From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
To: ffmpeg-devel@ffmpeg.org
Subject: Re: [FFmpeg-devel] [PATCH v2] lavfi/drawtext: Add localtime_ms for millisecond precision
Date: Thu, 20 Jan 2022 16:03:59 +0100
Message-ID: <AM7PR03MB6660E55B4F9858A5DA9C947B8F5A9@AM7PR03MB6660.eurprd03.prod.outlook.com> (raw)
In-Reply-To: <70afd793-820b-83df-6bc8-58e1787cd9c8@mail.de>
Thilo Borgmann:
> Am 20.01.22 um 13:04 schrieb Thilo Borgmann:
>> Am 19.01.22 um 04:16 schrieb "zhilizhao(赵志立)":
>>>
>>>
>>>> On Jan 18, 2022, at 8:52 PM, Thilo Borgmann <thilo.borgmann@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.
>
> Fixed off-by-one bug.
> Allows for several occurrences of %N parameter now.
>
> v9 attached.
>
> Thanks,
> Thilo
>
>
> + // manually parse format for %N (fractional seconds)
> + begin = fmt;
> + while ((begin = av_stristr(begin, "%"))) {
> + tmp = begin + 1;
begin = strchr(begin, '%')
- Andreas
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next prev parent reply other threads:[~2022-01-20 15:04 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <280498BE-226E-41E2-BE17-DE2D47EAFFC0@mail.de>
[not found] ` <tencent_9187CFF05512A70F389C961C4D142031CD07@qq.com>
[not found] ` <0768FA6E-731F-4214-8B90-A3F38764010F@mail.de>
[not found] ` <20211210164657.GF2829255@pb2>
[not found] ` <727CF2F6-C834-415A-B771-4F70661F8BE8@mail.de>
[not found] ` <AM7PR03MB6660ED0E212D1CCB2134A4DD8F729@AM7PR03MB6660.eurprd03.prod.outlook.com>
[not found] ` <3E808BD2-808B-4C53-B1F7-B9DFFE2BF687@mail.de>
[not found] ` <YbZXwy3d8Z9rG/hD@phare.normalesup.org>
2021-12-29 10:47 ` "zhilizhao(赵志立)"
2021-12-29 11:46 ` Nicolas George
2022-01-03 15:22 ` Thilo Borgmann
2022-01-06 11:27 ` Thilo Borgmann
2022-01-14 12:14 ` Thilo Borgmann
2022-01-14 13:17 ` "zhilizhao(赵志立)"
2022-01-14 17:40 ` Thilo Borgmann
2022-01-14 18:02 ` Zhao Zhili
2022-01-14 18:05 ` Andreas Rheinhardt
2022-01-14 18:15 ` Thilo Borgmann
2022-01-14 18:22 ` Andreas Rheinhardt
2022-01-14 17:57 ` Nicolas George
2022-01-14 18:04 ` Thilo Borgmann
2022-01-14 18:08 ` Nicolas George
2022-01-14 18:20 ` Thilo Borgmann
2022-01-16 11:06 ` Nicolas George
2022-01-18 12:52 ` Thilo Borgmann
2022-01-19 3:16 ` "zhilizhao(赵志立)"
2022-01-20 12:04 ` Thilo Borgmann
2022-01-20 14:58 ` Thilo Borgmann
2022-01-20 15:03 ` Andreas Rheinhardt [this message]
2022-01-20 15:32 ` Thilo Borgmann
2022-01-31 10:13 ` Thilo Borgmann
2022-01-31 13:08 ` Nicolas George
2022-01-31 20:59 ` Thilo Borgmann
2022-01-31 23:10 ` Andreas Rheinhardt
2022-01-31 23:40 ` Andreas Rheinhardt
2022-02-08 9:17 ` Thilo Borgmann
2022-02-08 9:27 ` Andreas Rheinhardt
2022-02-08 10:41 ` Thilo Borgmann
2022-02-22 11:36 ` Thilo Borgmann
2022-03-06 20:38 ` Thilo Borgmann
2022-03-08 12:30 ` Thilo Borgmann
2022-01-14 13:10 ` James Almer
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