[FFmpeg-devel] [PATCH v6 2/3] API: add AV_PKT_DATA_S12M_TIMECODE to AVPacketSideDataType

lance.lmwang at gmail.com lance.lmwang at gmail.com
Fri Jul 10 04:39:24 EEST 2020


On Thu, Jul 09, 2020 at 07:16:28PM -0400, Devin Heitmueller wrote:
> Given the questions regarding the format used for the timecodes, this
> patch from my personal repo might help:
> 
> commit e4c9ae661fb55e59eff1461140a8cd039b7c3f04
> Author: Devin Heitmueller <dheitmueller at ltnglobal.com>
> Date:   Thu Jul 5 17:18:36 2018 -0400
>     Clarify where the binary representation comes from for ffmpeg's SMPTE struct
> 
>     There are a number of different binary representations in which
>     SMPTE timecodes can use.  Make clear that the specific representation
>     that ffmpeg refers to corresponds to the DV video spec, which is
>     SMPTE S314M:2005 for standard definition video and ST 370-2013 for
>     high definition video.
> 
> diff --git a/libavutil/timecode.c b/libavutil/timecode.c
> index e9d8504ee7..93bba2af31 100644
> --- a/libavutil/timecode.c
> +++ b/libavutil/timecode.c
> @@ -117,6 +117,7 @@ static unsigned bcd2uint(uint8_t bcd)
> 
>  char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte,
> int prevent_df)
>  {
> +    /* See SMPTE ST 314M-2005 Sec 4.4.2.2.1 "Time code pack (TC)" */

Thanks for the clarify, I'll merge this comment for reference, but it seems
that it's not free, so I'll keep the detail format document without any change.


