[FFmpeg-devel] [PATCH v2] lavfi/drawtext: Add localtime_ms for millisecond precision
Thilo Borgmann
thilo.borgmann at mail.de
Thu Jan 20 14:04:43 EET 2022
Am 19.01.22 um 04:16 schrieb "zhilizhao(赵志立)":
>
>
>> On Jan 18, 2022, at 8:52 PM, Thilo Borgmann <thilo.borgmann at 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).
Indeed, simplified.
>> +
>> + 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.
As well, also added to skip "%%".
>> + }
>> +
>> av_bprint_strftime(bp, fmt, &tm);
>> return 0;
>> }
>> --
v8 attached.
Thanks,
Thilo
-------------- next part --------------
From 2f42ca23b35a5e2ecedfd60203298cf7dcafdba5 Mon Sep 17 00:00:00 2001
From: Thilo Borgmann <thilo.borgmann at mail.de>
Date: Thu, 20 Jan 2022 13:02:05 +0100
Subject: [PATCH v8] lavfi/drawtext: Add %N for drawing fractions of a second
Suggested-By: ffmpeg at fb.com
---
doc/filters.texi | 4 +++
libavfilter/vf_drawtext.c | 58 +++++++++++++++++++++++++++++++++++++--
2 files changed, 59 insertions(+), 3 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 05d4b1a56e..c3895138e0 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -11378,10 +11378,14 @@ It can be used to add padding with zeros from the left.
@item gmtime
The time at which the filter is running, expressed in UTC.
It can accept an argument: a strftime() format string.
+The format string is extended to support the variable @var{%[1-6]N}
+which prints fractions of the second with optionally specified number of digits.
@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.
+The format string is extended to support the variable @var{%[1-6]N}
+which prints fractions of the second with optionally specified number of digits.
@item metadata
Frame metadata. Takes one or two arguments.
diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
index 2a88692cbd..06d0c77c55 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 +1046,65 @@ 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')
+ const char *begin;
+ const char *tmp;
+ int len;
+ char *fmt_new;
+ 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 = fmt;
+ while ((begin = av_stristr(begin, "%"))) {
+ tmp = begin + 1;
+ len = 0;
+
+ // skip escaped "%%"
+ if (*tmp == '%') {
+ begin = tmp + 1;;
+ continue;
+ }
+
+ // 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 digit given, expect [1,6], warn & clamp otherwise
+ if (len == 1) {
+ num_digits = av_clip(*(begin + 1) - '0', 1, 6);
+ } else if (len > 1) {
+ av_log(ctx, AV_LOG_WARNING, "Invalid number of decimals for %%N, using default of %i\n", num_digits);
+ }
+
+ len += 2; // add % and N to get length of string part
+
+ div = pow(10, 6 - num_digits);
+ fmt_new = av_asprintf("%.*s%0*d%s", (int)(begin - fmt), fmt, num_digits, (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 = tmp + 1;
+ }
+
av_bprint_strftime(bp, fmt, &tm);
return 0;
}
--
2.20.1 (Apple Git-117)
More information about the ffmpeg-devel
mailing list