> 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.
> + }
> +
> av_bprint_strftime(bp, fmt, &tm);
> return 0;
> }
> --
> 2.20.1 (Apple Git-117)
>
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
