On Jan 18, 2022, at 8:52 PM, Thilo Borgmann <thilo.borgm...@mail.de>
wrote:
Am 16.01.22 um 12:06 schrieb Nicolas George:
Thilo Borgman (12022-01-14):
v6 does:
$> ffmpeg ... drawtext="fontfile=...:text='%{localtime \:%a %b
%d %Y %S}'" (seconds)
$> ffmpeg ... drawtext="fontfile=...:text='%{localtime_ms\:%a %b
%d %Y %S}'" (milliseconds)
I suggest v7 should according to your remark:
$> ffmpeg ... drawtext="fontfile=...:text='%{localtime \:%a %b
%d %Y %S}'" (seconds)
$> ffmpeg ... drawtext="fontfile=...:text='%{localtime \:%a %b
%d %Y %S}':show_ms=1" (milliseconds)
Good?
I dislike both versions, from a user interface point of view: if there
is a format string, then it stands to reason, for the user, that the
resulting text is governed by the format string, not by an extra
option
somewhere else.
There is no "use_four_digit_year=1" option, there is %Y instead of %y.
There is no "use_slashes=1" option, you write %Y/%m/%d instead of
%Y-%m-%d.
There are no "omit_date=1" and "omit_hour=1" options, you just write
what you want in the format string.
My proposal goes the same way:
$> ffmpeg ... drawtext="fontfile=...:text='%{localtime \:%a %b %d
%Y %S.%3N}'"
It has several merits over your proposal:
- It can be extended later to support printing the milliseconds at
another place than the end (for example to put the time in
brackets).
- It can be extended to support microseconds or centiseconds (%6N,
%2N).
- It is somewhat compatible with GNU date and possibly a few others.
And I do not think it is harder to implement.
Ok, did introduce a variable: %[1-6]N
Parsing and clipping value to valid range of 1-6.
Default 3.
That way it is position independent and can show any number of
decimals from 1 to 6.
diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
index 2a88692cbd..448b174dbb 100644
--- a/libavfilter/vf_drawtext.c
+++ b/libavfilter/vf_drawtext.c
@@ -51,6 +51,7 @@
#include "libavutil/opt.h"
#include "libavutil/random_seed.h"
#include "libavutil/parseutils.h"
+#include "libavutil/time.h"
#include "libavutil/timecode.h"
#include "libavutil/time_internal.h"
#include "libavutil/tree.h"
@@ -1045,14 +1046,82 @@ 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";
+ int64_t unow;
time_t now;
struct tm tm;
-
- time(&now);
- if (tag == 'L')
+ char *begin;
+ char *tmp;
+ int len;
+ char *fmt_new;
+ const char *fmt_tmp;
+ int div;
+
+ unow = av_gettime();
+ now = unow / 1000000;
+ if (tag == 'L' || tag == 'm')
localtime_r(&now, &tm);
else
tm = *gmtime_r(&now, &tm);
+
+ // manually parse format for %N (fractional seconds)
+ begin = (char*)fmt;
Make begin and tmp const char *, so the cast can be removed.
+ while ((begin = av_stristr(begin, "%"))) {
How about strstr() since ‘%’ is caseless?
+ tmp = begin + 1;
+ len = 0;
+ // count digits between % and possible N
+ while (*tmp != '\0' && av_isdigit((int)*tmp)) {
+ len++;
+ tmp++;
+ }
+ // N encountered, insert time
+ if (*tmp == 'N') {
+ int num_digits = 3; // default show millisecond [1,6]
+
+ // if digits given, parse as number in [1,6]
+ if (len > 0) {
+ av_sscanf(begin + 1, "%i", &num_digits);
+ num_digits = av_clip(num_digits, 1, 6); // ensure
valid value
We can ignore len > 1, then the code can be simplified as
if (len == 1)
num_digits = av_clip(*(begin + 1) - ‘\0’, 1, 6)
+ }
+
+ len += 2; // add % and N to get length of string part
+
+ switch(num_digits) {
+ case 1:
+ fmt_tmp = "%.*s%01d%s";
+ div = 100000;
+ break;
+ case 2:
+ fmt_tmp = "%.*s%02d%s";
+ div = 10000;
+ break;
+ case 3:
+ fmt_tmp = "%.*s%03d%s";
+ div = 1000;
+ break;
+ case 4:
+ fmt_tmp = "%.*s%04d%s";
+ div = 100;
+ break;
+ case 5:
+ fmt_tmp = "%.*s%05d%s";
+ div = 10;
+ break;
+ case 6:
+ fmt_tmp = "%.*s%06d%s";
+ div = 1;
+ break;
+ }
The switch-case can be replaced by “%0*d” and pow(10, 6 - num_digits).
+
+ fmt_new = av_asprintf(fmt_tmp, begin - fmt, fmt,
(int)(unow % 1000000) / div, begin + len);
+ if (!fmt_new)
+ return AVERROR(ENOMEM);
+ av_bprint_strftime(bp, fmt_new, &tm);
+ av_freep(&fmt_new);
+ return 0;
+ }
+ begin++;
Progress faster by taking account of len.
