[FFmpeg-devel] [PATCH v2 1/3] avutil/timecode: add ff_timecode_set_smpte

Timo Rothenpieler timo at rothenpieler.org
Sun Mar 2 19:56:59 EET 2025


On 02.03.2025 13:32, Timo Rothenpieler wrote:
> On 28.02.2025 23:46, Timo Rothenpieler wrote:
>> ---
>>   libavutil/timecode.c          | 27 +++----------------
>>   libavutil/timecode_internal.c | 51 +++++++++++++++++++++++++++++++++++
>>   libavutil/timecode_internal.h | 51 +++++++++++++++++++++++++++++++++++
>>   3 files changed, 105 insertions(+), 24 deletions(-)
>>   create mode 100644 libavutil/timecode_internal.c
>>   create mode 100644 libavutil/timecode_internal.h
>>
>> diff --git a/libavutil/timecode.c b/libavutil/timecode.c
>> index f454466f97..bca16b6ac2 100644
>> --- a/libavutil/timecode.c
>> +++ b/libavutil/timecode.c
>> @@ -29,6 +29,7 @@
>>   #include <stdio.h>
>>   #include "common.h"
>>   #include "timecode.h"
>> +#include "timecode_internal.h"
>>   #include "log.h"
>>   #include "error.h"
>> @@ -127,32 +128,10 @@ char *av_timecode_make_string(const AVTimecode 
>> *tc, char *buf, int framenum_arg)
>>       return buf;
>>   }
>> -static unsigned bcd2uint(uint8_t bcd)
>> -{
>> -   unsigned low  = bcd & 0xf;
>> -   unsigned high = bcd >> 4;
>> -   if (low > 9 || high > 9)
>> -       return 0;
>> -   return low + 10*high;
>> -}
>> -
>>   char *av_timecode_make_smpte_tc_string2(char *buf, AVRational rate, 
>> uint32_t tcsmpte, int prevent_df, int skip_field)
>>   {
>> -    unsigned hh   = bcd2uint(tcsmpte     & 0x3f);    // 6-bit hours
>> -    unsigned mm   = bcd2uint(tcsmpte>>8  & 0x7f);    // 7-bit minutes
>> -    unsigned ss   = bcd2uint(tcsmpte>>16 & 0x7f);    // 7-bit seconds
>> -    unsigned ff   = bcd2uint(tcsmpte>>24 & 0x3f);    // 6-bit frames
>> -    unsigned drop = tcsmpte & 1<<30 && !prevent_df;  // 1-bit drop if 
>> not arbitrary bit
>> -
>> -    if (av_cmp_q(rate, (AVRational) {30, 1}) == 1) {
>> -        ff <<= 1;
>> -        if (!skip_field) {
>> -            if (av_cmp_q(rate, (AVRational) {50, 1}) == 0)
>> -                ff += !!(tcsmpte & 1 << 7);
>> -            else
>> -                ff += !!(tcsmpte & 1 << 23);
>> -        }
>> -    }
>> +    unsigned hh, mm, ss, ff, drop;
>> +    ff_timecode_set_smpte(&drop, &hh, &mm, &ss, &ff, rate, tcsmpte, 
>> prevent_df, skip_field);
>>       snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
>>                hh, mm, ss, drop ? ';' : ':', ff);
>> diff --git a/libavutil/timecode_internal.c b/libavutil/ 
>> timecode_internal.c
>> new file mode 100644
>> index 0000000000..259ebf1664
>> --- /dev/null
>> +++ b/libavutil/timecode_internal.c
>> @@ -0,0 +1,51 @@
>> +/*
>> + * Copyright (c) 2006 Smartjog S.A.S, Baptiste Coudurier 
>> <baptiste.coudurier at gmail.com>
>> + * Copyright (c) 2011-2012 Smartjog S.A.S, Clément Bœsch 
>> <clement.boesch at smartjog.com>
>> + *
>> + * This file is part of FFmpeg.
>> + *
>> + * FFmpeg is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU Lesser General Public
>> + * License as published by the Free Software Foundation; either
>> + * version 2.1 of the License, or (at your option) any later version.
