"basetime", "set base time", OFFSET(basetime), AV_OPT_TYPE_INT64, {.i64=AV_NOPTS_VALUE}, INT64_MIN, INT64_MAX , FLAGS},
{"draw", "if false do not draw", OFFSET(draw_expr), AV_OPT_TYPE_STRING, {.str="1"}, CHAR_MIN, CHAR_MAX, FLAGS},
+{"expand", "set the expansion mode", OFFSET(exp_mode), AV_OPT_TYPE_INT, {.i64=EXP_STRFTIME}, 0, 2, FLAGS, "expand"},
+{"none", "set no expansion", OFFSET(exp_mode), AV_OPT_TYPE_CONST, {.i64=EXP_NONE}, 0, 0, FLAGS, "expand"},
+{"expand", "set normal expansion", OFFSET(exp_mode), AV_OPT_TYPE_CONST, {.i64=EXP_EXPAND}, 0, 0, FLAGS, "expand"},
+{"strftime", "set strftime expansion (deprecated)", OFFSET(exp_mode), AV_OPT_TYPE_CONST, {.i64=EXP_STRFTIME}, 0, 0, FLAGS, "expand"},
{"timecode", "set initial timecode", OFFSET(tc_opt_string), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS},
{"tc24hmax", "set 24 hours max (timecode only)", OFFSET(tc24hmax), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS},
{"timecode_rate", "set rate (timecode only)", OFFSET(tc_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, FLAGS},
@@ -484,6 +495,10 @@ static av_cold int init(AVFilterContext *ctx, const char *args)
}
dtext->tabsize *= glyph->advance;
+ if (dtext->exp_mode == EXP_STRFTIME &&
+ (strchr(dtext->text, '%') || strchr(dtext->text, '\\')))
+ av_log(ctx, AV_LOG_WARNING, "expand=strftime is deprecated.\n");
+
av_bprint_init(&dtext->expanded_text, 0, AV_BPRINT_SIZE_UNLIMITED);
return 0;
@@ -585,6 +600,138 @@ static int command(AVFilterContext *ctx, const char *cmd, const char *arg, char
return AVERROR(ENOSYS);
}
+static int func_pts(AVFilterContext *ctx, AVBPrint *bp,
+ char *fct, unsigned argc, char **argv, int tag)
+{
+ DrawTextContext *dtext = ctx->priv;
+
+ av_bprintf(bp, "%.6f", dtext->var_values[VAR_T]);
+ return 0;
+}
+
+#if !HAVE_LOCALTIME_R
+static void localtime_r(const time_t *t, struct tm *tm)
+{
+ *tm = localtime(t);
+}
+#endif
+
+static int func_strftime(AVFilterContext *ctx, AVBPrint *bp,
+ char *fct, unsigned argc, char **argv, int tag)
+{
+ const char *fmt = argc ? argv[0] : "%Y-%m-%d %H:%M:%S";
+ time_t now;
+ struct tm tm;
+
+ time(&now);
+ localtime_r(&now, &tm);
+ av_bprint_strftime(bp, fmt, &tm);
+ return 0;
+}
+
+static const struct drawtext_function {
+ const char *name;
+ unsigned argc_min, argc_max;
+ int tag;
+ int (*func)(AVFilterContext *, AVBPrint *, char *, unsigned, char **, int);
+} functions[] = {
+ { "pts", 0, 0, 0, func_pts },
+ { "localtime", 0, 1, 'L', func_strftime },
+};
+
+static int eval_function(AVFilterContext *ctx, AVBPrint *bp, char *fct,
+ unsigned argc, char **argv)
+{
+ unsigned i;
+
+ for (i = 0; i < FF_ARRAY_ELEMS(functions); i++) {
+ if (strcmp(fct, functions[i].name))
+ continue;
+ if (argc < functions[i].argc_min) {
+ av_log(ctx, AV_LOG_ERROR, "%%{%s} requires at least %d arguments\n",