>      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
> 
> 
> On Wed, Jul 1, 2020 at 9:40 AM <lance.lmwang at gmail.com> wrote:
> >
> > From: Limin Wang <lance.lmwang at gmail.com>
> >
> > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> > ---
> >  doc/APIchanges        |  3 +++
> >  libavcodec/avpacket.c |  1 +
> >  libavcodec/decode.c   |  1 +
> >  libavcodec/packet.h   |  8 ++++++++
> >  libavcodec/version.h  |  2 +-
> >  libavformat/dump.c    | 21 +++++++++++++++++++++
> >  6 files changed, 35 insertions(+), 1 deletion(-)
> >
> > diff --git a/doc/APIchanges b/doc/APIchanges
> > index 1d6cc36..7aa8d9e 100644
> > --- a/doc/APIchanges
> > +++ b/doc/APIchanges
> > @@ -15,6 +15,9 @@ libavutil:     2017-10-21
> >
> >  API changes, most recent first:
> >
> > +2020-06-xx - xxxxxxxxxx - lavc 58.94.101 - packet.h
> > +  Add AV_PKT_DATA_S12M_TIMECODE.
> > +
> >  2020-06-12 - b09fb030c1 - lavu 56.55.100 - pixdesc.h
> >    Add AV_PIX_FMT_X2RGB10.
> >
> > diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
> > index dce26cb..4801163 100644
> > --- a/libavcodec/avpacket.c
> > +++ b/libavcodec/avpacket.c
> > @@ -400,6 +400,7 @@ const char *av_packet_side_data_name(enum AVPacketSideDataType type)
> >      case AV_PKT_DATA_PRFT:                       return "Producer Reference Time";
> >      case AV_PKT_DATA_ICC_PROFILE:                return "ICC Profile";
> >      case AV_PKT_DATA_DOVI_CONF:                  return "DOVI configuration record";
> > +    case AV_PKT_DATA_S12M_TIMECODE:              return "SMPTE ST 12-1:2014 timecode";
> >      }
> >      return NULL;
> >  }
> > diff --git a/libavcodec/decode.c b/libavcodec/decode.c
> > index de9c079..f2244fc 100644
> > --- a/libavcodec/decode.c
> > +++ b/libavcodec/decode.c
> > @@ -1699,6 +1699,7 @@ int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame)
> >          { AV_PKT_DATA_CONTENT_LIGHT_LEVEL,        AV_FRAME_DATA_CONTENT_LIGHT_LEVEL },
> >          { AV_PKT_DATA_A53_CC,                     AV_FRAME_DATA_A53_CC },
> >          { AV_PKT_DATA_ICC_PROFILE,                AV_FRAME_DATA_ICC_PROFILE },
> > +        { AV_PKT_DATA_S12M_TIMECODE,              AV_FRAME_DATA_S12M_TIMECODE },
> >      };
> >
> >      if (pkt) {
> > diff --git a/libavcodec/packet.h b/libavcodec/packet.h
> > index 96f237f..0a19a0e 100644
> > --- a/libavcodec/packet.h
> > +++ b/libavcodec/packet.h
> > @@ -283,6 +283,14 @@ enum AVPacketSideDataType {
> >      AV_PKT_DATA_DOVI_CONF,
> >
> >      /**
> > +     * Timecode which conforms to SMPTE ST 12-1:2014. The data is an array of 4 uint32_t
> > +     * where the first uint32_t describes how many (1-3) of the other timecodes are used.
> > +     * The timecode format is described in the documentation of av_timecode_get_smpte_from_framenum()
> > +     * function in libavutil/timecode.h.
> > +     */
> > +    AV_PKT_DATA_S12M_TIMECODE,
> > +
> > +    /**
> >       * The number of side data types.
> >       * This is not part of the public API/ABI in the sense that it may
> >       * change when new side data types are added.
> > diff --git a/libavcodec/version.h b/libavcodec/version.h
> > index 05f5990..51fba22 100644
> > --- a/libavcodec/version.h
> > +++ b/libavcodec/version.h
> > @@ -28,7 +28,7 @@
> >  #include "libavutil/version.h"
> >
> >  #define LIBAVCODEC_VERSION_MAJOR  58
> > -#define LIBAVCODEC_VERSION_MINOR  93
> > +#define LIBAVCODEC_VERSION_MINOR  94
> >  #define LIBAVCODEC_VERSION_MICRO 101
> >
> >  #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
> > diff --git a/libavformat/dump.c b/libavformat/dump.c
> > index 1083d7d..46db039 100644
> > --- a/libavformat/dump.c
> > +++ b/libavformat/dump.c
> > @@ -34,6 +34,7 @@
> >  #include "libavutil/replaygain.h"
> >  #include "libavutil/spherical.h"
> >  #include "libavutil/stereo3d.h"
> > +#include "libavutil/timecode.h"
> >
> >  #include "avformat.h"
> >
> > @@ -407,6 +408,22 @@ static void dump_dovi_conf(void *ctx, const AVPacketSideData *sd)
> >             dovi->dv_bl_signal_compatibility_id);
> >  }
> >
> > +static void dump_s12m_timecode(void *ctx, const AVPacketSideData *sd)
> > +{
> > +    const uint32_t *tc = (const uint32_t *)sd->data;
> > +
> > +    if ((sd->size != sizeof(uint32_t) * 4) || (tc[0] > 3)) {
> > +        av_log(ctx, AV_LOG_ERROR, "invalid data\n");
> > +        return;
> > +    }
> > +
> > +    for (int j = 1; j <= tc[0]; j++) {
> > +        char tcbuf[AV_TIMECODE_STR_SIZE];
> > +        av_timecode_make_smpte_tc_string(tcbuf, tc[j], 0);
> > +        av_log(ctx, AV_LOG_INFO, "timecode - %s%s", tcbuf, j != tc[0] ? ", " : "");
> > +    }
> > +}
> > +
> >  static void dump_sidedata(void *ctx, const AVStream *st, const char *indent)
> >  {
> >      int i;
> > @@ -473,6 +490,10 @@ static void dump_sidedata(void *ctx, const AVStream *st, const char *indent)
> >              av_log(ctx, AV_LOG_INFO, "DOVI configuration record: ");
> >              dump_dovi_conf(ctx, sd);
> >              break;
> > +        case AV_PKT_DATA_S12M_TIMECODE:
> > +            av_log(ctx, AV_LOG_INFO, "SMPTE ST 12-1:2014: ");
> > +            dump_s12m_timecode(ctx, sd);
> > +            break;
> >          default:
> >              av_log(ctx, AV_LOG_INFO,
> >                     "unknown side data type %d (%d bytes)", sd->type, sd->size);
> > --
> > 1.8.3.1
> >
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> > To unsubscribe, visit link above, or email
> > ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
> 
> 
> 
> -- 
> Devin Heitmueller, Senior Software Engineer
> LTN Global Communications
> o: +1 (301) 363-1001
> w: https://ltnglobal.com  e: devin.heitmueller at ltnglobal.com

-- 
Thanks,
Limin Wang


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