>> + *
>> + * FFmpeg is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> + * Lesser General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU Lesser General Public
>> + * License along with FFmpeg; if not, write to the Free Software
>> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 
>> 02110-1301 USA
>> + */
>> +
>> +#include "timecode_internal.h"
>> +
>> +static unsigned bcd2uint(uint8_t bcd)
>> +{
>> +   unsigned low  = bcd & 0xf;
>> +   unsigned high = bcd >> 4;
>> +   if (low > 9 || high > 9)
>> +       return 0;
>> +   return low + 10*high;
>> +}
>> +
>> +void ff_timecode_set_smpte(unsigned *drop, unsigned *hh, unsigned 
>> *mm, unsigned *ss, unsigned *ff,
>> +                           AVRational rate, uint32_t tcsmpte, int 
>> prevent_df, int skip_field)
>> +{
>> +    *hh   = bcd2uint(tcsmpte     & 0x3f);    // 6-bit hours
>> +    *mm   = bcd2uint(tcsmpte>>8  & 0x7f);    // 7-bit minutes
>> +    *ss   = bcd2uint(tcsmpte>>16 & 0x7f);    // 7-bit seconds
>> +    *ff   = bcd2uint(tcsmpte>>24 & 0x3f);    // 6-bit frames
>> +    *drop = tcsmpte & 1<<30 && !prevent_df;  // 1-bit drop if not 
>> arbitrary bit
>> +
>> +    if (av_cmp_q(rate, (AVRational) {30, 1}) == 1) {
>> +        *ff <<= 1;
>> +        if (!skip_field) {
>> +            if (av_cmp_q(rate, (AVRational) {50, 1}) == 0)
>> +                *ff += !!(tcsmpte & 1 << 7);
>> +            else
>> +                *ff += !!(tcsmpte & 1 << 23);
>> +        }
>> +    }
>> +}
>> diff --git a/libavutil/timecode_internal.h b/libavutil/ 
>> timecode_internal.h
>> new file mode 100644
>> index 0000000000..8ef43d1f98
>> --- /dev/null
>> +++ b/libavutil/timecode_internal.h
>> @@ -0,0 +1,51 @@
>> +/*
>> + * Copyright (c) 2006 Smartjog S.A.S, Baptiste Coudurier 
>> <baptiste.coudurier at gmail.com>
>> + * Copyright (c) 2011-2012 Smartjog S.A.S, Clément Bœsch 
>> <clement.boesch at smartjog.com>
>> + *
>> + * This file is part of FFmpeg.
>> + *
>> + * FFmpeg is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU Lesser General Public
>> + * License as published by the Free Software Foundation; either
>> + * version 2.1 of the License, or (at your option) any later version.
>> + *
>> + * FFmpeg is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> + * Lesser General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU Lesser General Public
>> + * License along with FFmpeg; if not, write to the Free Software
>> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 
>> 02110-1301 USA
>> + */
>> +
>> +/**
>> + * @file
>> + * Timecode helpers header
>> + */
>> +
>> +#ifndef AVUTIL_TIMECODE_INTERNAL_H
>> +#define AVUTIL_TIMECODE_INTERNAL_H
>> +
>> +#include <stdint.h>
>> +#include "rational.h"
>> +
>> +/**
>> + * Convert SMPTE 12M binary representation to sei info.
>> + *
>> + * @param drop       drop flag output
>> + * @param hh         hour output
>> + * @param mm         minute output
>> + * @param ss         second output
>> + * @param ff         frame number output
>> + * @param rate       frame rate of the timecode
>> + * @param tcsmpte    the 32-bit SMPTE timecode
>> + * @param prevent_df prevent the use of a drop flag when it is known 
>> the DF bit
>> + *                   is arbitrary
>> + * @param skip_field prevent the use of a field flag when it is known 
>> the field
>> + *                   bit is arbitrary (e.g. because it is used as PC 
>> flag)
>> + */
>> +void ff_timecode_set_smpte(unsigned *drop, unsigned *hh, unsigned 
>> *mm, unsigned *ss, unsigned *ff,
>> +                           AVRational rate, uint32_t tcsmpte, int 
>> prevent_df, int skip_field);
>> +
>> +#endif /* AVUTIL_TIMECODE_INTERNAL_H */
> 
> will apply the series soon if nobody objects
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