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

[Matthieu Bouron]

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