Re: [FFmpeg-devel] [PATCH 1/3] avutil/timecode: add av_timecode_set_smpte

[Timo Rothenpieler <timo@rothenpieler.org>]

On 24.02.2025 21:51, Timo Rothenpieler wrote:
> ---
>   doc/APIchanges       |  3 +++
>   libavutil/timecode.c | 24 +++++++++++++++---------
>   libavutil/timecode.h | 17 +++++++++++++++++
>   libavutil/version.h  |  2 +-
>   4 files changed, 36 insertions(+), 10 deletions(-)
> 
> diff --git a/doc/APIchanges b/doc/APIchanges
> index ac506f4b56..71240d39fd 100644
> --- a/doc/APIchanges
> +++ b/doc/APIchanges
> @@ -2,6 +2,9 @@ The last version increases of all libraries were on 2024-03-07
>   
>   API changes, most recent first:
>   
> +2025-02-xx - xxxxxxxxxx - lavu 59.58.100 - timecode.h
> +  Add av_timecode_set_smpte().
> +
>   2025-02-xx - xxxxxxxxxx - lavu 59.57.100 - log.h
>     Add flags AV_LOG_PRINT_TIME and AV_LOG_PRINT_DATETIME.
>   
> diff --git a/libavutil/timecode.c b/libavutil/timecode.c
> index f454466f97..e6cd811a2b 100644
> --- a/libavutil/timecode.c
> +++ b/libavutil/timecode.c
> @@ -136,23 +136,29 @@ static unsigned bcd2uint(uint8_t bcd)
>      return low + 10*high;
>   }
>   
> -char *av_timecode_make_smpte_tc_string2(char *buf, AVRational rate, uint32_t tcsmpte, int prevent_df, int skip_field)
> +void av_timecode_set_smpte(int *drop, int *hh, int *mm, int *ss, int *ff, 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
> +    *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;
> +        *ff <<= 1;
>           if (!skip_field) {
>               if (av_cmp_q(rate, (AVRational) {50, 1}) == 0)
> -                ff += !!(tcsmpte & 1 << 7);
> +                *ff += !!(tcsmpte & 1 << 7);
>               else
> -                ff += !!(tcsmpte & 1 << 23);
> +                *ff += !!(tcsmpte & 1 << 23);
>           }
>       }
> +}
> +
> +char *av_timecode_make_smpte_tc_string2(char *buf, AVRational rate, uint32_t tcsmpte, int prevent_df, int skip_field)
> +{
> +    int hh, mm, ss, ff, drop;
> +    av_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.h b/libavutil/timecode.h
> index fe0fc83576..2685e48db2 100644
> --- a/libavutil/timecode.h
> +++ b/libavutil/timecode.h
> @@ -95,6 +95,23 @@ uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
>    */
>   uint32_t av_timecode_get_smpte(AVRational rate, int drop, int hh, int mm, int ss, int ff);
>   
> +/**
> + * 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 av_timecode_set_smpte(int *drop, int *hh, int *mm, int *ss, int *ff, AVRational rate, uint32_t tcsmpte, int prevent_df, int skip_field);
> +
>   /**
>    * Load timecode string in buf.
>    *
> diff --git a/libavutil/version.h b/libavutil/version.h
> index ee4a36cb17..4b584fd569 100644
> --- a/libavutil/version.h
> +++ b/libavutil/version.h
> @@ -79,7 +79,7 @@
>    */
>   
>   #define LIBAVUTIL_VERSION_MAJOR  59
> -#define LIBAVUTIL_VERSION_MINOR  57
> +#define LIBAVUTIL_VERSION_MINOR  58
>   #define LIBAVUTIL_VERSION_MICRO 100
>   
>   #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \

ping. Would really like a second pair of eyes on new public API before I 
push this.
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