[FFmpeg-devel] [PATCH 3/4] avutil/timecode: add function av_timecode_get_smpte_by_tc_string()

[lance.lmwang at gmail.com]

On Fri, Jun 19, 2020 at 04:48:46PM +0200, Nicolas George wrote:
> lance.lmwang at gmail.com (12020-06-19):
> > From: Limin Wang <lance.lmwang at gmail.com>
> > 
> > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> > ---
> >  libavutil/timecode.c | 26 ++++++++++++++++++++++++++
> >  libavutil/timecode.h |  9 +++++++++
> >  2 files changed, 35 insertions(+)
> > 
> > diff --git a/libavutil/timecode.c b/libavutil/timecode.c
> > index 60077ba..7a7ed1d 100644
> > --- a/libavutil/timecode.c
> > +++ b/libavutil/timecode.c
> > @@ -81,6 +81,32 @@ uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
> >             (hh % 10);        // units of hours
> >  }
> >  
> > +uint32_t av_timecode_get_smpte_by_tc_string(const char *buf)
> > +{
> > +    char c;
> > +    int hh, mm, ss, ff, drop;
> > +
> 
> > +    if (sscanf(buf, "%d:%d:%d%c%d", &hh, &mm, &ss, &c, &ff) != 5) {
> 
> This accepts garbage at the end. Is it on purpose?

No, in fact I reuse the code from av_timecode_init_from_string(), any suggestion with safety?


> 
> > +        return AVERROR_INVALIDDATA;
> 
> You cannot return an error code with that function signature.

My fault, I'll add a parameter to get the binary TC.

> 
> > +    }
> > +    drop = c != ':' ? AV_TIMECODE_FLAG_DROPFRAME : 0; // drop if ';', '.', ...
> > +
> > +    return 0         << 31 | // color frame flag (0: unsync mode, 1: sync mode)
> > +           drop      << 30 | // drop  frame flag (0: non drop,    1: drop)
> > +           (ff / 10) << 28 | // tens  of frames
> > +           (ff % 10) << 24 | // units of frames
> > +           0         << 23 | // PC (NTSC) or BGF0 (PAL)
> > +           (ss / 10) << 20 | // tens  of seconds
> > +           (ss % 10) << 16 | // units of seconds
> > +           0         << 15 | // BGF0 (NTSC) or BGF2 (PAL)
> > +           (mm / 10) << 12 | // tens  of minutes
> > +           (mm % 10) <<  8 | // units of minutes
> > +           0         <<  7 | // BGF2 (NTSC) or PC (PAL)
> > +           0         <<  6 | // BGF1
> > +           (hh / 10) <<  4 | // tens  of hours
> > +           (hh % 10);        // units of hours
> > +}
> > +
> >  char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum)
> >  {
> >      int fps = tc->fps;
> > diff --git a/libavutil/timecode.h b/libavutil/timecode.h
> > index 37c1361..7bb4b78 100644
> > --- a/libavutil/timecode.h
> > +++ b/libavutil/timecode.h
> > @@ -71,6 +71,15 @@ int av_timecode_adjust_ntsc_framenum2(int framenum, int fps);
> >  uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum);
> >  
> >  /**
> > + * Convert TC string to SMPTE 12M binary representation.
> > + *
> > + * @param buf      TC string
> > + * @return         the SMPTE binary representation, or AVERROR otherwise
> > + *
> > + */
> > +uint32_t av_timecode_get_smpte_by_tc_string(const char *buf);
> > +
> > +/**
> >   * Load timecode string in buf.
> >   *
> >   * @param buf      destination buffer, must be at least AV_TIMECODE_STR_SIZE long
> 
> Regards,
> 
> -- 
>   Nicolas George



-- 
Thanks,
Limin Wang