+ fct, functions[i].argc_min);
+ return AVERROR(EINVAL);
+ }
+ if (argc > functions[i].argc_max) {
+ av_log(ctx, AV_LOG_ERROR, "%%{%s} requires at most %d arguments\n",
+ fct, functions[i].argc_max);
+ return AVERROR(EINVAL);
+ }
+ break;
+ }
+ if (i >= FF_ARRAY_ELEMS(functions)) {
+ av_log(ctx, AV_LOG_ERROR, "%%{%s} is not known\n", fct);
+ return AVERROR(EINVAL);
+ }
+ return functions[i].func(ctx, bp, fct, argc, argv, functions[i].tag);
+}
+
+static int expand_function(AVFilterContext *ctx, AVBPrint *bp, char **rtext)
+{
+ const char *text = *rtext;
+ char *argv[16] = { NULL };
+ unsigned argc = 0, i;
+ int ret;
+
+ if (*text != '{') {
+ av_log(ctx, AV_LOG_ERROR, "Stray %% near '%s'\n", text);
+ return AVERROR(EINVAL);
+ }
+ text++;
+ while (1) {
+ if (!(argv[argc++] = av_get_token(&text, ":}"))) {
+ ret = AVERROR(ENOMEM);
+ goto end;
+ }
+ if (!*text) {
+ av_log(ctx, AV_LOG_ERROR, "Unterminated %%{} near '%s'\n", *rtext);
+ ret = AVERROR(EINVAL);
+ goto end;
+ }
+ if (argc == FF_ARRAY_ELEMS(argv))
+ av_freep(&argv[--argc]); /* error will be caught later */
+ if (*text == '}')
+ break;
+ text++;
+ }
+
+ if ((ret = eval_function(ctx, bp, argv[0], argc - 1, argv + 1)) < 0)
+ goto end;
+ ret = 0;
+ *rtext = (char *)text + 1;
+
+end:
+ for (i = 0; i < argc; i++)
+ av_freep(&argv[i]);
+ return ret;
+}
+
+static int expand_text(AVFilterContext *ctx)
+{
+ DrawTextContext *dtext = ctx->priv;
+ char *text = dtext->text;
+ AVBPrint *bp = &dtext->expanded_text;
+ int ret;
+
+ av_bprint_clear(bp);
+ while (*text) {
+ if (*text == '\\' && text[1]) {
+ av_bprint_chars(bp, text[1], 1);
+ text += 2;
+ } else if (*text == '%') {
+ text++;
+ if ((ret = expand_function(ctx, bp, &text)) < 0)
+ return ret;
+ } else {
+ av_bprint_chars(bp, *text, 1);
+ text++;
+ }
+ }
+ if (!av_bprint_is_complete(bp))
+ return AVERROR(ENOMEM);
+ return 0;
+}
+
static int draw_glyphs(DrawTextContext *dtext, AVFilterBufferRef *picref,
int width, int height, const uint8_t rgbcolor[4], FFDrawColor *color, int x, int y)
{
@@ -648,13 +795,19 @@ static int draw_text(AVFilterContext *ctx, AVFilterBufferRef *picref,
if(dtext->basetime != AV_NOPTS_VALUE)
now= picref->pts*av_q2d(ctx->inputs[0]->time_base) + dtext->basetime/1000000;
-#if HAVE_LOCALTIME_R
- localtime_r(&now, <ime);
-#else
- if(strchr(dtext->text, '%'))
- ltime= *localtime(&now);
-#endif
- av_bprint_strftime(bp, dtext->text, <ime);
+ switch (dtext->exp_mode) {
+ case EXP_NONE:
+ av_bprintf(bp, "%s", dtext->text);
+ break;
+ case EXP_EXPAND:
+ if ((ret = expand_text(ctx)) < 0)
+ return ret;
+ break;
+ case EXP_STRFTIME:
+ localtime_r(&now, <ime);
+ av_bprint_strftime(bp, dtext->text, <ime);
+ break;
+ }
if (dtext->tc_opt_string) {
char tcbuf[AV_TIMECODE_STR_SIZE];
--
1.7.10.4
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