[FFmpeg-devel] [PATCH 1/4] avutil: support 50 and 60 frame rates in timecode api

[Michael Niedermayer]

On Wed, May 30, 2012 at 08:27:19PM +0200, Matthieu Bouron wrote:
> On Sun, May 27, 2012 at 2:21 PM, Matthieu Bouron
> <matthieu.bouron at gmail.com> wrote:
> > ---
> > Hi there,
> >
> > This patch introduce support for 50/60 frame rates and a new function
> > av_timecode_adjust_ntsc_framenum2 to handle both 29.97 and 59.94 cases.
> >
> > Note: the original formula comes from:
> > http://www.andrewduncan.ws/Timecodes/Timecodes.html
> >
> > Regards,
> > Matthieu
> > ---
> >  libavcodec/mpeg12enc.c |    2 +-
> >  libavutil/avutil.h     |    3 +++
> >  libavutil/timecode.c   |   28 +++++++++++++++++++++++++---
> >  libavutil/timecode.h   |   13 ++++++++++++-
> >  4 files changed, 41 insertions(+), 5 deletions(-)
> >
> > diff --git a/libavcodec/mpeg12enc.c b/libavcodec/mpeg12enc.c
> > index 169f155..b045c74 100644
> > --- a/libavcodec/mpeg12enc.c
> > +++ b/libavcodec/mpeg12enc.c
> > @@ -300,7 +300,7 @@ static void mpeg1_encode_sequence_header(MpegEncContext *s)
> >             s->gop_picture_number = s->current_picture_ptr->f.coded_picture_number;
> >             av_assert0(s->drop_frame_timecode == !!(s->tc.flags & AV_TIMECODE_FLAG_DROPFRAME));
> >             if (s->drop_frame_timecode)
> > -                time_code = av_timecode_adjust_ntsc_framenum(time_code);
> > +                time_code = av_timecode_adjust_ntsc_framenum2(time_code, fps);
> >             put_bits(&s->pb, 5, (uint32_t)((time_code / (fps * 3600)) % 24));
> >             put_bits(&s->pb, 6, (uint32_t)((time_code / (fps * 60)) % 60));
> >             put_bits(&s->pb, 1, 1);
> > diff --git a/libavutil/avutil.h b/libavutil/avutil.h
> > index acef213..c1c228c 100644
> > --- a/libavutil/avutil.h
> > +++ b/libavutil/avutil.h
> > @@ -193,6 +193,9 @@
> >  #ifndef FF_API_OLD_AVOPTIONS
> >  #define FF_API_OLD_AVOPTIONS            (LIBAVUTIL_VERSION_MAJOR < 52)
> >  #endif
> > +#ifndef FF_API_OLD_TC_ADJUST_FRAMENUM
> > +#define FF_API_OLD_TC_ADJUST_FRAMENUM   (LIBAVUTIL_VERSION_MAJOR < 52)
> > +#endif
> >
> >  /**
> >  * @}
> > diff --git a/libavutil/timecode.c b/libavutil/timecode.c
> > index ad3f7fa..dcb93cb 100644
> > --- a/libavutil/timecode.c
> > +++ b/libavutil/timecode.c
> > @@ -31,6 +31,7 @@
> >  #include "log.h"
> >  #include "error.h"
> >
> > +#ifdef FF_API_OLD_TC_ADJUST_FRAMENUM
> >  int av_timecode_adjust_ntsc_framenum(int framenum)
> >  {
> >     /* only works for NTSC 29.97 */
> > @@ -39,6 +40,25 @@ int av_timecode_adjust_ntsc_framenum(int framenum)
> >     //if (m < 2) m += 2; /* not needed since -2,-1 / 1798 in C returns 0 */
> >     return framenum + 18 * d + 2 * ((m - 2) / 1798);
> >  }
> > +#endif
> > +
> > +int av_timecode_adjust_ntsc_framenum2(int framenum, int fps)
> > +{
> > +    /* only works for NTSC 29.97 and 59.94 */
> > +    int drop_frames = 0;
> > +    int d = framenum / 17982;
> > +    int m = framenum % 17982;
> > +
> > +    if (fps == 30)
> > +        drop_frames = 2;
> > +    else if (fps == 60)
> > +        drop_frames = 4;
> > +    else
> > +        return framenum;
> > +
> > +    //if (m < 2) m += 2; /* not needed since -2,-1 / 1798 in C returns 0 */
> > +    return framenum + 9 * drop_frames * d + drop_frames * ((m - 2) / 1798);
> > +}
> >
> >  uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
> >  {
> > @@ -48,7 +68,7 @@ uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
> >
> >     framenum += tc->start;
> >     if (drop)
> > -        framenum = av_timecode_adjust_ntsc_framenum(framenum);
> > +        framenum = av_timecode_adjust_ntsc_framenum2(framenum, tc->fps);
> >     ff = framenum % fps;
> >     ss = framenum / fps      % 60;
> >     mm = framenum / (fps*60) % 60;
> > @@ -77,7 +97,7 @@ char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum)
> >
> >     framenum += tc->start;
> >     if (drop)
> > -        framenum = av_timecode_adjust_ntsc_framenum(framenum);
> > +        framenum = av_timecode_adjust_ntsc_framenum2(framenum, fps);
> >     if (framenum < 0) {
> >         framenum = -framenum;
> >         neg = tc->flags & AV_TIMECODE_FLAG_ALLOWNEGATIVE;
> > @@ -139,7 +159,9 @@ static int check_timecode(void *log_ctx, AVTimecode *tc)
> >     switch (tc->fps) {
> >     case 24:
> >     case 25:
> > -    case 30: return  0;
> > +    case 30:
> > +    case 50:
> > +    case 60: return  0;
> >
> >     default:
> >         av_log(log_ctx, AV_LOG_ERROR, "Timecode frame rate not supported\n");
> > diff --git a/libavutil/timecode.h b/libavutil/timecode.h
> > index 41e56d6..525f2a9 100644
> > --- a/libavutil/timecode.h
> > +++ b/libavutil/timecode.h
> > @@ -57,8 +57,19 @@ typedef struct {
> >  * @param framenum frame number to adjust
> >  * @return         adjusted frame number
> >  * @warning        adjustment is only valid in NTSC 29.97
> > + * @deprecated     use av_timecode_adjust_ntsc_framenum2 instead
> >  */
> > -int av_timecode_adjust_ntsc_framenum(int framenum);
> > +attribute_deprecated int av_timecode_adjust_ntsc_framenum(int framenum);
> > +
> > +/**
> > + * Adjust frame number for NTSC drop frame time code.
> > + *
> > + * @param framenum frame number to adjust
> > + * @param fps      frame per second, 30 or 60
> > + * @return         adjusted frame number
> > + * @warning        adjustment is only valid in NTSC 29.97 and 59.94
> > + */
> > +int av_timecode_adjust_ntsc_framenum2(int framenum, int fps);
> >
> >  /**
> >  * Convert frame number to SMPTE 12M binary representation.
> > --
> > 1.7.10
> >
> 
> ping

i will apply this in the next few days if there are no comments/review
from anyone else


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The educated differ from the uneducated as much as the living from the
dead. -- Aristotle 
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